Electrical diagram of the s30 acoustic system. Refinement (upgrade) of the acoustic system Radiotekhnika S30. Main technical characteristics
Using visual examples, I will show how to repair “old and remote” acoustic speakers Radiotehnika S-30 with a small car power amplifier Weconic EQB-105, which is equipped with an output power indicator and a 7-band graphic equalizer. I will share interesting ideas for restoring dynamic heads, a circuit diagram of the UMZCH on the HA13001 and useful information on repairs.
Note: if you are only interested in repairing S-30 speakers, use the content navigation!
Instead of an introduction
While going through old/non-working electronics in my closet, I came across a small, but no longer working Weconic EQB-105 car power amplifier. Before I assembled my homemade Phoenix P-400 UMZCH, this little guy was rocking all my speaker systems and pleased me with a pretty good sound. Later, this amplifier burned out because it was supplied with a slightly too high supply voltage and driven to full power.
There were still non-working Radiotehnika S-30 acoustic speakers, I thought: “if they were repaired and combined with an amplifier, they would make excellent acoustics for a home TV”!
I didn’t want to buy a set of TV speakers for $150+, but here I had the opportunity to put together a budget Hi-FI audio system by investing a little of my time and quite a bit of money.
So, I'll start my story with the amplifier...
Weconic EQB-105 power amplifier review
This is what this amplifier looked like, although I got it without the side ears, which are used to attach the amplifier to the internal chassis of the car.
Rice. 1. Appearance of the Weconic EQB-105 power amplifier with a 7-band equalizer.
The amplifier manufacturer is WECONIC Professional Carhifi, a company owned by Inter-Union Techno GmbH, 76829 Landau (inter-union.de). She was engaged in the manufacture of various automotive audio equipment: acoustic systems (AS), power amplifiers, equalizers.
The Weconic brand has already become a thing of the past, leaving behind a set of various audio devices, one of which fell into my hands.
Amplifier characteristics:
- 4 outputs for connecting speaker systems;
- 2 signal inputs;
- Output power indicator of 5 multi-colored LEDs;
- Graphic equalizer for 7 bands;
- Balance regulator between each pair of speakers;
- Power supply - 12-14V.
I remember the first time I saw the inscription on the amplifier “100 Watt Live Sound” - I just couldn’t wait to connect it to my Amphiton 100AC-022, then I realized that this value was exaggerated. It was assumed that the amplifier produces 4x25W, but in reality you can get about 17W per channel provided there is good power supply.
Amplifier repair
The power amplifier is made using a bridge circuit using two HA13001 microcircuits. The preamplifier is assembled on four op-amps, which are contained in one BA10324 chip, the equalizer filters are assembled on 14 transistors, and the output power indicator is on the LB1403 chip.
Having completely disassembled the amplifier, I realized that there was a little more work to be done than expected.
Rice. 2. Weconic EQB-105 amplifier disassembled, only electronics (picture clickable).
What you have to do:
- Replace the HA13001 chip;
- Replace burnt out backlight bulbs;
- Clear everything of debris.
Although the amplifier had 4 outputs, it actually has 2 power amplification channels, and the power distribution between the four channels is done using a dual ceramic variable resistor. The handle of this resistor is combined with a switch that allows you to connect the signal source through the amplifier (pressed, the amplifier is on), or directly to the speakers (pressed).
One of the HA13001 microcircuits in the amplifier burned out. As it turned out, this is a rather rare microcircuit from Hitachi Semiconductor.
Rice. 3. Chip Hitachi HA13001 (Japan).
Searches for this microcircuit in online stores did not yield results; a trip to radio points on the market was also unsuccessful. One of the old-time radio amateurs at the bazaar told me that Hitachi ULF microcircuits were very difficult to counterfeit, so they were valued.
In one of the local electronic components stores, I still managed to find two HA13001 microcircuits, although one had a broken leg - I took both at a discount! Then I found HA13001 chips on AliExpress.
Characteristics of HA13001:
- Output power, stereo - 2 x 5.5 W;
- Output power, bridge - 17.5 W;
- Supply voltage, min. - 8 V;
- Supply voltage, typ. - 13.2 V;
- Supply voltage, max. - 18 V;
- Quiescent current - 80mA;
- Reproducible frequency range - 20-20000Hz;
- Maximum output current - 4.5A;
- Gain - 50 dB.
Rice. 4. Schematic diagram of a two-channel and bridge power amplifier on the HA13001.
Replacing the microcircuit immediately produced results - both channels began to sing, but for some reason one of them played an order of magnitude quieter. I was already a little upset, but then Mr. “chance” came to the rescue.
Guests came into my room with a baby, who immediately became interested in what was playing and even glowing. Taking the baby away from the working amplifier, I lifted the board a little - both channels started playing smoothly for a second.
Apparently there is no contact somewhere: bad soldering, a torn conductor, a damaged part, a crack on the board? - the cause had to be found out and eliminated.
Having felt all the details and conductors, I did not hear any changes in the sound. Turning on the desk lamp and armed with a magnifying glass, I began a thorough inspection of the printed circuit board and electronic components for any visible defects. All the parts are intact, I only soldered some connections, but I still couldn’t find the location of the missing contact.
I really didn’t want to, but I still had to unsolder the board with the regulators and look for the reason on it. Getinaks printed circuit boards are very delicate - if the contact is slightly overheated with a soldering iron, any trace can easily fall off.
Rice. 5. Sealed equalizer board with regulators (picture clickable).
As expected, several tracks fell off - no problem, then we will replace them with heat-resistant conductors and everything will be OK.
I soldered the suspicious connections on the regulator board, and since the board was sealed off and there was easy access to the components, I decided to replace all the control panel backlight bulbs at the same time.
A quick measurement of the current consumed by one light bulb showed me a value of 34mA. And if all 4 light bulbs light up - approximately 140mA of current to nowhere, 12V*0.14A=1.68W!
Rice. 6. Measuring the current consumed by an incandescent lamp to illuminate the panel.
I decided to replace incandescent light bulbs with blue LEDs, which turned out to be very economical. I connected one LED through a 10 kOhm variable resistor to a +12V power source, turning the resistor knob I achieved a fairly bright glow at a current of only 4 mA. Having measured the resistance of the resistor in a fixed state, I got a value of 2.5 kOhm.
Result: 4x4mA=16mA (versus 140mA) + pleasant blue glow.))
As it turned out, it won’t be possible to simply install LEDs - their diameter is 5 mm versus the diameter of the light bulbs 3.5 mm. The solution here is simple - adjust the dimensions of the housing of each LED using a needle file.
Rice. 7. Adjusting the size of LEDs using a diamond file (clickable).
I soldered the LEDs in place of the incandescent lamps, and connected 2.5 kOhm quenching resistors in series to each LED with a surface-mounted mounting on the back side of the board, having previously cut the tracks so that each pair of LED + resistor was connected in parallel.
Rice. 8. Soldered LEDs with quenching resistors.
Rice. 9. LED glow test for the backlight panel.
The brightness of the light is excellent; then all that remains is to solder an LED to illuminate the volume control area. We've sorted out the backlight, let's return to the problem with the skew in the volume of the channels.
Having soldered the board with tone controls to the main one and connected the amplifier to the power supply, I was convinced that the problem had not disappeared, now no deformation of the board or its bending affected the operation of the amplifier in a positive direction.
I unsoldered the front panel board back, decided to connect both boards with flexible conductors and then look for the cause of the problem in this form. This had to be done right away, but I hoped that the problem lay in the solder joints of both boards - as it turned out later - almost so, but not quite.
Rice. 10. Temporary connection of boards using flexible conductors.
After playing a little with these scarves, rotating them, squeezing them and feeling the details, the reason for the distortion in the sound of the channels was found. It was hidden in a cracked path near the hole-groove for inserting part of the main board.
It was not possible to notice this crack by visual inspection - it was hidden under a thin layer of rosin. I began to unsolder one by one all the conductors connecting both boards and analyze them. Having unsoldered one of the outer conductors, I noticed that this did not affect the operation of the amplifier in any way - strange. Having cleared the track to which this conductor was soldered of debris, I immediately noticed a defect - HURRAY!
Rice. 11. The reason for the distortion in the sound of the amplifier channels is a crack in the track (clickable).
The cracked track was cleaned and soldered. To connect the contacts in places where the tracks disappeared, I decided to use a heat-resistant wire with fluoroplastic insulation - MGTF.
Rice. 12. We restore the tracks by connecting the contacts with heat-resistant MGTF wire.
After restoring the tracks and connecting the boards, all that remains is to remove all debris on the variable resistors, clean the case and controls from dust. To do this, I used a piece of cotton wool soaked in alcohol and wound around a cleaned match.
Rice. 13. Cleaning the amplifier case and components from dust and debris.
Rice. 14. Refurbished Weconic EQB-105 amplifier.
Acoustic speakers Radiotehnika S-30
I figured out the power amplifier, it’s time for the Radiotekhnika S-30 speaker systems. The speakers are old, but they sound very good if everything is put in order.
Technical characteristics of S-30:
- Rated electrical power - 10 W;
- Rated electrical power - 30 W;
- Nominal electrical resistance - 4 Ohms;
- Nominal sound pressure (in the frequency range 100 - 4000 Hz) - 1.2 Pa;
- Reproducible frequency range - 50-18000 Hz;
- Speaker system dimensions - 364x214x195 mm;
- The mass of the speaker is 6 kg.
The schematic diagram of the Radio Engineering S30 speakers is shown in the figure below.
Rice. 15. Schematic diagram of acoustic speakers Radiotehnika S-30.
We disassemble the speakers and inspect problem areas
In one of the speakers, the low-frequency (LF) speaker hardly plays anymore. Everything is covered in dust, the woofer grilles are deformed.
Rice. 16. Speakers Radiotehnika S-30 (condition before repair).
There is also a clearly noticeable defect in the bass reflexes of the speakers - the foam rubber has turned into a deformed and solid mass, in one of the speakers it completely blocked the bass reflex hole.
I removed the cover of the first speaker and measured the length of the bass reflex tube made from old foam rubber - 5 cm.
Rice. 17. The first speaker S-30 with the cover removed, we measure the length of the pipe of the partially preserved bass reflex.
Rice. 18. Second column S-30 with the cover removed, the foam rubber has turned into a solid mass.
In the second column there is an even more terrible sight. Part of the foam rubber has turned into a solid mass, part of it crumbles like powder, and another part has become a sticky mass that it is better not to touch with your fingers.
I cleaned off the remaining foam rubber using a screwdriver and knife. I unscrewed the screws from the protective grilles from the woofers, thereby freeing them for subsequent removal.
Rice. 19. Remove the protective mesh from the woofer of the Radiotehnika S-30 column.
Carefully, using a screwdriver, I removed the woofer, which was placed on a mixture resembling plasticine. When unsoldering conductors from the speaker, it is very important to remember their connection: two conductors connected to one point go to the minus of the speaker, one conductor to the plus.
In order not to get confused in the polarity of connecting the speaker after repair, the conductor going to the plus of the speaker can be wrapped with a piece of electrical tape or marked with a marker. In any case, you can refer to the circuit diagram of the speakers.
A bag of cotton wool was removed from the speaker, followed by a walk outside to blow out the remains of powdered foam rubber and other debris that had accumulated there over the entire life of the speaker.
Rice. 20. Removing the subwoofer from the Radio Engineering S30 column.
Rice. 21. Speakers 10GD-34-80 (4 Ohm) from Radiotehnika S-30 speakers.
Repair of flexible flagella leading to speaker diffusers
Having freed up space on the desktop and put the speaker housings aside, I set about repairing the 10GD-34-80 speakers. A very common cause of speaker failure in Soviet-made speakers is a fracture of the flexible braided cords running from the contact block to the diffuser, which leads to loss of contact with the magnetic system coil.
Rice. 22. The reason for the inoperability of the 10GD-34-80 speaker is a flexible flagellum broken off from the diffuser (clickable picture).
When starting repairs, in addition to a soldering iron with a thin tip, you will need: wire cutters, a small screwdriver, tweezers and a thin scalpel. If you don’t have a scalpel, you can make a small homemade cutter from a metal saw blade by turning it on a sharpening machine.
Rice. 23. Necessary tools for repairing flexible flagella.
The flagella going to the diffuser were sealed off from the speaker contact blocks, and the insulating rubber tubes - cambrics - were also removed.
Rice. 24. Unsolder the flagella from the contact columns in the 10GD-34-80 speaker.
Rice. 25. Remove the end of the contact flagellum with the insulating tube.
Very carefully, slowly, I bent the two antennae to the sides, which press the flagellum of conductors to the diffuser. To do this, you can use a scalpel or a small screwdriver with a thin tip.
Rice. 26. Unbend the antennae that hold the electrically conductive flagellum on the speaker diffuser (clickable).
After this procedure, it is very important not to move the flagellum or tug on it, since it is no longer secured and a conductor from the coil of the speaker’s magnetic system is soldered to it.
Using a soldering iron with a thin tip, the flagellum was sealed off from the coil conductor. If a soldering iron with a thin tip is not available, then you can make a temporary thin tip by winding a thick (3-5 mm cross-section) copper conductor, cleared of enamel, onto a thick soldering iron tip, followed by sharpening the wound tip using a file.
Rice. 27. The damaged flexible conductor was removed from the speaker, the thread remained and the wire mesh was broken.
Having unsoldered all four flagella (for 2 speakers), I began to look for a donor for new flagella - flexible conductors going to the diffuser.
Cable conductors that connect telephone handsets to the base can be an excellent donor - they are twisted into a spiral and are very flexible, resistant to repeated bending. Finding such a conductor will not be difficult at the bazaar, or by visiting local telephone operators.
Rice. 28. A cable from a telephone handset is a donor for making flexible flagella.
Rice. 29. Structure of a flexible telephone cable (click on the picture to enlarge).
A telephone cable consists of three cores, each of which is a conductor in multi-colored insulation, which in turn consists of six cores, and each core is an electrically conductive foil wound on a fibrous base (thread).
The cable insulation was carefully cut along the entire required length, all three conductors were removed and cleaned of insulation. The length of the donor conductors required to repair two speakers is approximately 35 cm.
Rice. 30. Flexible conductors removed from the cable from the telephone handset.
At first I thought of simply twisting two or three sets of conductors into one, but a more sensible idea came to mind - weave all three sets of conductors into a braid!
Rice. 31. We braid a pigtail from flexible telephone conductors for repairing Radiotehnika S30 speakers (click on the picture to enlarge).
A few minutes of magic, with the help of dexterous fingers, and the braid of three sets of six conductors is ready!
Rice. 32. Finished braid of 18 flexible conductors (3 sets of 6 pieces).
The flagellum turned out to be a little thicker than the original one, and it is also much more flexible than the previous one, it will be an excellent replacement!
The length of the braided braid was divided into four even parts, each approximately 8 cm long (with a margin). The length of the original flagella is approximately 6-7cm.
Rice. 33. We measure the length of the original flagella from the woofer from the Radiotehnika S30 column.
One of the ends of the cut pigtail was well tinned with lactic acid, thus all 18 conductors were soldered together.
If there is no lactic acid, then rosin will do; in this case, you may have to pre-clean the conductors before tinning.
Rice. 34. Tinned end of a pigtail (harness) made of flexible conductors from a telephone.
An extra piece of the harness (not tinned, on the left) was bitten off using wire cutters and placed between the tendrils on the speaker diffuser. For ease of installation, the speaker can be slightly raised by placing an unnecessary book or other object about 4-5 cm high under it.
Rice. 35. The flexible flagellum is attached to the diffuser using through metal tendrils (click to enlarge).
After the antennae were carefully bent, the speaker was slightly raised. Using a small piece of hard material on the back side of the antenna mount, I pressed well on the place where the harness was attached to securely fasten it between the antennae. After this, the tinned end of the flagellum was soldered to the terminal of the coil of the speaker’s magnetic system.
The joint can be slightly filled with rosin or a small amount of glue, for example the Globus brand, can be applied to it.
The second end of the harness was threaded through the hole in the contact block, after which a sufficient length was selected and the excess end was bitten off using wire cutters.
The length of the flagellum and its fastening should be such that it bends freely and without tension when the diffuser moves in different directions, but does not touch the diffuser itself. When selecting the length of the harness, you can move the diffuser a little in different directions and see that everything is in the best possible shape.
An insulating tube was put on the remaining end of the flagellum and it was soldered to the block, having previously laid the tube in a special cutout in the speaker body.
Rice. 36. A flexible homemade harness is soldered to the diffuser and speaker block of Radiotehnika S-30.
When I removed one of these tubes, it literally crumbled from old age, so I replaced it with heat shrink of the same length, taking a obviously slightly larger diameter and using a heated soldering iron, pulled it together on a bundle to the desired condition.
Rice. 37. We use heat shrink instead of a damaged insulating tube when repairing a speaker.
The mounting points for the antennae on the diffuser, on the opposite side, were secured using fusible silicone; glue could also be used.
Rice. 38. We fix the attachment points of the holders for the electrically conductive harness.
In this way, all the flexible harnesses in each of the speakers were replaced.
Replacing tubes for bass reflexes
To replace bass reflex tubes made of foam rubber, you can choose a variety of materials. If you need harder bass, then you can use PVC tubes, and if the bass needs to be soft, then we use fiber material.
I used a strip of artificial synthetic fiber, which turned out to be quite dense and from it it is quite possible to roll up a tube for a bass reflex.
Rice. 39. A skein of artificial synthetic fiber.
When disassembling the acoustic speakers, the approximate length of the bass reflex tube was measured - 5 cm, so I cut a strip of exactly this height. The length of the strip was approximately 40cm.
Rice. 40. Cut a strip of material to make a bass reflex tube.
Then this strip was twisted around the bass reflex protrusion on the speaker cover so as to form a tube. The places where the strip begins and ends were fixed with fusible silicone.
Rice. 41. We wind a synthetic pipe for the bass reflex and fix the ends of the strip with silicone.
To ensure that the front cover fits tightly to the wooden box of the speaker, two round gaskets were cut from the same synthetic material in the place where the hole was made for the bass reflex. Essentially, we got two donuts, each with an outer diameter of 85mm and an inner hole of 35mm.
Rice. 42. Rings for tightly pressing the tube to the body and column cover.
The rings at several opposite points were impregnated with fusible silicone and glued together, then with the same silicone they were glued to the previously prepared tube. For reliability, the tube was additionally wrapped with nylon thread.
Rice. 43. Finished bass reflex tube for Radiotehnika S-30 loudspeakers.
As a result, two such bass reflex tubes for speakers were manufactured.
Correcting deformation of protective nets
The protective grilles of both woofers are slightly dented in the middle. It is very difficult to simply align them with your fingers - correcting a deflection in one place of the mesh will result in deformation in another.
Rice. 44. Deformed grids from Radiotehnika S-30 woofers.
As a basis for leveling, you can use some kind of small, solid, spherical object or the round protrusion of an old wooden chair.
I took a simple wine rind, installed it vertically, put a mesh on it and, resting my palms on it, easily aligned all the deformed places on the mesh.
Rice. 45. Restored grids for Radiotehnika S-30 woofers.
Putting the speakers back together
Before putting the speakers back together, I’ll describe what else can be done during the repair:
- disable the overload indication circuit if it is not needed;
- replace all conductors in the speakers with thicker ones made of copper, with a cross-section of 1 mm or more;
- Cover the inside of the body with soft material.
As for me, the conductors in my speakers are of sufficient thickness, the display circuit does not interfere, and gluing the body inside will take a lot of extra time.
Before installing the woofers, it was necessary to remove the old plasticine, which had become very hard and was no longer suitable for a tight fit of the dynamic head. I quickly and carefully performed this “medical procedure” using a scalpel.)
Rice. 46. We remove old unusable plasticine from the S-30 body.
I was lucky to find a piece of plasticine in the school trash, so I didn’t have to buy anything. Small pieces were twisted from it, which lay around the perimeter of the hole for the woofer and were carefully rubbed evenly along the groove of the wooden case.
Rice. 47. Apply plasticine evenly along the groove near the round hole for the speaker.
Rice. 48. The platform for installing the speaker is ready.
Everything is ready to install the woofers in their places. I turned on the soldering iron, and while it was heating up I decided to do some cosmetic cleaning of the front panels of the speakers.
To clean, you can use a cotton swab soaked in alcohol, or simply take a damp antibacterial wipe with a neutral odor. At the same time, I cleaned the speaker grids from dust and dirt, as well as the rubber surrounds of the low-frequency heads.
Rice. 49. Cleaning the front panel of Radiotehnika S-30 speakers.
I soldered and screwed the low-frequency speaker together with the protective mesh, and placed a synthetic tube over the bass reflex protrusion.
To install the LED, the manufacturer provided everything so that its terminals were pressed with a foam rubber tube, and in my case that’s what happened - I didn’t have to glue anything.
Rice. 50. Reinstalling the LED to indicate AC overload.
Everything is ready, you can screw on the covers and try the sound of the restored Radiotehnika S-30 speakers!
Rice. 51. The speakers have been restored, all that remains is to screw on the covers.
Connecting speakers and power amplifier
To power the Weconic EQB-105 power amplifier, a small switching power supply (PS) from some computer peripheral was found. At the output, the power supply produces 12V at a current of up to 3A, which is quite enough to power this amplifier and produce about 2x15W at the output.
To connect the power supply to the amplifier, I found an old high-frequency coaxial connector, the kind used in old Ethernet computer networks based on coaxial cables. What I found, I applied.)
Rice. 52. Power supply for the amplifier.
I connected a holder with a 4A fuse to the gap in the positive power supply conductor of the amplifier, just in case.)
Rice. 53. Amplifier power connector with fuse.
I thought about putting heat shrink on the part of the connector that goes to the amplifier, but there was no suitable diameter in stock, so I simply insulated it and tied everything together with nylon thread - it turned out quite neatly and reliably.
Rice. 54. We isolate the connection of the conductors and the connector using a thread.
Since the amplifier has four independent (not pressed to ground) conductors for supplying a signal to each of the channels, I decided to do this: I connected one conductor from each input together and connected it to the power supply negative.
As a signal cable, I found a piece of shielded cable from some device with a USB connection, about 1.5 m long. The cable contains 4 cores in a dense screen with a binding of conductors.
I connected the two wires of the cable to each other and connected them together with the screen to the ground (minus) of the amplifier. I used the remaining two free wires in the cable as signal wires for the right and left amplification channels.
Rice. 55. Connecting the amplifier inputs to the signal cable.
The "Mini-Jack 3.5" connector was removed from non-working headphones. Soldering it to the signal cable was not difficult; the common conductor connected to the screen was covered with heat shrink. The connector at the junction was tightly and under tension wrapped with thread.
Rice. 56. Connecting the Mini-Jack 3.5 connector.
To connect the speaker to the amplifier I used a two-core audio cable. I cleaned the ends of the cable that will go to the terminals of the speaker systems by about 15mm and completely tinned them, and left the ends that will go to connect to the amplifier longer - about 40mm and tinned them only at the end so that the conductors do not unravel.
Rice. 57. Preparing conductors for connecting speakers to an amplifier.
The result of the work carried out can be seen and listened to in the short video below:
Composition playing in the demo: John Petrucci - Glasgow Kiss.
In conclusion
I and my family really liked the result of the work. The amplifier with speakers Radiotehnika S-30 is quite enough to watch a movie/concert with high-quality and detailed sound, listen to music, amuse your child with a cartoon with various sound effects, play toys on a laptop or Raspberry Pi, which is connected to the TV. In general, a budget Hi-Fi made from junk turned out to be quite successful!
Have a good and clear sound!
At one time I was the proud owner of an S-30B speaker. In itself, this acoustics is quite worthy, it does not mean schematic solutions, which 95% of users are simply not interested in, but, so to speak, the assessment is based on the final result, the sound. The sound from these babies is very decent.
First of all, let's look at what we have in the database.
Speakers:
25gdn-1-8-80 was used as the low-frequency link, 6gdv-1-16 was used as the high-frequency link.
The woofer is quite good and provides quite deep and rich bass for its size. In general, its power is quite enough for comfortable listening to songs in an average living room. In general, everything is learned by comparison, for this reason, from personal experience, I can say for sure that the speaker itself is good, but it can’t compete with the bass driver from the S-90 (75gdn-1-4), due to the fact that it works here golden rule: the larger the speaker cone, the higher quality sound it can produce; but nevertheless the sound is decent. It should also be noted that the quality of the low-end part, and in the case of the S-30B, the mid-range part of the spectrum at the same time, is of great importance not only the speaker itself, but also its acoustic design, which can be improved, but more on that later.
I still really like the high-frequency speaker; if you compare it with the high-frequency sound from the S-90 (10gdv-2-16), then the 6gdv-1-16 has a much more decent sound. The highs are gentle, laconic and clear; among the Soviet tweeters there were more successful options, but nevertheless, these are also quite good, and it still depends on the user’s ears (some people like the sound only from silk domes).
Revision:
As noted earlier, the overall sound of the speakers is not bad, but as we know, there are no limits to perfection, for this reason I will post a small instruction that will allow you to try to improve the sound.
Action plan:
- We disassemble the speakers and clear out everything from there. Carefully take out the speakers and put them aside, take out the bass reflex and hide it too, by the way, I don’t recommend splitting it and damaging it - you’ll lose the settings and the sound will change accordingly. We pull out the cotton wool, wires, filter board, protection board, and remove the terminal block too.
- Now let's move on to the terminal block. I advise you to throw out this dear “miracle”, there are 2 options for development:
- We look for a new terminal block in stores and install it (don’t skimp and look for something more sophisticated).
- We are trying to modify the old one (we use old plastic and put new terminals in it).
After soldering the wires to the terminal block, we install it in place and seal it securely. We also immediately seal the entire body, using either sealant or plasticine.
- Now let's move on to the filter board. Here's a diagram by the way: Perhaps the format of this image is not supported by the browser. I’ll say right away that it’s better to throw out the protection board (however, you can leave it so that there isn’t a gaping hole where the LED should be, but don’t connect it). Make sure that no iron parts are used in the filter design, as... this affects the parameters of the coils. Then we glue the board to the speaker body from the inside (it’s better to move it away from the axis of the woofer, but make sure it doesn’t interfere with the bass reflex). After this, solder the wires from the terminal block. I advise you to unsolder the wires for the speakers before placing the filter in the speaker. Take acoustic wires made of oxygen-free copper, with a cross-section of 2 mm 2. Solder the wires; any connectors are not allowed.
- Hull damping. Ideally, you would coat the inside of the body with vibration-absorbing mastic, and then cover it with foam rubber or felt (we look at finances), but foam rubber, 10-15 mm thick, is enough, and then put cotton bags in place, if there were any; if you didn’t, just make more yourself Don’t take up 1/3 of the building, otherwise you’ll make things worse.
- We put the bass reflex in place and make sure that the entrance to it is not covered with anything.
- We put the speakers in place (soldering them in advance), it is better to place the woofer on a rubber ring to absorb vibrations, do not tighten the woofer too much, otherwise you will make it worse. The HF can also be placed on the sealant.
- We put the grate in place. Before installation, you need to decide one question: do you need it? Since it spoils the sound, but it protects the speakers, if you live on your own (at least without small children), then you can eliminate the grilles. If you still leave the bars, then tighten them (look carefully at them from the inside and you will know how). Also, when installing the panel in place, apply sealant at the point of contact between the bass reflex and the panel, otherwise it will rattle. I also placed foam rings around the woofer and tweeter to eliminate panel vibrations.
That's all in principle. I also want to say that it is better to hang this speaker on the wall, almost to the ceiling, this will cause the bass volume to drop somewhat, but the high-frequency section will give a truly rich sound.
- I dream of “dressing” the Radiotehnika S-90D speaker system in a different housing. After several falls it doesn’t look very good, and I would like to fit it into the overall interior. What is the best material to choose for this? Is glued wood (board) suitable? What are the rules to follow when changing the configuration of the system's appearance? I want to know the answers to my questions, but I don’t know how to communicate yet, I’m a newbie.
- It is best to use chipboard (particle board with glue, so to speak, due to the glue it absorbs vibrations better); when designing the case, it is better to completely repeat the old case, this way you will ensure that the settings laid down by the manufacturer are preserved. If you want to change something, you can probably move only the midrange and tweeter, since this will have the least effect on the sound of the speakers; it is better to leave the bass as it is, it is shifted to the side to reduce standing waves. It is also recommended to mount the HF on the back side of the front panel, which will provide a more balanced sound. Take chipboard of a thickness slightly larger than in a real speaker (in my opinion it is 16mm). If you decide to change the entire body, you will have to change the parameters of the bass reflex; if you are interested in this, I can provide you with literature in which this is described in detail. About the consequences of the alteration - there will be a change in sound and in which direction it depends only on you.
- A huge HUMAN THANK YOU! This is how I collect bit by bit what I don’t know. It would be nice to read something about the bass reflex parameters. Thanks in advance!
- Those. Are you interested in literature on the construction of AS? If so, I’ll be happy to share this. I’ll just coordinate the issue with the administration.
- +5! (S30B) This is truly worthy and successful! As in any successful commission, alterations should be reduced to eliminating the flaws of the “factory” “soviet?” assemblies! And the “bourgeois” at that time were not even close!
- With gratitude to mar1lynmanson - Better late than never. Interesting article. I’m looking for literature to understand some of the terms. Alas, I’m an amateur. BUT I really want to harmoniously integrate the AC-90D into my home.
- Look for Mrs. Aldoshina, I think the book is called high-quality sound reproduction, and look at Mr. Klyachin (he has a website, google it easily)
- Thank you for your concern. I have already figured out some things with your help.
- There are such S-30 with a round phasic, they can be improved according to your method and questions, the filter needs to be covered with something, otherwise the air conditioners are also metal, replace three air conditioners with one, how does the scatter of capacity affect. And if you cut out a simple S-30 phasor, which one is needed diameter and length are your recommendations. Thank you
- In order: 1) Find the circuit and remove the indication board (the coils are on it); 2) Change the filter accordingly - on a new substrate, for example, made of wood - in no case made of metal. 3) Place the coils in different places, otherwise at the factory they were cleverly stuck on top of each other. 4) Fasten the parts with stringers, and do not use anything iron. 5) There is no point in changing the speakers (except for expensive ones, but these will still serve well), by the way, keep in mind that the circuit could change, since the quality of the speakers differed from year to year. (Applies to filters only). 6) Change the clamps on the back to modern ones, just buy normal ones, don’t take very expensive ones - there’s little point - just look at the quality and take screw ones. 7) Coat all joints with plasticine/sealant - whichever is easier for you - but it’s not important, you just need to seal it. Plug the LED hole. 8) Place the filter board inside and solder it to the connectors (those that are new on the bottom of the speaker), and secure it accordingly. Solder the wires for the speakers right away (don’t forget the phasing). 9) Cover all the walls with foam rubber/felt - about 10 millimeters thick, you can experiment with the thickness, it doesn’t cost much, you’ll suffocate the volume. Experiment. An interesting option if you glue it in pieces to get a ribbed surface. You don't have to mess with the front. 10) Install speakers and solder the wires to them, just solder them, otherwise they are on connectors in the base. 11) Under the speakers of the stock there are rubber gaskets made of porous rubber; in order to reduce vibrations, do not tighten the fasteners too much. 12) When installing the front plastic cover, put thin foam rubber, it will resonate less (I did this for the S-30B and then look at the design) Phazik - a plastic pipe from the sewer will do. Calculations….. Look for Aldoshina, it’s there
- I’ll say a few more words about improving these speakers: 1. It is advisable to replace all wires with music wires made of oxygen-free copper. 2. The internal cavity of the speakers must be filled with cotton wool or something similar. If there is no amplifier for such speakers, then it can be assembled from the tape recorder with which the speakers were purchased. We take the circuit, find contacts for the left and right channels, solder the connector and the amplifier is ready.
- You need to be careful with this matter because you can overdo it.
Electrical and electroacoustic parameters of the S-30B acoustic systems comply with the requirements of technical specifications 3.843.055TU and the second complexity group according to GOST 23262-83.
The acoustic system is designed for high-quality sound reproduction as part of household electronic radio equipment.
The speaker system has an indication of speaker head overload, which is triggered when a signal is applied to the speaker with a level exceeding its rated power. For the speaker system to operate, it must be connected to an amplifier that has the highest (maximum) power at the output of each channel, ranging from 20 to 50 W. If the OVERLOAD indicator starts to light up during operation of the acoustics, then you should reduce the level of the input signal supplied to it (by using the volume control in the amplifier to which the acoustic system is connected).
The circuit diagram can be downloaded here: 92kB.
Refinement of the acoustic system
Characteristics, I must say, are not very...
Or does it seem so to me from the height of the S-90? Moreover, I still remember how I brought them (this is not an S-90, one column at a time and off you go!) and loved it. For my ears at that time, the sound was just right! So thoughts like - S-30 ha... but rejected right away! There are no bad speakers, but only stuck ears :).
Therefore, it is dedicated to all S-30 owners. If you are already tired of their sound, and your finances do not allow you to buy more, read the following:
So, in the presence of S-30, 2 pieces, a soldering iron, straight hands (preferably gold), available materials: cotton wool, felt (batting, linoleum), copper wires (even from wiring, single-core ones are recommended, with a cross-section of 2.5 mm2), plasticine , tires, speaker layout, free time and the desire to modify it unlimitedly. We remove the front panel (8 bolts) and both speakers (in the 30s, horror of horrors, they were not even soldered to the wires, but on connectors!...)
Remove the back cover (nameplate) with the filter. Let's start editing:
- We seal the case (coat all the seams with plasticine or sealant), during which time the soldering iron heats up.
- Let's take care of the filter: Turn off the overload indication unit (if the amplifier is not more powerful than 25-30 W - otherwise then listen with caution) - according to the diagram, we cut the track from the input (red wire +) to VD KA522B (see diagram) and unsolder the capacitor C2 10 μF and the transistor VT2 KT315b. We cut off the XP plug connector and solder the wires going to the speakers (we throw out the old ones! We put in their place audio wires with a cross-section of at least 2.5 mm2, in extreme cases, copper wires from electrical wiring) directly to the board, on the back side of the connector. From the bass driver (LF) “+” to connector No. 2 and “-” to connector No. 3. The tweeter (HF) is respectively “+” to No. 5 and “-” to No. 2 (this is necessary - it is in antiphase). The filter is finished.
- Frame. We dampen it - we cover it with batting, felt, an old blanket, fiberglass, felt-based linoleum (choose a sound absorber to your taste among the material at hand), preferably in several layers and alternating them. This is the most dreary thing, due to the small volume. The main thing is not to choke the volume!
- Replace the back cover with the filter (on plasticine/sealant).
- We screw the tweeter (after soldering (soldering! Never onto the connectors) the wires to it, observing polarity and taking into account the antiphase!) through the rubber gasket and seal it with plasticine.
- We sew a bag for cotton wool (although you can use what you had - like a synthetic mesh) We stuff it with cotton wool (about 1/3 of the volume of the body, don’t forget to fluff it) and place it in the upper part, preferably against one of the walls for asymmetry.
- We solder the bass driver (again, observe the polarity!) and place it in the body through a rubber gasket. We fasten it with screws (we also pass the screw heads through rubber gaskets) and seal it around the perimeter with plasticine.
- We remove the protective grilles from the front panel from the tweeter and, if desired, from the woofer.
- We put the front panel in place (it is advisable to put foam rubber under it where necessary so that it does not resonate).
That's it with the column improvements!
Now let's finish the second speaker and enjoy the sound. Already the first minute of listening will show a clear improvement in sound. The characteristic 30th buzz at the bottom will almost disappear. The high ones will improve by an order of magnitude. The sound will become “softer” or something. The mids will appear and the bass will soften. Come on, listen for yourself. The sound is difficult to describe in words :).
ATTENTION!!! It is necessary to pay attention during assembly so that the bass reflex is not covered by anything and has direct access to the woofer speaker cone! Also, special attention to observing phasing!
If, despite the improvements, you soon want more, then we continue with budget tuning:
- We install copper wires to the speakers (at least the same wiring), or better yet, HI-FI type speaker cables. We make sure that polarity is observed!
- We grind out the spikes (there will be an article about them here soon) and install the speakers on them (for a very budget modification, we drill the bottom of the case and install it on 3 M10 bolts, pointed at the bottom). If you don't mind, you can buy real acoustic tweezers.
- We modify the amplifier or replace it with a new one.
- We install a normal interconnect cable from the audio to the amplifier.
- Let's shield the sound card (If the speakers are playing as part of the computer's speaker system).
Speakers Radiotehnika S30 characteristics
The development of acoustic systems does not stand still, but this does not mean that the equipment produced in the last century is no good.
On the one hand, there are connoisseurs of high-quality equipment, on the other, the mechanics of the sound reproduction process have not advanced much over the years. In addition, widespread savings on components often result in poor quality of final products.
Thus, the Radiotekhnika S30 speakers, manufactured in accordance with GOST 23262-76 (current edition of 1988), at the REMZ plant (Riga Electromechanical Plant) back in 1983 can be used in everyday life today.
What is called, “Made in the USSR”.
Rice. 1. Speakers Radiotekhnika S30
Characteristics
- The maximum power according to the product data sheet is 30 W.
- Nominal - about 10 W.
- Peak – up to 300 W.
- The range of reproduced frequencies is from 50 Hz to 18 kHz.
- Working – 50-16000 Hz.
- The weight of one column is 6 kg.
- Dimensions (height/width/depth) - 364x214x195 mm.
- Nom. resistance – 4 Ohms.
- Minimum impedance – 3.2 Ohm
- Average sound. pressure – 1.2 Pa.
- Sensitivity – about 84 dB.
- Speaker for low and medium frequencies - 25 GDN-1-4 (equivalent to 10 GD-34).
- Speaker for high frequencies - 6 GDV-1-16 (equivalent to 3 GD-2).
- Filter separation frequency (into two ranges, 1 – LF+MF, 2 – HF) – 5 ±0.5 kHz.
- Harmonic distortion (total coefficient) – 1-2%.
- The frequency response looks like this.
Rice. 2. Frequency response of speakers
Description
The equipment was equipped with a first-order filter for high frequencies (the main speaker for low and medium frequencies was connected without a filter) with a frequency of 5 kHz.
Structurally, the body was a box with walls made of chipboard, trimmed with veneer (imitation of several variants of expensive wood species was offered).
The front panel contains both speakers, a bass reflex (in the lower part of the body, diameter 30 mm), an overload indicator and a nameplate with the frequency response.
The rear panel contains connection terminals (screws) and a fastening element for wall mounting.
The plant produced several modifications of these speakers:
- S30A,
- S30B.
They differed slightly in appearance and frequency response graph.
HF filter circuit
The characteristics of the S30 turned out to be so good that the speakers remain in demand among music lovers to this day.
In case of repair of a failed filtration unit, we have attached a schematic diagram.
Rice. 3. Schematic diagram of acoustic systems S-30
Publication date: 20.03.2018
Readers' opinions
- Rinat / 05/15/2019 - 10:29
2 Master Sound: if without bass reflexes, this is the S30A option. 2 Seabreeze: look for “filter for s30 fagear” - this is an updated board using the same circuit, you can install modern, more compact components (except for the coil - it’s better to use the original one). But this is an option for do-it-yourself soldering. - Ruslan / 05/07/2019 - 12:58
Can you tell me how much I can buy it for? - Seabreeze / 04/14/2019 - 10:59
What is a more compact replacement for the high-pass filter? Can anyone recommend something from Ali Express? - Master Sound / 04/10/2019 - 00:04
I bought these speakers for only 1350 rubles. They sound great. They look the same. Only there are no phase inverters and an overload signal, and instead of a filter board there is a condenser and a resistor. Despite this, the sound is excellent. Moreover, my amplifier is my own Radiotekhnika U 101, but already modernized. All capacitors were replaced with similar imported ones. volume, timbre and balance resistors were replaced with new ones and the stereo unit was turned off, which does not distribute the signal into channels, but mixes them with each other. I use these speakers as near-field studio monitors and perfectly mix soundtracks even for famous Russian pop artists. P.S. Well, if you want to KILL the sound, then buy Chinese plastic active monitors from YAMAHA or Sound King. This is a 200% proven kill :-)
So, in the presence of S-30, 2 pieces, a soldering iron, straight hands, available materials: cotton wool, felt (batting, linoleum), copper wires (even from wiring, stranded ones are recommended, with a cross-section of 2.5 mm 2), plasticine, rubber, speaker layout, free time and the desire to improve unlimitedly.
We remove the front panel (8 bolts) and both speakers (in the 30s, horror of horrors, they were not even soldered to the wires, but on connectors!...) We remove the back cover (nameplate) with the filter.
Let's start editing:
1) We seal the case (coat all the seams with plasticine or sealant), during which time the soldering iron heats up.
2) Let's take care of the filter: Turn off the overload indication unit (if the amplifier is not more powerful than 25-30 W - otherwise then we listen with caution) - according to the diagram, we cut the track from the input (red wire +) to VD KA522B (see diagram) and unsolder capacitor C2 10 μF and transistor VT2 KT315b.
We cut off the XP plug connector and solder the wires going to the speakers (throw out the old ones! We put in their place audio wires with a cross-section of at least 2.5 mm2, in extreme cases copper wires from electrical wiring) directly to the board, on the back side of the connector. From the bass player (bass) "+ " to connector No. 2 and "-" to connector No. 3. The tweeter (HF) is respectively “+” to No. 5 and “-” to No. 2 (this is necessary - it is in antiphase).
The filter is finished.
3) Housing. We dampen it - we cover it with batting, felt, an old blanket, fiberglass, felt-based linoleum (choose a sound absorber to your taste among the material at hand), preferably in several layers and alternating them. This is the most dreary thing, due to the small volume. The main thing is not to choke the volume!
4) Replace the back cover with the filter (on plasticine/sealant).
5) We screw the tweeter (pre-soldered (soldered! In no case onto the connectors) the wires to it, observing polarity and taking into account the antiphase!) through the rubber gasket and seal it with plasticine.
6) We sew a bag for cotton wool (although you can use what you had - like a synthetic mesh) We fill it with cotton wool (about 1/3 of the volume of the body, don’t forget to fluff it) and place it in the upper part, preferably against one of the walls for asymmetry.
7) Solder the bass driver (again, observe polarity!) and place it in the case through the rubber gasket. We fasten it with screws (we also pass the screw heads through rubber gaskets) and seal it around the perimeter with plasticine.
8) Remove the protective grilles from the front panel from the tweeter and, if desired, from the bass driver.
9) We put the front panel in place (it is advisable to put foam rubber under it where necessary so that it does not resonate).
That's it with the column improvements!
Now let's finish the second speaker and enjoy the sound. Already the first minute of listening will show a clear improvement in sound. The characteristic 30th buzz at the bottom will almost disappear. The high ones will improve by an order of magnitude. The sound will become “softer” or something. The mids will appear and the bass will soften. Come on, listen for yourself. The sound is difficult to describe in words :).
ATTENTION!!! It is necessary to pay attention during assembly so that the bass reflex is not covered by anything and has direct access to the woofer speaker cone! Also, special attention to observing phasing!
If, despite the improvements, you soon want more, then we continue budget turing:
A) We install copper wires to the speakers (at least the same wiring). We make sure that polarity is observed!
B) We grind out the spikes (there will be an article about them here soon) and install the speakers on them (for a very budget modification, we drill the bottom of the case and install it on 3 M10 bolts, pointed at the bottom)
C) We are finalizing the amplifier (According to the principles outlined here)
D) We install a normal interconnect cable from the audio to the amplifier.
D) Shield the sound card (If the speakers are playing as part of the computer's speakers).
P.S. As always, there are some downsides. After the above, you will obviously have to buy another HDD for music... Since MP3 at 128 Kbps will become impossible to listen to - only 256-320 (but that's a completely different story...).
