The ultimate remake of Radiotehnika S30. Amplifier class d Correcting the deformation of the protective grids

In this article I will try to describe the basic principles for refining this acoustic model. After buying an Audigy 1 and Microlab X2/5.1 speakers, my life has changed. Music has gradually come to the fore and replaced computer games. For almost a year I sat on Microlabs and thought that better sound no, but then they ceased to suit me, because a person always strives for the best, so I began to strive. For myself, I figured out the following thing: not everything that sounds good is expensive and you can turn to Soviet audio engineering. For a long time, 6AC-222 was gathering dust on my closet, one fine morning I paid attention to them and decided to use them for the good of the cause. After simple actions with a soldering iron, the speakers were connected instead of the front in Microlab X2 and it started ........

I immediately warn you that you make all changes to your acoustics at your own peril and risk. The author is not responsible for your actions.

So I finally bought the legendary Soviet S30 shelf speakers with round bass reflex. (S30b are also present in the photographs. I received the camera by the end of the assembly, so what was filmed was what was already redone by a friend (S30b))

They were bought on Friday for a symbolic 400 rubles. After half an hour of listening to them as they are, I decided that I would immediately refine them. I left one column connected, the second began to disassemble. More about disassembly of columns.

The workers of the plant did not skimp on the “sealant”, if it can be called that, and missed almost all the holes with it (for speakers), naturally, no one remembered about the cracks. A good 1.5 hours were spent cleaning the front and back panels.

I must say right away that it is better not to remove the seal on the rear panel (plastic cover with connectors), because it helps to cope with vibrations. I ripped it clean, for which I later paid the price. The lid rattles under certain conditions, and even the rubber gasket does not change the state of affairs. So the back is better to leave everything as it is.

As I “deepened” into the column, I was more and more surprised. First of all, I was struck by the connecting wires of monstrously small thickness. In the S30b modification, the wires are not soldered to the speaker contacts, but are attached to the clamps, which is really bad! The joints of the panels are smeared, apparently, with PVA glue, which has already cracked from time to time, because. speakers were born back in 1986 (I'm only a year older ;-)). This was followed by a filter, consisting of a handkerchief the size of a palm, four paper capacitors, two electrolytic type K50-6, an inductor and several resistors.

The entire board is attached to a plastic plug on the back wall, which I wrote about above. The phase inverter is made of foam rubber, which has lost its shape over time and has become hard as a stone. That's all the insides. Let's try to extract practical benefits from all this goodness.
The wires in the filter turned out to be the same negligible thickness as those going to the speakers. The first thing I did was to replace them. For replacement, copper wires from a burned-out computer PSU were used. They are not acoustic, but still better than the ones that came before. All soldering operations took no more than half an hour.
The next day I went to Chip and Dip and bought an acoustic cable for 15 rubles per meter.

I laid it from the filter to the speakers themselves. This replacement is one of the most significant, because it gives the most noticeable change in sound. The speakers acquire a voice, clear and fairly transparent. The difference between what was and what was immediately heard. The laziest can limit themselves to just replacing the wires, while the rest read on.
I took out the cotton wool from the speakers completely. Someone will judge me, but I liked the way they play without cotton wool. If before that there was bass, but it was somehow screaming and hit somewhere in the back, then after I removed the cotton wool, the mumbling disappeared, the clarity increased, and now the bass began to hit the floor and became pleasant and juicy.

Now begins the most interesting, the most difficult in technical terms, if you can call it that. Lubrication of panel joints and crevices with sealant (I used a car sealant) and gluing the walls of the speakers with sound-absorbing material.

In my case, linoleum with a synthetic winterizer or something similar on the other side (“Warm” linoleum) acted as such material. The whole difficulty lies in the fact that the speaker housing is non-separable and lubrication takes a lot of time and effort. It took about 2 hours before I finished lubricating one column. Everything needs to be smeared! Internal joints, external and all the cracks that we meet on the way. Because if this is not done, then air will flow through them, which will introduce distortions into the sound, various wheezing and whistling. Why do we need this? Right! We don’t need anything, so let’s miss it on our conscience. We finished with the lubrication, we go directly to the sizing with linoleum itself. This activity is not for the faint of heart. Someone may not stand it, someone will not start at all, I decided to go to the end and do everything that is possible.
We take the dimensions from the columns and proceed to the cutting of linoleum. You can simply attach the column to the surface of the linoleum and circle it with a marker (I personally did this), and then subtract about 1.5 cm from each side and start cutting along the contour. 1.5 cm eats up the wall thickness. After cutting out the workpiece,

we put it inside the column and circle the connecting corners with a marker, because they will interfere with gluing exactly linoleum. Circled, now cut with scissors or a knife. Ready? We put it back into the column, check, if everything matches, then we smear the surface of the column with glue. I used a glue that is similar to Moment, but it is transparent and dries fairly quickly. Gently, with a thin layer, smear over the surface and apply the pattern. Do not forget to straighten everything with your hands, because. waves are inevitable.
Now we ventilate the column, because it smells of glue and other nonsense.

While the speaker was drying, I cut out the spacers from the car's speaker chamber. We apply the speaker

With the front side to the rubber, circle with a marker or pen. We cut and screw the resulting blank in place of the speaker. Next, we circle a piece of rubber from the inside of the column so that the speaker itself freely enters the resulting hole. Similar operations are done for all speakers. We carefully try on the gaskets, if somewhere the rubber does not fit snugly, then we expand the hole so that the linoleum sheet lies flat. In addition to the gaskets for the speakers, cut out the gaskets for the heads of the screws so that they do not come into direct contact with the speaker. They cut it out, checked it, and the column was already dry. You can try to put. Do not forget to make holes for the screws in the attachment points in the rubber. It is possible to smear the hole in the front speaker under the woofer with sealant, although this action is unnecessary. Everything is set, now we are listening. The difference should be audible immediately, although it all depends on the training of the ear. Happy, now let's move on. I redid the phase inverters. Everyone may have a different situation. Personally, they looked very depressing to me. Made of foam rubber about 20 years ago, they lost their shape and became hard and brittle. crumbled at the slightest movement.

For the new phase inverters, I bought plastic sewer pipes of a suitable diameter (35 mm) and length (the original FI is 8 cm long).

In order for the FI to keep normally in the hole for it, I had to wrap it with a narrow piece of linoleum, the length of which was about 1.5 meters. The resulting structure is screwed into a hole in the wooden front panel so that the outer part of the FI protrudes by about 0.5-1 cm.

In order to properly place the FI, it was necessary to modify the front front panel.

I used a dremel to cut off the plastic circle that went inside the old FI and slightly widened the hole so that the new FI would butt up with the panel. It turned out pretty badass. The new phasic performs its duties better and separates the bass guitar from the general sound, which is now heard very clearly at any volume. The most important thing is that it does not mumble, but works very correctly, it is important not to confuse anything when choosing the length and diameter of the FI.
Well, now the finale. We assemble the entire structure into a single whole, screw everything together as expected and connect it to the amplifier.

Turn on the music and start having fun

P.S. A little about the connecting wires.
A couple of days later, after finishing the speakers to mind, I decided to buy an audio cable from the amplifier to the speakers. I opted for a cable from Luxmann with a cross section of 1.2 mm2 oxygen-free copper. The sound has improved even further. The drum sounds like it's playing behind your back. The speakers began to play cleaner at higher volumes and more accurately convey the smallest details and shades. So it's not worth saving on such a thing as a connecting cable. Personally, I bought 18 meters at 25r / meter. All pleasure rose to 450r.

The whole alteration as a whole, excluding the audio cable from the amplifier to the speakers, required about 250 rubles. This price includes:

1. Insulated linoleum - 1.5m2 112r
2. Audio cable for internal laying - 12r / meter (2 meters was enough) 24r
3. Glue - I don’t know how much it costs, I got it for free (one tube for two columns)
4. Sealant - I also don’t know how much it costs, because his father gave it (one tube for 2.5 columns)