The RIAA standard was approved back in 1955. Until that time, record makers made records according to a variety of, often their own, performance standards. This situation required to provide for several types of recording correction in the amplifier or to use tone controls.

With the proliferation of gramophone records as the main carriers of sound, this approach became more and more incorrect. The number of record firms grew, and so did the number of standards.

For these reasons, the International Electrotechnical Commission (IEC) since 1958 adopted a correction according to the RIAA (Recording Industries Association of America) standard, which has entered the standards of most countries, for example, GOST 7893-72, DIN 45 541.

Recording on the records is carried out by the head-cutter. The speed of movement of the cutter near the equilibrium point (midrange area) is directly proportional to the value of the signal applied to it. Therefore, when the signal is constant in amplitude, the speed also remains constant. And the amplitude of the cutter and, accordingly, the width of the groove will be inversely proportional to the frequency of the signal. Simply put, at high frequencies, the groove width will decrease and the signal-to-noise ratio will deteriorate. At low frequencies, the width of the groove increases, which requires an increase in the distance between the grooves and leads to an increase in the level of distortion. From all this, it follows the need to reduce the amplitude at the low frequency and increase it at the high frequency. The use of RIAA correction ultimately leads to an improvement in the signal-to-noise ratio, equalization and a decrease in the width of the tracks on the plate and, accordingly, to a longer duration of the sound of one plate.

The RIAA-approved recording performance is suitable for both mono and stereo recordings.

The RIAA standard defines three zones

• Low frequency zone (LF), where the signal is attenuated by 6 dB per octave
• Mid-frequency zone (MF), where the inflection point is at a frequency of 1 kHz at a level of 0 dB
• The high frequency (HF) zone where the signal rises by 6 dB per octave.

This characteristic is obtained using three time constants τ

• 3180μs - corresponding to 50Hz
• 318μs - corresponding to 500Hz
• 75μs - corresponding to 2100Hz

These three points determine the zigzag shape of the recording curve, and three time constants are used in calculating the values ​​of the correction filter elements.

Crystalline pickups, which were used earlier, had the opposite characteristic and did not need to be corrected. frequency compensation was obtained automatically. However, such pickups do not meet high sonic requirements and have been completely supplanted by magnetic pickups. Magnetic pickups, in turn, have a linear frequency response. What makes it necessary to use the RIAA - pickup signal corrector.

Accidentally I got into my hands a turntable "Arctur-006-stereo". Therefore, there was an urgent need for a phono stage. On the Internet, I came across A. Bokarev's scheme, according to which I decided to make a much-needed device.
The back of the player has two output connectors (SG-5 / DIN): one from the built-in phono stage (500mV), the other bypassing, for connecting to an external one (5mV). When using the built-in phono stage, a jumper is installed in the second output.

I didn’t like the characteristics of the built-in corrector, and when I turned it on, it turned out that it was defective - I heard only 50 Hz hum in the speakers. There was no desire to restore it, I turned off the built-in corrector board completely.
I will listen to my own version.

Photo source: vega-brz.ru

The electric player of the highest complexity group "Arctur-006-stereo" has been producing the Berdsk radio plant since 1983. The turntable is made on the basis of a two-speed EPU G-2021, with an ultra-quiet electric motor and a direct drive. There is a pressure regulator and a roll-off force compensator, adjustment of the disk rotation speed by a stroboscope, hitchhiking, microlift, a speed switch and an automatic return of the tonearm at the end of the record.

Vinyl-proofreader circuit

Rice. 1

The circuit is quite simple, which is very good for a beginner radio amateur, but it does an excellent job at the same time.

Quote: Bokarev Alexander

I use operational amplifiers in this version: input op-amp OPA2134. Output op-amp NE5532. Alternatively - TL082, but its load is weaker, and the shift is larger.

Rice. 2. The original circuit of the corrector "WEEKEND"

The power supply of the circuit is made according to an extremely simple scheme: a bipolar half-wave rectifier with parametric stabilization on 2C175A zener diodes, we put two of them in series on the shoulder. Gorgeous stubs, scanty spread, non-polar.

The rectifier uses 1N5819 or 1N5822 Schottky diodes, it doesn't matter. the task is to get a Volt 25-27 at the input of the stabilizer.

I tried to power the circuit in a brazen one, without stabilizers at all, gave 12 Volts of change, received two 16 Volts each, the circuit did not notice such rudeness and played as before.

Immediately advice: be sure to shunt the primary of the network transformer with a capacity of 1 microfarad 600V, otherwise, when you turn it off, sometimes terrible clicks occur.

Corrector printed circuit board based on the drawing M. Vasilieva. I added holes for capacitors of different sizes and adjusted the PCB to fit my parts.
I designed the power supply board myself.

Rice. 3. View of the PP

The main task for me was the manufacture of the power supply unit. The circuit requires a bipolar voltage of ± 15 volts. In the stash I found only a transformer with one 15 Volt secondary in the form of an external power supply unit.

Rice. 4. Power supply circuit on chips 78/79

I sketched a board in Sprint Layout, on which I implemented bipolar power supply with two half-wave rectifiers with stabilizers 7815 and 7915 at the output. Capacitors used from a disassembled computer SMPS, diodes 1n4007.

Rice. 5. View of the PP power supply

Making the boards and sealing the parts took me about 3 hours. Then he could not resist, soldered temporary wires and connected the whole thing to the player.

To my surprise, everything worked from the first start! No "special effects" and no background. Listening to music is also pleasing: the sound is clear, transparent and airy.

--
Thank you for the attention!
Igor Kotov, editor-in-chief of the "Datagor" magazine

Schematic diagram and user manual for "Arctur-006-stereo"
▼

If you look at the tracks of the record with a magnifying glass, you will see that these tracks are by no means perfectly parallel to each other. Their edges sway and wriggle from side to side, sometimes finding themselves dangerously close to adjacent paths. These throws are determined by the amplitude of the low-frequency components of the signal and it is they that limit the recording density, and hence the playing time of the record.

Recording high frequency signals involves a different kind of nuance. If the amplitude of the high-frequency recording details is small, then the level of these details will be comparable to the level of the inherent noise of the record. In addition, high-frequency oscillations are troublesome to read - the mechanical elements of the reading system have mass, that is, they are inert, which imposes restrictions on the frequency of oscillations that can be read and converted into an electrical signal, and they are not absolutely elastic bodies, that is, part of the read high-frequency information will not reach from the surface of the plate to the destination - the sensor, but is damped in mechanics - therefore, high-quality needle holders tend to be made of the lightest and hardest materials, such as beryllium. Among other things, the lighter the element, the higher its natural resonance frequencies, and the shift of the resonance frequencies of the mechanical elements of the sound-generating path further beyond the audible region is a problem that has been familiar to developers for a long time.

It seems obvious that in order to restore the signal at the output in the form as close as possible to the original state, the curves of the transformations carried out during recording and playback must a) correspond to each other, be mirror images of each other, and b) be regulated by an appropriate standard so that any plate can be play on any player. This was not obvious, however, for about a quarter of a century - until the 1950s, record manufacturers implemented a similar frequency equalization "who in what," which now leads to a headache for those who want to hear the old record in the "right" quality.

Strictly speaking, the nonlinearity of the frequency response of the plates drew attention back in 1926 - almost immediately after the appearance of electric recording, in 1930 the question arose of what to do with the noticeable rise in the mid-frequency region introduced by condenser microphones, and by the mid-1930s the correction of the reproduced signal was already in full swing practiced - for example, on the radio. Accordingly, correction began to be used in the production of records. But it was not until the 1940s that a premonition of the need for a single standard arose, which shifted from a premonition to a demand of the times at the border of the 1940s / 1950s - when the marketing battles of Columbia vs RCA from media formats and recording speeds spilled over to correction schemes, darkening the cloudless future of the recording industry with anarchic entropy.

Since 1942 work on the standard began NAB (National Association of Broadcasters) and in 1949 NAB recommendations began to be used in the production of records; after presentation in 1948, Columbia released its correction scheme; in 1949 RCA responded with its "New Orthophonic" equalization scheme, the details of which were published in 1953. As a result, the RIAA (Recording Industry Association of America) was formed in 1952 to develop a uniform standard. By her efforts, by 1955-1956, a standard was formed, which, with minor additions, is used to this day. Curiously, now on the RIAA website technical standardization is in the last place in the list of tasks, and in the first place is - rightly, the fight against piracy. Standards are standards, and the most sensitive place in the body is still the wallet.

But it was a saying: so to speak, the generally accepted version of events, and now -.

Article published on 2011-09-21
The author of the articles or the translator is Dmitry Shumakov, unless otherwise indicated. When quoting, please put a link to the record store websiteBe the first to comment!

Introduction

The RIAA curve is the generally accepted standard for vinyl records. It has been in use for a long time since 1954. By 1956, the new standard, which became known as the RIAA Curve, had supplanted competing formats and took over the US and Western European markets. In 1959, the RIAA curve was approved, and in 1964 it was standardized by the International Electrotechnical Commission. In 1976, the IEC modified the RIAA's standard bass response curve; the innovation met with fierce criticism and was not accepted by the industry. In the 21st century, the vast majority of preamp manufacturers follow the original RIAA curve standard without the changes introduced by IEC in 1976.

Frequency equalization according to the RIAA standard can be implemented with both active and passive filters, and combinations of filters of two types. Many use equalizers built entirely on passive filters in the belief that they sound "better", but the circuit shown here is implemented by combining the two types of filters. This concept was developed by me long before the advent of the Internet, and the diagram shown (with a few minor changes) was first published on the ESP website in 1999.

The above graph shows the theoretical and actual RIAA frequency response normalized to 0 dB at 1 kHz. Most RIAA phono preamplifiers have an additional (and unwanted) zero at some frequency above 20 kHz. This additional zero is absent in the described design, because the circuit uses a passive low-pass filter that extends the frequency response curve above 20 kHz, with the final limit well above 10 MHz (depending on the capacitor's own inductance).

The terms "pole" and "zero" need some (in this case, simplified) explanation. One pole causes the signal to descend at a rate of 6 dB / octave (20 dB / decade), and one zero causes the signal to rise at the same rate. If a zero is entered after the pole (as shown above), then the effect is to translate the frequency response into a horizontal form. Horizontal frequency response is observed at frequencies from 500 Hz to 2100 Hz. The next pole (2,100 Hz) will cause the signal to decline again. An "undefined" zero above 20 kHz is caused by the fact that many preamplifiers cannot reduce their gain below some fixed value defined by the circuitry. However, not all proofreaders have this problem, nor is it in the above diagram.

It should be noted that striving for “perfect” accuracy is pointless, since a lot depends on the stylus, arm, and (of course) the recording. When you buy vinyl, nobody will tell you which EQ was applied during mastering, and the frequency response degrades after repeated playback. Therefore, ultimately, you must let your ears be the final judge of what is best for you.

The phono stage presented follows the RIAA curve, it is very “quiet” and provides much better sonic efficiency than the vast majority of those devices that are cited in various magazines. Like the rest of the preamplifier stages, the phono stage uses the NE5532 op amp. It has low noise, high speed and reasonable price. It is ideal for this kind of application. Another great op amp is the OPA2134.

Rice. 1. Phono stage circuit

The input capacitor is marked with * (C LL, and its equivalent on the right channel - C LR) and is optional. In almost all cases, this is unnecessary, as the cable capacitance between the pickup and the preamp will be (more than) sufficient. Some manufacturers indicate the required load capacity, but many do not. The vast majority of pickups are of the lowest capacitance possible, and adding an extra capacitor is unlikely to improve the situation. Few have the ability to measure the capacitance of interconnects or internal arm cables, but it is typically in the 100pF range with standard cables. In case the pickup manufacturer has stated a higher capacitance, feel free to experiment with the C L value. It is best to connect these capacitors directly to the input connectors rather than placing them on the PCB. The capacitors must be sized (accurate to 1%) so that the left and right channels remain properly balanced.

Capacitors with high capacities can be non-polar electrolytic, since there will (practically) no direct current flow through them. However, they are quite large in size and standard electrolytic or even tantalum capacitors can be used instead. Polar capacitors will function normally without the influence of DC voltage, and tantalum is my least favorite type of capacitor and therefore not recommended. The AC voltage flowing through C2L / R and C3R / L will never exceed ~ 5mV at any frequency up to 10Hz, and these capacitors play no role in the RIAA curve. Feel free to increase the value if you like (100uF is not a problem).

Capacitors with low capacities must be accurate to 2.5%, otherwise it will be difficult to find the ones that are closest to the required value. There will be some deviation from the ideal RIAA curve if the ratings of these capacitors are too far from the specified values. Most important is the match between channels - it should be as accurate as possible.

Resistors - metal film with 1% accuracy and low noise. This design differs from most others in that the shaping of low and high frequency is performed independently - an active low-pass filter and a passive high-pass filter. Due to the low value of the output resistor, the input impedance of the next stage will drop to 22 kΩ and cause a slight distortion in the RIAA curve.

In fig. 1 shows only one channel and the other uses the remaining half of each op amp. Remember that the + for power goes to pin 8 and the - for power goes to pin 4.

The generally accepted curve equalization at 50Hz has not been fully implemented, as most listeners find that bass sounds much more natural without it. In this regard, we can say that the accuracy is not enough, but I still use this inaccuracy and did not identify any problems with low frequency noise.

Please note that it is not necessary to use an HF filter. The circuit provides a -3 dB level at about 3 Hz. HSPs play an important role, especially if you are using a subwoofer. A well-damped and insulated turntable platform is an excellent option. I have successfully used a large concrete slab, carpeted and damped using foam rubber. Getting it right will take some experimentation. Generally, good results are obtained by compressing the foam to 70% of its normal thickness under the weight of the concrete slab and turntable. A shelf attached to the wall is another good method of providing infrasonic isolation.

If low frequency noise does occur, you will see a vigorous cone movement even if there is no bass. In this case, I recommend including a subsonic filter (Project 99) in the circuit. The standard configuration is 36 dB / octave with -3 dB attenuation at 17 Hz. This generally helps to eliminate even the strongest low frequency interference caused by using curved discs. This usually helps to eliminate low pass feedback problems as well, but these should be below the cutoff frequency of the filter.

RIAA Curve Characteristics

As you can see from the table, the deviation from the standard is less than 1 dB, and the gain at 1 kHz is about 40 dB (100), so a nominal 5 mV from the cartridge output will give 500 mV. This value can be increased if necessary by increasing the value of the 100 kΩ resistor in the second stage. Care must be taken not to increase the gain too much and cause clipping. As you can see, the second stage has a gain of 38 (31 dB).

If the 100 kΩ resistor is increased to 220 kΩ, the overall gain will be slightly more than doubled by 38 dB. An input signal at stage 2 of 17 mV (5 mV from the pickup output) gives a normal 1 kHz output (before the passive filter) from 1.12 V RMS. The theoretical output at 20 kHz exceeds 9.75 V RMS, but this never happens because at 20 kHz all records will be 15-20 dB below the level at 1 kHz (see frequency response in Figure 2).

This means that the actual output level at 20 kHz is typically around 1 V RMS at best. However, if the gain of the second stage is increased too much, there is a risk of clipping. This possibility is unlikely due to the nature of the music - there is very little fundamental frequency of any instrument (except synthesizer) above 1 kHz, and most harmonics roll off naturally by 3-6 dB per octave above 2 kHz - but it must be taken into account.

One factor that is often overlooked in phono stage is the capacitive loading of the op-amp output at high frequencies. This is eliminated in this design, and since the NE5532 and OPA2134 can handle 600 ohm loads with ease, the 820/750 ohm resistor isolates the output stage from any capacitive load. The first stage is 10k ohms coupled with a capacitor, so capacitive loading is not a problem.

Each op amp must be shunted with 10 μF x 25 V electrolytic capacitors from each power leg to ground and 100 nF capacitors between the power pins.

Note that when using a moving coil cartridge, an ultra-low noise step-up transformer or pre-amplifier must be used. This circuit is for use with a standard moving magnet.

Signal level versus frequency

There is very little information on the net and elsewhere to give anyone an idea of ​​what level they should expect to hear at any frequency. The image in fig. 2 was captured using the "Visual Analyzer", one of the many FFT-based computer programs available. The signal was taken from the FM tuner - you can see the steep roll-off above 15 kHz and the 19 kHz pilot tone used to decode the 38 kHz FM subcarrier. The capture was filmed from an Australian "alternative" radio station, so it includes several different genres of music as well as speech.

Rice. 2. Typical frequency response

The capture was tuned to hold the maximum level found over the sample time (more than 2 hours), so it represents the highest level recorded across the entire frequency band. Correction was not used on the received signal, the broadcast signal was captured directly. Although everything above 15 kHz is removed, the overall trend is clearly visible. While there will always be deviations and exceptions with different musical styles, the general trend is at work in a wide range of musical styles.

The "reference" level is -9 dB at 1 kHz. The maximum peak levels are observed between 30 Hz and 100 Hz, while the level between 200 Hz and 2 kHz is quite “flat”, showing approximately 3 dB of drop within this frequency range. A slope of 6 dB per octave is observed in the 2-4 kHz range, followed by a 10 dB attenuation in the 4-8 kHz range.

Of greater interest is the amplitude of the highest peaks because overload will occur at the peaks rather than mid-range levels. At 10 kHz and above, there are peaks at -18 dB and some additional peaks (-24 dB) at just below 15 kHz.

Based on this, it is reasonable to expect that the worst case signal level at frequencies above 15 kHz will not exceed -30 dB, and this is 21 dB below the level at 1 Hz (slightly less than 1/10). Therefore, a cartridge with a 5 mV output at a 1 kHz reference frequency will not have more than 5 mV at any frequency around 20 kHz - the highest level we can expect.

When using the recommended RIAA component values, the maximum possible signal level at the output of the second stage is about 1 V RMS - quite well within the capabilities of the proposed operational amplifiers. Even if the maximum level is 50 mV (same result at 20 kHz as at 1 kHz), the second stage will still be below the overload level.

So, I tell you in detail how to make a fairly high-quality proofreader myself, with crystal tops, a lively voice and a natural, full-bodied bass, i.e. exactly what sets vinyl sound apart from any digital music medium. The main time for making a proofreader will be spent on searching for parts, but the structure itself can be easily assembled, even without the experience of a Vsedelkin master, in one Sunday. A schematic diagram of a high-quality and easy-to-assemble and in detail vinyl corrector is shown in the attached picture. The equalizer is built on a lumped correction circuit according to the RIAA standard, optimized for all possible parameters to optimize its parameters relative to its middle class and the possibility of connecting it to transistor amplifiers with a standard input impedance value. Do not be confused by my average rating of this corrector, this rating on the absolute scale of sound quality, where all the brands you know are on the lower stage, for example Sony, Marantz, Technics, Creek, MF, and in general almost everything that is made of transistors, like and most of the lamp technology of average cost from brands and, moreover, from the so-called "Roshyenders".
The equalizer is built on old octal lamps, which can be easily found on any radio market and in most companies selling Soviet radio components, i.e. these lamps are not in short supply at all, and are even produced by lamp factories to this day. We will not aim at foreign ones, such foreign lamps of the highest sound quality are very expensive, since everything related to vacuum tubes in the West has long since passed into the category of a fetish. We want old lamps produced by MELZ, they have the best sound from domestic ones, although it should be added that foreign ones sound even better. You should not pay attention to the year of manufacture, although the older, the more thorough the result. For lamps, you need to buy ceramic sockets for octal lamps, they are also not in short supply and are sold in the same place where you will buy lamps. All resistors with a power of 0.5 ... 1 W, brands C2-10, C2-29, MT are suitable. You can also use BC carbon resistors, which were used in old tube radios. It is advisable to find resistors R3 and R6 with an accuracy of 1%, and the resistor R6 is composed of a series connection of resistors of 30 k and 2 k. at the indicated power, but the sound quality will fall short. Capacitors C1 and C8 are electrolytic, produced by ELNA, HITACHI, RUBYCON, NICHICON, preferably sound series. In no case should you use Samsung, Samyungi, Chemicons and other similar low-quality capacitors, which for some reason Russian sellers sell at comparable prices with high-quality products. The sound from such a neighborhood will immediately become dirty and disorganized. Capacitors C2, C3 need to be found mica, series SSG, SGM, KSO, K31, with an error of no more than 2%, although it is quite possible to try a 5% tolerance. Capacitor C5 is also desirable mica, for example SSG, KSO with a nominal value of 0.047 ... 0.1mk, but in the absence of a paper K40U-9 or KBG. Because the main thing, of course, is to assemble the circuit so that it works, and in the future you can really improve its sound, replacing the parts you use with better ones, for example, foreign audiophile ones. Capacitor C6 is electrolytic, from the same manufacturers as the first electrolytes, although you can add Sagno to that list, some of their organic dielectric capacitors sound very decent. It is advisable to find a paper capacitor C7, K40U-9 for a voltage of 200 Volts, in the absence of a polypropylene one from any K78-xx series, the main thing here is not to make up this capacitor from several. The battery in the cathode of the first lamp is a nickel-cadmium battery of a standard AAA size, at 300mAh, it is imperative to use a non-Russian manufacturer, at least a Taiwanese GP. Any choke L1 for a current of more than 20 mA and an inductance of 2 ... 10 H, for example, from Soviet tube TVs. With the details sorted out, it remains to assemble the structure.
To do this, take any wooden board made from native Russian wood, about 15 by 20 cm in size and about 10..18 mm thick, and make three holes in it for lamp panels. We make one hole on the axis of symmetry along the long side for the first 6Н9С lamp, in which there are physically two identical (almost) triodes, they will each work for us on their own, right or left channel. The socket of this lamp must be fixed in a wooden base through a gasket made of viscous rubber with a thickness of about 10 mm, this is necessary to decouple the lamp from mechanical vibrations of the base. It is also necessary to acoustically decouple the lamp bulb from mechanical vibrations transmitted through the air. This can be done by covering the lamp bulb with a glass with a wall thickness of about 5 mm, glued from several layers of loose cardboard with Phoenix-type glue. This glass is attached with the same glue to the same rubber gasket that decouples the lamp from chassis vibrations. Vibration protection is required for this type of lamp. We make two other holes for 6Н8С lamps at a distance of 7 ... 8 cm from the first lamp along the long axis of the base, at the same distance on each side of it symmetrically to each other, since the triodes of each of these lamps operate on their own sound channel. The sockets of these lamps are attached directly to the wood base.
Further, in front of the 6H9C lamp, symmetrically to the long axis of the base, we make holes of the corresponding diameter and fix, each from the side of the corresponding stereo channel, two standard RCA panel connectors, preferably high-quality ones, for example, from NEUTRIK, which can be easily found on sale. This pair of connectors will be the input of the corrector. The same connectors must be fixed next to the corresponding 6H8C channel lamps, on the opposite side from the 6H9C lamp location. These will be the output connectors of the corrector. Next, you need a copper plate with a thickness of 0.5 to 1 mm and dimensions of 15 x 10 cm.From it, along one long side, we cut out strips that will serve as supporting contact pads for desoldering parts (petals, terminals) on them, measuring 10 x 25 mm , on both sides of which we make holes with a diameter of 2 ... 3 mm. One of these holes is for attaching the petal to a wooden base using a conventional screw of the appropriate size. After these support pads are fixed in the places of your choice of the wooden base according to the schematic diagram, you can bend them in any way so that it is convenient to attach the leads of the parts corresponding to these pads to them. In the figure, all of these pads are marked in pink. Other pins of the parts are fixed either on the pins (petals) of the lamp panels, which are marked in black on the diagram, or on the ground bus common for both channels, cut from the same copper plate in a special way. Only the leads of capacitors C7 and resistors R10 of each channel are attached directly to the signal pin of the corresponding output RCA connector. If the length of the leads of the parts is not enough for you to connect them according to the corrector circuit, then as conductors you will need to use strips two to three millimeters wide cut from a copper plate, insulating the latter, if necessary, with cotton or plain paper tubes. The ground bus common for both channels is a figured plate cut from the same copper plate for your specific design and your specific details, starting from the ground contacts of the RCA input connectors, then passing over the back side of the socket of the first 6H9C lamp common for both channels and enveloping this socket. then again descending to the wooden base and passing between the panels of the second 6H8C lamps of each stereo channel and ending at the cut of the ground contacts of the RCA output connectors, and this figured ground bus plate with its larger area is perpendicular to the wooden base. The minimum width of the shaped plate is about 10 mm. On the side of the wooden base, at the earthen bus, petals should be provided (cut out and bent 90 degrees) for attaching, using the same screws, the figured plate of the earth bus to the wooden base at least at three points - near the input connectors, after the figured plate has been bent around the panel of the first lamps and between the sockets of 6Н8С lamps of each channel. The ground bus in the figure is indicated by a blue-red line of conductors, and the orange pads at the ends of this line denote the common (physically) attachment points of the parts, whose terminals in the schematic diagram are connected to the common bus on the orange pads. After you understand the scheme and understand how to organize it in the "hardware", the main thing remains - to force yourself to assemble the structure, while suppressing the soviet urge for innovation. And you are guaranteed to join the vinyl community!

Some particulars

1. The corrector is conceived and calculated in such a way that DOES NOT REQUIRE ANY ADJUSTMENT! You only need to assemble it correctly, as shown in the diagram and described in the description. I repeat on purpose once again - without fail suppressing any urge to innovate. For example, to the shunting of electrolytes with small film capacitors, because this corrector is not an electric motor.
2. The sound is revealed after a three-day warm-up.
3. The corrector should be located near the turntable.
4. The power source is a separate, sufficiently distant from the corrector (under a meter somewhere), construction.
5. It is desirable to use a transformer kenotron rectifier with a C-L-C filter at the output as a high-voltage power source. Maximum current consumption for high voltage is not more than 16… 18 mA for both channels of the corrector, i.e. it is quite possible to use a 6Ts5S lamp or its finger equivalent as a rectifier.
6. As an incandescent power supply for lamps, it is advisable to use a constant voltage of 6.3 Volts, stabilized by any suitable integral stabilizer with an operating current of more than 2A, for example, from the LM series: 138, 150, 338, 350, which are widespread and very cheap. The current stably delivered by the filament winding of the transformer must also be at least 2A.
7. Further decoration of the corrector design depends on your personal preference.
8. In the future, it is supposed in this series to lay out a description of the assembly of a high-quality and simple amplifier on tubes with a real tube sound. That is, such an amplifier, which has a transparent, clean, with a large and stable spatial stage, and, with all this, at the same time also savory sound. Well, and the general power supply for the amplification system obtained together with the corrector. The only problem is that it is, as usual, in the absence of affordable and at the same time high-quality output transformers. So a competition is announced for the transformers for this amplifier.
9. And of course, any lamp technology is a device with an increased risk of electric shock, so I beg you, do not stick your fingers into the included structure, before doing this, be sure to make sure that the circuit is de-energized and the electrolytic capacitors have had time to discharge.