Good sounding single-ended amplifier with horizontal tubes. Umzch on "television" lamps with transformers tn Single-ended tube amplifier for 6p36s

Hello friends! I want to tell you about the creation of my tube ULF on 6P36S. This is a push-pull with a fixed bias according to S. Sergeev's scheme.
It was during the summer holidays, there is a lot of time, there is knowledge, there is a desire. So I decided to make some kind of tube stereo amplifier for listening to music. Yes, yes, it was the lamp one, I never liked “stones”.

I began to think, what scheme to take, on which lamps? I decided to choose from the lamps I have something. For some reason, I didn’t want to use lamps 6P15P and 6P43P. I considered the 6P13S option, but read a negative review. As a result, I settled on 6P36S. I also liked her appearance: such a big, impressive one. And yes, the reviews are positive.

Scheme of the tube amplifier S. Sergeev

High power and the presence of suitable lamps in the driver stage persuaded me to build my first push-pull.

The amplifier sounds very good and has the following parameters:
Supply voltage 360 ​​Volts
Power consumption from the mains 170 W
Sensitivity 0.7 Volt
Output power 40W

Armed with a list of parts and went to the market. Unfortunately, this is the only place where you can buy radio components in my city.

Power transformer TSA-270

As a supply transformer, I wanted to use an unwound standard transformer, for example, TS-180. There was only TCA-270 for me, which I bought and went home, quite satisfied. Although the aluminum winding (index A), it provides passport parameters.

TCA-270 I connected like this:

Findings 7-17 used to obtain the bias voltage of one channel

Findings 4-14 for anode power supply of one channel

Conclusions 11-(21-12)-22 for heating 6P36S of one channel. Leads 20-(10-10’)-20’ to the glow 6N1P of both channels.
The windings given by me just provide the necessary voltage and current.

Output transformer TS-180

I used the TS-180 as an output transformer and connected it according to the scheme proposed by Manakov.

Board for surface mounting

I want to draw attention to my non-standard way of creating boards. The fact is that I do not etch the signet, I cut the foil on the textolite into squares measuring 2 cm x 1 cm and come up with a scheme for desoldering the parts. For example:

The scheme according to which I soldered the parts to the board.

The dashes between the squares are jumpers. There are also longer connections, they are drawn as lines. The arrows on the squares indicate the place to which the wires from the lamp panels will be soldered, or power, etc. For example, 3L1 means that the 3rd output of the first lamp (6N1P) is soldered there, 8L2 means that the 8th output of the 2nd lamp (6P36S) is soldered there. Those. the first digit is the pin number, the letter just separates, and the second digit is the lamp number.
I'm not suggesting you do the same, it's just that this method is simple and saves time and money. It turns out a "canopy" on the textolite.

Here is the board I got

First start

The first launch was successful. One thing is a pity: at that time I did not have a multimeter at hand. The old one broke, I haven't bought a new one yet. In general, I set it up in a barbaric way: I adjusted the offset so that it was minimal, but the anodes did not turn red.
Everything seems to be working, it's time to hide it in the case. And then I was very lucky: a friend of my father gave me an old non-working guitar ULF "Minor", which was instantly gutted.

The case from Minor fit perfectly, two TS180 output transformers (lying) and 2 boards of the ULF itself fit into it, but the TSA-270 power transformer did not fit. Therefore, a separate case was made for the PSU from chipboard and plywood. The top of the case is glued with self-adhesive.

Holes for panels were drilled. Everything is installed, and here is the long-awaited launch in the case. I turn it on and ... I almost went deaf from the whistle as the lamps warmed up! Swearing, I turn off the power, and go to the market for a shielded wire, I buy with a margin.

Fighting Arousal - Shielding

To eliminate self-excitation, manifested by whistling, it was necessary to shield the grid circuits of the 6N1P triode, the wires in the grid circuit of two 6P36S. Anodes 6P36S did not shield. The whistling stopped.

I start again and hear: one channel works fine, and in the other clicks instead of bass, plus a sluggish and hoarse middle. This is where I got upset. And what have I not tried, but the reason turned out to be the wrong screening of the grids. Shields were not properly grounded.

I redid it, grounded the ends of the screens with a star - this is when all the wires are at one point and on the case. Pickups and excitement disappeared, clicks in the bass stopped, the bass became clear, elastic, both channels began to sing equally beautifully.

Details

In the amplifier, I used MLT and OMLT resistors with a power of 1-2 watts. I bought all the resistors with a power of 1-2 watts. Capacitors C3 and C4 are type K73-17, and C2 was supplied by BMT-2. In the driver, I have a 6N1P light bulb, which can be replaced with 6N23P without any alterations in the circuit. But I like the sound more 6N1P.
Output lamps 6P36S, to increase the power of the amplifier, can be replaced with 6P42S by setting a larger quiescent current, somewhere around 106 mA (drop on cathode resistors 1.06 V)

Fixed offset setting and feature

After buying the multimeter, the setup became easy, the device was operational and at hand: with the R9 resistor, I set the same voltage on the cathodes of the lamps, and with the bias resistor, I set the voltage to 0.55 Volts.

True, there is one unpleasant feature of a fixed offset. When the mains voltage changes, the lamp mode changes. Once the voltage in the network rose to 250 V and one 6P36S left the mode, the anode heated up, the quiescent current increased to 80 mA (with the prescribed 55 mA)! Fortunately, I immediately noticed this and turned off the ULF.
I had to install a voltage stabilizer "Ukraine-3", mine gives out 215 V. Due to insufficient voltage on the primary (and, accordingly, on the secondary), the voltages on the anodes also dropped from the prescribed 330 V to 313 V. I raised the quiescent current to 64 mA ( drop across resistors R12, R13 = 0.64 V).

Push-pull tube stereo amplifier on a 6P36S tube NEW! February 25th, 2011

Finally got around to the article. Let's start.

Tube sound differs from semiconductor for the better. There are many, but I will not tell. The only negative is that making a lampach is a dreary and difficult business. But it's worth it. To avoid questions, you should read.

I have already assembled the acoustics so that there are no disputes, I’ll say right away that it has 102db of sensitivity - for the lamp it’s the best!
http://community.livejournal.com/ru_audiomania/1540.html

Let's move on to usu. It is assembled according to a push-pull (PP) circuit on 6n23p lamps in the first stage and 6p36s in the output.

Scheme

Scheme by Sergei Sergeev with my modifications.
The 23x filaments will be connected to ground through a 150 ohm resistor from each pin. Also chokes on the anode. Well, I'll put more electrolytes.
The setting consists in setting the voltage across resistors R12 and R13 to 0.55 volts.

transformers
First of all, I made them.
For network and two outlets, I used iron from TSSh-170 trances with a plate thickness of 0.35 mm. I made the frames again, although it was not easy.

Weekend options:

We divide the frame with the middle cheek. We wind the halves in different directions.

On each half:
Primary - two sections of 560 turns (10 layers of 56 turns) of PEV-2 wire 0.355 mm.
R primary act - 98 ohm.
Secondary - between them - 112 turns of the same wire in two layers, taps from the 56th and 79th turns for 4 and 8 ohms, respectively. 112 turns - for 16 ohms.
There are three such secondary buildings in parallel on each half.
R secondary act - 0.88 ohm. Given - 352 ohms.
We connect the primary windings cross-series, the secondary - in parallel. See the monograph by G. Tsykin for more details (she is cunning, by the way).

In total, there are 2240 turns on the frame in the primary winding and 112 in the secondary.
Iron, of course, is going to overlap without a gap.

Each trance wound 12 hours. Chew. But what is the result:

I just wound up the networker to get 280v ~.
We end up with 360v at the anode, taking into account drawdowns.
For the 23rd, we wind two separate glows.
We need 8 amps to heat the exhaust. Without problems, a standard winding will give them. Near trans offset:

Chassis

I thought of the layout and design myself. The chassis and all boxes of trances will be stamped and welded automatically at the factory, otherwise it will simply be ug (besides, I have long wanted a normal case).
(pictured is a layout with another trance and a couple of chokes)

For reliable ground and glow, I use these beautiful tires:

Well, for fastening all sorts of dowels I bought:

Trial mock-up gave the go-ahead, I liked everything, the sound is excellent!
Watching the video is a MUST!!! Everything is visible there.
I specifically asked a friend for a camera!
It’s a pity YouTube has worsened the sound quality, so it’s advisable to watch at least 720p, but better all 1080p!

While there is nothing to write, the chassis is still being cooked at the plant. When it appears immediately article will continue! For now, write your thoughts, impressions, opinions here. I will gladly answer questions.

======================================== =====

Continuation.

The chassis has arrived! Everything as he said, steel 2mm, holes only for panels:

Here, and the silovik arrived in time. From the c1-1 tube oscilloscope, which is great for my purposes:

Panels will be flush:

The main idea is without a single prominent bolt.
Therefore, the method of soldering flat head bolts to the chassis was undertaken. It is necessary to clean the surface very well so that it does not fall off and holds firmly. Then solder with a 100 watt soldering iron.

As a result, all elements of the circuit are located on special panels for surface mounting.
Electrolytes of the anode are located on special holders, thermally insulated from the chassis.
The setting consists in setting the lamp modes and balancing.
Then it was decided to add shunts to the anode power supply at KBG 500v 5uF.

Sound.

The sound is as expected at a very high level. Low THD 0.5% at 28W. For my speaker, this will be enough, given its very high sensitivity.
While I plan caps for the weekend.

The diode bridges in the power supply rectifiers are the same. To a certain extent, this is due to the use of high-capacity storage capacitors in them. In the rectifier, you can use the VD3 diode bridge with a lower current limit value (for example, series

KTs402), but in this case, a current-limiting resistor with a resistance of 80 ... 100 Ohm should be connected in series with the winding (5-15).

A fan (it is located on the rear panel of the case - see the layout of the nodes and panels of the blocks in Fig. 3) for forced ventilation (exhaust) - almost any from a computer switching power supply, but if possible it is better to choose one with a lower level of acoustic noise.

The power supply uses chokes used in old tube TVs, but other suitable ones can be used. The inductance of the chokes L1, L2 is 0.4 H, and L3 is 5 H.

Various types of parts can be used in the amplifier: resistors - MLT, MON, VS of the corresponding power with a tolerance of no more than 10%; non-polar capacitors - film polyethylene terephthalate K73-9, K73-16 or K73-17 for a voltage of at least 400 V. It is also possible to install paper capacitors from old equipment - KBG-I, BMT-2, K40U-9, MBM. Oxide capacitors in the power supply and amplifier are imported from Jamicon or domestic series K50-35, K50-26, K50-27.

Signal level indicators in each of the channels (PA1) are pointer (M42305 or similar for 50-200 μA). Basically, they perform an auxiliary function and aesthetically bring some dynamics to the operation of the device. The illumination of the indicators can be organized using LEDs or miniature incandescent lamps powered by a 12 V voltage source in the power supply.

The amplifier has a peculiar design. Below is the power supply, made on its chassis; at the top - an amplifier block (two channels), also on a separate chassis (see Fig. 3).

The amplifier uses a volume control with an electric motor ALPS RK27 100 kOhm stereo (Blue Velvet); this allows you to connect a wired remote control, which has one two-pole switch (toggle switch) with three fixed positions (SA1 in the diagram of Fig. 2). Another possible option is a joystick, which, depending on the direction of its deviation, connects the electric motor of the drive to a 12 V voltage source using two-pole contact groups in the appropriate polarity (you can also use suitable electromagnetic relays, for example, RES22 or similar) * However, remote control not necessarily - this is to a certain extent a tribute to fashion

Particular attention should be paid to the manufacture of the body Since the amplifier operates in a difficult temperature regime, the wood must first be well dried. In this version, the boards were dried naturally in room conditions for 6 months. After finishing the boards, a body was made from them (photo in Fig. 4). The blanks were cut at the ends at an angle of 45 ° and glued together with "Joiner-moment" glue. After that, the case was installed near the central heating radiator and covered with a blanket along with it. In this state, it was dried for another two months, after which the required holes and windows were cut out and decorative elements of the front, top and rear panels were glued. After these operations, the corps within a month

again dried by the radiator, covered with a blanket. Then it was polished and painted with the "Belinka-TOPLAZUR" tinting compound of "mahogany" color (No. 28) in four layers. All this was done so that in the future there would be no surprises during the operation of the amplifier.

The amplifier has a rather intense temperature regime in the upper part of the case, while the lower compartment almost does not heat up. Under-dried body material (in this case, pine) can burst along the fibers. I had to work hard to get a good result: for the past three years there have been no complaints about the hull. If there is no desire to deal with bars, the body can be made of plywood 15 ... 20 mm thick, pasted over with veneer.

The side panels of the case are cut out of tinted glass "Turquoise" 5-6 mm thick. When the amplifier is operating, they can be slightly shifted back, as it is at rest in the photo of Fig. 5; while ventilation

hull will be greatly improved. To make life easier for the amplifier, a computer cooler is installed on the rear panel, which operates in two modes - at 8 and 12 V. It can be turned on or off at will.

The back and front panels are cut from 2-3mm aluminium, sanded and finished with clear acrylic spray paint.

Holes with a diameter of 5...6 mm are drilled around the lamp panels to ensure natural air convection. The top panel of the case has a protective metal grille, which is freely inserted into the decorative frame on this panel.

In this amplifier model, output transformers are not usually made. They are made on the basis of a TS-90 network transformer with a ShL magnetic core. All windings are removed from the standard coils, while the new ones are wound in bulk with a bundle of nine PELSHO wires. Of these, seven PELSHO-0.33 wires are used in the primary winding, and two PELSHO-0.8 wires - in the secondary. The connection diagram of these wires in the windings is shown in fig. 6.

A bundle of these nine wires, about 10 m long, is wound around the frame of each coil until it is filled (about 70 turns are obtained). Then these coils are boiled in paraffin for 15 ... 20 minutes in a water bath C

options are also possible with an output transformer. 6P36S lamps have a rather low internal resistance, and for a push-pull amplifier on such lamps, from 700 to 1000 turns of the primary winding (for the used magnetic circuit) with a tap from the middle are sufficient.

The amplifier and power supply are equipped with circuit boards made of foil-lined fiberglass. Due to the fact that they have a very simple pattern, it is cut with a cutter made from a hacksaw blade. A view of the installation of small parts and assemblies in the block chassis is shown in the photo fig. 7.

On the rear panel of the case there are output terminals for both channels, input connectors, a remote control connector, a network connector, a fan switch (red key), a fan mode switch - a toggle switch (voltage 8 or 12 V), a case ground terminal and a block with fusible inserts (one in the primary network circuit and two - in the anode power circuits of each of the channels)

From the editor. In the case when the fan is located below powerful lamps, forced ventilation should be organized as a forced ventilation.

Comments on the article:

6P45S is a very consumer lamp! For such a healthy bandura, it is made very poorly! First, a large spread in parameters. Secondly, the cathode with the output is very poorly connected, stuck with some kind of thin wire that burns out with any overvoltage. I screwed up 5 lamps like that. Only two of them didn’t burn out the cathode right away, it burned out ... in a day! And only one worked for a month. To avoid soldering, I wanted to parallelize two pieces, but the filament current of 5 A seemed too much. I used them in my tube high-voltage converter:
http://stalin.flyback.org.ru/tubeflyback.htm
Then I put the 36th instead of the 45th, everything has been working for about a month, the 36th really calmly keeps 600 (!) Volts and 30 watts on the anode. Reliable as a stone (in a good way).
Arkady Antonov

> anode power 6p36s-20 watts

Maybe it is so, but the lamp calmly holds 27 - 28 watts at the anode ... Yes, and don't frighten it with thirty

From my experience, 36 sounds more convincing (chess 45th)
Pronin

The best of the frame tetrodes sound, in our opinion, 6P42S lamps WITHOUT A CHAMBER ANODE. True, they are extremely rare, and the meaning of their production in Svetlana in 1972-1975 is generally incomprehensible. However, they exist, you can find them. Also very good are 6P36S and 6P42s with a white "fluffy" anode. They are also absolutely "indestructible", apparently due to the anode coating.

The sound characteristics of these lamps are highly dependent on the modes used.
Therefore, it is difficult to talk about sound outside of these "regime" bindings.

> And vsiotaki kakoi rezim beam for 36 and 42?

I like the mode 300 V, 125 mA for 6P42S and 300 V, 72 mA for 6P36S.
Load - quite right - 2 and 4 com respectively.

You can wind it on 2 com, put two sockets and listen to either one 6P42S or two 6P36S in parallel.

No need to set 5Ts3S, the sound will be musical, but slow. Put two 6D22S, and achieve musicality by selecting parts.

And in any case, it’s not worth loading the kenotron to the most nowhere.
Shalin

Well, tell me who are the optimal modes for this lamp in a triode and internal resistance and Mu at the operating point ... I broke off - I listened to the amplifier on these lamps, so they play better than EL34 and much better than EL84 with an ideal circuitry. Unlike 6P45S, they stably keep the mode without floating away in thermal currents in a fixed bias. Well, in general, help someone with what they can. I so monim there are no anode graphics for this lamp in nature - even I don’t have a “ministry” in my reference book.
Gajdar

Then it’s better to use 6P36S. She plays EVEN BETTER than 6P44S
Shalin

> Hello Alexey. Since you are on the forum, then tell me the mode for SE 6P36S and

> reduced load or a couple of options. Thanks Eduard.

For 6P36S: 330 V, 70 mA, Ra = 5 com.
I like this mode
Shalin

> Just 6P36S is similar to 6P42S of the first releases.

> A 6P36S have a smaller spread and are more stable.

And today I was convinced of this - I was just picking up pairs from 6p36s:

Of the 15 pieces managed to choose
1 perfect match
1 imperfect quartet
4 lamps accelerated
Well, 5 pieces are completely different.
40% yield is a good result

And this perfect couple sounds very beautiful.
Beard

There are Svetlanov and Ulyanovsk 6P36S with light gray anodes - they play better than just gray ones.
Shalin

Better with the "42nd". 42 anode - a little more than the 36th and similar to it, and the 45th -
1.5 times higher and at the ends on both sides there are three rectangular holes of approximately 6x6 mm. It seems that A. Shalin somewhere posted pictures of the correct 42. 36th so - if the anode is almost white and "fluffy" or light light gray and again "fluffy" - then you need to save it, even second-hand.
HRYUN

You need to turn it on for 2-3 minutes, just long enough for the lamp to warm up. Feel normally. It's not overheating yet. Forty-fifth - strong aunt. They are only badly collected.
The meaning of such a check is as follows. In the beam tetrode, both grids have the same pitch, and must be set so that the threads of the grids are exactly opposite each other. This is how rays are formed. 6P45S and 6P36S have almost the same cathode-grid design - 4 frames with welded wires. Two frames on one side of the cathode, two on the other. It turns out two sets of rays in different directions from the cathode, to the opposite halves of the anode. Let's assume that on one side the frames were not aligned correctly. Then the beam current from this side will be less than from the other, and the anode half from this side will heat up less than the opposite one. Half of the lamp is a beam tetrode, and half is a regular one. And these two tetrodes, different in characteristics, are connected in parallel. In principle, you can use a pyrometer to measure the temperature of different parts of the anode, but in the absence of such, heat the lamp for a short time, until redness appears. If on the one hand it blushes more strongly - a clear sign of a factory marriage. It will work fine in horizontal scanning, but it’s better not to put it in sound. Such defective lamps are approximately 80-90%.
Oleg

A message from Khryun
And the truth is - HORRIBLE ...! I will reveal my terrible secret: somehow (a long time ago)
I have 6P36S (old ones) worked for a long time in 250 V mode,
160 mA (40 W however...) with auto-bias (more precisely, almost with auto-fix, at that time no one knew that it was auto-fix). And nothing, they remained alive .... Gridlik was, it seems, 51 kOhm.

Likewise. Only my BU "shny Svetlanov 6P36S worked for several months in the 100 mA 400V mode, and with a fix.
Dalka

And this is the reason for the bad sound... I came across 45s that blushed on one side at 40 watts on the anode, maybe a little more. They immediately went trash. How much power can the selected lamp dissipate before turning red?
Sergey Z

Selected at 60 - practically do not blush. Only in complete darkness a slight glow is noticeable. Indeed, this is a good alternative to 6S33S. It is much easier to swing, and much more linear.
Oleg

I looked at the triode VACs of the 45th.
Found one mod:
250V, 180mA, -50V on grid.
Ri = 290 ohm, Ra = 2380 ohm, alpha = 8.2.
Uam = 181 V, Iam = 76 ma,
P~ = 6.88 W.

The linearity in this mode is very high.

In the 250 V, 240 ma mode, a load of more than 1242 ohms cannot be made, because then the right half of the load line will even crawl out of the power curve of 60 (!!!) watts.

In a word, whatever one may say, but the use of 6P45S with an anode power of more than 45 watts is doubtful for me ...
Shalin

6P36S - very vibration-resistant lamps with strong frame grids, they have a small microphone.
Shalin

IMHO, in 6P44S, in comparison with 6P36s, at first the novelty of sounding is carried away, then, having listened,
you understand that the sound is “prickly - ruffy”, but there are more subjectively high ones,
when measuring a longer harmonic tail, comparative measurements were carried out only
one output stage on different lamps, all other things being equal.
As for the dispersion, the Svetlanov 6P44S have closer parameters than the 6P36S,
6P44S has an average spread of up to 30-35%, 6P36S up to 50%.
Everything is known in comparison, but previously unused, selected 6P31S, IMHO have the most
natural sound, close to the sound of 2A3 in the midrange and treble.
Manakov

Dmitry, one of my amps on 6P36S has been working for 8 years at 20 watts on anodes without changing lamps. My friend has three years at 27 watts.
Somewhere Khryun pointed out that in the forced (36 watts at the anode) mode, Ri in 6P36S drops to 450 ohms.
I myself try not to “torment” 6P36S for more than 28 watts.
Shalin

Dmitry, this means that the lamps did not come across very well
Good 6P36S and with 33-100 ohms in the grid behave perfectly. But anti-excitation measures are definitely needed, that's true.

I didn’t test the 6P36S with more than 32-33 watts of anode power, but my friend in the 6P36S amplifier (my assembly) tinned them with 37 watts each, and it lives normally with a fix and even without an anode stub.
Shalin