What kind of amp?

audioinnovation · 8th September 2005, 03:33 PM

What kind of tube amp is this? I know that it is a 2x50w class a push/pull double tretrode 6R3S-1/GU-19-1 but not how it`s connected.
Here`s the schematics

gingertube · 9th September 2005, 12:00 AM

Pentode Amplifier (V1) driving a common cathode triode amplifier with direct coupled comcertina (cathodyne) phase splitter (V2) and push pull output tubes (tetrode connected).
The OUT2 and OUT1 connections are the feeds to the push and pull sides of the output transformer.
The NFB (Negative Feed Back) connection comes from the secondary of the output transformer (with other side of secondary going to earth)

The Output Tubes are new to me. The first tube is a bit of a mystery - all those shields on pin 2 and 7 (check EF86??), the common cathode/concertina splitter dual triode may be a 6SN7 (correct pin numbers).

It would seem to have a lot of gain so probably ran a lot of feedback to get a low output impedance (good damping factor).

Just my thoughts - from a quick look.

Cheers,
Ian

Johan Potgieter · 9th September 2005, 01:27 AM

The first tube is an EF86, the second an ECC85 or ECC88 (probably the latter). The power tubes I cannot find right now but I have seen them somewhere. I think they are some of these high power sweepers found in tv sets. Impressive for high power amplifiers but their transconductance can be a bit varying.

Unasked advice: Don't put this circuit high up on your list of future projects - one could do better with the twin triode as a Schmitt phase inverter directly coupled to the EF86, and tetrodes or pentodes in the power stage for high fidelity is not a good idea. Sorry.

audioinnovation · 9th September 2005, 08:54 AM

The first tube is a EF86 the 2nd a 6H6N? russian double tetrode, The output tubes are these below:

argo · 9th September 2005, 09:40 AM

It's an old Soviet time amplifier more know by the name of "Briboy" Audes also used to build them. During the years there has been numerous modifications made by several Russian hobbyist to make it sound better. While the output iron, output and driver tubes are good, the first modification would be to change the input gain tube and all the old capacitors.

Do you own this amp or intend to build from scratch?

gianis · 9th September 2005, 10:39 AM

This is the pic of the output tube , its double beam tetrode for audio use..6P3C-1 (Russian)

audioinnovation · 9th September 2005, 10:45 AM

I got my hands on one in 1996/97 but after a output tube imploded i forgot about it until now, i didn`t know how it was build or how to read the schematic but i`m modifying it right now with Mundorf capacitors to see if it`got any pontential at all.
So far so good

audioinnovation · 10th September 2005, 09:25 AM

Can anyone tell me how i can check the bias and were?

audioinnovation · 3rd October 2005, 06:37 PM

How do i change the NFB? is it only replacing the 6.8k resistor?

Ansius · 2nd November 2006, 10:10 AM

:d seams an old therd but:
first of all, get rid of thse 6Р3С (latin 6r3s) they are really unstable (u can't leave the amp un and not wach it - tubes tend to overheat and then melt, as well revire heating in paralel to be more stable). Aftre few week I will get one amp, and now I'm looking for altrenate schematic.
tbes are 6Ж32П (EF86), 6Н6П (I don't know analog, close mach would be 6AH4-GT, ECC88 could do but you have to redo the shematic then)
in attachmetnt is russian "Прибои" (latin "Priboi") inside picture. I'll poste wholl schematic as well. they had two versions 50W and 75W (only diference is in Plate supplay voltages).

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9th September 2005, 12:00 AM	#2
gingertube diyAudio Member Join Date: Oct 2004 Location: Adelaide South Oz	Pentode Amplifier (V1) driving a common cathode triode amplifier with direct coupled comcertina (cathodyne) phase splitter (V2) and push pull output tubes (tetrode connected). The OUT2 and OUT1 connections are the feeds to the push and pull sides of the output transformer. The NFB (Negative Feed Back) connection comes from the secondary of the output transformer (with other side of secondary going to earth) The Output Tubes are new to me. The first tube is a bit of a mystery - all those shields on pin 2 and 7 (check EF86??), the common cathode/concertina splitter dual triode may be a 6SN7 (correct pin numbers). It would seem to have a lot of gain so probably ran a lot of feedback to get a low output impedance (good damping factor). Just my thoughts - from a quick look. Cheers, Ian

9th September 2005, 01:27 AM	#3
Johan Potgieter diyAudio Member Join Date: May 2005 Location: Pretoria, South Africa	The first tube is an EF86, the second an ECC85 or ECC88 (probably the latter). The power tubes I cannot find right now but I have seen them somewhere. I think they are some of these high power sweepers found in tv sets. Impressive for high power amplifiers but their transconductance can be a bit varying. Unasked advice: Don't put this circuit high up on your list of future projects - one could do better with the twin triode as a Schmitt phase inverter directly coupled to the EF86, and tetrodes or pentodes in the power stage for high fidelity is not a good idea. Sorry.

9th September 2005, 09:40 AM	#5
argo diyAudio Member Join Date: Feb 2001 Location: Estonia	It's an old Soviet time amplifier more know by the name of "Briboy" Audes also used to build them. During the years there has been numerous modifications made by several Russian hobbyist to make it sound better. While the output iron, output and driver tubes are good, the first modification would be to change the input gain tube and all the old capacitors. Do you own this amp or intend to build from scratch?

9th September 2005, 10:45 AM	#7
audioinnovation diyAudio Member Join Date: Sep 2005	I got my hands on one in 1996/97 but after a output tube imploded i forgot about it until now, i didn`t know how it was build or how to read the schematic but i`m modifying it right now with Mundorf capacitors to see if it`got any pontential at all. So far so good

10th September 2005, 09:25 AM	#8
audioinnovation diyAudio Member Join Date: Sep 2005	Can anyone tell me how i can check the bias and were?

3rd October 2005, 06:37 PM	#9
audioinnovation diyAudio Member Join Date: Sep 2005	How do i change the NFB? is it only replacing the 6.8k resistor?

2nd November 2006, 10:10 AM	#10
Ansius diyAudio Member Join Date: Mar 2006 Location: Latvia - Ogre	:d seams an old therd but: first of all, get rid of thse 6Р3С (latin 6r3s) they are really unstable (u can't leave the amp un and not wach it - tubes tend to overheat and then melt, as well revire heating in paralel to be more stable). Aftre few week I will get one amp, and now I'm looking for altrenate schematic. tbes are 6Ж32П (EF86), 6Н6П (I don't know analog, close mach would be 6AH4-GT, ECC88 could do but you have to redo the shematic then) in attachmetnt is russian "Прибои" (latin "Priboi") inside picture. I'll poste wholl schematic as well. they had two versions 50W and 75W (only diference is in Plate supplay voltages).

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