Help to identify transformers

Croc · 3rd January 2010, 02:08 PM

Dear All,

attached pics of the amp (300B push pull).

are those transformers look familiar to you?

All if them have "made in england" marking.

What is this black box? a choke? a double interstage?

Many thanks,
Gennady

Richard Ellis · 3rd January 2010, 02:58 PM

Well the 'black box' if it has just two wires coming off it as it seems to from your pix that would make it a choke. Four wires would make it an interstage or?...do you have some underside pix? Have you chased down the schematic, the wiring?.....where your mystery box goes to?
It looks like your amp is tube rectifyed...as in you most likely have a choke input PS. And that would be you "first" choke in the PS circuit.
It does have a fancy looking case granted....I like those little heat dissapation 'fins' up top.
The spacing IS correct, as a choke on a Choke input PS needs to be as far away as possible from other components so as to not induce currents in nearby structures.

__________________________________________________ ____________Rick..

Croc · 3rd January 2010, 07:41 PM

the amp is SS recitified.
it has 6sn7 driving all four 300Bs.
another one (ecc88 i think) is in PRE section and is overrided when using "direct" input.

all trannies actually run very cool, except the powe one........

Croc · 3rd January 2010, 07:49 PM

inside pictures:

a little messy inside, isn't it?..........

Croc · 8th January 2010, 07:30 PM

is it a good idea to change those integrated rectify bridges by some low noise discrete diodes?

dhaen · 8th January 2010, 08:39 PM

I think the black box is an "always on" power supply for the remote control system.

It's messy...

jerluwoo · 9th January 2010, 11:00 AM

There are the interstage transformers below the deck there. Probably used for gain and phase splitting.

3rd January 2010, 02:08 PM	#1
Croc diyAudio Member Join Date: Jan 2005 Location: Israel	Help to identify transformers Dear All, attached pics of the amp (300B push pull). are those transformers look familiar to you? All if them have "made in england" marking. What is this black box? a choke? a double interstage? Many thanks, Gennady

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3rd January 2010, 02:58 PM	#2
Richard Ellis diyAudio Member Join Date: Sep 2006 Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.	Well the 'black box' if it has just two wires coming off it as it seems to from your pix that would make it a choke. Four wires would make it an interstage or?...do you have some underside pix? Have you chased down the schematic, the wiring?.....where your mystery box goes to? It looks like your amp is tube rectifyed...as in you most likely have a choke input PS. And that would be you "first" choke in the PS circuit. It does have a fancy looking case granted....I like those little heat dissapation 'fins' up top. The spacing IS correct, as a choke on a Choke input PS needs to be as far away as possible from other components so as to not induce currents in nearby structures. __________________________________________________ ____________Rick..

3rd January 2010, 07:41 PM	#3
Croc diyAudio Member Join Date: Jan 2005 Location: Israel	the amp is SS recitified. it has 6sn7 driving all four 300Bs. another one (ecc88 i think) is in PRE section and is overrided when using "direct" input. all trannies actually run very cool, except the powe one........

3rd January 2010, 07:49 PM	#4
Croc diyAudio Member Join Date: Jan 2005 Location: Israel	inside pictures: a little messy inside, isn't it?..........

8th January 2010, 07:30 PM	#5
Croc diyAudio Member Join Date: Jan 2005 Location: Israel	is it a good idea to change those integrated rectify bridges by some low noise discrete diodes?

8th January 2010, 08:39 PM	#6
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	I think the black box is an "always on" power supply for the remote control system. It's messy...

9th January 2010, 11:00 AM	#7
jerluwoo diyAudio Member Join Date: Feb 2006 Location: Ashland,Ky U.S	There are the interstage transformers below the deck there. Probably used for gain and phase splitting.

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