Analogman BART transistors?

[Mcentee2]

Does anyone know what the AM BART transistors are?

I have trawled Google images etc and cant see any clear pictures showing the markings.

They are described as "Big A** Russian Transistors" - quite large metal cans.

When I had a BART Sunface it was very thick fuzz, lots of volume, usable fuzz knob, and still cleaned up well.

I sold it last year (or poss the year before, time flies!) and my tweakers hat is on wanting to put one together for myself

[Mcentee2]

I did eventually find one picture showing GT402b, in Cyrillic of course, so that at least identifies them.

[POTL]

I did eventually find one picture showing GT402b, in Cyrillic of course, so that at least identifies them.

A banal choice among Russian transistors. Many local builders love them, I compared them with the MP42B (MP42B), after replacing the 10n output capacitor with 100n the difference was barely noticeable.

[Mcentee2]

I did eventually find one picture showing GT402b, in Cyrillic of course, so that at least identifies them.

A banal choice among Russian transistors. Many local builders love them, I compared them with the MP42B (MP42B), after replacing the 10n output capacitor with 100n the difference was barely noticeable.

Thanks, that's good to know!

From what I recall when I had my BART, it had similar characteristics to the Dunlop Bonamassa, except the latter was lower gain so didn't really splat as much at the high fuzz end.

That is useful though to know they are nothing special in themselves

[FlyingWild]

Could you see if they are GT402B for both positions, I too have trawled photos looking for identifying marks on the BA RT transistors, which are surprisingly thin on the ground.

Thanks.

[Mcentee2]

Could you see if they are GT402B for both positions, I too have trawled photos looking for identifying marks on the BA RT transistors, which are surprisingly thin on the ground.

Thanks.

I only found one photo, on a Reverb listing of old,  where one was very clearly a russian "gt402b", the other I couldn't see the transistor number but could see the symbol like a Phi or something that goes between the number and the date code, whether this was a "b" or another hfe ranged one I can't say but is still looked like a gt402 physically.

All the rest of the photos out there seem to have been sanded off or something.

[FlyingWild]

Is this the image you found: https://reverb.com/item/33122367-analogman-sunface-germanium-fuzz-bart-9mm

I think given the proximity of the bias pot and sunface pads to the transistor marked GT402B it is Q2. But I don't know for sure.

Q1 might be the same, or he might have found another that compliments it nicely, I think there are a few makers using a GT402B in Q2 but something different for Q1. For example https://www.popprockshop.com/thefuzzfather/

I'd like to build a germanium FF, and Russian transistors seems the best option but trying to decide which ones to buy is where I've come unstuck, and so I've been looking to see what other people are choosing to use.

[POTL]

Is this the image you found: https://reverb.com/item/33122367-analogman-sunface-germanium-fuzz-bart-9mm

I think given the proximity of the bias pot and sunface pads to the transistor marked GT402B it is Q2. But I don't know for sure.

Q1 might be the same, or he might have found another that compliments it nicely, I think there are a few makers using a GT402B in Q2 but something different for Q1. For example https://www.popprockshop.com/thefuzzfather/

I'd like to build a germanium FF, and Russian transistors seems the best option but trying to decide which ones to buy is where I've come unstuck, and so I've been looking to see what other people are choosing to use.

The link has a photo that shows the filling of 4 pedals at once and we can conclude that both transistors are the same. I have heard many times that the GT402B is a direct replacement for the AC128, but I have never heard anything special about them compared to other germanium transistors. A few years ago, I traded a small pile of these transistors for one 3PDT footswitch.

[FlyingWild]

In the Fuzzfather photo of the four pedals you mention, the maker states: Q1 is either a MP20B or P416B Q2 is a GT402B.

What's odd is that the both the MP20B and P416B don't look like the GT402B yet in the photo all four pedals look to have the same style of transistor. But I was really just using it as an example of a maker that uses GT402B for Q2 but something else for Q1.

The first link is to a pic of the BART Sunface where both transistors look the same but only one is identifiable as a GT402B.

[Mcentee2]

Is this the image you found: https://reverb.com/item/33122367-analogman-sunface-germanium-fuzz-bart-9mm

I think given the proximity of the bias pot and sunface pads to the transistor marked GT402B it is Q2. But I don't know for sure.

Q1 might be the same, or he might have found another that compliments it nicely, I think there are a few makers using a GT402B in Q2 but something different for Q1. For example https://www.popprockshop.com/thefuzzfather/

I'd like to build a germanium FF, and Russian transistors seems the best option but trying to decide which ones to buy is where I've come unstuck, and so I've been looking to see what other people are choosing to use.

Yes, that's the one I found.

[Mcentee2]

Is this the image you found: https://reverb.com/item/33122367-analogman-sunface-germanium-fuzz-bart-9mm

I think given the proximity of the bias pot and sunface pads to the transistor marked GT402B it is Q2. But I don't know for sure.

Q1 might be the same, or he might have found another that compliments it nicely, I think there are a few makers using a GT402B in Q2 but something different for Q1. For example https://www.popprockshop.com/thefuzzfather/

I'd like to build a germanium FF, and Russian transistors seems the best option but trying to decide which ones to buy is where I've come unstuck, and so I've been looking to see what other people are choosing to use.

The link has a photo that shows the filling of 4 pedals at once and we can conclude that both transistors are the same. I have heard many times that the GT402B is a direct replacement for the AC128, but I have never heard anything special about them compared to other germanium transistors. A few years ago, I traded a small pile of these transistors for one 3PDT footswitch.

Just to note, and you might already know

The AM gt402 is a Cryllic  "b", not a Cyrillic "B", just in case any readers get confused, I know I do when reading these things in English Vs Cyrillic!

[FlyingWild]

I was aware it was a Cyrillic b... but not fully enough to appreciate the use of B was wrong 

I've got some GT402b on order, and will see how they are for gain and leakage, and if nothing is suitable for Q1 then I'll start looking.

[FlyingWild]

I've just received 10 IT402b, 2 had hFE of over 160, but the rest are 80, 85, 109, 111, 115, 118 & 123 (measured at 25ºC)

I think a bit or bread boarding is in order.