The Amp Garage

marshall may have used CC resistors for their long legs, typically as cathode resistors or other resitors that went across the whole the board. otherwise, it is almost always carbon film, first piher, then iskra, and then later pihers again. the RS dlx OT differs greatly from the drake -103 (the dag...

Reeltarded wrote: ↑Thu Dec 07, 2023 9:52 am I think he uses Heyboer.

He has absolutely torn down as many originals as nyone, surely.

yes, heyboer builds the marstran transformers to Brian's specs. But it seems to be Brian himself that does teardowns

That would be frustrating all right. You and kato answered my questions perfectly. I have a plan to rebirth this amp into a confusing beast that looks straight but it's bent as can be. There is no way I will do it myself. I need to find an experienced winder with an understanding of exactly what I ...

Having it on with no load and no signal going in , or even with signal going in with the volume(s) down will not do damage to a OT even if left on for weeks because the speaker jacks are shorted out when no cable is plugged into the amp and that's perfectly fine. not the case with old marshalls unf...

ask Brian at MArstran?

Running w/o a load may blow the output transformer, but no pilot light and no heater light indicates blown mains fuse or blown mains transformer. Check first to see what the issue is

Cheaper transformers, called the red series, looking promising
https://pacificaudiomagnetics.com/colle ... Red+Series

Mitch is doing the early 68-69 superbass Page used before he introduced kt88s around 1975: https://www.sundragonamps.com/ the original has serial no SB A10053. it looks like a late 68, early 69 amps with filter caps on top (https://www.thegearpage.net/board/index.php?attachments/img_1365-jpg.1165857...

I have a similar issue with similar tubes in two ac30s with 50R cathode resistors and 320+v plate voltage. most tubes draw too much current and redplate. but these tubes would be better for another amp with colder bias, such as the 82R cathode resistor used on early ac30s.

where are you situated? I have one. or check weber 6v30

I think he generally sounds like he is playing through a 67 SL on about 4 which sounds like a Major on about 3. heh 69* Generally post 75* Song remains the same tour was the last of the decent tone . Those classic live 72 metal panel tones are replaced by that resistant clean sound he struggles to ...

I often wonder how much better this old timers tones could be if they had access to the knowledge base of this forum . I honestly feel annoyed every time I hear JP post 1973, and I don’t think it’s just because the dude got sloppier or whatever excuse people often attribute to him. I think he modde...

Probably a petersburg amp, see here https://reverb.com/item/1898278-petersb ... -amplifier

http://www.tubevoice.ru/?page=products& ... 00&lang=en

What am I seeing with tube layout ? Looks like the v1 v2 preamp tubes are positioned further back than the phase inverter . Thought it was an optical illusion, but the changing camera angle seems to confirm this . Has me curious . I have only really seen this with the Marshall majors, so I guess I ...

Measure the voltage drop and current with the Weber PT if you can still make it work, then with a new PT measure the voltage drop and current when playing or with signal and work out what resistor size you need. otherwise you will just have to take a guess. You could probably measure the secondary ...

Is this right for the evolution of the fender tonestack: 1) 250pF, 0.02µF, 0.02µF 2) 250pF, 0.02µF 0.1µF 3) 100k slope resistor replaces 56k 4) 250pF, 0.05µF, 0.1µF An evolution of the values certainly makes more sense than random combinations. 1) are as seen in 5F6 and 5F6-A schematics, 2) + 3) ar...