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View Full Version : Marshall Re-issue Amps (tubes and biasing content)


saltydogg
12-28-2009, 02:14 PM
Marshall fans,

I have 59SLPRI (2006?) and have recently had the original tubes replaced (via an amp tech) to Groove Tube EL34's.

Does anyone know what Marshall used for the stock tubes? The old tube reads:

Marshall EL34
VLVE-00042
22/06

Chinese? Russian? Sovtek? Mullard?

I ask because I was considering trying the Mullard Re-issues and wanted to make sure that Marshall wasn't using these Mullards in their amp re-issues under the 'Marshall Name".

Having said all this (and I haven't pulled the amp from the cabinet yet) can you tell me where the bias adjustment is located in the amp/chassis?

I tried Marshall's site, but couldn't find the info.

Thanks, guys.

VanR
12-28-2009, 02:42 PM
Mine had SED's (winged c) EL34's in it.

Mooncusser
12-28-2009, 03:02 PM
Salty,

Those OEM originals were re branded Svetlana's.
For the bias, here's the schematic:
http://www.drtube.com/schematics/marshall/1959-01-60-02.pdf
Take care~~

saltydogg
12-28-2009, 04:12 PM
Salty,

Those OEM originals were re branded Svetlana's.
For the bias, here's the schematic:
http://www.drtube.com/schematics/marshall/1959-01-60-02.pdf
Take care~~


Thanx, mooncusser.

I have not re-biased a 100W amp to date. Is this a single bias pot on the '59 used for all 4 tubes? Is there a website that explains this procedure on the '59?

How about the Mullard Re-issues? Any experiences with them- soundwise?

Thanks again, guys, for your help.