Marshall Amp Forum - View Single Post

gemather · 07-10-2009, 09:46 AM

Hello,
in my JCM 900 MK3 from 1991 there is missing the the extra grid fusees inside.
I do not mentioned what them for - and placed 6550 Tube´s to run my amp.

Quite funny and strong sound.
Yust some of the United States in my room.
... Until a year later one of the tube´s kicked of.

It burned my whole amp,cause the mostlys in there is for maximal 500volts.
The Grid of an 6550 Tube´s got upon to 670volts.
The Grid of an 5881 Tube´s got upon to 470volts.
In fact of loosing one, there is a lot damage to be done by 670volts trespasing up to mainfuse.

Today,after repair,i use 5881 better.Sounds also good enough for angry cats.

07-10-2009, 09:46 AM	#42 (permalink)
gemather Junior Member Join Date: Jul 2009 Location: northern europ Posts: 27	Re: JCM 900 6l6 to EL34 Conversion problems Hello, in my JCM 900 MK3 from 1991 there is missing the the extra grid fusees inside. I do not mentioned what them for - and placed 6550 Tube´s to run my amp. Quite funny and strong sound. Yust some of the United States in my room. ... Until a year later one of the tube´s kicked of. It burned my whole amp,cause the mostlys in there is for maximal 500volts. The Grid of an 6550 Tube´s got upon to 670volts. The Grid of an 5881 Tube´s got upon to 470volts. In fact of loosing one, there is a lot damage to be done by 670volts trespasing up to mainfuse. Today,after repair,i use 5881 better.Sounds also good enough for angry cats.