Cathode Biased

rich24a · 11-05-2009, 11:16 AM

I read that the Marshall Class 5 is cathode biased, as it is a class A amp. I was wondering what this means. Does it mean when you replace the output valve(s) you don't have to bias the amp?

PaoloJM · 11-05-2009, 07:16 PM

Quote:

Originally Posted by rich24a

I read that the Marshall Class 5 is cathode biased, as it is a class A amp. I was wondering what this means. Does it mean when you replace the output valve(s) you don't have to bias the amp?

It does mean that you do not need to adjust the bias when replacing the output valve, in fact you can't without replacing components.

It's not cathode bias because it's Class A though. Class of operation and bias type are in no way related, though it is more common that a Class A would also be cathode biased.

rvin28 · 11-27-2009, 07:12 PM

So this does mean that any new EL84 can be used in the amp without biasing and will not potentially damage the output transformer??

MartyStrat54 · 11-27-2009, 08:05 PM

That's correct. If you want to roll different EL84's in the Class 5, you can do it without harming anything.

11-05-2009, 11:16 AM	#1 (permalink)
rich24a Member Join Date: Aug 2009 Location: Sandhurst, UK Posts: 73	Cathode Biased I read that the Marshall Class 5 is cathode biased, as it is a class A amp. I was wondering what this means. Does it mean when you replace the output valve(s) you don't have to bias the amp?

11-27-2009, 07:12 PM	#3 (permalink)
rvin28 Junior Member Join Date: Oct 2009 Location: Near Southend on Sea Posts: 19	Re: Cathode Biased So this does mean that any new EL84 can be used in the amp without biasing and will not potentially damage the output transformer??

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