Want more gain on my 50 watter

[louis]

Hi guy's '

Is there a simple way or a change of value
somewhere to get more gain and less grainy
breakup on a stock 50 watter ?

The amp sounds very good and it's a 68 spec
design but would love to have it a little more gain
without adding the whole shabang !!

Thank's

[neikeel]

So you have both 0.68uF caps and want more smooth (not ratty or loose gain)?
What volumes do you use it at?
Try an 820R instead of 2k7 on V1b cathode first. That affects the gain at lower preamp volumes.

If you use the amp dimed all the time then try a little less NFB (although IMO 47k/8ohm is sweetest) you could try 100k on 4ohm like a metal panel. A 0.68uF on the presence can give more too. Might be a bit looser too.

I find that a virtually dimed cascaded amp, like a 2204, gives the same amount of gain as an NMV with the volumes above 8. But conversion to 2204 specs and upwards (ie 2204 with tweaks) is an option for lower volume gain boost.

If you want more gain at high volume after that you are looking at potentially more major surgery (extra tube or using the tone stack, V2b as a gainstage) etc.

[louis]

Thank's !!.............Appreciate'

I'll try this

[SteadyEddie]

Change the plate resistor on V2A (usually on the tube socket) to 170k or so.
I find changing the plate on the first stage affects the feel ... makes it too soft or spongy, kills that Marshall "attack"
But V2a, it keeps the front end attack and adds some squish and compression at the back end. Notes hold on a little longer.

[HTH]

Increase the dropping resistors to the preamp so the voltages are lower - will squish up a bit easier.

[stef]

You want more GAIN with less grainy breakup - that's easy - change the power amp tubes - 6ca7, 6550, 6L6.
The EL34's are grainy and have less gain (output - loudness, punch etc) than 6CA7's - in my experience.

[louis]

Thank's guy's '.........Very nice of you !

Appreciate a lot !!


Lou