amp techs - can anyone help with a mod?

[dstroud]

So I got my Marshall avt50 and I'm trying to get some more crunch out of the clean channel. Here is a link that has a schematic in the thread (2nd thumbnail is the preamp section). TIA!

http://music-electronics-forum.com/t13445/

 

[RJF]

OD pedal up front. Done.

 

[dstroud]

OD pedal up front. Done.

well I'm using a Tubescreamer already, and it still needs a little more gain, hence I'm trying to get a little more from the amp.

 

[jerrydyer]

wish i knew more about solid state technology.

 

[RJF]

OD pedal up front. Done.

well I'm using a Tubescreamer already, and it still needs a little more gain, hence I'm trying to get a little more from the amp.

Try channel 2.

 

[splatter]

I can't view the schematics at work .

How much gain are you looking for ? Are you just tryng for a slight bluesy type breakup or do you really want some gain ?
If the answer is you really want some gain try adding a diode clipping ckt .depending on how much gain you want would determine which type of clipping ckt and where in the signal path you put it .

 

[tschrama]

Unfortunatly, due to the topology of the gain stages, I cann't see an easy way to mod the ch1 without also altering the tone of the other channel. You might want to try a Proco RAT if the TS9 is not enough.

If you want to try a mod, try this: pickybag another 5k6 over R47 (also 5K6). It will provide a little more gain and a little bit more tone shaping.

 

[tschrama]

OK, I see a way to only alter ch1, leaving ch2 in tact.

Replace L3 with 10K. From the side of that 10K that connects to pin3 of IC3, connect another 10K to the GND side of R64. You need more gain, try 4k7. Need moer tone shaping, try 4k7 in series with 47nF. You can halve or double any of these values and see what you like best.

 

[dstroud]

OK, I see a way to only alter ch1, leaving ch2 in tact.

Replace L3 with 10K. From the side of that 10K that connects to pin3 of IC3, connect another 10K to the GND side of R64. You need more gain, try 4k7. Need moer tone shaping, try 4k7 in series with 47nF. You can halve or double any of these values and see what you like best.

perfect thanks!!! I'm a 1 channel guy so if I change channel 2 I don't care, but sounds like 2 will still be in tact. thanks so much!

 

[dstroud]

I can't view the schematics at work .

How much gain are you looking for ? Are you just tryng for a slight bluesy type breakup or do you really want some gain ?
If the answer is you really want some gain try adding a diode clipping ckt .depending on how much gain you want would determine which type of clipping ckt and where in the signal path you put it .

yeah that old circuit out of the electra guitars would probably do what I need. I'm gonna try the below suggestions 1st and will revisit that idea if that doesn't work, thanks!

 

[RJF]

Have you tried either a hotter pedal, like a full on distortion pedal? The other option is two pedals in front of the amp. I've heard of guys double boosting old Marshalls.

 

[dstroud]

Have you tried either a hotter pedal, like a full on distortion pedal? The other option is two pedals in front of the amp. I've heard of guys double boosting old Marshalls.

really not interested in anything other than what I'm asking for.