Interesting thought on a mod.....

ACDCG400 · Post by **ACDCG400** » Sun Aug 05, 2007 11:05 pm

hey guys! well i have a idea. i made a 69' superbass and i like it besides some of the problems it has. but i want to be able to switch between that and the superlead and superbass sounds. what controls that, and can i switch between them?

any help? because i need to consolidate amps and if i can have essentially a superbass and superlead.

77custom · Post by **77custom** » Mon Aug 06, 2007 6:13 am

ACDCG400 wrote:hey guys! well i have a idea. i made a 69' superbass and i like it besides some of the problems it has. but i want to be able to switch between that and the superlead and superbass sounds. what controls that, and can i switch between them?

any help? because i need to consolidate amps and if i can have essentially a superbass and superlead.

Marshall had made a 50 watt lead/bass the model is a 1964 or 2100 (2x12 version) I think if you can find the schematic it would be what you need.

ACDCG400 · Post by **ACDCG400** » Mon Aug 06, 2007 12:03 pm

thanks alot!

ACDCG400 · Post by **ACDCG400** » Mon Aug 06, 2007 12:25 pm

i found nothing. does anyone have one or at least know a generic layout or switch for the mod?

stoo · Post by **stoo** » Mon Aug 06, 2007 12:34 pm

I searched around on the schematics and "to me" it looks like the only difference is the PI to output tube coupling caps. .02 for lead and .1 for the bass!
stew

toner · Post by **toner** » Mon Aug 06, 2007 12:54 pm

I think the superbass has a shared cathode on V1. I installed a switch on my 100w for split/shared and I love it. You might want to try it.

More info:
http://forum.metroamp.com/viewtopic.php?t=12039
http://forum.metroamp.com/viewtopic.php?t=832

diagram:
http://forum.metroamp.com/download.php?id=294

Here's a model 1992 "super bass" schem:
http://www.drtube.com/schematics/marshall/1992u.gif

77custom · Post by **77custom** » Mon Aug 06, 2007 12:58 pm

ACDCG400 wrote:i found nothing. does anyone have one or at least know a generic layout or switch for the mod?

I'll look in my History of Marshall book when I get home. I know Mike Doyle has some schematics in the back of it. I looked on Dr. Tube and found nothing. I can't seem to get to schematic heaven, it said the account was suspended.......anyone else having that prob??

ACDCG400 · Post by **ACDCG400** » Mon Aug 06, 2007 5:52 pm

me too. nothing for schematic heaven. thats pretty strange. i thought those caps were the only difference. but is there a way to switch between them.4pdt switch maybe?

ACDCG400 · Post by **ACDCG400** » Thu Aug 09, 2007 1:17 pm

here we go guys. a layout off of soultone. can i just put the caps on a 2p4t switch?

toner · Post by **toner** » Thu Aug 09, 2007 2:41 pm

Comparing a 20w with a 100w probably won't help.

Switching between .022uF and .1uF output couplers isn't a huge change in tone. It's almost like turning the bass pot up/down. I'm sure there's a way to wire the two sets of caps on a switch but I don't think it will do you much good. Have you tried .022uF caps in your amp to make sure it's something you even want?

Switching between shared/split cathode will give you more variety, IMO.

ACDCG400 · Post by **ACDCG400** » Thu Aug 09, 2007 3:12 pm

well, i plan to do that as soon as I found the pot for it, i don't believe george carries it, i might be mistaken. i just want it to sound like a superlead at the flick a switch, or 2...

jerrydyer · Post by **jerrydyer** » Fri Aug 10, 2007 2:25 pm

I would focus more on a 1st stage cathode switch. A super lead and a superbass can both have .1's on the output tubes coupling caps. I do that in mine i like the .1 better so , you want a trebly sound and a superbass sound as is now right? I would do the standard 1st gain stage cathode switch. your amp now has a shared cathode config, right? split it, have one 820/330 and the 2.7/.68 boom treble and bass. you can even make that switch a 2rdt and bring in and out a bright cap for the volume control. Make it a 3rdt and bring in and out a differnet mix resistor set. I wouldnt switch around big filter caps though. Its cool that you saw the difference but if your going to do that you might as well make two amps. two much switching to make them two identicals in one amp.

ACDCG400 · Post by **ACDCG400** » Fri Aug 10, 2007 3:10 pm

ok then, ill do that. also, will a 56k to 33k and 500p to 250p make much of a difference?

jerrydyer · Post by **jerrydyer** » Thu Aug 16, 2007 3:25 pm

yep 33k is a little fuller sounding 56 k a little more treble and the bass is shifted I beleive. BUt thats another switch . How many switches is too many for ya?

ACDCG400 · Post by **ACDCG400** » Thu Aug 16, 2007 3:32 pm

never too many, i already the resonance mod and like 3 mini toggles for various things, 1 or 2 more won't hurt.

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Interesting thought on a mod.....

Interesting thought on a mod.....

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