Dsl-401 tone modification

[jkwylde78]

I have a dsl401, and looking for the right way to kill the buzziness in the distortion.

Seems like I could add small caps across the mid-hi tone control pots, or adjust the value of the stock ones.

Any recommendations to getting a few more db boost out of the o.d. channels..just a TAD more - nothing crazy.....

Will these amps run on 2 of 4 output tubes? which 2 are the ones to pull if so?

I notice the bias specs, stock, are way different than my other marshall was, kinda wierd....

[Gibsonman63]

I had good luck getting the buzziness out of my DSL-401 by upgrading my tubes and speaker. It has not been a bad little gigging amp, but having a JCM-800 half-stack and a 1979 JMP half-stack at the house, I have never been very satisfied with the tone in comparison. I recently acquired a 1985 JCM-800 1-12 combo and the difference is night and day when compared to the DSL-401. The JCM-800 is only slightly larger than the DSL-401, but it weighs twice as much, which tells me there is a lot more transformer there.

[Enzo]

I'd also suggest the exploration of tubes.

ANd I agree with the speaker idea. The speaker is THE one thing you can change on an amp for the greatest impact on tone.

[jkwylde78]

Well,

I have been using a real warm set of 80's model magnalab 12 inch, (rare as heck, but used by carvin a little bit way back when) and the sound just lacks the fullness I need. Sounds like a direct injected signal - stale - when I add enough hi's to get the tone right, and buzzy. Got a set o tubes headed this way, jj's, Ill burn them in, install them, and play with the bias until I get it closer, I just dont see the buzziness in OD2 coming out - and the added problem of bass presence in the signal - Ive tried all kinds of tone settings, and nothing gets it done.....

[Gibsonman63]

It is hard to go wrong with a Celestion Vintage 30... unless you want to play metal.

[Guitarist]

I second the tubes exploring. Maybe you can find someone with boxes of them and swap them in while you narrow things down. Otherwise buy some dusty 12ax7s and/or a 12ay7, 12dw7 and a 12au7 and move those throughout. The buzz may give way to muscle-tone.

You can add a 600V cap across one of the preamp's later plate resistors; 470pF up to .0022 uF and you'll smoke things out some ; )

N.B.
250K audio/log pots are something I just discovered. Very rarely do I CRANK an amp so one of these would work well after a Marshall tone stack/cathode follower as the master volume; the harshness will mellow and you wont need a treble bypass cap either. Hey, it's cheaper than a tube but way more work.

[jkwylde78]

This sounds like it - or close enough....

That sounds like what I would like to do to the tone circuit. It will happen.
I have some NOS Elektra factory 6P14P coming for output section, and 8 various preamp tubes on the way. I know tubes will help out a lot, I feel like the treble is a bit harsh on this amp, and the low end lacks girth - we'll see what the tube set does, and ANOTHER question -

After doing some research on the amp, it seems many tech's feel the bridge rectifier is actually too small. What would be the correct diodes to use If I simply home-made a bridge rectifier so that instead of washing heat out, blah, blah, I could simply have the correct power handling rectifier in there. Various threads online indicated it was at least 20 percent to 50 percent too small, anyone here simply put in a larger capacity B.R. instead of all the heatsinking, fans, etc? Just curious.....

I second the tubes exploring. Maybe you can find someone with boxes of them and swap them in while you narrow things down. Otherwise buy some dusty 12ax7s and/or a 12ay7, 12dw7 and a 12au7 and move those throughout. The buzz may give way to muscle-tone.

You can add a 600V cap across one of the preamp's later plate resistors; 470pF up to .0022 uF and you'll smoke things out some ; )

N.B.
250K audio/log pots are something I just discovered. Very rarely do I CRANK an amp so one of these would work well after a Marshall tone stack/cathode follower as the master volume; the harshness will mellow and you wont need a treble bypass cap either. Hey, it's cheaper than a tube but way more work.

[CottonMouth]

Hey, glad to see someone is asking these questions! I didn't see a reply to the one asking about using only 2 of the 4 '84 output tubes, I was curious about that too. I recently got a used DSL 401 on a trade deal and it sounds like it needs a little help.The pots sound dirty & while the clean ch. is ok the OD 1 & 2 aren't giving me the sound I want. I'm sure new tubes would help but not sure what else it might need. One thing I am curious about, has anybody tried to mod OD2 with a Volume/Gain control? It's 1 thing to have a shared EQ but it's almost useless without any control over gain & Vol. from OD1. How much trouble/work would that take if it could even be done? Any other tips would be welcome! Thanks.