DSL100 too bright compared to my 401, any ideas on modding?

[rickjohns]

Everyone, I have both a DSL401, and a DSL100. I love both, but the DSL100 is alot brighter than the 401, even with the tone and presence at 0. The 401 has more of a classic tone, and is smooth, and the 100 is just shrill sounding when comparing them through my 1960a cab. Does anyone know if there is a bright cap in the circuit that I could remove or change to make the tone darker? I just got the 100 retubed with jj tubes, and it was gone over by a great tech in the area. Both amps have the same preamp tubes. I would love to install a switch that I could go from dark to bright tone if possible. Any help would be very appreciated.

[Leader]

Sounds like the dude biased it to hot. I had the same problem with my DSL50 until I lowered the bias.

[Papalazarou]

Hi mate , try your amp through a different cab,when I had a 1960a I always found the sound too shrill no matter what amp or settings,just the nature of these cabs,worth a go before modding,I recently had a Behringer ultrastack 4x12 with Jensens in it & they are a bit sweeter than the Stock celestions in the 1960a,so it tamed things a lot,My mate has the 1960v cab with vintage 30's & that is not as toppy either.

Might be worth asking the guy who retubed your amp what he set the bias to as this can alter tone quite a lot too !

best of luck & keep us posted

[rickjohns]

It is definitely not bias, it is the voice of the amp. Bias is set at 70mv. I have set it at that before when I retubed it in the past. It is the difference in tone between the combo and the head, through the same cab. The 401 is voiced differently. I like it better. There has to be a cap that will make it less shrill in the preamp if I remove it. Thanks for the help so far.

[Cdvision]

I didn't care for my DSL-100 though my 1960A until I swapped out the speakers in the 1960A with Hellatone 60's and 30's in a x pattern. Now it sounds great. In all fairness the Cellestion G12-T75's in the 1960A should smooth out over time . I didn't want to wait to find out.

[rickjohns]

Anybody? There has to be a mod to change the input stage tone characteristics. I refuse to believe I need to buy over $400 in speakers to make my amp more dark sounding. Anyone know the schematic of this amp that could tell me which capacitors are responsible for what in the input stage? If anyone can help me I would really appreciate the information.

[cnumb44]

Try this.

http://www.drtube.com/marshall.htm#JCM2000

Also, the EL84s in the 401 will be darker sounding than the EL34s in the 100. I'm not being patronizing, so don't take this the wrong way.

[Howley]

HAve u tried setting your bias up differently on ur dsl100? i know you say you've always had it at 70mV but some people would say thats pretty low, and mite be worth seeing what tonal differences you find when its biased e.g. 80-85mV... before you get the scalpel out and go to work on the caps?

Just a thought... good luck!

[rickjohns]

Hey guys, thanks for the replies. I didn't think about the el84's, they are darker. The local Marshal tech recomended 70 mv, 90 is too high for the tubes in his opinion. I'll try to bump it up. I searched the forum and found a response to this same question from 3 years ago. There is a bright cap across the volume pot in the lead channel. I am going to remove it and see if it gets better. And I'll try the bias too this weekend.

[rickjohns]

Holy Shit! I set the bias @ 90mv, and pulled the C13 capacitor. This amp is the shit now! C13 is a bright cap, and it just emphasizes a harsh mid/high frequency. It is still clear, but more refined. I must have played through it in my studio for 5 straight hours this afternoon, I didn't even realize I was playing that long. Thanks for all of the tips. Hope this one helps anyone else looking to mod theirs.

[shaggydawg]

This amp is the shit now!

Always nice to read a success story!

Thanks for the follow-up.

[distorted]

Holy Shit! I set the bias @ 90mv, and pulled the C13 capacitor. This amp is the shit now! C13 is a bright cap, and it just emphasizes a harsh mid/high frequency. It is still clear, but more refined. I must have played through it in my studio for 5 straight hours this afternoon, I didn't even realize I was playing that long. Thanks for all of the tips. Hope this one helps anyone else looking to mod theirs.

When you say that ou pulled C13 do you mean that you just pulled it out? Or did you leave a bridge in its place?

Thanks,
Distorted

[rickjohns]

I just removed it, you don't want to put a bridge in it's place. If you do, your lead channel will be stuck on full volume. It is really easy to mod, when you pull out the chassis, there are 3 boards, the input board, the output board, and then the tube section boards. Just take the knobs off and loosen all of the nuts on the pots, and pull the input board out, you don't even have to unhook anything. Take out the C13 and put the board back in.

[distorted]

I just removed it, you don't want to put a bridge in it's place. If you do, your lead channel will be stuck on full volume. It is really easy to mod, when you pull out the chassis, there are 3 boards, the input board, the output board, and then the tube section boards. Just take the knobs off and loosen all of the nuts on the pots, and pull the input board out, you don't even have to unhook anything. Take out the C13 and put the board back in.

Thanks for the reply. For some reason my pfd opener was less than cooperative so I couldn't see the schematic before I asked...

[Howley]

Does anyone know if there are any potential damages that could be caused by removing the capacitor? It would be intresting to hear some examples of what your mod has done to the tone of the lead channel? I agree the lead channel sounds thin and fairly harsh compared to the crunch channel krankt.

Congrats on finding ur solution