marshall tsl 602 - dull sound

[psemrad]

Hi I have the exact same problem you have with your amp. My treble and presence have to be all the way up for the amp to sound near normal. would replacing the electrolyt capacitors be a quick fix?

Hi,
in my opininion that isn't good fix.
There are some ideas to move the amp into vintage-modern territory:
1. remove C41
2. remove C53
3. remove C84, change the value to 220 pF and make it switchable through a FET (control signal from D22)
4. make R88 switcable to 0R
5. replace R92 with Pot 1M
6. make make C86 switchable 22-220-440 pF
7. add switchable C 0-180-440 pF for OD1 and OD2 channel throw a FET (control signal from D25)
8. make R98 swithable 150-220-330 k
9. add triode - pentode switch

PS

[Enzo]

I think we have to be sure if the new poster is trying to fix his amp so it works like it did at an earlier time, as opposed to modifying it to sound differently altogether.

[psemrad]

I think we have to be sure if the new poster is trying to fix his amp so it works like it did at an earlier time, as opposed to modifying it to sound differently altogether.

Yes, I agree.
The dull sound on the OD1 (crunch) channel is normal behavior of TSL-60x amps.

PS

[Palantine]

Hi,
in my opininion that isn't good fix.
There are some ideas to move the amp into vintage-modern territory:
1. remove C41
2. remove C53
3. remove C84, change the value to 220 pF and make it switchable through a FET (control signal from D22)
4. make R88 switcable to 0R
5. replace R92 with Pot 1M
6. make make C86 switchable 22-220-440 pF
7. add switchable C 0-180-440 pF for OD1 and OD2 channel throw a FET (control signal from D25)
8. make R98 swithable 150-220-330 k
9. add triode - pentode switch

PS

[ATTACH=CONFIG]22373[/ATTACH]
[ATTACH=CONFIG]22374[/ATTACH]
[ATTACH=CONFIG]22375[/ATTACH]
[ATTACH=CONFIG]22376[/ATTACH]

Dear Psemrad,
I followed your advice on C84. Clipped out from the circuit.
I also changed C85 for a 270p and C86 for a 10p
Maybe now is to too much but I can dial my treble pot in the middle and presence at noon and I have plenty of sparkle with my Les Paul even in the middle position.
Now I can play with tubes, serching for a dark pair to put in V2 and V3 (cathode follower) and trying balancing the sparkle.
My question is: what do you thing it's happened by lovering C85 and C86?? Seems to me I gained not only treble but also something is gone in the tonal spectrum...mids peraphs; I can't explain but something is different...I have a kind of HI FI tone....a bit sterile

[psemrad]

Hi,
I think, that you opened hi-frequences in your amlifier too much. Look https://www.ampbooks.com/ for some classics circuits. For a good overdriven guitar tone is the midrange tonal spectrum especially important
PS

[psemrad]