Modified Laney VH100R lacks mids

[Emetal]

Ok so far we have following suggestions:

C7 putting back the original value or putting in 470 Ohms in series with 1uF

Trying anything up to 2.2uF in parallel with R16

Braking ground at a Mid pot and installing 10K Ohms

Changing the value of mid pot to 50k

[Deric]

Cameron I do not see caps anywhere from plate to grid.

V1 Mods:
-There is an added 22J (I guess that means 22pF) cap between pins 6 and 7 (which is V1B A. and V1B G.)

[Cameron]

Cameron I do not see caps anywhere from plate to grid.

V1 Mods:
-There is an added 22J (I guess that means 22pF) cap between pins 6 and 7 (which is V1B A. and V1B G.)

Thats it.

[Reeltarded]

heh

That makes it oddly nasal.

[VacuumVoodoo]

You can leave the 22pF in place but reduce the 22k gridstopper to 10k. This moves that gain stage HF roll-off -3db point from ca 5.5kHz to ca 11kHz, enough to still act as RF filter. If there's any nasality in the sound after this it comes from somewhere else. BTW another name for nasal sound is "midrange honk".
F.Y.I. I sometimes install a small 2pF-12pF trimmer capacitor between grid and plate on the input triode socket and adjust HF roll off to somewhere between 12-15kHz. Bearing in mind that guitar loudspeakers roll off sharply after 5-6kHz.

[Emetal]

Yes people nasal tone or honk yes! Now you are describing my problem those are the words I was missing OK I believe we are up to something now!!!

Deric and Reeltarded I was tired last night and completely forgot about that 22pF.

Question 1:
Vacuum Voodoo when you say 22k gridstopper to 10K do you mean 20k to 10k ? I see only 20K I do not se 22K ?

Question 2:
Can I just take out that 22pF out and try amp like that, am I going to screw something up?

People sorry for silly questions I am not that good with electronics I only do this when I must from time to time.

[VacuumVoodoo]

Yes, the 20k resistor. You can remove the 22pF cap altogether, but don't be surprised if the amp oscillates on high gain/treble/presence/volume settings. It may or may not, depending on whether that cap was put there as prevention or a cure. You will find out.

[Emetal]

Ok people big update, that grid stopper that I was thinking is 20K was masked with black tar when I removed it there was another color ring so this is Brown Black Black Red Gray which is 10K or other way around would be 820 Ohms. Is that possible? I guess the 10K that would make sense. So it's already there. Now from the new perspective what now? Should we look for source of nasal sound somewhere else, sholud I go on and fiddle with other ideas, like C7 putting 470 Ohm and 1uF to recover some low mids..

[Reeltarded]

Remove the 22p cap and instead put a 47p or 100p over the plate resistor for that stage. Now it doesn't squeal or sound pinched.

But that isn't to do with the thing you describe. It might be an additive, but that is another thing..

I still haven't looked at this schematic.. what is the slope and what is the treble cap? brb I need a battery.

33/470 hmm... Damn. Ok, mid pot to 50k and make sure that R31 and C21 are 33k and 470p. Might the 470p have been changed to 250p? That drops mids in a ditch.

You can just add a 33k off the mid pot to see if that is going to work for you.

Too much schematic for an ipad lol

[Emetal]

Ok I have reversed C6 to original and got more low mid growl, I liked it, will leave it like that I think. It was a bit dark sounding but for Metal I thought will be cool, then I tried without 22pF the sound changed again got more highs, (which I liked even more) but after removing 22pF I am having more microphonics. I do have a nice analog noise gate so I can fight that providing I like the sound, it's a trade off...Now what I am going to do is try the amp out in a rehearsal room with the whole band and different space, because right now I am trying it in my apartment..
After that I will move on to C7 fiddling and other stuff you guys comeing up with...
PS I have new strings on the guitar also so it will definitely take few days (over the weekend) and rehearsal space to verify these two changes...

[Reeltarded]

Battery die forum crash! Boom!

You need suppression. Add a small cap over that stage's plate resistor. That microphonic thing is going to prove that it is massive oscillation at volume.

47p-100p or maybe even higher. After the taming it's about your own taste.

[Emetal]

Wait a second if 22pf was pinching the sound (but was enough to stop microphonics) why would I put higher value like 47p-100p isn't the higher value going to pinch my sound even more, am I getting this right? Or maybe it's the opposite: higher pF will not pinch the sound but will still keep microphonic away?

[tictac]

[quote="when you say jumping those caps C10 and C2 what exactly does that mean, taking them out completely or jumping one to another by some wire? [/quote]

What is meant by "jumpering" is to run a small piece of wire in parallel with the cap ... basically you are shorting the cap out, effectively removing it from the circuit.

You can also do this with a switch which would be a mid-boost like the mid-boost switch seen in some Dumble amps...

TT

[Reeltarded]

A plate bypass is a different way of suppression. Not the same thing. The plate to grid thing is like a hot shield. In the worst case these are both dangerous. Failed cap makes voltage up to the input. You know what the input connects to?

I don't like either. It sounds like a cocked wha pedal, plate bypass much less so.

Use the smallest that works. 47p-100p should do it without making it dull.

[Emetal]

Ok I apologize for beeing boring so 47p-100p is going to the same place where 22pF was? Between pins 6 and 7 (which is V1B A. and V1B G.) That sholud keep some of the nice highs I got after removing 22pF but will get rid of some microphonics because that is the goal right now.. correct?