Modified Laney VH100R lacks mids

[Emetal]

The amp seriously LACKS MIDS, so much that I can only use amp if I use EL34's (which are known to have more mids then any other power tubes) with V30 Celestions speakers and MIDS on the amp set to 7.5 or 8 in order to get enough mids in my sound and btw I play Metal where I do not need a lot of mids.
It is impossible to use 6L6 tubes with this amp, the little mids that I have now are then totally gone.
I have Emailed Voodoo amps but got no response. I have opened the amp and these are the mods I have noticed:

(These are located on Page 4 in PDF schematics)

C1 has been replaced with 1uF 50v cap
R1 has been replaced with 2.2K
C6 the 2,2nF that is suppose to be there alone now is put into a serial connection with a little circuit consisting of 470K resistor in parallel with a very small brown cap (I cant read the value)
C7 instead of 680nF now there is a serial connection of 47K resistor and 0.47uF 50v
R9 has been replaced with 4,7K
C19 has been replaced with 22uF

(These are located on Page 2 in PDF schematics)

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.)
- 68K that is going from V1A G. to PAD 8 has been replaced with 820 Ohms

V2 Mods:
-There is an added 1uF cap between pin 3 (which is V2A K.) and middle pin
-Connection wire that is going from V2A A. to V5A G. has a hidden (shrinkwraped) resistor of unknown value added in serial.
-Connection wire going from pin 2 (which is V2A G.) to PAD 12 also has hidden (shrinkwraped) unknown resistor added in serial.

Following things I believe are not mods but just printing mistakes in schematics:
-PC Board 9078_3 next to PAD 8 says it’s connecting to V3B G. it should say V3A G.
-PC Board 9078_3 next to PAD 18 says it’s connecting to V4B G. it should say V4A G.
- Schematics says that V5B A. is connected to V4B A. via 100K. In reality V5B A. goes to PAD 22. (which does say next to that PAD) and it is V5A A. that is connected to that 100K line from V4B A.

Now can anybody PLEASE figure out which one of these mods is eating my mids

[Reeltarded]

What is the value of the mid pot?

[tictac]

at first glance the two pairs of 4n7 caps in series would cut mids to a degree... jumpering one cap (C10, C2) on each pair would be a mid boost (you could put it on a switch too)

Also returning C7 to a 680n cap without the 47k in series would boost mids...

Not familiar with this amp but it's a start...

TT

[Emetal]

Reeltarded: Mid pot says B22K exactly as it says on the Schematics so I do not think that was changed...

Tictac: I have a probably funny question but I do not do this often I just know a little bit about electronics so 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? Although I'm not inclined to do more moding, I would be happier to actually figure out which mode to reverse, so C7 reversal sounds good but I will keep everything in mind you sad, and please if you see anything else tell me

[thejaf]

1. Are you sure R1 was changed from 2k7 to 11k?

2. Have you tried an original circuit to see if you even like that version?

3. Break ground at mid pot and install a 10K resistor between mid pot and ground.

I have a 50-watt hex, 15-watt Witchdoctor, and have known Trace for years. Lack of mids is not how I would describe any of his amps.

[Emetal]

1. well I read it as Brown Brown Black Red Red maybe it's the other way around Red Red Black Brown Brown than R1 would be 2.2 KOhms does that sounds more logical? Sorry if I made a mistake, I don't do this electronic stuff too often.
2. I tried that amp before the mode but it was years ago can't really remember equipment I had at the time and all I remember that had loose bottom end, lot of buzzing highs kind of fizzy which these amps are known for...Maybe I am describing it bad, but something is missing, it sounds dead and sterile... I am thinking it's the mids missing, maybe upper mids or part of the highs but the only way it sounds good is with EL34, V30 Celestions and MID pot to 7.5
3. I had great experience with Voodoo amps before and I can't really say why they did not answer my Email for ten days now Even to say hey we do not want to explain this it's a professional secret or whatever just to hear something..

[Emetal]

Ok so far returning C7 to original value or braking ground at a Mid pot and installing 10K Ohms are the ideas I can do myself, keep thinking people

[VacuumVoodoo]

I have opened the amp and these are the mods I have noticed:

(These are located on Page 4 in PDF schematics)

C1 has been replaced with 1uF 50v cap. This extends low end marginally
R1 has been replaced with 11K Makes no sense on the 1st gain stage, are you certain it's not 1.1k or 1k which together with C1 would give some 3db gain boost and low mid expansion.
C6 the 2,2nF that is suppose to be there alone now is put into a serial connection with a little circuit consisting of 470K resistor in parallel with a very small brown cap (I cant read the value) C6 is 22nF on the schematic and it's grounded - a drafting error, it 's connected to top of R8. Putting in series with 470K and a parallel cap makes it identical to C9 and circuit following it. This gives high mid/bright boost
C7 instead of 680nF now there is a serial connection of 47K resistor and 0.47uF 50v That 47k makes the 0.47uF disappear to the signal. 470 Ohm and 1uF would let you recover some low mids.
R9 has been replaced with 4,7K It changes clipping conditions somewhat. Anything from 1k to 33k goes, it's a matter of taste.
C19 has been replaced with 22uF Inconsequential as to tone, only reduces ripple on bias voltage a little more than 10uF

(These are located on Page 2 in PDF schematics)

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.) Nothing to do with midrange, RF filter.
- 68K that is going from V1A G. to PAD 8 has been replaced with 20K That's why he installed the 22pF.

V2 Mods:
-There is an added 1uF cap between pin 3 (which is V2A K.) and middle pin
-Connection wire that is going from V2A A. to V5A G. has a hidden (shrinkwraped) resistor of unknown value added in serial. Probably a large value grid stopper I'd guess between 100k to 470k I would remove that 1uF and put in parallel with R16.
-Connection wire going from pin 2 (which is V2A G.) to PAD 12 also has hidden (shrinkwraped) unknown resistor added in serial. as above

Following things I believe are not mods but just printing mistakes in schematics:
-PC Board 9078_3 next to PAD 8 says it’s connecting to V3B G. it should say V3A G.
-PC Board 9078_3 next to PAD 18 says it’s connecting to V4B G. it should say V4A G.
- Schematics says that V5B A. is connected to V4B A. via 100K. In reality V5B A. goes to PAD 22. (which does say next to that PAD) and it is V5A A. that is connected to that 100K line from V4B A.

Now can anybody PLEASE figure out which one of these mods is eating my mids

Read the red stuff above And turn down Treble pot. Very often what one may think is lacking is in fact an overdose of the opposite.

[Reeltarded]

2k2 sounds more inline there. You could swap the mid pot for a 50k and probably call it done.

And I agree with the above post 102%.

[Emetal]

Vacuum Voodoo as far as R1 I read it as Brown Brown Black Red Red obviously it's the other way around Red Red Black Brown Brown than R1 would be 2.2 KOhms
Now let me see, what you recomending is two things:

-C7 I should put 470 Ohms in series with 1uF

-I should remove 1uF from V2 and put it in parallel with R16.

Ohhh wait a second 1uF IS ALREADY in parallel with R16. It is going from V2A K. to MIDDLE PIN in the center of the base and that is a ground

[Emetal]

So basically there is only one suggestion that you are saying I could do, that thing with C7, am I right or I am missing something...

[VacuumVoodoo]

-I should remove 1uF from V2 and put it in parallel with R16.

Ohhh wait a second 1uF IS ALREADY in parallel with R16. It is going from V2A K. to MIDDLE PIN in the center of the base and that is a ground

If that 1uF cap is on V2A.K pin 3 than it is parallel with R10 NOT R16. Assuming schematic on p4 is a true representation of reality, and I have reasons to claim it is not.... Anyway, try up to 2.2uF in parallel with R16.
BTW you can measure cathode and plate resistors in circuit with a DMM provided the amp is disconnected from mains and drained of any residual voltages. If there's acap parallel with the resistor you need to watch the DMM readin and wait till it stabilizes.

[Cameron]

So basically there is only one suggestion that you are saying I could do, that thing with C7, am I right or I am missing something...

if there caps anywhere from plate to grid on the tube socket....take them out. He adds these in most of his mods and ...IMO with some mods, these cloud the mids.

[roberto]

Some mods are just crazy.

I had one VH100R some years ago.
R4 becomes the classical 470k//470p, 4n7 as a coupling cap between 1st and 2nd stage, added 470p in parallel to R7 and C10 removed, IIRC.

The 10k between screen and PI supply becomes 20k.

Resosance switch adds 100k//4n7 in series with the 100k, instead of a 100k in parallel. 10k Presence pot instead of 22k.

[Emetal]

Vacum Voodoo I am looking at page 2 in the schematics, the pc board 9079_3 has a PAD 16 next to it says it's connecting to V2A K. which is third pin on V2. That is exactly how it is in my amp. Pad 16 then is connected to R16 little printed resistor, which ends up in the ground, therefore anything (1uF) that is put between ground and third pin is parallel to R16. Pad 10 is connected to V2B K. end then to R10 and ground. So page 4 and page 2 are in collision and I am confirming that page 2 is corresponding to reality in my amp

The other option (up to 2.2uF) is easy to try and I will Thanks.

Roberto I am not shore are you suggesting me to do some of these things or you just mentioning all the stuff you have seen but do not agree with

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