Peter / anybody: How do I eliminate the compression on CH3 on the VH4?

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diezelboy

Member
-------------------------- ISSUE SOLVED!!! -------------

I put a 12AT7 in V3 and now it's kicking some serious a$$. The compression is pretty much gone and it's all balls out now!!!
I need to up the gain control quite a bit there's plenty on tap!!

Thanks to getsetforsound who posted the right tube chart for the VH4.

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PETER / ANYBODY

I'm wondering is there a way to eliminate the FAST COMPRESSION on CH3 that kicks in as soon as you pick a string on the guitar especially on the lower strings?

- I tried lowering the gain to the point where I couldn't use it.
- I upgraded the tubes to KT88s (and rebiased it) and that improved things, but it's still there! It was happening with 6L6s and EL34s like crazy.
- I used lower gain 12AX7s (like the Sovtek WBs).. it's still there. I will try the JJ ECC83s (as that's what's written on the chassis if that'll make any difference).

When I do heavy fast riffs on the lower things can get muddy at times because of this compression "issue". This channel sound awesome for soloing however!

I love the tone, the punch, the sound definition of CH3, but wanna get rid of that compression and still want to have enough usable gain. I'm not into heavy thrash / hardcore / thrash so I don't need ultra gain, but I need tightness and less compression on CH3.

I tried the Herbert with 6L6s and I found CH2 doesn't "feature" this compression issue, however CH3 does. It's just it's so noticeable.

Now some ppl suggested using 12AT7s or 12AU7s but I'm not sure of the tube position (V1, V2 or V7??)

Here's the tube chart from Rich @ Salwender
V1 - all channels
V2 - ch 3
V3 - ch 2,3,4
V4 - all channels
V5 - mixer and send buffer
V6 - return driver
V7 - phase inverter

What is the correct SAFE cure for this? Is it safe to throw in other pream tubes other than 12AX7 (like was suggested... 12AU7 or 12AT7)?

Any suggestions?
Thanks in advance
 
Well I did ask UWE for any suggestions and apparently this is a known issue and it looks like there might be a mod for it.
Here's the message from him

"We're workin on a mod for cases like yours. I have some other customers with similar issues. We feel that the amps prior to the aluminum face plate have better definition at gain, and are less dense in teh low end, which seems to be part of your problem.
You can try a 12AT7 in position 1and 2, perhaps"

Peter / Olaf: What time frame are we looking at here? What's this mod Uwe is mentioning.

I want this mod if it gets rid of that heavy compression in the low end!
 
Well I tried this and sorry but it doesn't cut it. 12AT7 in V2, I also tried 2 of them in each: V1 and V2, V2 and V3 The best results are just ONE in V2. Yes it gets rid of a bit of the compression, but it doesn't eliminate it. It also gets rid of quite a bit of gain which I don't mind all that much... but just so ppl know.

PETER / OLAF , I AM LOOKING FOR A SOLUTION TO THIS. Can you please let me know if there's a mod for this?

Uwe was mentioning a MOD so I'd like to hear about this more please.

I was seriously considering the Herbert, but channel CH3 has the same issue which is not too bad, cuz I can use that channel for soloing and that would work great.
CH2 on the Herby is not as compressed and sounds tighter. I find the VH4 more versatile than the Herbie, that's for sure, so it's a tough decision!
 
Hmmm..... I mean it´s part of the Diezel sound.
Sure we can mod it. But if You sell it, it´s no more
a regular Diezel.
Next problem is I want do mod it by myself.

Please check it out with a weak pickup around
8 to 10k.

:confused:
 
Thanks for the reply Peter. Well I want to get the mod done because I simply love the sound of the amp! If I can get this amp to sound like it sounds now WITHOUT the low end compression but with TIGHT PERCUSSIVE low end then I won't have absolutely no reason to sell it. This would be the Holy Grail as they say.

All around the VH4 is the best and most versatile amp I played hands down (and I've played or owned TONS of amps).

The thing is that I live in North America. Shipping it to Germany would be killer. Would you suggest shipping it to Uwe and get it modded when you're around (NAMM time or something)? I'm open to suggestions!

I need useable gain without the compression. I don't really wanna compromise by giving up gain. That's what makes this amp so rich and with harmonic galore! I hope you understand. Thanks so much again!
 
:|::QBB:
Peter Diezel":4dce4 said:
Hmmm..... I mean it´s part of the Diezel sound.
Sure we can mod it. But if You sell it, it´s no more
a regular Diezel.
Next problem is I want do mod it by myself.

Please check it out with a weak pickup around
8 to 10k.

:confused:
Click to expand...

Pete I totally agree with what you're saying. Changing from PAF pickups (low output) and other alnico to ceramic (high output) gives a different flavor to the amp's sound and Diezel's can strip your instrument for sure. A great guitar will sound better while a bad guitar only worse.
 
While different pickups offer various flavors I don't think I should be forced to change pickups in all my guitars. The compression in the low end is there and there's no question about it. It's noticeable even on my Strat with Kinman single pickups which around 7.5 k.:(

If I can get my VH4 to sound as tight and uncompressed as a VHT UL Pitbull in the low end I will be a happy man. The VH4 to me is richer and fatter than a VHT UL that's why I like the VH4 sound over many other hi-end amps, but I really want it TIGHT and uncompressed in the low end. That's all.
I am looking forward to the MOD.;)
THANKS.
 
This may seem like a ridiculous notion, but you could also turn down the volume on your guitar. One thing I like about ch3 on the VH4 is that it offers further tone opportunities below max volume level on the guitar. I often keep the volume on my guitar down almost halfway for tight sections and then raise it during the more saturated sections.
 
Right...and all the glory and richness of that channel are cut in half... I want usable gain. I don't want to sacrifice gain. My CH3 gain is around 2pm. That's kinda the sweet spot for now...
I agree with you. I love how sensible the amp is to all the nuances of the player / instrument... It's one of the reasons I still own it despite the "issue" I described above.
 
:|::QBB:
diezelboy":6d894 said:
Right...and all the glory and richness of that channel are cut in half... I want usable gain. I don't want to sacrifice gain. My CH3 gain is around 2pm. That's kinda the sweet spot for now...
I agree with you. I love how sensible the amp is to all the nuances of the player / instrument... It's one of the reasons I still own it despite the "issue" I described above.
Click to expand...

Well, I like to say it the input gain is cut by -6dB rather than in half. :D

2:00 seems to be a bit high on ch3 if you don't want muddiness for low notes. My guitar is tuned down to C (I favor low notes), and I rarely go above 12:00. Usually I set it at 11:00, but often down around 9:00.
 
The channel gain setting is so relative.. it depends what power and preamp tubes you use... what guitar and pickups you got.
If I turn to 12 it's pretty much vintage classic rock distortion which I can't use for what i'm playing.
What tubes, guitar and pickups do you use?

I noticed that putting in the 12AT7 takes away a bit from the body and richness of the sound as well. :aww:
 
:|::QBB:
diezelboy":f45c6 said:
The channel gain setting is so relative.. it depends what power and preamp tubes you use... what guitar and pickups you got.
If I turn to 12 it's pretty much vintage classic rock distortion which I can't use for what i'm playing.
What tubes, guitar and pickups do you use?

I noticed that putting in the 12AT7 takes away a bit from the body and richness of the sound as well. :aww:
Click to expand...

Interesting. For me 12 is heavily saturated. I have a Les Paul type gutiar with Dimarzio Super 2's. I'm using Shuguang 12AX7's and Ruby 6l6GCMSTR's. Maybe it has something to do with your bias setting?
 
Hmm... So are you telling you got NO compression at all in the low end when you FAST riffs in dropped tunning? I cannot believe that. Both mine and my buddy's VH4 do this... Mine's a 2001 and his is 2000. OK 12 is a tad bit more than vintage, but nowhere near as heavy as say Staind.
The compression always kicks in for a split second on your pick stroke, but if you play fast enough you can beat it and it all becomes unclear.

I use JJ KT88, tried the Ruby 6L6GCMSTR, Svet 6550s, Svet 6L6s and I had Sovtek 12AX7WB, and now I use Tung-Sol. I have tried some NOS Briamar in V1 along with Sylvania and some newer Rubys, EH... same deal.

I don't know if you ever heard the VHT UL, but that's TIGHT with the gain all the way. Never ever gets compressed on CH2. I've owned 2 of them in the past. Awesome amazing amps too! Hats off! But regardless.... the issue is still outstanding.
 
I definitely get a lot of compression in ch3, but I like it. Different strokes for different folks, I guess. :cool:

One comment on the Tung Sol 12AX7s. I tried those and they have an awesome tone to them, but I switched to Shuguangs because the Tung Sols were muddy on fast riffs. You might consider switching to the Shuguang 12AX7s, as it added a lot of definition to the notes for me. I missed some of the "3D" sound of the Tung Sols when notes were ringing though, so I'm running one in V1 (Shuguangs for all others) and it's a nice compromise.

Never heard the VHT UL. But the last thing I need is more GAS. So I'll try to forget you mentioned it. :aww:

How do you liek the KT88 compared to the other power tubes you've tried?
 
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