Taming the compression on VH4 ch4 ?

H

hopkinWFG

Well-known member
Been a newbie on VH4... VH4 voicing towards a more raw tone have my preference on VH4 more than da Herbert.. but hence i spent more time on VH4 ch4 i start to know/learn about what many have said its way way too compressed and its true...

Now that i appreciate my Herbert mk2 more against da VH4 ch4... needless to mention the VH4 ch3 is a really really awesome channel with the right tightness and tone for me !!

Have come to read about Peters VH4 ch4 resistor mod to 330K i read in his service manual... i am kinda hesistant to change whats originally on the VH4 chassis... does anybody know if i could change the preamp tubes on CH4 from currently what i have in them are all JJs... i am thinking of putting Tungsol 12ax7 or EH 12ax7 to tame down the compression ?

Or else do i have to change the resistor to 330k according to Peters manual ? I have mine a 2008 and i believe this is a later update and revision on more gain, presence and less compression... but i still find ch4 overwhelming in my opinion.... any advise here plz ?
 
Volume.

Not sure what SPLs you're running the VH4 at, but things start to open up with volume.

Let us know how that works out for you :rock: :thumbsup:
Unkle Mo
 
Ventura":1z9s8r04 said:
Volume.

Not sure what SPLs you're running the VH4 at, but things start to open up with volume.

Let us know how that works out for you :rock: :thumbsup:
Unkle Mo
Click to expand...


Thanks Ventura... but whats SPLs ? I experiment with whatbya said and i found it to be slightly tighter when i crank up the masters... the tone also got "drier"

I ended up having these combination on my 2008 VH4 and it plays well !!! So will say stiffer and i like it harder lol

V1= Mullards 12ax7 RI
V2= china 12ax7B
V3= china 12ax7B
V4= JJ ECC83s
V5=JJECC83s
V6=JJECC83s
V7=Sovtek 5715

May change V4 V5 V6 to china but its not contributing to any channel tone and feel i guess and am tight on cash i may leave it....

Am thinking of putting 12AT7 or 12 AU7 thou but not sure of it will work to be even hard hitting on channel 4... but i guess am safe as 5751 is a direct replacement for 12ax7 with lesser gain factor? Not sure of 12AT7 or the AU...

Maybe can Peter chime in again :)
 
hopkinWFG":k4h85uny said:
Ventura":k4h85uny said:
Volume.

Not sure what SPLs you're running the VH4 at, but things start to open up with volume.

Let us know how that works out for you :rock: :thumbsup:
Unkle Mo
Click to expand...


Thanks Ventura... but whats SPLs ? I experiment with whatbya said and i found it to be slightly tighter when i crank up the masters... the tone also got "drier"

I ended up having these combination on my 2008 VH4 and it plays well !!! So will say stiffer and i like it harder lol

V1= Mullards 12ax7 RI
V2= china 12ax7B
V3= china 12ax7B
V4= JJ ECC83s
V5=JJECC83s
V6=JJECC83s
V7=Sovtek 5715

May change V4 V5 V6 to china but its not contributing to any channel tone and feel i guess and am tight on cash i may leave it....

Am thinking of putting 12AT7 or 12 AU7 thou but not sure of it will work to be even hard hitting on channel 4... but i guess am safe as 5751 is a direct replacement for 12ax7 with lesser gain factor? Not sure of 12AT7 or the AU...

Maybe can Peter chime in again :)
Click to expand...
As per RyeDaddy - ya, SPL = Sound Pressure Level.

The Phase Inverter you have in there now is a 5751, not 5715, correct?
Your preamp bottles are fine as is - I'd ditch the 5751 (although this can be a great PI tube for sure) and go Sovtek LPS. Otherwise, HG Chinese flush across the board is a great starting point.

Volume seems to open Diezels up, IME. So it depends on your playing space and such, sometimes ya just can't get the amp there. On lower volumes, I find keeping the Masters DOWN and opening up the preamp (Channel) volumes as much as possible opens the tone a little more - otherwise, you're squelching your initial signal with compression as soon as it moves from the input jack through to V1 and gets squished down from there with the preamps turned down and gain turned up - it's just lots of clipping and compression. The powersection MV is just that - the power section. It'll take your pre tone and amplify it. So, sensing that you're not going wide open on either side of the fence - try low MVs (as powertubes are less susceptible to "compression" and "clipping" when not fully opened) and open your preamp volumes to let that signal flow.

However, ultimately, the sonic alchemy really starts to get magical when the MVs are at noon and the channel volumes are into the 2-3 o'clock range - it's fucking loud. With the VH4 - specifically - it tends to get louder up to about 1 o'clock on the MV, after that, it just gets fuller (PT saturation etc). But these are levels rarely attained - but they're fun when you can :yes:

Try more open preamp volume, less open MV and move from there. I'd not be soldering anything different into this amp - the VH4 is notoriously stiff. This is true. The 5751 is a GREAT bottle in the PI slot - DO NOT MOVE AWAY FROM 12AX7-ECC83-5751 bottles in the PI slot. The resultant feed to the PT section may get fucked up as the circuit wasn't designed for AU7 or the like; and those tubes have a lot more amplification rating than the aforemention 12AX7 design tube (5751 is just a mil-spec 12AX7 with slightly lesser gain, FYI).

Peace
Unkle Mo
 
Ventura":33umt2g1 said:
hopkinWFG":33umt2g1 said:
Ventura":33umt2g1 said:
Volume.

Not sure what SPLs you're running the VH4 at, but things start to open up with volume.

Let us know how that works out for you :rock: :thumbsup:
Unkle Mo
Click to expand...


Thanks Ventura... but whats SPLs ? I experiment with whatbya said and i found it to be slightly tighter when i crank up the masters... the tone also got "drier"

I ended up having these combination on my 2008 VH4 and it plays well !!! So will say stiffer and i like it harder lol

V1= Mullards 12ax7 RI
V2= china 12ax7B
V3= china 12ax7B
V4= JJ ECC83s
V5=JJECC83s
V6=JJECC83s
V7=Sovtek 5715

May change V4 V5 V6 to china but its not contributing to any channel tone and feel i guess and am tight on cash i may leave it....

Am thinking of putting 12AT7 or 12 AU7 thou but not sure of it will work to be even hard hitting on channel 4... but i guess am safe as 5751 is a direct replacement for 12ax7 with lesser gain factor? Not sure of 12AT7 or the AU...

Maybe can Peter chime in again :)
Click to expand...
As per RyeDaddy - ya, SPL = Sound Pressure Level.

The Phase Inverter you have in there now is a 5751, not 5715, correct?
Your preamp bottles are fine as is - I'd ditch the 5751 (although this can be a great PI tube for sure) and go Sovtek LPS. Otherwise, HG Chinese flush across the board is a great starting point.

Volume seems to open Diezels up, IME. So it depends on your playing space and such, sometimes ya just can't get the amp there. On lower volumes, I find keeping the Masters DOWN and opening up the preamp (Channel) volumes as much as possible opens the tone a little more - otherwise, you're squelching your initial signal with compression as soon as it moves from the input jack through to V1 and gets squished down from there with the preamps turned down and gain turned up - it's just lots of clipping and compression. The powersection MV is just that - the power section. It'll take your pre tone and amplify it. So, sensing that you're not going wide open on either side of the fence - try low MVs (as powertubes are less susceptible to "compression" and "clipping" when not fully opened) and open your preamp volumes to let that signal flow.

However, ultimately, the sonic alchemy really starts to get magical when the MVs are at noon and the channel volumes are into the 2-3 o'clock range - it's fucking loud. With the VH4 - specifically - it tends to get louder up to about 1 o'clock on the MV, after that, it just gets fuller (PT saturation etc). But these are levels rarely attained - but they're fun when you can :yes:

Try more open preamp volume, less open MV and move from there. I'd not be soldering anything different into this amp - the VH4 is notoriously stiff. This is true. The 5751 is a GREAT bottle in the PI slot - DO NOT MOVE AWAY FROM 12AX7-ECC83-5751 bottles in the PI slot. The resultant feed to the PT section may get fucked up as the circuit wasn't designed for AU7 or the like; and those tubes have a lot more amplification rating than the aforemention 12AX7 design tube (5751 is just a mil-spec 12AX7 with slightly lesser gain, FYI).

Peace
Unkle Mo
Click to expand...

Thanks uncle Mo for explaination... am not used to getting the Channel volume up.. it just didnt have the ballsier tone to it... do you think if i were to back down on my biasing on my EL34 to 50% or 55% tube dissipation would help to prevent early saturation of the PT ?

Am about to recieve my EL34BSTR but many have said its gotta own compression to it... i wont wanna miss the mids that EL34 is having but wanna getta less compression type EL34 bottle will you happen to give few idea on which brand to look out for...
 
hopkinWFG":38ym17nl said:
Thanks uncle Mo for explaination... am not used to getting the Channel volume up.. it just didnt have the ballsier tone to it... do you think if i were to back down on my biasing on my EL34 to 50% or 55% tube dissipation would help to prevent early saturation of the PT ?

Am about to recieve my EL34BSTR but many have said its gotta own compression to it... i wont wanna miss the mids that EL34 is having but wanna getta less compression type EL34 bottle will you happen to give few idea on which brand to look out for...
Click to expand...
32mA per tube is good for the EL34, 34mA okay, 35mA and above is pretty hot... less than 30mA just sounds bricky.

Lean on the idea of keeping the masters low, and the channel volumes high - as mentioned - this eliminates pre-power-section compression/clipping (outside of the gain controls per channel). As for PT saturation, dude, you gotta be running this amp at 1 o'clock on the MV before it starts to bloom, and when it does, it's fucking glorious. But honestly, I don't know many people who run their VH4 at more than 1 o'clock on the Master (with their channel volumes in the 3 o'clock range). I've ran my Diezels - actually all my amps - at wide open (both channel and master) with all settings at noon (gain included) in a separate room with a 25ft cable to separate me from the nuclear blast, I set my guitar volume at zero, and then commence working it up to full. Why do I do this?? I like to play the amp at this level for a good 10min per channel, palm muting in between to hear any "artifacts" (pops, crackles, etc), on each channel. It's a way I gauge my amp and the tubes. It's ridiculously loud - and yes, it's hissy on gainier channels (that goes for ALL amps) but I just wanna know it can go there. Once that test is done, I know the tubes are good, and everything's fine.

I only mention this because it's in these cases I've moved past 1 o'clock on the MV with channel volumes wide open - as mentioned - the VH4 doesn't get louder past 1 o'clock, just more gnarly and fierce, but I don't expect ANYONE to play the amp at this level under any "NORMAL" circumstances. THIS is the level (about 1 o'clock on the MV of the VH4) where you'll experience some degree of "power tube/section saturation". So worrying about your bias levels at this current point in time seems a moot point as I don't believe you're going to these SPLs with your VH4.

New tubes, 34mA for light use, 32mA for regular use. Hope this helps.
Anything specific - ask me here or PM me - always happy to help.
Peace,
Unkle Mo :rock: :rock: :rock: :rock: :rock:
 
As usual, Unkle Mo dishes out truth :rock:
I've started setting up my vh4 with the channel 3 volume full up, using the channel vols on 1&2 to balance everything out, and setting the overall volume with the main master.
( I rarely use ch4 )
This really opens the amp up and is a total game changer for me.
I can get the goods at just about any volume now vs having to go nuclear blast to get the amp to open up and give me the tone I'm looking for.
I feel like an idiot for not trying this before :doh: :doh: :doh:
I think this even tops the Ventura "try 6550's in the Twin Jet " tip for me :thumbsup:
Thanks bro!!!
 
fusedbrain":629d7q08 said:
As usual, Unkle Mo dishes out truth :rock:
I've started setting up my vh4 with the channel 3 volume full up, using the channel vols on 1&2 to balance everything out, and setting the overall volume with the main master.
( I rarely use ch4 )
This really opens the amp up and is a total game changer for me.
I can get the goods at just about any volume now vs having to go nuclear blast to get the amp to open up and give me the tone I'm looking for.
I feel like an idiot for not trying this before :doh: :doh: :doh:
I think this even tops the Ventura "try 6550's in the Twin Jet " tip for me :thumbsup:
Thanks bro!!!
Click to expand...
Always happy to help :LOL: :LOL:

Thanks guys!! :thumbsup: :rock:
Unkle Mo

(PS: gotta admit though them 6550s in the TJ really do open up a can of serious whoopass eh?? :D )
 
What I think you're after is best achieved by the resistor swap, I've done it and it's great.

You're not going to get the noticeably better articulation and tightness on the VH4 ch4 mod from a tube change. If that was the case Peter wouldn't have suggested to me and others to do the resistor when we asked him how to archive this articulation/tightness when soloing fast on ch4.

I don't use ch4 for anything other than soloing with gain so it was an easy choice, but if you're also using it for rhythm guitar than I can see the hesitation as it makes it closer to ch3 but still with more gain.
 
- Thread rehash -

I found CH4 had some huge hum in mine and was sounding pretty awful lately. I swapped out the V2 for a standed working, non-HG 12AX7 ECC83 Yugo, (a JJ803S worked well too) and the hum is gone and its sounding real nice. I also set the channel different to the rest, which seemed a little unusual to my usual thinking, when compared to the other channels, basically running the Channel Vol at about 3pm, and the gain knob at about 10-11am.
The channel now sounds fantastic for me, no hum, and the channel sound quite articulate and crisp, not noisey and mushy anymore. Most of my other channels I tend to run the gain knob higher and the vol knob a little lower. I know Peter recommends a 12AX7 HG+ AC5 style, but I'm finding a good basic 12AX7 is working great for me. It possible my Ruby HG+AC5 had just gone to shite, but I don't recall ch4 ever sounding as good before to me.

Anyway, just thought I'd share my story with Readers Digest. :)
 
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