Collection of all kind of Diezel modifications

[fusedbrain]

Cool
I hope you like the change.
Try it out before you put the amp back in the head shell.
If it doesn't work for you, then 2 minutes to put it back and it's all good
And make sure you get those channel volumes up and control the amp with the master vol's.

 

[jdel77]

Cool
I hope you like the change.
Try it out before you put the amp back in the head shell.
If it doesn't work for you, then 2 minutes to put it back and it's all good
And make sure you get those channel volumes up and control the amp with the master vol's.

I should add to this thread that I did do the mod and it's killer!
However, I much prefer the Channel Volumes to be lower to add less output saturation to my sound, and then crank up the Master Volume for full thump.
I use a Boost and Gate before the preamp and another Gate in the FX Loop - this way at crazy stage volume there's no feedback/squealing.
Love this VH4S now!

 

[LightsOfSorrow86]

I moved the NFB connection on my 2018 VH4 from the 8 ohm jack to the 4 ohm jack. Not a huge change, but it opens the amp up a little bit and I prefer the tone.
With that one little change, I now feel like the amp is "perfect" for me.

Edit: a few guys have PM'd me about this, so here's rundown.

The pic shows the output jacks and output transformer of my VH4.
The white wire on the output jacks is the negative feedback wire. The orange wires are the leads from the output transformer.
Originally, the white wire was connected to the 8 ohm (middle ) set of jacks along with the middle orange output transformer lead.
Simply un-solder the white wire from the 8 ohm jacks and solder it to the 4 ohm jacks as I have in the picture.
That's it!!
If you don't like it, put it back. It takes 30 seconds.

hey man, do you still have the VH4? Thanks

 

[fusedbrain]

Yes I do!
A lot of stuff has come and gone, but I don't expect to ever sell the vh4.
Great amp, and yes, it still has the nfb mod : )

 

[LightsOfSorrow86]

Yes I do!
A lot of stuff has come and gone, but I don't expect to ever sell the vh4.
Great amp, and yes, it still has the nfb mod : )

Perfect considering you have done the NF mod by yourself, do you feel comfoortable to send me some pictures of the insde of the amp? I'd like to compare it with mine, if possible. If yes, I'll send you my e-mail so you can send them there. Thanks a lot.

 

[fusedbrain]

There's a picture in this thread of the output transformer and speaker jacks inside my amp. All you are doing us moving a wire from one jack to another.
I don't have any other pictures of the inside of my vh4, and I moved recently and all my gear is still packed up. I won't be taking the amp out of the headshell anytime soon. Sorry man, but I'm up to my eyeballs in alligators right now lol!
You should be fine with the pic already posted.

 

[angelspade]

Yes I do!
A lot of stuff has come and gone, but I don't expect to ever sell the vh4.
Great amp, and yes, it still has the nfb mod : )

I think I may do this mod shortly. Questions: After the mod, does the amp simplly sound a bit "brighter" overall? Or is it more reflected in only the high-presence frequencies (sizzzle)? finally, does the amp feel tighter or less compressed after the mod? Thanks so much, appreciated.

 

[pipboy90]

I think I may do this mod shortly. Questions: After the mod, does the amp simplly sound a bit "brighter" overall? Or is it more reflected in only the high-presence frequencies (sizzzle)? finally, does the amp feel tighter or less compressed after the mod? Thanks so much, appreciated.

I’ve done the mod before. The amp will be overall louder, a little looser, and brighter.

 

[Techdeth]

I’ve done the mod before. The amp will be overall louder, a little looser, and brighter.

I like brighter but not looser

 

[LightsOfSorrow86]

I like brighter but not looser

But doing that you involve the negative feedback. I do this example a lot. Mesa Mark: lots of negative feedback, tighter, more mids. Rectifier in modern mode: no negative feedback, looser, more bass and treble, scooped.

 

[Techdeth]

But doing that you involte the negative feedback. I do this example a lot. Mesa Mark: lots of negative feedback, tighter, more mids. Rectifier in modern mode: no negative feedback, looser, more bass and treble, scooped.

Interesting
I’d like to do something with my vh4 . I have 4 Diezel heads and my Vh4 is my least favorite, not that I dislike it

 

[LightsOfSorrow86]

Interesting
I’d like to do something with my vh4 . I have 4 Diezel heads and my Vh4 is my least favorite, not that I dislike it

I asked before but I'll be more than happy if any of you can send me pictures of the inside. What you don't loke of your VH4? I love mine more than any amp I've ever owned, and they are more than 30.

 

[Techdeth]

I asked before but I'll be more than happy if any of you can send me pictures of the inside. What you don't loke of your VH4? I love mine more than any amp I've ever owned, and they are more than 30.

It’s feels Like it’s missing some fullness. Especially against vh2 . I was blown away by v2 new channel

 

[LightsOfSorrow86]

Strange, I don't have any problem in that sense. Which year is yours?

 

[pipboy90]

It’s feels Like it’s missing some fullness. Especially against vh2 . I was blown away by v2 new channel

How old are the tubes? I have a newer VH4 and it has more fullness than I could ever need.

 

[Techdeth]

How old are the tubes? I have a newer VH4 and it has more fullness than I could ever need.

It’s still full but pitted against vh2 the channel 2 just comes together fuller . It’s a new channel . But it could use new tubes . But I will say channel 2 of vh2 sounds more modern and different. I want to sell it but I end up loving it. I’ll also had vh4 still has more punch. I like them all a lot. No channels are not great on either amp

 

[Me]

If you have channel "A" and "B" output transformers, and 2 negative feedback wires connected to the channel "A" and "B" 8 ohm jacks, then you would do the mod X 2.

Or you could do it once. Then do a demo video so we can all geek out and directly compare the tonal difference of modded vs unmodded in an identical setup. Then either do the other one, or put the first one back based on your taste.

 

[saxxamafone]

If you move the NFB wire from the 8 ohm tap to the 4 ohm tap, what is physically changing is you are sending LESS negative feedback signal back to the phase inverter. The result is less damping of the PI output ( less compressed ) and more harmonic distortion (perceived as more brightness). This is a simplified technical explanation, but you get the idea

Any speaker output can still be used. The white wire is soldered to the same lug on the jacks as the wire from the output transformer, so there is a permanent negative feedback connection, regardless of which jack the speaker cable is plugged into.

If you have channel "A" and "B" output transformers, and 2 negative feedback wires connected to the channel "A" and "B" 8 ohm jacks, then you would do the mod X 2.

Wonder if this same mod would apply to a Herbert?

I did this on my VH4 and preferred the mod

 

[Michiel Kemper]

There's a picture in this thread of the output transformer and speaker jacks inside my amp. All you are doing us moving a wire from one jack to another.
I don't have any other pictures of the inside of my vh4, and I moved recently and all my gear is still packed up. I won't be taking the amp out of the headshell anytime soon. Sorry man, but I'm up to my eyeballs in alligators right now lol!
You should be fine with the pic already posted.

Will this work on a Lil Fokker? (A predecessor of the VH2)
I like the amp but a bit more open sound or a bit tighter low end would benefit this amp.
Is this NFB similar to the known decompression mod?

 

[headcrash]

This mod (moving nfb signal from one OT out to another, in this case from 8 Ohm to 4 Ohm) should work on literally any class AB push pull tube power amp with nfb (negative feedback).
Downside is, that your nfb controls (Deep and Presence) will have a little less effect. Which may or may not be a good thing, depends on your taste.
I found the Diezels I have had, and/or played to be too smooth and muffled.
Moving the nfb from 8 Ohm to 4 Ohm tap could be a good and simple mod, to up treble and high mids a little.

To tighten up the low end from the preamp gain side, this mod will not help, IMO. I think, using lower output, PAF type pickups help a lot (or increasing pickup distance to strings, can make a huge difference !).
IF I were to mod a Diezel for a tighter distortion, I'd rather change some of the mud-killing high passes early in the signal path. But tbh, the rather fat and muffled (or warm) base sound is a rather Diezel-specific sound quality, and if you don't like this, maye another amp is better for you?