VHT D-50 Mod Journey

[Reeltarded]

YES

@Reel I'm guessing you own a D50? If so some ideas:
- Replace v1 with a tested high amplification factor 12ax7 (I don't have the means to test tubes, but my understanding is they are all over the place)
- Delete the v1b negative feedback - that's good for a few more DB
- Tweak the tone stack to be lower loss (it is a very lossy beast)
- Run a boost in front? (yeah cheating but I'm putting in all the ideas. The real thing had that FET stage, which you can buy as a VHT pedal, so there's that maybe)
- Reduce negative feedback in the power amp to make it easier to overdrive - can put that on a switch

I don't, but I have three rebuilds lined up.

These amps will get pick of the litter EH tubes in every position.
The LNFB is good, but it will be on a switch and the resistance will be based on what the players like.
The tone stack might be changed slope only. 82k 'sounds' like a good start

Three guys to experiment on. The plan is replace all that MO and dial in the clean, then go insane on the OD sections. One of the amps is for a modern metal rig. That one gets pseudo Marshall TS (series mid with small treble) a variable slope. Might even leave the first snubber. I would not want this guy staring at the OD trigger with his fingers. lol we will go with internal trimmer.

[Reeltarded]

Holy crap.

These amps sound like Hell.

[neskor]

Holy crap.

These amps sound like Hell.

What mods did you do?

[Reeltarded]

Not a thing, yet. Resistors and caps and some of these values need a great deal of attention.

The clean channel sounds like crap. The OD sections sound like crap. It sounds terrible. There is no question of how it reacts. It does not react. It isn't stiff. It doesn't meet taughtness contest requirements to be considered. This thing is awful.

It isn't as good as my description. I know, it sounds almost misleading to tell you it's the worst amp I have ever heard, but there simply isn't a thing beyond.

It's hyper terrible.

Imagine the moment in your life that was the biggest let down. Ok. Now, imagine that with volume and rabies... it's 118° and you just chugged a buttermilk milk shake. A big one. Like 40oz. Oof.

It's worse.

[Reeltarded]

Electronic hate crime.

[bwest]

@Reel I'm very interested to hear about your journey with the amps. Few questions:
- How many copies do you have? If more than one do they all sound the same?
- Have you changed the tubes yet? I was surprised how much of a sound difference that made in my (used) copy. Not sure how it sounded new or how it was treated before I got it, but preamp tube swap materially changed the tone for the better for both clean and OD

[Reeltarded]

They don't sound the same. They do not sound good. There is no basis for a comparison. Everything is worse than you thought it could be just seconds ago. It did get worse. This is how bad it can get.

I do not like these tubes.

First stop: Clean channel. This thing is not switching until the clean channel does ANYTHING expected. Everything in the signal path is guilty!

[bwest]

If you get a minute to post some audio I'm curious to hear what yours sounds like stock. It is interesting that it is almost a dead ringer of that other D schematic (183? On my phone not looking) but neither of ours sounded great stock...

[erwin_ve]

If you get a minute to post some audio I'm curious to hear what yours sounds like stock. It is interesting that it is almost a dead ringer of that other D schematic (183? On my phone not looking) but neither of ours sounded great stock...

Wiring aka leaddress is very important. If wiring is not consistent you get unconsistent amp behaviour. Then there's a component choice, cap orientation, care for specific voltages on the triodes.
There are a lot of variables, with the same schematic.

Erwin

[jelle]

Hi, old timer here, I have been away for a while to focus on my business and perfecting my craft. This is the first time I have seen pics of the guts of one of these. Lots of bang for the buck in terms of work that was done to make these amps, but based on what I see, this amp does not have a chance of sounding like a Dumble as it is now. The parts selection is just not there to support that tone.

Why?

The resistors used have a dense dark low mids sound, and at the same time have a harsh crummy upper midrange and top end. Its antithetical to what Dumble is trying to do in his amps, which is sweet clarity and smooth midrange. I cannot comment on the blue mylar caps, as I have never used those.I do know those ceramics though, and they are very bright, in a non musical way. Then there is layout, and at first glance, one may think its done well, but the devil is in the details. I'm actually curious to see how many hours and $$$ in parts it would take me to get these to sound good. Well, kinda curious.....not that curious, really lol

Enioy modding, it will be a journey, if you like the process, like most of us do here, you will learn a lot.

[Reeltarded]

These amps mark a moment in the development of human culture where we might decide music doesn't belong.

[bwest]

@Reel have you started working on your amps? How did they sound with a tube change? We just had a baby so going to be pretty sparse on the posting for a while - hoping to get more clips up soonish

[Reeltarded]

starting tonight on resistor swapping been busy staying side-tracked with othe..

squirrel

[Reeltarded]

Things have been weird here. Got a chance to think about it.

Opened amp. Removed insane LNFB.

Great amp.

[neskor]

I put my LNFB on a toggle switch