VHT D-50 Mod Journey

[dorrisant]

I changed every preamp component (Roedersteins, Dralorics, 6PS) in the one I had here that belonged to Shane... I still thought it wasn't quite right with all of that. Changed about half of it yet again to a #124 and that was where it really sounded great. I had the phase inverter trim dialed in exactly the same for both iterations Same AC and DC measurements. Used the same 3 12AX7s in the same positions too. I know it is just a preference of #124, but changing to the right composition parts and adjusting the PI with the right tube (I rolled 3) really made a huge difference. Maybe Shane will comment and verify what his ears detect...

[Reeltarded]

left to do are grid leaks, od entrance rework, and cat thodes.

It sounds somewhat underbiased and that hardly matters. Thing screams like Bob Gjika's wife if you hit it hard.

That is super inappropriate.

[Reeltarded]

Pretty much done except cathodes.

The cap before OD deleted. So much gain returned. Installed 8M8/.047 LNFB and still have enough gain hidden in there to scare a child.

These things are addictive because they are fun and the annoying questions are already answered, like "is my power string going to be all metal oxide resistors?" The answer is "yes".

Solen used for presence. I like it.

Mustard 18n coupler on OD1

It's a mixed bag of 102/183. The thing is better than fair.

C51C5570-8DC7-4B8B-AF09-DCD6C86BE3A1.jpeg

[bwest]

@Reel thanks for the update. I'm curious - does the deleted 10n cap before the OD section cause any popping to appear when you switch from clean to OD?

Been playing with the amp (as in with a guitar, not changing stuff) a good bit and have really found a groove where I like what its doing. Totally different guitar/pedal setup than my normal humbucker/marshall thing. I bought a squier strat and swapped the pickups for some fluences I had around for another project, so now I have a stratty guitar to test! I'm not telling you guys anything you don't know but wow what a different beast.

Basically here's what sounds good to me:
- Strat into Wampler ego compressor, always on
- Clean amp v1b local nfb off
- power amp feedback full up (normal); power amp set clean (master low)
- Bass all the way up, mid noon, treble maybe 11 o clock (using a closed back veteran 30 in my garage and it is super duper bright without this)
- Wampler (I like wampler stuff) tumnus (Klon klone) for light boost, or 808 tubescreamer clone gain set low for boost/tone shaping/cut the bass

Set like the above - it sounds killer. But that tweaked OD section which I liked so much with humbuckers (V2B unbypassed 820ohm) for its dry and almost metal-esque thing I really hated with the strat. So I put in a 0.68u on V2B with the 820 ohm - brought back that wetness while keeping some of the crunch. Generally I would say it sounds pretty good - maybe I would bump it up to 1u if I had one, but I don't right now, so I'll leave it there for now.

TLDR if you want a metal amp having V2B unbypassed like that 820 is great. WIth a tubescreamer in front it really did chug - that plus the spanky clean and voila you have something like an old school Mesa Mark amp for 1/4 the price (and easier to repair).
But for that strat thing if you want to keep it wet I would keep the caps bypassed - need to pull out the pedals tonight to try the pedals above with the 820/0.68u combo but am bullish.

Am considering adding a "smooth" switch which would either be a high cut or a high shelf post OD section - just to cut some of the brightness - trying to find best way to do that (on front OD level pot perhaps as a switched pot? any ideas)

[bepone]

Pretty much done except cathodes.

if you are interested, check how is the positive feedback done with the cathode wires in dumble amp in V1 and V2 position

[erwin_ve]

Hi Miles,

I looked at your pics. Something to tinker with is the v2 cathodes to ground. You have them connected at the PI ground.
Move them to the v1 cathode junction to ground.
Soundwise it is subtle, less weird overtones. Ymmv.

Erwin

[Reeltarded]

hah THAT has to be the nutty overtones.. if you really dig in with the OD controls set low it gets a little Octave Divider ring that is not terrible.. very slight. The grounding absolutely needs some tweeks! Will do that first thing after pot swapping.

The amp needs shielding. Saving less than a dime by relying on wires to reject hum was brave and hopeful! VHT should change their company motto to Brave and Hopeful! It has been almost two years since the release of this model, and the end user videos are all sad people plunking hopelessly for a useful tone. The future of these things is amazing. They are going to be $500 soon. That makes them my favorite new starting place for a day project.

This amp as it is right now works a little bit like an early model (RAW!) with 4th gen gain range. Instead of the very smooth Boogie sort of OD, the OD acts like the UP blonde Showman. It is a wild horse. Loveable.

I am not totally happy with the tone controls. There is missing treble authority. I think it's pot values. The pres works but very short range and out of bounds on the knob action.

Removing the cap in the OD entrance and copying 183 was a big deal. I still have to install the internal 100k and get the trim control off the back of the amp.Response between clean and OD is more as expected.

The style of board is convincing. I see why you guys are so happy about using printed boards to stuff with magic. It makes the amp far more servicable and that is as much of the goal as making them sound great.

Fun! Cheap! Interesting! Did I mention cheap?

[Reeltarded]

@Reel thanks for the update. I'm curious - does the deleted 10n cap before the OD section cause any popping to appear when you switch from clean to OD?


Am considering adding a "smooth" switch which would either be a high cut or a high shelf post OD section - just to cut some of the brightness - trying to find best way to do that (on front OD level pot perhaps as a switched pot? any ideas)

No popping. It opened up the throat of the OD. Everything bad in these amps was deliberate. lmao

In an ideal world, OD1 would have a single tone control like a tweed. You might like 250-500p plate bypass over OD1 plate?

The LNFB I settled on after getting so much gain back is 2M2-2M2-.047u-2M2-2M2. That moved the gain range of clean where 7 is what 3 used to be and the clean channel sounds like my favorite dumble marshall and fender mods. Better than ODS amps, generally.

[bepone]

sockets are rotated also in worst possible angle to make good wiring. difficult to make wiring like dumble, and also difficult to make even better wiring than dumble (input signal from guitar to pin 7 for lower noise). here is impossible to start in good order

so i would remove wiring from V1 and V2, drill new holes for mounting the sockets, rotate in first or second option and proceed following the mentioned lead dress..MOX in cathodes yes or no? i'm still not clear with that because i have one JTM45 Metroamp at home with MOXes in cathodes and is very very good amp..

[Reeltarded]

sockets are rotated also in worst possible angle to make good wiring. difficult to make wiring like dumble, and also difficult to make even better wiring than dumble (input signal from guitar to pin 7 for lower noise). here is impossible to start in good order

so i would remove wiring from V1 and V2, drill new holes for mounting the sockets, rotate in first or second option and proceed following the mentioned lead dress..MOX in cathodes yes or no? i'm still not clear with that because i have one JTM45 Metroamp at home with MOXes in cathodes and is very very good amp..

I think I see a way of doing it as it is. I am gong to do the wires and cathodes next along with replacing both the OD pots.

[dorrisant]

How do you feel about the OT? I mean, would you feel that you can live with it? Or swap it out?

[Reeltarded]

No reason to think it isn't at least adequate. Trying to make a cheap amp for cheap.. its already around $1400 without labor.

[Colossal]

How do you feel about the OT? I mean, would you feel that you can live with it? Or swap it out?

That chinese OT probably has more silicon in the steel than a breast implant, but hey, it's rock n' roll, I guess

[Reeltarded]

we need a video meme of a pick scrape with this amp going in the trash

[bwest]

Re:. Output transformer - with so much feedback in the output loop does the quality matter much? Real question - I'm guessing the feedback (if power section is played clean) will make anything half decent sound good. All bets are off once distorting power section though

I put a 2.2n cap across the OD section output pot as a high cut and it really darkened up the amp. I'm kind of back to fuzz territory, but it cleans up better. Not sure I like it but easy to reverse.