High Voltage Hijinks

cheers. It seems Europe has either replacement for vintage stuff (so vintage in more of an overpriced way), Hammond via Mouser or Digikey, or smaller companies that do semi customs. For the PT it’s not too bad, for the OPT it’s more difficult if you want something for guitar. I could ask Rondo Mueller for a toroidal (my choice for PT but they can do OPT) and I found Thermionic Lab in Italy that does high end EI for a relatively low price (150€ for a 60W, 4.2K with better specs that Hammond). Might be what I go with.
 
Right on, sounds like you have a path forward.

I have all parts on hand for my next four preamp builds. Artwork done for all of them, and layouts done for two. I'm going to do one last trace of my layouts tonight and then onto cutting and drilling the FR4.

I do keep finding more stuff I want to build though. I think I may do the Langner DCP-1 preamp... potentially leaving out the clean channel, and maybe the boost stuff too. Just boil it down to it's core flavor.

I also have a larger chassis I was going to use for a amp build that might be cool to do a Mesa mashup preamp with a Mark IIC channel, a Dual Recto channel, and then end capped both with the Mark EQ.
 
Last edited:
More on the PSRR side of things. For tube use in pedals etc the more the merrier.


I did use this in the tube compressor before the last change simplified the output section. In short I didn't have the right components to build it without grid leak and blocking issues, so eventually I had to remove the lower triode - it used the same technique to feed B+ noise into the lower triode, the resulting 180 phase shift then cancelled it out in the output signal. Broskie (TubeCad) reports a good 80dB PSRR, so coupled with a low noise regulator you'll get the additive effect and even more PSRR.
 
Hal Harvey said:
Right on, sounds like you have a path forward.

I have all parts on hand for my next four preamp builds. Artwork done for all of them, and layouts done for two. I'm going to do one last trace of my layouts tonight and then onto cutting and drilling the FR4.

I do keep finding more stuff I want to build though. I think I may do the Langner DCP-1 preamp... potentially leaving out the clean channel, and maybe the boost stuff too. Just boil it down to it's core flavor.

I also have a larger chassis I was going to use for a amp build that might be cool to do a Mesa mashup preamp with a Mark IIC channel, a Dual Recto channel, and then end capped both with the Mark EQ.
Click to expand...
Do a deliverance pre, I think it’s a really cool grain and much more versatile than people think ;)
 
Asdrael said:
Do a deliverance pre, I think it’s a really cool grain and much more versatile than people think ;)
Click to expand...

You already convinced me hah.

malvolence.jpeg

I try to tip my hat to the original while firmly in my aesthetic. So here the green power and large chicken heads (stealth chickens though).

The other one I finished layout for is the Laney AOR:

Dragonaut Front Panel V2 16 003.jpeg

This will cover the 6 knob MV AOR Matt Pike used but also the AOR gain stage some of the other models had will be toggle-able (overdrive here).
 
Hal Harvey said:
I need to look into a CNC lol. I'm sure the small cheap ones couldn't cut and drill the G10/FR4 though.
Click to expand...
My first CNC was a cheap desktop setup where the frame (aside from a couple steel braces and the leadscrews themselves) was literally made of PVC. It could mill FR4/G10 no problem, and that's almost exclusively what I used it for, until I started milling aluminum enclosures with it too. Don't doubt the little machines.
 
Just noticed this thread. I have a DIY 4 x EL34 bass amp build that’s been languishing for about five years now, hopefully one of these days I’ll finally get back to it. I don’t do clones anymore, but here’s one of my older original design rack bass preamps using one 6SL7 and a pair of 6SN7s in Aikido format:

IMG_0754.jpeg

The “new” amp will use a similar front end, but one 12SL7 and two 12AU7s. All the daughter boards are long since stuffed and ready to go, it’s a mishmash of PCBs and little turret boards. The power section is a repurposed NOS commercial PCB with a transformer splitter/driver section, which sounds really great for clean bass. I bought several of these boards, plus the matching power trafos, a few are 60 watters with just two power tubes. Could be trade bait, I’ll certainly never use more than a couple.

Oh, and I modded the heck out of a Laney AOR amp back when I was gigging on guitar, gutting the goofy solid state EQ section. I did twin tone stacks, pre and post boost stage. Post EQ was on internal trimpots, which worked out surprisingly well.
 
Last edited:
Well, my schematic and part selection is done, I have quotes for the transformers, know more or less where I'm heading in terms of footprint etc. So now I'm having fun. More or less half way in, with the difficult half behind me. 12ax7 distance center to center should end up at 5cm. Hopefully will stick everything in a smallish form factor. Maybe a bit deeper due to the massive ass choke.

1757794507460.png
 
Those pcb traces and pins are a little close for my liking for the HV. What clearance are you using?
There was an American electronics site that gave minimum clearance and creepage spacing for pcb tracks and layers/sides.

Using an IPC-2221 PCB Clearance Calculator for High Voltage Design

An IPC-2221 calculator helps ensure your next high voltage design has the right trace spacing. In this latest PCB design expert blog, we’ve compiled some important results here for your convenience.
resources.altium.com resources.altium.com
 
Last edited:
I am at least at 6mm clearance for anything above 200V difference. Should be good (displayed grid is 1mm scale). I am using 'rough' traces right now to place components in a way that makes sense (what a headache), then I will fine tune and double check. My Deliverance was built using the same type of rules and didn't blow up so I guess it's good enough ;)
 
Paradox916 said:
I’m torn do I spend my free time practicing and attempt to chase my goal of playing at 200bpm or do I build.
Click to expand...

You know what to do. That's going to be bad ass! I'm going do a 5 tube X88R build (lead and crunch channels only) after these next two I am working on.

My current status is I finished chassis layout, drilled, etc. I only have two band aids on my fingers.

6 knob Laney MV AOR:
Photo Sep 13 2025, 10 32 28 PM.jpg

Deliverance:
Photo Sep 13 2025, 10 32 35 PM.jpg

I plan to get the art on the two chassis tomorrow.
 
Hal Harvey said:
You know what to do. That's going to be bad ass! I'm going do a 5 tube X88R build (lead and crunch channels only) after these next two I am working on.

My current status is I finished chassis layout, drilled, etc. I only have two band aids on my fingers.

6 knob Laney MV AOR:
View attachment 102883

Deliverance:
View attachment 102884

I plan to get the art on the two chassis tomorrow.
Click to expand...
Man you are building all kinds of stuff… how are you planning on doing the channel switching for the x88r
 
Paradox916 said:
Man you are building all kinds of stuff… how are you planning on doing the channel switching for the x88r
Click to expand...

Making just the preamp stuff is a bit easier (and cheaper).

For the XR88R I'm going to do it in the larger chassis so I'll have room for relays , that said since I'm only doing the two channels, and I really only play for my cats and dog, I'll probably just use a DPDT toggle. Here's my tentative panel art:

XR Front Panel V1 16 001.jpg
 
Hal Harvey said:
Making just the preamp stuff is a bit easier (and cheaper).

For the XR88R I'm going to do it in the larger chassis so I'll have room for relays , that said since I'm only doing the two channels, and I really only play for my cats and dog, I'll probably just use a DPDT toggle. Here's my tentative panel art:

View attachment 102887
Click to expand...
Okay I misunderstood I thought you were making a 3 channel with 2 rhythm( maybe voiced differently) so it’s kind of like an sp77 but the rhythm not a clean channel?
 
You must log in or register to reply here.
Back
Top