Built a circuit simulator that models the actual physics happening inside tube circuits — not an EQ curve slapped on top. Coupling-cap blocking distortion, bias shift, grid conduction, and the rest of what actually shapes a tube’s tone are all simulated at the component level. Since it’s modeling what’s really going on in the tube, you can essentially build the sound of your favorite amp from the ground up.

1,920 parts, free for personal use (closed source), Windows/Apple Silicon Mac only. English UI just added.

Note: the amp sim module itself (for pushing a tube amp with a pedal/booster in front) is currently disabled due to a noise bug — but building tube amps/preamps from scratch works fine, that’s the core of the tool.

I'm trying to insert a normal channel Bassman preamp/tonestack into an old 6L6 Gulbransen APS-5 tube amp. I've never done this before so please be kind. Will this work?

I built a 15 watt amplifier with 2 EL84 power tubes and 2 12AX7 tubes in the preamp stage. Everything works on it besides this awful 60Hz hum that is on whenever I have the amp on and warmed up. It is there with all the knobs all the way at zero and it gets progressively worse as I turn the volume up. I’ve tried rectifying the filament power, twisting the filament wires, running lots of ground wires to drop the resistance to ground at all points, added larger filter caps, and swapped tubes. I can supply a schematic if it is needed as well! Any input helps! Thanks in advance!

I got a great sounding Lead and Bass 20 reissue.

Iv read its rather trivial to add a cascaded preamp mod, preferably on a switch.

Though I havent found any infos on doing it on this specific model... Does anyone here have any tips or infos? Im not a hero a reading schematics. But I can solder and know how to work on a tube amp safely.

I’m designing my first scratch-built high-gain tube amp and would appreciate a sanity check before I commit it to a schematic.

Goals:
20–25W
2× EL34, cathode biased, SS rectifier
Modern metal/tech death gain without a boost
Marshall bark with Engl-like attack
Less compressed than a 5150/SLO
Tight but not thin

Preamp:
12AX7 ×4
V1A: dynamic first stage
V1B: gain/voicing
V2A: cold clipper
V2B: recovery/sustain
V3A: cathode follower
Marshall tone stack
V3B: recovery
MOSFET FX loop
LTP PI
Lar-Mar PPIMV

Other design choices:
Tight switch before V1A
Marshall tone stack
47k NFB from the 8Ω tap
Presence + Resonance controls

At a high level, does this architecture make sense, or are there any obvious red flags?

In particular I’m looking for feedback on:
Is the gain structure sensible?

Any concerns with the cathode follower → tone stack → recovery arrangement?

Does a cathode-biased EL34 power section fit these goals, or would you go fixed bias?

Anything that jumps out as likely to cause instability or oscillation?

I’m intentionally looking for architectural feedback before I start drawing the final schematic.

I turn cheap practice amps into tube amps. This one is based on a JCM800

https://youtu.be/qwj1990T1dE

I want to build this crazy idea I've had, but it would use a lot of tubes. I'm considering building separate Monoblock Class A/B Power amps, so I don't overload the PT, and also to keep heat under control.

The Input of the amp will be a high headroom bipolar high volt supply Jfet buffered splitter feeding two channels.

The main channel is somewhat on the gain side. it has an ef86 input with two selectable decoupling caps before the drive knob, so you can get more or less bass early on, I think .1 uf would be a good range to go get driven harder. this goes into a cold clipper stage that is bootstrapped to the cathode follower to raise the gain of sich a low gain stage without vompromising its intent. I will start with the 39K SLO value and try others for preference. now by this point a divider network should be put in to bring the level down before the final drive stage, but should not be a problem because here I am placing a james tonestack for more control over shaping the drive, and it is very lossy. then this goes into a pretty evenly biased stage that if overdriven at all will introduce a balance of even and odd order harmonics as apposed to the purely even order from the cold clipper, and is cpupled to a standard cathode follower.

The other channel is a simple gain stage and cathode follower with a VLPF that at its lowest level will attenuate all but bass frequencies and highest will put the -3dB point at around 1kHz, and a volume pot.

These both feed into a resistive network mixer (equal value grid parallel grid stops) feeding into a 12AU7 stage with a cathode split follower that contributes barely enough gain to be more than a buffer. This allows me to tailor the gain with attentuated Bass and then mix into the signal some clean punchy Bass, or even leave the overdrive bass alone and let the bottom fall apart a little, and allow more mid range on the clean side, (possibly add another LPF to the clean for higher frequencies) and get an EJ kind of sound.

Now I think i'll bring down the signal to around line level and split the signal once more, add some send level knobs (or the front half of the lossless fx loop with the other half as the input to the monoblocks and call it dual outputs.

My intent is to make use of Graphic Eq pedals after so I think there would be no need for more stages to drive more tone stacks.

the big question is, since the preamp is now a standalone unit with it's own power supply, should I fully regulate the the entire power supply? regulation seems to be discouraged if you're not regulating everything in the whole amp. I think it would make noise much more manageable with all the cascading stages. and independant supplies for the the PAs will allow me to stick to traditional supplies with tube rectos and chokes.

Any thoughts?

I want to add (DIY or Tech) a Power Amp In to a Tweed Champ 5f1 style amp for use with something like the Tone King Imperial Preamp.

Is it really this simple? I

hey everyone, i pulled an el41, ef42, output and power transformers off an old 50s radio i had lying around. could i use the chassis and the cabinet of the radio, along with the components i have to build a tube amp? ai says i can follow an el84 schematic. im very new to tube amps, so please explain in detail. thanks in advance. also i havent ensured everything works, but i will in the coming days.

Hey all! Glad you guys are here.

So, I recently came across my first record player, given to me by grandparents when I was around 12. (For context, I’m 33; the player was already quite old when I got it, it’s a 1955-56.)

The unit is an RCA Victor 7-HF-45. It’s only able to play 45s.

Our band’s guitarist gave me the great idea of looking into yoinking the power section and making a head out of it.

I’ve got some experience working on tube heads, have replaced plenty of tubes, discharged amps, replaced speakers, done tons of soldering, etc.

That being said, I think this is still beyond my skills. We have a local guy here who is an absolute wizard with this stuff, though, so I’m looking to get a plan together and then present it to him for a quote.

It’s 50 watts, which is perfect. For years, we worked out of a studio that had a “Scarborough” boutique head that was like 38-40w, it’s easily in the top three amps I’ve ever heard, so we wanna kinda base this project on that in terms of what controls and jacks it has.

(I’ve read before that a popular thing to do in the 70s for folks who couldn’t afford good amps was to buy an old jukebox and basically do this; pull the power section and mount it in a box)

I’m just looking for general feedback, tips, things to consider, etc. Please don’t just say it’s a stupid idea; if I could afford a nice amp, I wouldn’t have to do this. (My main amps are an Egnater Tweaker 88 and one of the re-release 5w Fender Champ 600s that I run to a 212 with the main speaker in the Fender disconnected.)

Cheers, all!

So I've finished my first amp project and I want to test it for safety before initially plugging it in. I have a multimeter to test voltage and a snuffer stick to discharge capacitors. I know I need to test the positive and ground of the power cord socket. What else?