r/diytubes

Hello all, my Tiny Terror build has gone unexpectedly quick, its working and sounding great. So off to the next step:

This amp doesn't really have any EQ capabilities, only a basic treble cut control. So I thought it would be nice with an effects loop, I think an EQ pedal between the preamp and PI on this amp will really open up a lot of cool sounds.

So applying my newly acquired and very rudimentary knowledge I was thinking like this: the PT has enough filament current to heat one more 12AX7, what if I wire the first half as a cathode follower before the send jack, as a buffer and with a pot to dial down the signal level to not clip the pedals. And then the other half as a triode after the return jack, to restore the signal level, also with a gain pot.

So far so good, or have I gone off the rails already?

Because then I thought that a 12AX7 in triode circuit, that is a gain stage, like the gain stages in a modern high gain amp, that can add distortion. So I was thinking , can I configure the caps, resistors and pot for this stage to span the whole range from clean signal recovery to heavy clipping? So that say in the first half of the pot sweep it acts like a typical effect return level control, and for the second half it turns into an increasingly saturated distortion stage.

Does this make sense or am I completely off the rails now?

Thanks in advance :)

I registered on ampgarage.com 5 days ago and still haven't been approved as a user. I answered their one question correctly. Does anyone know what's going on there?

Hello all, my Tiny Terror build is working and sounding good, and I did some measurements on voltages. It is a 2xEL84 push/pull with 120 ohm cathode bias resistor shared by both tubes. The cathode voltage is 10.4 V. B+ is 319 V.

I have read that target bias voltage is 12 V, so am I running the tubes too hot? Should I change to a 150 ohm resistor?

Is this mainly about tube lifespan or can I expect some change in the sound if I increase bias voltage to 12 V?

Thanks in advance

I am working on a 5F2A Tweed Princeton built around a Hoffman turret board. First time building a 5F2A.

I'm getting the wiring squared away and realized my PT has a center tap for the heaters. In past builds, I have not used a heater CT... I just followed whatever layout verbatim, tied the CT off with heat shrink and used a virtual CT with two matched resistors.

Can anyone school me on using the CT versus not?

From what I've gathered, it might be best practice to use the CT if one is available. In which case should I:

1. Tie the CT it into the PT ground lug; or
2. Ground CT at the cathode (pin 8) of the 6V6?

Thanks!

Has anyone out there had experience using KiCad? I want to create a schematic that I can easily modify and share. Are there better tools? And is it good for both tube and solid state components?

I'm kicking around the idea of building a DIY guitar amp and I'm trying to decide between a 6G2 and a 5F2. I'm more interested in having something that produces the sound of a 6G2, but I also don't want to get in over my head. I know the 6G2 is still relatively simple, but I kinda don't know what I don't know, so I'm looking for your input. Some info:

My soldering skills are passable. It's mostly been cable assembly rather than components, but I can get by. I at least know what good soldering and wiring should look like.

I know next to nothing about how electronics work. I can read a schematic and identify parts and how they're connected, but am clueless as to why 95% of it's there or what it's actually doing.

I'm only interested in building an amp head, not a combo.

I have zero interest in replicating the original aesthetics of either of these amps. I would build this inside of an old radio or other shell of more-than-ample size. If I can salvage components, great, but I'm not banking on that and am not looking to hot rod an existing circuit.

I'd most likely source the parts myself from a list rather than buying a pre-made kit. Partly to (hopefully) save money. Partly because I haven't found a 6G2 kit (there are 6G3 kits).

Thoughts? Am I making too much out of this?

Hey all!

I ordered an AA1164 Princeton kit from Amplified Parts - seemed to be the best value when considering quality. They only offer a 1x10 cabinet option and I’m pretty set on a 1x12 arrangement. This has me looking at other companies for the cab. Mojotone seems to be a good option and offers custom covering and grill cloth so I’m leaning there.

Anyone have experience interchanging the chassis and vans between these vendors? The measurements seem about right but neither company was able (or willing) to confirm compatibility. I’m planning to get the cab without the chassis holes drilled, so it’s really just dimensional fit that I’m worried about as I’ll take care of the mounting part. I guess I can just wait until I have the chassis in hand but I’d love to get the cab on order since there’s a little lead time for building it.

This will be my first build so I don’t know what to expect as the norm from these kits (do have other experience troubleshooting amps and electronics)

As a side note, I was looking hard at the Weber kit and then upgrading components but, since that kit no longer includes a set of tubes, the total cost to build looks to be similar or higher than competitors using much higher quality components. Am I missing something there?

Hey r/diytubes,

First post here. I’m a tube amp builder and I’ve spent way too much time in weird high-voltage rabbit holes GMI-90, MC1/60, GU-81, and more normal audio/guitar amp stuff too.

I got tired of always jumping between datasheets, old PDFs, SPICE files, forums, calculators and tube folklore, so I started building the tool I wanted for myself.

It’s called Ampera:
https://amperatubes.com

It’s basically a free tube design/learning workbench. Pick a tube, look at the curves, move the operating point, change the load, check dissipation, compare another tube, look at SPICE/Koren data, and try to understand what is actually happening electrically.

I’m trying to keep it anti-dogma. Not “this tube is magic”. Not “this topology always sounds better”.More like: what changed, where is the operating point, what load does the tube see, is the bias sane, and why is the damn thing humming? It has tube pages, datasheets, pinouts, loadline tools, comparison tools, SPICE models, and a Learn section with guides on loadlines, bias, power supplies, tone stacks, troubleshooting, hum/ripple/grounding, etc.It’s still beta, free, and very much open to being corrected.I’d love feedback from DIY tube people: wrong data, bad assumptions, missing tubes, questionable models, unclear explanations, or anything that would make it more useful at the bench. Not a replacement for datasheets, measurements, a scope, or experience. Just a tool I wish existed when I started.Also, there are a few dumb little easter eggs in the site because I apparently can’t help myself. Try typing internet and enter in the search bar (more than 50 hidden...).

This doesn’t replace datasheets, RDH4, Merlin, measurements, a scope, a meter, or experience. It’s just meant to sit between “I found this tube” and “I understand what I might build around it.”
And yes: high voltage can still kill. Especially with the kind of dumb big-tube projects I like. Please be careful.

Thanks to anyone willing to take a look.