The Amp Garage

Thanks, that is helpful. I hadn't seen that page before. It seems that I have it right in terms of cathode bias.

I do still wonder about whether it's ok to run the 6.3 supply for the other tubes from the same transformer winding, or if I should use a different one.

Hi all, I'm starting a push-pull guitar amp project using the 6397, a subminiature "power" pentode with a directly heated cathode. The datasheet can be found here , for anyone interested. The filament has a center tap, and I would like use cathode bias. This is my first project using a directly heat...

Oh cool, I've look at your page before. That amp was/is one of my inspirations. Re: the push-pull triodes, I know what you mean. I've gone back and forth on whether to use triodes in the output stage or whether to try to use some small pentodes. I actually have a couple of 6397 tubes, and it appears...

For clarification, aren't you describing the resistor that is circled in red on the image below? Yes, that's the one. Thanks, that's a big help! Are you looking for the input or output impedance, or even both? I don't have a decade box or a power variable resistor available in order to do this meas...

Thanks Katopan, Yeah, I'm aware that everything needs to be rebiased. Luckily, I have a uTracer, and have been able to run some tests on the 6112. It seems like the plate resistance is around 36K, so I'm going to be using 75K load resistors. How did the 18W with 5902's turn out? And did you make a p...

I was kind of hoping that the particular component values would be irrelevant, and that the info above about the subcircuits would be enough. The Tiny Terror is not, after all, a particularly complicated circuit and it's mainly the grouping of the various components and subcircuits that I'm interest...

Hi all, I've been working on implementing a version of the Orange Tiny Terror circuit using subminiature tubes. I'm using 6112s for the first two stages and LTP, and a 6021 or 6111 for the "power stage". I have to say though, that I seem to be much better at turretboard layouts than PCBs, so I was h...

Sorry for monopolizing the thread this morning, but there is one other thing that I've always wondered about the Tiny Terror, which is the (to my mind) somewhat odd gain pot circuit. Specifically, does anyone have any thoughts about why Orange puts a resistor in parallel with the potentiometer, rath...

I LOVE these hot rodding projects... 8) I'm not sure I understand your plans really well, though. The schematic seems to be available on the internet so I don't see the need to trace it... :? If you already didn't do it, I highly recommend that you look at Aaron "xtian'" builds - not just its Orang...

While you're at it, could you measure the impedance of that OT? There are a couple OTs out there that are listed as replacement/upgrades, but they vary somewhat in specs. I'm going to be attempting a subminiature version of the TT soon and it would be good to know what the load line in the original ...

yes sneakers563, this site is FULL of dumble schematics :P Alright, alright :oops: I'll add a couple in the next version. Speaking of which, I just submitted the bugfix for that slider issue to the app store. It generally takes Apple 1-2 days to review the submission and approve it, but it should r...

I've been playing with your iOS version. Excellent! I am presenting a tube amp seminar at the local college next week--this will be a great tool to show! Noticed a bug: I just played with the sliders in all the free tone stacks, then I returned to the AB763 model, and, though the sliders were all a...

Xtian: Thanks - I think I can add something to make sure that doesn't occur.

10thTx: I'll look around for some Dumble schematics. I think they're kind of hard to find, but I will see what I can find.

Thanks!
I just need to get the screenshot "share" thing working. It shouldn't be much longer.

Hi All, I've created a cross-platform mobile app called "Tonestack Kit" that builds on Dave Cigna and Duncan Munro's work in Duncan's Tonestack Calculator. The iOS version is available now in the App Store. I am in the process of testing the Android version and should have that available in the next...