The Amp Garage

Schematic looks good! I'd be concerned your primary impedance is too low (the datasheet echoes bepone's suggestion for 12k ohms) -- I'm not sure how much mismatch is acceptable, but a quick Reverb search shows that, for example, a Blues Jr OT can be found for about $25 before shipping. That has a pr...

WhopperPlate wrote: ↑Thu Apr 11, 2024 5:52 pm Not even I can defend this

I was going to hop in with a "tone fuse" joke but was concerned someone down the road might take it seriously

Yeah,263AX should give you a B+ of ~280V. The problem with 263AX is that it doesn't have a 6.3V tap. 269AAX also has a 200V HT secondary but has a 6.3V secondary for the heaters, so that'd be the better option. 261M6 is rated for 215V @ 269mA and has a 6.3V secondary, so it'd also be even closer to ...

Gotcha -- yeah, I don't think there's a ton of difference between the grid stopper values listed anyway, so that makes more sense. Regarding the B+ string, yeah I think that'd be a solid starting point. You may want to tweak values once you get the amp built. You might even want to go with more radi...

Yep, 315 is the maximum rated plate voltage. Assuming you proceed as-discussed, you're still well above that limit (I estimate your B+ to be about 385V with full-wave rectification). I know people run 6V6s all the time way over the rated maximum, but I'm not that familiar with 6k6, so I'll hold off ...

Agree regarding PT being a prior question and that 275-0-275 makes sense if you're trying to run the 6k6 within datasheet spec. Do you have strong preferences either way in terms of low- or high-voltage sounds? If you go lower B+ (probably a good idea), I'd also suggest considering revising your B+ ...

I'm glad I re-searched this because I was about to ask how to scale filtering from 50w to 100w or vice-versa in the tech section. Really helpful mathematical analysis -- thanks! I did want to get clarification on something, though: it's not really clear to me why filtering would scale as a square-ro...

I'm not sure I understand the design goal. Are you after a wet/dry rig with one side doing reverb and the other dry signal? If the goal is reverb-only on one side rather than reverb mixed with the "original" guitar signal, I think that's only possible with two separate channels, whether that's usin...

My understanding is a stereo signal required two outputs, one for "right" and one for "left". A single speaker cannot, by definition, deliver a stereo image. The half wave feed to a speaker seems impossible. Perhaps an alternative would be running two parallel PP output stages, but then how do I in...

I appreciate the sentiment of wanting to build something like this. I have a Fryette Power Station, it's a very good device, but overkill for what I want - a good non-tone-sucking attenuator, an opportunity to add post-power-tube-distortion effects, and then something to amplify the signal back to ...

Agree with the Hammond enclosures if you have the ability to machine the chassis. If you don't, I have ordered from Modulus in the United States without issues since I also wanted their aluminum JTM-style chassis and don't have the tools or space for machining that I would find visually acceptable (...

Curious, like others here, what you meant by "feed a speaker a half-wave signal". Best .. Ian I wondered if you could run two SE output transformers, with each power tube being fed by one plate of a phase inverter. Would the design goal be to simplify a stereo build by using the PI as a mixer? If s...

Why not just build a reactive dummy load and reamping device without necessarily copying the Power Station? It seems to me that there's enough information about the Power Station to inform tweaking a something of your own design, and there's a ton of information on the Fryette Youtube channel, inclu...

Build finished, fired up successfully. 316v plates – 10.3 cathode = 306v plate-to-cathode, 10.3v across 130R cathode resistor = 80mA, or almost exactly 100% dissipation, so that's nice. I have a LOT of noise at idle. It's not the gNFB, it's just a huge amount of gain following the Volume pot. If I ...

or 1980.. Picking caps by Walter Jung and Richard Marsh people knew more 100 years ago.. today again we need lo learn basics..and again and again....... https://milbert.com/Files/articles/Picking_Capacitors_1.pdf https://milbert.com/Files/articles/Picking_Capacitors_2.pdf This is exactly the kind o...