London Power 3 channels amplifier project - Printable Version +- Tube Amp Forum: The Ultimate Tone (https://theultimatetone.com) +-- Forum: Tube Amp Community (Hi-fi too!) (https://theultimatetone.com/forum-1.html) +--- Forum: Personal Projects (https://theultimatetone.com/forum-6.html) +--- Thread: London Power 3 channels amplifier project (/thread-70.html) Pages:
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RE: London Power 3 channels amplifier project - Vostre Roy - 01-20-2019 Greetings again! I've been quiet as of lately, had to complete some home projects before I could pour some money in this one. As of right now, I've got a brand new steel chassis and a knockout punch kit coming my way so as soon as I get back home later next week, I'll be able to jump back on this project. Now, quick question to Mr O'Connor: reading the PA-66 document, I just realized that to be able to have a switch to alternate between fixed and cathode bias, I'd need a DPDT switch for every single power tube, I'm I understanding the document correctly? If that's the case, I might just disregard that option and go with the Fixed-Bias option, unless you have a better recommendation. Cheers and (late) happy new year to all! RE: London Power 3 channels amplifier project - K O'Connor - 01-21-2019 Hi Vostre There are three options for having individual fixed / cathode bias switching control for each tube 1 - Use a separate DPDT for each. 2 - Install the relay type listed in the PA66 notes, then use a simple SPST or SPDT per tube. The relays mounbt on the board directly. 3 - Buy PA66-S2 which provides two relays and two switches, as required for each PX66 card (the power tube portion of the PA66). Have fun RE: London Power 3 channels amplifier project - Vostre Roy - 01-21-2019 Greetings Kevin, Thanks for the answer, I will get myself 4 relays to be able to use a single switch for the cathode and fixed bias option. I don't really plan to mix cathode and fixed bias between the tubes (might be a cool feature but for my personal use, controlling all tubes at once is more convenient). I didn't noticed that the shape of the connection on the PCB was meant to accommodate the use of a relay but now that you mention it, it is so damn obvious ahah Cheers! RE: London Power 3 channels amplifier project - Vostre Roy - 01-21-2019 Also, I think I've settled on what I will use as a third switch for this project. The following schematic was drawn by me but the original idea came from a website that I can no longer find, else I'd give the proper credit to it: It basically change one resistor and one capacitor value in the tone stack (sorry I don't recall their precise name). I've done that mod in my first ever amp built and really dig that I can tweak the EQ depending on what I feel like playing. I obviously won't install it right of the bat, I'll build the amp stock first and then add this mod (along with the gain and bright switch) afterward. Cheers! RE: London Power 3 channels amplifier project - K O'Connor - 01-22-2019 Hi Vostre In your EQ schematic you can use the SPDT centre-OFF switches, which are not too expensive. Note that "m" is milli and "M" is mega. Have fun Kevin RE: London Power 3 channels amplifier project - Vostre Roy - 02-11-2019 Greetings folks! Not a big update, but one nonetheless. I've received my knockout punch kit (I don't recall the company's name but its not Greenlee, given I do around one amp a year they'll do the trick). Result is way closer to my expectations: I've also populated the PSU board but didn't took any pictures, more to come at my next time off! Cheers! RE: London Power 3 channels amplifier project - makinrose - 02-12-2019 Nice job man--- It's looking good! RE: London Power 3 channels amplifier project - Vostre Roy - 02-12-2019 Thanks man! Now that I have those punchouts, preparing a chassis is a whole lot easier, my next project will probably get started as soon as this one is done. I still have the issue of having a non-heated garage, so I try to avoid having to work in there during the winter ahah RE: London Power 3 channels amplifier project - peteotto - 04-21-2019 Pretty cool what you have going. It is going to be tight in there for sure. I find it interesting that
RE: London Power 3 channels amplifier project - jmcd - 04-28-2019 Good job on the chassis! Looks very nice! RE: London Power 3 channels amplifier project - FormyxAmps - 12-10-2019 Hi all, Vostre Roy, great project! That drilled chassis looks very good! Any recent updates on your project? |