Tube Amp Archive

Thanks for the replies, and apologies for the late response.. So.. the way I picture it then; one wire from the output transformer (290v on the schematic) goes to the plate of the 12AX7 (pin 1). The 1M resistor and 10n cap(s) connect to the grid (pin 2). The 1k resistor that goes to ground, connects...

Hello there, A while back, I built a clone of the selmer little giant. (Please find the schematic attached). Here also is a schematic of a phase oscillator circuit (with footswitch) from http://www.valvewizard.co.uk/trem1.html that I plan to use. I'm just not quite sure how to integrate it into the ...

That is right, there are just the two wires that go to the speaker output jack

http://www.ampmaker.com/store/5W-single ... ormer.html

Thats brilliant, thanks for the advice; when I eventually get my tubes I'll have a go at adding those in. Its a british amp, and I think the line voltage over here (in the UK) has always been that high. The originals had Mullards in.. which perhaps could handle the punishment. When it was functional...

Hello, I recently built a clone of the selmer little giant MKIII circuit, I posted about it here actually, https://tubeamparchive.com/viewtopic.php?t=24208&view=previous&sid=c1a7dfe6d7ba64fd83fa2355ea984180 I've finally got time to have a go at resolving some issues. The amp seems to be eating throu...

Okay, I've done some measurements and here are my calculations. Plate voltage = 285v (pin 7) Cathode voltage = 8.09v (pin 3) Actual plate voltage = 285 - 8.09 = 276.91v 8.09/120 = 0.06741 Plate dissipation = 276.91 x 0.06741 = 18.666v That is certainly too high. If I put a 100r 5w cement resistor in...

Finally at that time of the week. I can now start testing voltages and I'll post my findings shortly. I'll start with sorting out the cathode resistance, but for the 10uf filter cap, is it supposed to go in between the 270k resistors and the 100k resistor, what about the polarity? Or does the positi...

I'm in London. Most of my parts I have gotten from barry at ampmaker, (high quality and affordable), but for the odd bit, I tend to visit the techs on Denmark street. Most of my tubes are actually from Hong Kong, I look forward to being back there come the summer, it really is electronic heaven. I'v...

Good work indeed! Now I'm interested, gonna have to build one of these "British Champs". EL84 cathode resistor and plate current thoughts. The typical Rk for a PAIR of EL84 was 130R. It's possible you're subjecting your output tube to an early burn out with sky high plate current. I'd start with 30...

Nice job! I see you even bent your own chassis. Very nice. Voltage specs on caps are a do-not-exceed voltage. So it's no trouble to have a 400v cap where the schematic specs lower voltage, for example on your power tube cathode, and as you noted, it only gets around 25 volts. Yes indeed, you're pro...

Hello, I've just finished my first amp build. A clone of the Selmer Little Giant MKIII. It is working pretty well, it is certainly loud, and plays very similar to the originals I have tried. I'm yet to house it, but here are a couple pics of the build. [IMG:1024:768]http://i163.photobucket.com/album...