The Amp Garage

Well I got my hands on a 2 amp fuse today from the car garage, and figured what the heck. Went through steps above and everything is fine - the hissing sound I first heard was the rectifier tube (presumably burning off some chemical or something?) but it stopped after 5-6 seconds, and subsequent pow...

Thanks guys. Would be lovely yeah... When the light was on the few times, and the 2 times it powered up with the rectifier tube though it hissed and then blew - now maybe that was the hairline short on the lamp. When I get the new fuses I'd run through this procedure: a) power up with no secondaries...

Missed your response ToneMerc. Thanks also.
Yes it was (supposedly) all wired according to the first diagram. I've spent a long time on it today, tracing and buzzing things through. I found a short between one heater and ground on the lamp, so with luck that and maybe a surge on power up is it.

Thanks tubeswell.

Nothing is open here on Sundays, but I'll get some next week. It's really baffling me this. Can't explain how sometimes it started and gave a light, other times just blew the fuse immediately. I learnt a fair bit though which is good.

The normal ones are 0.5A 250V (T500mA250V) - same as came in the kit
The fast blows are 0.25A (F250m250V) - I bought today, to just test the heaters.


[I'm in Denmark, so 230 from the wall]

The normal ones are 0.5A 250V (T500mA250V) - same as came in the kit
The fast blows are 0.25A (F250m250V) - I bought today, to just test the heaters.


[I'm in Denmark, so 230 from the wall]

Indeed... This is intermittent. I feel kind of ridiculous having blown 13 fuses today. But I tried again - a slow blow this time, all secondaries either free flying, or connected to the octal for the rectifier (no tube in, so they are open). Powered up fine - I switched on, off several times - no pr...

Ok... So with all secondaries disconnected, the fast blow fuse just blew on power up immediately (with a nice little flash just like the others). PT is hosed right? In doing this, I saw a small hairline strip of solder across the lamp -> ground. Would that have been enough to bring this all down? Th...

Hey Firestorm,
It's a http://www.tubeampdoctor.com/en/shop_Ma ... models_103

The 2 unused are red/black and black/yellow and they're both on the primary.

Hey Firestorm,
It's a http://www.tubeampdoctor.com/en/shop_Ma ... models_103

The 2 unused are red/black and black/yellow and they're both on the primary.

Now it's back to intermittently blowing fuses with no rectifier in. Maybe that's enough for 1 day.

I feel stupid asking this, but can someone please confirm the diode and the cap look oriented correctly at the back? I assume the "-" arrow points to negative and the solid line on the diode casing means the bar.

Thanks tubeswell, mark. Orange wire now disconnected, and confirmed no rect. tube seems ok, but with the rectifier it hisses quickly and blows or blows fuse immediately. I've checked wiring and don't spot anything immediately wrong, but now will buzz everything through to see. I guess this is how we...

Thanks guys. Quick update: I connected everything up again, and removed my drain resistor I put on the cap. With no tubes, I have 700+ and 5VAC on the rectifier pins, so I now assume my PT is not hosed (phew). Sorry I am a bit new on this. Could you please confirm that the orange wire should be remo...

Thanks Mark! Kind words, but alas I am just following a tubeampdoctor build so I just follow the instructions (or not as it appears today) The circuit and layout I am following are http://www.tubeampdoctor.com/images/File/Doku_PRV_US_komplett_200912.pdf The light is good - verified in my other amp. ...