chris_w_uk
Responses from chris_w_uk
| 5AR4/GZ34/5U4/5Y3 SS conversion The B+ has gone from 300V to 325V and from 290V to 315V at the OP valve plates, so as it is cathode biased I'm not too concerned. I'll put the tester inline with one of the OP valves and see what the plate and cathode current is to see if it's wit... | |
| How loud are you typically listening? 60db in the 13' x 13' room I use is plenty. that's about No4 on the dial. Any more than about 70db and you can feel the base through the sofa :^) | |
| FRANK pram 30 watts Ultra-linear Stereo tube amplifier Two parallel 1K 5W resistors in the B+ gives me 325V at the rectifier and 320V on the plate. I might need to add a 600 Ohm or so resistor into the bias, as with the new diode in place of the selenium the lowest it will adjust to is -13.1V. Not to ... | |
| FRANK pram 30 watts Ultra-linear Stereo tube amplifier After much fiddling I have managed to dismantle the selenium rectifier and rebuild it using UF5407 Diode 800V 3Amp Soft Recovery Ultrafast Rectifier Diodes. So it now looks original.https://cursorium.co.uk/images/modified-selenium.jpg | |
| FRANK pram 30 watts Ultra-linear Stereo tube amplifier I'm assuming this would be better than the UF5408 as I don't know about the recovery characteristics of the UF 5408.https://www.ebay.co.uk/itm/321930598840 | |
| FRANK pram 30 watts Ultra-linear Stereo tube amplifier Thanks for the reply. I didn't realise it could make that much difference, I have some UF5408, I'll swap out the 1N5408 for the UF5408. |