04-30-2024, 12:48 PM
Hello All;
I found this interesting thread on a British radio forum about the Bush DAC-90, and modifications one fellow made. Some of the mods make sense, others not so much, like adding a 220 uf cap as a cathode bypass on the UBC41 first audio tube, assuming this was not in error. Most of the North American AC/DC sets don't even have a cathode bias resistor on the first audio tube at all, it goes directly to the B-. What I find odd is that of all the mods he made he didn't add a cathode bypass capacitor on the UL41 power output tube in parallel with the 150 Ohm cathode bias resistor there, nor did he change the B- wiring to make it into a floating chassis set, give the high line voltage they use there.
https://www.vintage-radio.net/forum/show...hp?t=35784
https://www.vintage-radio.net/forum/atta...1230506945
Regards
Arran
I found this interesting thread on a British radio forum about the Bush DAC-90, and modifications one fellow made. Some of the mods make sense, others not so much, like adding a 220 uf cap as a cathode bypass on the UBC41 first audio tube, assuming this was not in error. Most of the North American AC/DC sets don't even have a cathode bias resistor on the first audio tube at all, it goes directly to the B-. What I find odd is that of all the mods he made he didn't add a cathode bypass capacitor on the UL41 power output tube in parallel with the 150 Ohm cathode bias resistor there, nor did he change the B- wiring to make it into a floating chassis set, give the high line voltage they use there.
https://www.vintage-radio.net/forum/show...hp?t=35784
https://www.vintage-radio.net/forum/atta...1230506945
Regards
Arran
