Start feeling it is about time to make another amp... Look through my bins, and try to figure out what type of amp I'm going to build this time.
First, I am looking at my last un-finished project: PC switching power utilization. I got a PC power unit, and tested with a dummy load 10 ohm and signal wire pin24 to pin23. The power is up, I connected a 110/220 v to 8 v transformer in reversed way to the switching transformer output side. 8 v to output side, thought I would get about 250 v ac in high frequency. But to my surprise, there is no output from this external transformer at all. (7/28/2010)
Continue: (7/29), back from work, and tried to connect the same way yesterday I did, but carefully checked connection, and used one of toriod transformer, wow, there is pretty high voltage, however since it is high frequency, the v-meter does not work. Now I have to think about something else...
Continue: (7/29), back from work, and tried to connect the same way yesterday I did, but carefully checked connection, and used one of toriod transformer, wow, there is pretty high voltage, however since it is high frequency, the v-meter does not work. Now I have to think about something else...
Continue: (7/31), browsed on internet, and found someone mentioned control signal is between Pin 14 and ground. But with current connection, I had no problem to power on.
Searched frequency requirement for diode that I connected to the transformer, I think it is because the one I am using is really a not ultra fast diode, so need to get 1 or 4 to test that out.
On e-bay, I saw 50 of them cost about $6.
Continue: (8/20), bought a surplus 150 v: 2x4.5v small transformer from a local shop, connected to the PC power, this time I used HPS40 Scope to watch the output, there are 10 v and 3.5 v from the pc power unit, I connected transformer 4.5v terminal to 3.5v output on PC power side, and the scope test terminal hooked on the transformer150v side, it comes out as 240v high frequency voltage. If I connect to 10v output from PC power then the output from 150v side shows about 430v high frequency voltage. I connected with an ultra fast diode, the read from the scope is about 220 v. The experiment concluded that, yes with this simple way, you can use PC power to support your tube amp!
One thing I noticed, the transformer is warm! The small transformer is not toriod core, it is conventional E core, so there must be large lose there. I can't seem to find 1:40 toriod core transformer from online.
posted by Taichitoday at 6:31 PM
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