|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
72.235.7.37
I have this pair of supposed Electraprint Single Ended OPT. The primary I just tested to come up with about 1.2K impedance, red and black wires. and there are 3 wires, green purple blue in the secondary which measure, green to blue .7 ohms, and green to purple .8 ohm. If I use purple as ground I measure green at .4 ohms, and blue at .7 ohms. I measured the inductance on the primary at 5 Henries. The dimensions are sizable at lxwxh being 3 3/4" x 4 3/4" x 4 1/2".
If anyone knows what tubes they were designed for I would be very pleased to know. TIA, Dak
Follow Ups:
they are very helpful.
You need to calculate the impedance ratio. I would expect it to be 2500 ohms to 3000 ohms. In the old days he used to wind primarily the multi-tap outputs. These are probably more recent transformers.
Since he does not usually put any markings what-so-ever on the transformer, to know for sure you will have to calculate the ratio of input to output.
Hi Chip, I used that method and measured about 12vac to 1v on the secondaries. Squaring that gives 144 x 8ohm is 1.2k reflected impedance. I am assuming that the taps are 4 and 8 ohm in the secondary. regards, Dak
So now you have 2400 ohms (2500 ohms, close enough).This would be what I would assume although the 5Hy is confusing. Should be more.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 10/16/14
Yeah, it could be 8 and 16. Is the actual DCR any indication? I wrote electra print and am expecting a response soon.
Anyway, if the secondaries are 4 and 8 ohms what tubes would be suitable for a 1.2k impedance?
parallel 2a3's would be happy with a 1.2k ohm load.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Jack will know. In the meantime, I'd take a look at this:
http://www.one-electron.com/Trans/UBT1_20.pdf
That is a 1600 ohm output transformer and the data sheet gives you all kinds of tubes you can parallel to be in the ballpark. Single ended parallel.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: