Diy Tube Tester help needed !
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Diy Tube Tester help needed !
by Thor61 » Wed Mar 10, 2010 2:20 pm
I found this very simple to build tube tester and was wondering if anyone could help me out ! My problem is I'm not quite sure where to get a transformer for USA use ect... Here is the link to the schematic > http://www.kolumbus.fi/risto.kivioja/Ri ... vanced.pdf
- Thor61
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by Ty_Bower » Wed Mar 10, 2010 5:40 pm
"It's a different experience; the noise occlusion, crisp, clear sound, and defined powerful bass. Strong bass does not corrupt the higher frequencies, giving a very different overall feel of the sound, one that is, in my opinion, quite unique."
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Ty_Bower - KT88
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by Thor61 » Wed Mar 10, 2010 6:21 pm
Ty, I had found a transformer w/120v primary and a secondary of 260v @ 100mA and 6.3v @ 3.0A. Will this work or be to small for whats needed ? Also I had looked at Edcor but dont really want to swing $ 50.00+ usd w/shipping included. Antek has a toroidal # AN-1T250 which is rated for 200mA @ $29.00 The first transformer mentioned is $25.00 In the schematic posted it shows a diode coming off the 260v side, what type should I use ? Please let me know what you think !
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by Ty_Bower » Wed Mar 10, 2010 6:41 pm
100mA will be fine for EL84, 6V6, and 12AX7. It's probably a little less than you need for the EL34 and 6L6 types, but it's not like you're going to have the thing running for more than a minute at a time. It would probably be fine.
The Antek would probably work great.
The Antek would probably work great.
"It's a different experience; the noise occlusion, crisp, clear sound, and defined powerful bass. Strong bass does not corrupt the higher frequencies, giving a very different overall feel of the sound, one that is, in my opinion, quite unique."
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Ty_Bower - KT88
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- Joined: Wed Mar 21, 2007 2:50 pm
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by Thor61 » Wed Mar 10, 2010 6:43 pm
What about the diode ? Will 1n4007 type work ok ? Foolish "newbe" question what do you think about the tester in general ? Probably a toy by your standards ! For what its worth I've been reading about tubes, basic electronics and amps now for a couple of years. I still don't know SH#@$*&TTT ! I just now am attempting to build a real tube amp after all this time. Please do not perceive me as being overly persistent, I have so much to learn, just trying to catch up and/or get a learning handle on things !
- Thor61
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by Ty_Bower » Thu Mar 11, 2010 3:41 pm
Thor61 wrote:Will 1n4007 type work ok? ...what do you think about the tester in general?
1N4007 is perfectly good for 1 amp and 1000 volts. The reverse voltage calculation is funny - the diode will see roughly 2 * sqrt(2) * 260VAC, or about -730 VDC. This is within the parts rating, so it will be fine. You'll start to run into trouble once the PT goes over about 350VAC (or 700VCT for a full wave supply). They do make parts with high PIV ratings, but they start to get expensive. For some applications, the Fairchild ISL9R8120P2 is suggested. It's rated 1200PIV @ 8A.
I usually buy UF4007 because they cost only pennies more than 1N4007, and they switch faster (are quieter). This property is useless in a tube tester application, but is nice to have in an audio amplifier's power supply. By the way, the Fairchild part suggested above switches even faster than a typical UF4007.
If you need more than 1 amp, you can use a 1N5408. They're cheap and good for 3 amps, but you don't need it here.
The tester looks like "just" a simple emissions tester, verifying reasonable cathode currents at a fixed operating point. It's certainly a reasonable way to cull out the obvious losers. I'm sure you could pay more and get a less useful tester taking your chances on some vintage piece of equipment from eBay.
"It's a different experience; the noise occlusion, crisp, clear sound, and defined powerful bass. Strong bass does not corrupt the higher frequencies, giving a very different overall feel of the sound, one that is, in my opinion, quite unique."
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Ty_Bower - KT88
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- Joined: Wed Mar 21, 2007 2:50 pm
- Location: Newark, DE
by Thor61 » Thu Mar 11, 2010 9:35 pm
Ty, Thank-you for taking the time to explain things to me. I have a very tough time understanding things merrily from reading, I'm more apt to learn from doing. That's why I have chosen to build this simple tester 1st, than later try my hand at something like the "Steve Bench - Rat Tube Tester" PS: I already built the Bucking Auto former as instructed from your links ect... Its now sitting till I complete my amplifier !
- Thor61
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by Ty_Bower » Fri Mar 12, 2010 5:30 am
Thor61 wrote:PS: I already built the Bucking Auto former...
Have you checked it? Use your AC volt meter, and verify that it correctly lowers the voltage. Keep in mind the autoformer does not provide isolation between primary and secondary. It should be mounted in some kind of enclosure where there is no possible way you could come in (electrical) contact with the transformer frame or any exposed wiring.
"It's a different experience; the noise occlusion, crisp, clear sound, and defined powerful bass. Strong bass does not corrupt the higher frequencies, giving a very different overall feel of the sound, one that is, in my opinion, quite unique."
-
Ty_Bower - KT88
- Posts: 1494
- Joined: Wed Mar 21, 2007 2:50 pm
- Location: Newark, DE
by Thor61 » Fri Mar 12, 2010 2:05 pm
I have done a test and it seems to work as described, though I have not put any kind of load on it ! I'm still trying to come up with a good looking enclosure for it. I had thought of using a die-cast dual or triple gang box painted black, with the transformer mounted sideways on a piece of aluminum angle attached to some 1/4" plywood to isolate it ect... Though something like this may be better if things get hot > http://www.grainger.com/Grainger/items/3HMY8
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