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Old 9th September 2009, 10:02 PM   #1
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Default my third RH84

Hey everyone! Im just starting my third RH84 on an ''existing chassis'' and i've got three 9 pin sockets and one octal on a very small chassis. My power transformer has two 6.3v secondaries and no 5v, so ive been trying to think of a tube solution.

Does anyone know of a 6.3v octal FW rectifier capable of 150 or so m.a.d.c.? I have a few 6X5's but there not capable of that kinda current...

Thanks!
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Old 9th September 2009, 10:15 PM   #2
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How about a 6BY5G, good for 175ma. It does drop a bit of voltage thou.

Jeff
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Old 9th September 2009, 10:25 PM   #3
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PERFECT!!! I could stand to lose that kind of voltage too. Thanks for the help! And cheers! to mr. Kitic for the design and for sharing it. Previously I used some japanese output transformers from a nice reel-to-reel and that amp is simply amazing!
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Old 9th September 2009, 10:46 PM   #4
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Glad to help where I can.

Quote:
Originally Posted by mctavish View Post
Previously I used some japanese output transformers from a nice reel-to-reel and that amp is simply amazing!
Akai perhaps?

Jeff
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Old 10th September 2009, 12:01 AM   #5
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Hmmm... yes Akai. What a hidden gem. I've picked up many over the years just to butcher them. There dipped in wax (so no corrosion) and each have their own power tranny and cute little choke. Its a recipe for nice S.E. amps, and if your lucky they come with some good Matsushita EL84 's!
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Old 10th September 2009, 03:18 AM   #6
dsndblm is offline dsndblm  United States
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I used the 6BY5 on my lastest amp build. They are nice tubes. In directly heated cathode, nice sound and have a really nice glow at night!
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Old 10th September 2009, 07:53 AM   #7
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Since your've built two successful RH84 amps, why not try a bit of variety. The partial feedback approach works best with a high output impedance driver - so a pentode is just the job. I have had great success using a 6AU6 in similar circuits. I would be more than interested to find out if there was a noticable difference in sound quality doing it the right way.

Shoog
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Old 10th September 2009, 11:26 AM   #8
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I've tried A triode-strapped EF86 in some experiments which sounded very nice, Plenty of gain. I've also built an amp with trioded EF804 driving 6v6's with some p2p feedback for my father-in-law with a pod dock and he seems quite pleased.

Were you using the 6au6 as a pentode? I vaguely remember a push-pull thread with some plate to plate feedback going on, was that you Shoog?
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Old 10th September 2009, 11:54 AM   #9
bigwill is offline bigwill  United Kingdom
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Wiring pentodes as triodes in this position defeats the point, you need a high dynamic impedance so that the feedback signal isn't eaten by the tube's anode

Last edited by bigwill; 10th September 2009 at 11:56 AM.
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Old 10th September 2009, 01:59 PM   #10
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Yes I did use the 6AU6 as a pentode in two partial feedback PP amps now. As Bigwill says doing anything else defeats the object of the exercise.
The EF86 doesn't make the best candidate - you need something which will carry a standing current of at least 5mA at about 150V on the plate - this makes the 6AU6 an excellent candidate - and its dirt cheap.

Shoog
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