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First time DIY tube amp
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Author:  billnchristy [ 27 Jan 2009, 21:44 ]
Post subject:  Re: First time DIY tube amp

But yes. the tube dictates the output transformers primary impedance.

Any brand will work if you stick with the right impedance.

Author:  CloudStrife [ 27 Jan 2009, 23:03 ]
Post subject:  Re: First time DIY tube amp

Edcor makes a few too. They're cheaper than the Hammond and look better, but they don't have the 4-8-16 ohm range, just 4, 8, or 16 only.

Author:  jmillerdoc [ 01 Sep 2009, 12:14 ]
Post subject:  Re: First time DIY tube amp

Hi,
Has anybody tried wiring this circuit in pentode mode? Just curious, I am in the process of acquiring parts for it, Edcor seems to have the best prices and I have used their OPTs with excellent results. The closest they have in a power trafo is the XPWR033 which is 380-0-380 at 200mA. It is about $84. It may require a small value resistor in the PSU to bring it down to the 400v, but not much I imagine.

I was also wondering if one could get by with just one choke on the preamp stage with both channels wired to it or will 2 chokes be needed , one for each side? I just happen to have a 5hny choke on hand, but only one and it is an old Chicago Standard. I doubt I could find another to match it.

Can anybody tell me what the target plate voltage is for the preamp tube?

Thanks for the help.
Jeff
Lawton, OK

Author:  cjkpkg [ 02 Sep 2009, 07:45 ]
Post subject:  Re: First time DIY tube amp

Check out the Allied 6K7VG - basically the same as a Hammond 274BX but only about $50 from Allied Electronics. I use it in my tubelab SimpleSE. I am currently running KT-88s with it and I recently acquired a set of James 6123s...before that I was running the inexpensive Edcor XSE15-8-5s and they too sounded very good - especially for only $20 ea.

I am also running a large motor run cap 90uF 375VAC (ebay) and a Triad C-14X choke(inexpensive at Allied or Mouser) in the PSU and it is really really quiet.

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