Re: kt88's to replace the EL 34's in a eico hf-60 design

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In Reply to: kt88's to replace the EL 34's in a eico hf-60 design posted by rcb on May 12, 2007 at 07:43:28:

You don't need to do anything. The KT 88's will draw more heater power than the EL 34, but not a whole hell of a lot more, so you may be okay. Ordinarily, you would want to put 350VDC on the screens, as opposed to the 400VDC on an EL 34, but the HF 50/60 is an ultralinear design and will abuse either tube in exactly the same way. The differences in pin out for the two tubes make it sometimes tricky to move from a KT 88 to a n EL34, but not from an EL 34 to a KT 88. So, other than ensuring that your power transformer has plenty of heater power, building for one output tube will allow you to utilise the other. Just remember to rebias for the different types.

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Follow Ups Full Thread

Topic - kt88's to replace the EL 34's in a eico hf-60 design - rcb 07:43:28 05/12/07 (6)

Yes you have to change the neg bias resistors - Michael Samra 09:54:42 05/12/07 (4)

looking for the 22k neg bias resistors - rcb 13:27:39 05/12/07 (1)

Re: looking for the 22k neg bias resistors - Michael Samra 08:27:09 05/13/07 (0)

Re: Yes you have to change the neg bias resistors - Michael Samra 09:56:42 05/12/07 (1)

eico hf-60 maual - rcb 07:56:33 05/15/07 (0)

Re: kt88's to replace the EL 34's in a eico hf-60 design - corerosin 08:24:25 05/12/07 (0)

Follow Ups

Re: kt88's to replace the EL 34's in a eico hf-60 design - corerosin 08:24:25 05/12/07 (0)

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