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Old 1st October 2016, 02:24 PM
Richard Richard is offline
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Join Date: Dec 2005
Location: Notts
Posts: 4,936
Default Re: KT88 Output Transformer

Hi again,

The originals were 10K 6R and you're perhaps unlikely to get them off the shelf.
A few of us used Sowter UO82 which are 8K 8R.

Any of the better known makes designed for EL34/KT88 should be fine. They are generally 6K6 8R and you can use them pentode or UL as you wish.

(Speaker loads vary and will reflect their load back into the primary. Lower impedance speakers will result in lower primary impedance and vice/versa hence both specs are needed along with knowing what your speakers are.
KT88 valves are also biased with more current than EL34 so get a larger and better spec Mullard 5-20 type if you choose your own.)

The Sowters are huge and expensive but fit ok and perform superbly.
A less expensive option might be the Danbury VT1330 from Mike Holmes. I've used a pair of these on a Mullard 5-20 designed for EL34 and KT88 and they are very good indeed. If you post the dimensions of yours I can check mine to see if they would still drop through etc.
Attached Images
File Type: jpg Kit88.jpg (45.9 KB, 37 views)
File Type: jpg UO82S.jpg (94.7 KB, 30 views)
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