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Old 17th April 2013, 08:34 AM   #1
Dagwood is offline Dagwood  New Zealand
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Default RH807 output transformer....what did you use?

Old design but I have a few 807's in the shed

How critical is the 6k primary on the OPT's ??? Edcor do the CXSE25-8-6.5K (EDCOR - CXSE25-8-6.5K) would this be close enough??

What have other DIYers used??

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Old 17th April 2013, 09:00 AM   #2
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It is not that critical. For 6L6 (which 807 also is) the recommended load resistance varies from 2k5 to 6k.
The plate voltage with 6k5 should be some 450 V to get optimum results.
Then the screen voltage should be limited to 200...250 V.

If only some 300 V is available as +Ub, then the load resistance should not be more than 4k5.
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Old 17th April 2013, 09:38 AM   #3
Dagwood is offline Dagwood  New Zealand
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Thanks

B+ is likely to be just under the 350v in the design.

Will look at this one,
15W, single ended tube output transformer for 3.5K Ohms to 8 Ohms.
GXSE15-8-3.5K
EDCOR - GXSE15-8-3.5K
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Old 17th April 2013, 12:05 PM   #4
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That should be fully OK.
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Old 17th April 2013, 04:07 PM   #5
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25 w is better 15 w! More iron - better sound.
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Old 18th April 2013, 06:45 AM   #6
Dagwood is offline Dagwood  New Zealand
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Great, thanks Artosalo

25 watts would be nice be the shipping kills ot to New Zealand!

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Old 18th April 2013, 06:49 AM   #7
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I have used Edcor's GXSE 15 W series transformers with 15 W 811A SE with excellent results,
but obviously CXSE 25 should be even better, but it is essentially more expensive.
The reason for this is not the amount of iron, but the amount of copper and other things.
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Old 21st April 2013, 02:31 AM   #8
Dagwood is offline Dagwood  New Zealand
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Yip, I've got about 4 projects needing iron so FedEx are going to make a fortune out of me! ! Might be cheaper for fly up to Edcor myself
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