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Any audio differences for EL-84 P-P OPT?

Looking into upgrading my EL-84 Maggie amp with new PP OPT and will probably get the Edcors. Looking at their site the choices comes down to 8K, 8.6k or 10k.

So what are some of the sonic differences between 8k and 10k? I noticed the Dynaco SCA have 8k and other amps use 10k. I'm just looking for a clean, sweet, focused and solid sound from this amp. Also, I'm keeping the same paraphase circuit that came with it.

Anyone with experiences listening to both trannies in a A/B testing?
10K is supposed to be better for cathode bias with the 8K fine with fixed bias.

I think Dave Gillespie's EFB fixed bias mod would a great one for improved output tube life, sonics, and a little more power. Lot's of info @ diytube under the ST-35.

The 25% UL winding Edcor offers is supposed to be better for EL84 tubes and that's what the Dynaco Z-565 had.

There was a thread where someone tore down a dead Dynaco Z-565 and it had 5 interleaved layers and they were surprised as it was quite complicated.

I read of a fellow in Europe doing the same with the Edcor CX PP and it only had 3 layers, but it is a less expensive one to buy compared to the replicated Dynaco ones. In all the overall cost difference is low as even the replicated Dynaco Z-565 is low priced compared to many alternatives.

Magnaquest was the first to clone a Z-565 one and it is a higher quality appearing one but the most expensive and well regarded. It is also exactly the same as the original even down to the 8 & 16 ohm secondary outputs.

Triode was next with their's, but it has 4 & 8 ohms. Dynakitparts followed with their version with 4 & 8 ohm secondaries.
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Check your chassis space. How much space do you have?

The Edcor 25W transformers have a footprint of 3.22" X 3.43" (X 3.81" Tall) and may not fit.

The Z565 is smaller at 2.5 X 2.19+" (X 3" tall) and is more likely to fit. Only the center to center dimension is given for one axis.

I replaced one set of transformers with Edcor 10W transformers and they fit fine. But the 15W transformers might not have fit. The 25W transformers certainly would not have fit.

The discussion of sound difference is moot if the transformers won't fit.
Another couple of options from Edcor are:

EM0775-PP : 15W, 8K, 40%UL, Multiple secondary
EM0776-PP : 15W, 8K, 25%UL, Multiple secondary

I think I paid around $56 each for them a couple of years ago when I had them made. I've already paid the custom design charge.

They aren't listed on the web site, but you can order them.