Poor student DIY toroid output xfos

Hi,

I'm a 3rd year uni student and I've completed my first complete tube amp design up to the output stages. I've chosen my output tube (EL34 as SE pentode), and most of the parts and got a nice preamp/tone control module up and working. Now I'm at the point where I need to consider output transformers...I've designed most of the amp according to the parts and tubes I could easily get my hands on (budget constraints), summing at about 35$ per channel [God bless surplus Sovtek tubes] (doing it mono 1st, once proven it'll go stereo :P) NOT INCLUDING the xfo. Looking at the price for 40W transfos, my jawbone is dropping at the prices (70$USD including shipping is WAY out of question).

I'm not unexperienced to winding transformers with critical impedences and turn ratios [did a few RF baluns and xfo secondary-voltage-divider-based PSUs], and I still have my material at home and I have access to cheap enameled copper wire, so the idea of winding them myself obviously came right to me. Reading across previous posts on this forum, I came across the toroids OPT thread. Winding toroids is a daisy so this sounds like the most interesting option. However, being of very experience in the tube field, I'm a bit sceptical about the overall size of a decent toroid able to drive 40W in 8 ohm speakers (although the self-shielding property does take a bit off the xfo casing's size and complexity).

What topology would you recommend to use? Seperate windings on opposite core sides or 2-layer winding around the core? I'm also not used to computing core saturation issues with AF and such high inductances (RF obviously requires so much less).

NOTE TO SELF-SUFFICIENT BLOATERS [you know who you are]:
Being a student, I do not have access to expensive materials. The main idea of the project was to learn to design with tubes, not to build a tube monster that would amplify a fly's fart to 90dB with 0.00001% THD. I loved my experience with tube design and would like to get a nice sound off the tiny amp I built. I'd love references to design litterature or comments based on experience and technical parameters (core inductance,inductance/impendence ratios, etc). Brand plug-in ["Get a Lundahl, they sound great, Hammond makes decent ones too"], or strictly qualitative comments about amp design other than output transformers ["PP outputs are much better sounding"] are only a proof of how desperate you are of finding a discussion where people are not yet annoyed of hearing your obvious lack of reading skills and general comprehension for anything that is not related to your personal issues and positions.

Thanks in advance,

GLM

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