Zero Feedback Impedance Amplifiers

I need 4 channels, so the price becomes an issue.
Yes, understand - at four transformers per channel it does add up.
I have a full 5.1 setup, but only the stereo LR channels have a stepped attenuator - all the other just a fixed 1:2 input step-up.
If your source is digital, then one doesn't need the attenuators, otherwise it looks like the only option is the SILK STA-522A Transformer Volume Attenuator, or a stepped inductor, if you use depletion mosfets they are ground referenced. I prefer transformers as I like my system to be galvanically isolated.
I am working on a stepped-attenuator design myself in the background - but nothing finalized yet; it will be expensive since it uses Amorphous cut c-cores.
As to the EI-120 x 2" transformers, the input-stage SE line-driver can be simply quad-filar 0.8mm wound to nicely fill the bobbin. The output transformer does need the dual chamber bobbin, quad-filar 1.0mm wire. Perfect winding with nice flat layers is nice, preferred, but not absolutely essential.
Hope this helps.
 
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No worries, just you sharing this project is above and beyond stellar :*
I'm looking to sourcing all the transformers from the East, I do not have the money for Sovters and I am not to keen on trying it myself.
I'm looking at the pages that specify the transformers. I just wanted to know if they were still correct or if some details should be added if I ask to have them produced.

I need 4 channels, so the price becomes an issue.
There is a transformer manufacturer local to me who tells me he can make the transformers at a more palatable price. PM me if this is of interest to you.
 
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Yes, SE Class A amps need a cap multiplier or other ripple eater device. I am able to get ripple down to 1mV rms under a continuous 3.5A load for my cap multiplier (follows 15mF/0.2R/15mF CRC). Makes a huge difference.
Choke input supplies are much quieter but almost unheard of outside niche valve use. I had / have plans to try one on the JLH 69 but life keeps getting in the way.