I'm interested in cloning a pair of Eico HF-22 monoblocks, as I think the Mullard style of topology will be a little more forgiving in terms of transformer selection. I'm interested in using the 50 watt ultralinear OPT's sold on Ebay by a Greek company calling itself Thermionic Labs. They seem very high quality, run a little over 3 Benjamins for a pair, and the specs seem right on, with 6k6 primary impedance and 43% UL taps. I'm curious if anyone has ever used their product, or any others I might consider first. Also, I would love to hear any other advice from folks who have been down this road before. I plan on triode-strapping the EF86 tube
The Eico HF-22 schematic that I was able to find had Ultra Linear, and 430V on the screens.
Please use a 6L6GC, screens are rated at 450V.
All other 6L6 types have screens rated at 270V.
All 6L6 tubes will work in the Eico HF-22, but . . .
Your Mileage May Vary.
Please use a 6L6GC, screens are rated at 450V.
All other 6L6 types have screens rated at 270V.
All 6L6 tubes will work in the Eico HF-22, but . . .
Your Mileage May Vary.
6A3sUMMER, yes, I was planning on using 6L6GC or 63PS-E tubes. Does anyone have a recommendation for a choke? I had planned on adding a 10 Henry type, as is used in the Mullard 5-20 schematic and parts list, as this mod to the Eico, as well as added filter capacitance is really supposed to turn the HF-22 into something very special
I would definitely propose this guy! I know him in person and he is winding all my transformers. He is capable of very good quality transformers and he is a very knowledgeable guy! Highly recommended from me as I have used a lot of his opts and chokes. Also he can listen to your very specific needs and design customizations and last but not least all done with excellent craftsmanship and very low prices. His personal e-mail is thermioniclab@gmail.com if contact him outside eBay mention my name and you are going to save even more on his prices. Check this one he built for me a while ago based on my split design…
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I have used a lot of 6P3S-E as UL with 440 V. No problem of any kind, but of course the plate dissipation must be within the limits.
Why a choke ? Original Eico HF-22 did not have a choke. In general, a PP-amplifier does not need it.