01-28-2018, 03:11 AM
Mike;
I don't know much about the EICO HF-22s but I had a friend whom owned a pair of HF-20s, he used them to power a pair of higher end Technics speakers and they sounded very nice.
They did have one drawback however, the power transformers got rather warm after about 20 minutes of use, I don't know if this was because they used a barely adequate transformer just to keep the retail price down or if it was due to some leakage in the filter or bypass caps, whilst they worked they were unrestored. I believe that restuffing might be your best option with the filter cans, some radial lead Nichicons or other Jap brand caps should fit nicely inside even if you have to stack them vertically. If you don't care then go the under chassis terminal strip route or just cut the cans open and slap them back together with aluminum tape, but I think a clean cut with an internal piece to couple the sections together looks good, and is not too obvious. From what I can recall of the HF-20 it used an ultra linear sort of setup where the output transformer had a pair of extra windings to employ some inverse feedback to the input of the preamp tube/s, that may help explain the lack of hum with the pi filter setup, of course they were also using fairly big value filter caps.
Regards
Arran
I don't know much about the EICO HF-22s but I had a friend whom owned a pair of HF-20s, he used them to power a pair of higher end Technics speakers and they sounded very nice.
They did have one drawback however, the power transformers got rather warm after about 20 minutes of use, I don't know if this was because they used a barely adequate transformer just to keep the retail price down or if it was due to some leakage in the filter or bypass caps, whilst they worked they were unrestored. I believe that restuffing might be your best option with the filter cans, some radial lead Nichicons or other Jap brand caps should fit nicely inside even if you have to stack them vertically. If you don't care then go the under chassis terminal strip route or just cut the cans open and slap them back together with aluminum tape, but I think a clean cut with an internal piece to couple the sections together looks good, and is not too obvious. From what I can recall of the HF-20 it used an ultra linear sort of setup where the output transformer had a pair of extra windings to employ some inverse feedback to the input of the preamp tube/s, that may help explain the lack of hum with the pi filter setup, of course they were also using fairly big value filter caps.
Regards
Arran
