15-07-2011, 08:05 PM
(15-07-2011, 09:01 AM)AlanBeckett Wrote: David,
I've just noticed on your picture that you've left C22, a Hunts(?) Moulded installed. Was it OK?
I changed it along with the two waxies.
I think I'm going to take the chassis out again as the hum is more than I would expect. Not obtrusive when on a station but it's there in between. I've got a 32 + 32 I think, and the 8 can be a tubular.
Alan
Re the Hunt moulded jobbie, that's a good point. My brain is programmed to routinely replace all Hunts Waxies, but I don't know if the moulded ones were problematical too. I guess that Hunts has become synonimous for duff caps, and although the cap seemed OK, it wouldn't have been a big deal to swap it.
There was no hum at all on either of the two that I fettled up. Just one section of the 'three in a can' electrolytics was duff, and was pulling down the HT. It's a very small can with no prospect of stuffing it, so I fitted a 33 uF under the chassis. The 25uF 25V cathode by-pass cap was duff, and I find that they almost always are. I'm not sure what the role of C21 is - the 8uF cap in the can, unless it's just some additional smoothing.
You made some interesting points about additonal economies at the R&D stage that could have been made by Pye, but weren't. It's anyone's guess what was in the mind of the designer(s).
I think it's an attractive little set that doesn't look out of place today, in a kitchen, bedroom, wherever. I don't think that the thermoplastic cabinet would fare well in strong sunlight though, but you can update us on that in due course!
David
