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Equipment Repairs => DVD/VIDEO/Home Cinemas/Hi-Fi/Mp3/Camcorder => Topic started by: Turnip on March 29, 2014,08:47:43

Title: Cambridge Audio amplifier Model A1 Mk1
Post by: Turnip on March 29, 2014,08:47:43

Hi folks,

Had one of these in this morning with a blown mains fuse - Turned out to be the toroidal mains transformer short circuit primary - I isolated the secondaries to make sure.

Note this trannie has two secondaries - voltages unknown, can't find any info.

Note that YouTube has a video showing how 'CA' toroidal mains transformers give crisper Hi-Fi sound - The only observation seemed to indicate doubts.

Any thoughts ? - Thanks - Chris.

Title: Re: Cambridge Audio amplifier Model A1 Mk1
Post by: jordan on March 29, 2014,10:38:38

??

Title: Re: Cambridge Audio amplifier Model A1 Mk1
Post by: Turnip on March 29, 2014,11:11:36

Hi Jordan - Nice one,

Seems that instead of a centre tapped trannie, the two windings are connected as centre tapped giving a rectified output of + and - 28v.

Seems the biz for a 25 watt amplifier - Off to Fleabay for a 25/25 trannie.

Thanks - Chris.

Later - Got a nice toroidal double 25v @ 120w from the Flea - Was the only bidder at £6.99 + Post.

Thanks again Jordan.

Title: Re: Cambridge Audio amplifier Model A1 Mk1
Post by: Turnip on April 04, 2014,12:44:43

Just an update,

Fleabay 25/25 trannie fitted, works well, but secondary voltages +34v and -34v rather more than +- 28v specified.

As amp uses 2N3055 varient outputs, might not be a problem, as they seem to be happy with a less than a 100v supply.

Here's hoping - Chris.