🚀 go-pugleaf

In article <luke.726426475@barney> Luke Whitaker, luke@cs.city.ac.uk
writes:
>Is there any technical reason why small signal AF
>transformers are a problem - I don't understand transformer technology
very
>well. The small transformers that are available seem to have frequency
>responses way above audio. I saw some post here about why HF
transformers can
>be smaller than AF transformers, although the original post has expired
on this
>site. Does this imply that AF transformers *are* readily available,
albiet 
>physically large ?

There are several issues here :
Availability : Audio trannies are available in just about any config
you desire - the big problem is cost 
Jensen (California) make all manner of *extremely expensive* ones
aimed at the professional audio (mixers, PA co's,studios) market
Entry price - about $20 up (and up...and up) cheaper by the 1000
Sowter (UK) cover the same market, also Pico etc do a broad range
of devices - telephone up to pro-audio quality. There are many other
manufacturers. - At the other end of the market is the scungy little
trannies you find in modems, Rat shack shelves etc. These are low fi
in the extreme. - this brings us to 
Size : Broadly speaking, the bigger the better. The more iron, the less
likely the thing is to saturate at low frequencies/high drive levels.
There are other factors such as interwinding capacitance, core quality
Winding interleaving etc, all of which contribute to the quality (or 
lack of) of the device. You get what you pay for. I too would love to
hear of a budget supplier of superb quality transformers (BTW it 
pays to hang around recording studios, tv studios etc that are being
torn apart)
cheers
	Mike.