MOTM

Hi all,

I think if you are building a little prototype board then the SSM parts
make good sense. They are small, 8 pin DILs, and they provide good
performance for line level balanced applications. If you are designing a
PCB, then I think the op-amp designs are the way to go. They are cheaper
and all parts are easily available. At Soundcraft we were constantly
being pushed to use the SSM parts by AD reps, but in reality, the op-amp
approach is always the one to go for. Cheaper and no single source
problems.

Transformers are also very good, but they do colour the sound somewhat.
They have been said to improve the sound, but we get into the subjective
area of audiophiles here. They do of course provide the only real way to
get isolation, with the exception of fibre optics.

If we are dealing with line level signals and we don't need tens of
volts of isolation then the electronic balanced system is excellent.
Even the single op-amp input circuit is good enough for most actively
driven line level signals.

If I were to be building a universal input/output module, then I would
go for electronically balanced inputs. With the option of adding
transformers if you wanted. The mic amp could be somthing similar to
that used on Yamaha desks... nice and cheap but with excellent
performance. Standard four op-amp EBOS on the output.

Regards,

Tony Allgood  Penrith, Cumbria, England

Oakley Modular Synth and TB3030:
www.techrepairs.freeserve.co.uk/projects.htm
My music: www.mp3.com/taklamakan