On Sat, 15 Apr 2006 10:15:08 +0100, "Jem Raid"
wrote:


"Don Pearce" wrote in message
...
On Sat, 15 Apr 2006 09:49:34 +0100, "Jem Raid"
wrote:

I'm thinking of making a headphone amp and have found various sites with
circuits.

I've also found the circuit diagram for the Grado RA1 amp, turns out to be
a
single chip of £0.50 value and a few resistors, it gets great reviews and
costs anywhere between £350 and £400. It is in a mahogany case though.

I intend to make mine in a roomy Scottish Shortbread biscuit tin we got
for
Christmas. I do also have an old, smaller and thicker gauge but rather
battered Smith's Crisp's tin from the 1950's does anyone think that
vintage
tins may perform better than new ones?

Jem


Scottish Shortbread may be OK, but if you can find it, the archetypal
tin for these kinds of project was the metal OXO tin. I've just
recently had to build a small in-line battery powered pre-amp for a
microphone. I used a very old Altoids cough sweet tin, and the
performance was all I could wish for. It just held two nine volt
batteries side by side and a small piece of Veroboard for the amp
itself - perfect.

d

--
Pearce Consulting
http://www.pearce.uk.com

Ahhhh a Cmoy clone, and I thought Penguins were biscuits.
http://tangentsoft.net/audio/cmoy-tutorial/

Jem

What on earth is that power supply circuit all about? He has two 9
volt batteries, just like me, but instead of using the centre point of
the batteries for ground, he has put in a pair of resistors - which
drain an extra couple of milliamps from the battery. If he had just
used a double pole switch for power, all that silliness would have
been avoided.

d

--
Pearce Consulting
http://www.pearce.uk.com