On Wed, 20 Oct 2004 22:39:33 +0100, Ian Bell
wrote:

Pooh Bear wrote:

Wally wrote:

As some of you may be aware, I have an on-going speaker rebuild fantasy
bubbling away in the background. The plan is to bi-amp, and part of this
involves a second line output on the pre-amp, to send a signal to the
bass amp. The bass/midrange driver will have no high-pass components in
the crossover - I intend to let the bass roll off naturally, and try to
match the low-pass filter feeding the subs to this roll-off. I'm edging
towards trying to make a prototype filter and would welcome comments...

The pre-amp is a Cambridge A75. The chips it uses are NE5534N op-amps,
evidently low-noise and suitable for high quality audio. My intention was
to use the same chips for my active filter / output stage, on the
assumption that the pre-amp's PSU will be delivering the right
voltage(s). However, it looks like these chips are no longer made - what
would be a suitable alternative?

5534s are most certainly still made. What made you think they aren't ?

Available from many places. Best audio op amp ever made IMHO. Try Maplins
for starters.

If it's good enough for Meridian output stages, then it's good enough
for me! :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering