Trevor Wilson wrote:

"Woody" wrote
"Serge Auckland" wrote
"TonyL" wrote

I've found a couple of HY60 amplifier modules in my junk box. I have a
data sheet which indicates a +/- 25v power supply voltage rails
requirement but no indication of current. Power into 8 ohms is 30W. If I
put a power supply together what sort of current should I be expecting
to supply to each module ? Presumably, a simple dual rail
transformer/rectifier/electrolytic type of supply would be OK ?

Any gotchas with this project ?

Nice little amps!

For their day, certainly. Still credible I'd say.


Assuming that you're not going to be using these amps to drive some
extreme loads, then 30 watts into 8 ohms is a current of 1.94 amps, add a
little for the amp's overhead, and so you need a minimum of 2 amps per
amplifier. If you're building a single supply to power both amps, then I
would go for a 5 amp supply. If the 'speakers you're going to use are
closer to 4 ohms than 8, you may like to double the current capacity.

No particular "gotchas" with these as far as I'm aware, they do what they
say they do.
--
http://audiopages.googlepages.com

Agreed. Of their time superb amps. They were later replaced with a power
MOSFET version which had a somewhat higher slew rate, but nontheless the
HY was a very good amp.

Just make sure, as above, that the supply can provide the current. You
should even consider a regulated supply as (and I'm sure someone will
enlighten us) you will get better and cleaner bass. Although the HY60s
have built-on heatsinks it would still be wise to attach them to a chassis
that is capable of dissipating at least some of the heat.

I built a dual mono MOSFET power amp based on the Ambit boards containing
a Hitachi design. It was good and provided 110wpc without difficulty. I
then built the regulated supply designed by the late great John
Lindsey-Hood and fitted that - and the aural difference was dramatic, and
not least that it did 110W into 8R and 220W into 4R. The PSU design also
provides d.c. offset protection for the speakers. I think I have a copy of
the circuit of anyone wants it.

**Those figures are, of course, impossible in this universe. Particularly
with MOSFETs. You may get close to a doubling in power, but You'll never
quite get there, regardless of power supply regulation.

"Woody" is clearly a Grade One imbecile.

Graham