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 ?

Thanks

TonyL

"TonyL" wrote in message
...
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 ?

Thanks

TonyL

Nice little amps!

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.

S.
--
http://audiopages.googlepages.com

"Serge Auckland" wrote in message
news

"TonyL" wrote in message
...
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 ?

Thanks

TonyL

Nice little amps!

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.

S.
--
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.


--
Woody

harrogate three at ntlworld dot com

In article , Woody
wrote:

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.

That isn't really a matter of changing to an actively regulated PSU. Just
one of ensuring the PSU has a low output impedance and ripple even when the
current demand is high. if the "aural difference was dramatic" then I'd
suspect something was wrong with the unregulated PSU you'd used.
Unregulated supplies can give the advantage of providing higher peak
transient powers. Given that music tends to have higher crest factors than
test sinewaves that can be quite useful. However the amp has to be built to
cope.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Jim Lesurf wrote:

Woody wrote:

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.

That isn't really a matter of changing to an actively regulated PSU. Just
one of ensuring the PSU has a low output impedance and ripple even when the
current demand is high. if the "aural difference was dramatic" then I'd
suspect something was wrong with the unregulated PSU you'd used.
Unregulated supplies can give the advantage of providing higher peak
transient powers. Given that music tends to have higher crest factors than
test sinewaves that can be quite useful. However the amp has to be built to
cope.

Even pro amps with SMPSs don't make any serious attempt to regulate the rails.

Graham

"Eeyore" wrote in
message

Even pro amps with SMPSs don't make any serious attempt
to regulate the rails.

Why should they?

"Jim Lesurf" wrote in message


That isn't really a matter of changing to an actively
regulated PSU. Just one of ensuring the PSU has a low
output impedance and ripple even when the current demand
is high. if the "aural difference was dramatic" then I'd
suspect something was wrong with the unregulated PSU
you'd used.

Agreed.


Unregulated supplies can give the advantage
of providing higher peak transient powers. Given that
music tends to have higher crest factors than test
sinewaves that can be quite useful. However the amp has
to be built to cope.

I've done a number of experiments powering power amps via power supplies
that have current limiting. As long as a reasonable energy storage
reservoir is available, amplifying music does not require a great deal of
average current.

"Arny Krueger"


I've done a number of experiments powering power amps via power supplies
that have current limiting. As long as a reasonable energy storage
reservoir is available, amplifying music does not require a great deal of
average current.


** Correct.

The important thing is to HAVE a large electro cap at the output of the
regulator - so the series pass device will not "see" the current peaks being
drawn by the amplifier.

In the OP's example of a 30 watt @ 8 ohms amplifier with +/- 25 volt DC
rails - even full sine wave power requires under 1 amp of DC current per
rail while normal music programme with peaks to full power will require no
more than 1/3 of that.



..... Phil

"Woody" wrote in message
...
"Serge Auckland" wrote in message
news

"TonyL" wrote in message
...
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 ?

Thanks

TonyL

Nice little amps!

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.

S.
--
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.


--
Trevor Wilson
www.rageaudio.com.au

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