Hi,

I inherited a Quad 34 pre that weirds out now and then. The preamp
comes on, with the default source selected. Either by itself, or when
selecting another source, all the selector leds light up dimly, and
the sources are lost (pre does not work).
Any one have a schematic that they may scan for me. It seems that the
tactile switches drive a row of 8 transistors that probably do the
switching part...

would appreciated any help.

BTW, does this thing sound ok? I am a bit put off by all the tl071
opamps that populate this thing. Aby recommended mods?

nicolas

I inherited a Quad 34 pre that weirds out now and then. The preamp
comes on, with the default source selected. Either by itself, or when
selecting another source, all the selector leds light up dimly, and


Hi Nicolas

Lucky inheritance.

From recent experience (although these things change!) Quad themselves will
offer good advice either by e-mail or by 'phone and there first tack doesn't
seem to be "send us a blank cheque and we'll fix it" Might even send you a
copy of the relevant circuit?

BTW, does this thing sound ok? I am a bit put off by all the tl071
opamps that populate this thing. Aby recommended mods?

Sound is OK - a wee bit noisy compared to recent designs but a v. good phono
stage if my memory is intact. Not sure about the tweekability - in my
experience it almost always results in a worse sound than the original.

Have fun with it

David

I inherited a Quad 34 pre that weirds out now and then. The preamp
comes on, with the default source selected. Either by itself, or when
selecting another source, all the selector leds light up dimly, and


Hi Nicolas

Lucky inheritance.

From recent experience (although these things change!) Quad themselves will
offer good advice either by e-mail or by 'phone and there first tack doesn't
seem to be "send us a blank cheque and we'll fix it" Might even send you a
copy of the relevant circuit?

BTW, does this thing sound ok? I am a bit put off by all the tl071
opamps that populate this thing. Aby recommended mods?

Sound is OK - a wee bit noisy compared to recent designs but a v. good phono
stage if my memory is intact. Not sure about the tweekability - in my
experience it almost always results in a worse sound than the original.

Have fun with it

David

In message , nicolas
writes
Hi,

I inherited a Quad 34 pre that weirds out now and then. The preamp
comes on, with the default source selected. Either by itself, or when
selecting another source, all the selector leds light up dimly, and
the sources are lost (pre does not work).
Any one have a schematic that they may scan for me. It seems that the
tactile switches drive a row of 8 transistors that probably do the
switching part...

would appreciated any help.

BTW, does this thing sound ok? I am a bit put off by all the tl071
opamps that populate this thing. Aby recommended mods?

nicolas


I replaced those with OPA604s in my 34. It lowered the noise level but
that's about all.

I have the service manual for the original DIN socket version. I don't
have a scanner but my brother has one. I could scan the schematic in a
weeks time or so for you.
--
Chris Morriss

Chris Morriss wrote:


In message , nicolas
writes



I replaced those with OPA604s in my 34. It lowered the noise level but
that's about all.

I have the service manual for the original DIN socket version. I don't
have a scanner but my brother has one. I could scan the schematic in a
weeks time or so for you.
Hi,
Thanx for the offer; that would be great. Mine has the DIN sockets also..

regards,

nicolas

Hi,

FWIW, the Serial Number on this preamp is 6277

regards,

nicolas

Hi,

FWIW, the Serial Number on this preamp is 6277

regards,

nicolas

Chris Morriss wrote:


In message , nicolas
writes



I replaced those with OPA604s in my 34. It lowered the noise level but
that's about all.

I have the service manual for the original DIN socket version. I don't
have a scanner but my brother has one. I could scan the schematic in a
weeks time or so for you.
Hi,
Thanx for the offer; that would be great. Mine has the DIN sockets also..

regards,

nicolas

In message , nicolas
writes
Hi,

I inherited a Quad 34 pre that weirds out now and then. The preamp
comes on, with the default source selected. Either by itself, or when
selecting another source, all the selector leds light up dimly, and
the sources are lost (pre does not work).
Any one have a schematic that they may scan for me. It seems that the
tactile switches drive a row of 8 transistors that probably do the
switching part...

would appreciated any help.

BTW, does this thing sound ok? I am a bit put off by all the tl071
opamps that populate this thing. Aby recommended mods?

nicolas


I replaced those with OPA604s in my 34. It lowered the noise level but
that's about all.

I have the service manual for the original DIN socket version. I don't
have a scanner but my brother has one. I could scan the schematic in a
weeks time or so for you.
--
Chris Morriss

In article ,
nicolas wrote:
It seems that the
tactile switches drive a row of 8 transistors that probably do the
switching part...

IIRC, they're CMOS switches. And IIRC again were replaced with a better
type at some stage in the amp's production.

--
*When companies ship Styrofoam, what do they pack it in? *

Dave Plowman London SW 12
RIP Acorn