Quad 34 Problem
 

I've just plugged in a Quad 34 preamp that's been unused for a few
years. When I turn the volume control up there's a series of loud high
pitched clicks through the speakers, a bit like LP static discharge
maybe. It was fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob

Quad 34 Problem
 

"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few
years. When I turn the volume control up there's a series of loud high
pitched clicks through the speakers, a bit like LP static discharge
maybe. It was fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob



I think you need to go into a bit more detail - it clicks but does it
play music? Are the clicks as you move the volume control or after you
have moved it and taken your hand off?

Ultimately Quad kit is well made and relatively simple. If you can find
the handbook it probably contains the circuit diagram so should be
fairly easy for someone competent in electronics to repair. Or you can
send it to Quad in Huntingdon where they have a superb service
department.



--
Woody

harrogate three at ntlworld dot com

Quad 34 Problem
 

"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few years.
When I turn the volume control up there's a series of loud high pitched
clicks through the speakers, a bit like LP static discharge maybe. It was
fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?


Sounds to me like poor contact between the volume control wiper and the
track caused by surface tarnishing whilst the amp was out of use. Using it
should cure the problem.

David.

Quad 34 Problem
 

Woody wrote:
"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few
years. When I turn the volume control up there's a series of loud high
pitched clicks through the speakers, a bit like LP static discharge
maybe. It was fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob



I think you need to go into a bit more detail - it clicks but does it
play music? Are the clicks as you move the volume control or after you
have moved it and taken your hand off?

Yep - clicks as music played, as if a connection is loose, loud crackle,
and continue once hand removed. Slight occasional rustling noise when
volume set to zero. It's been on about 10 hours with no
improvement/deterioration. To add insult only one channel is working,
with both working when the mono button is pressed.

Ultimately Quad kit is well made and relatively simple. If you can find
the handbook it probably contains the circuit diagram so should be
fairly easy for someone competent in electronics to repair. Or you can
send it to Quad in Huntingdon where they have a superb service
department.

Yes - I gather, and if it was rare/loved I'd have it serviced. But as it
is it's not of any particular significance, and is quite old (sn 3942),
although it all looks new inside/out, apart from the volume knob. I
might get £30 on ebay making repair possibly uneconomic.

Quad 34 Problem
 

"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few years.
When I turn the volume control up there's a series of loud high pitched
clicks through the speakers, a bit like LP static discharge maybe. It was
fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob

It is the volume control that needs replacing. It's a very common problem
in most audio circuits of that age and the design of the control doesn't
help. No need to bin the preamp, just find another volume control.
Maplin will sell something suitable for around £2-3. I would solder it in
or
get a friend who can - you will save a fortune.

Quad 34 Problem
 

"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few years.
When I turn the volume control up there's a series of loud high pitched
clicks through the speakers, a bit like LP static discharge maybe. It was
fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob

See if you can spray some contact cleaner in and then twiddle the control
for a while with the unit off. Leave it to dry out and try it again.
Go for something like Servisol.

Quad 34 Problem
 

"h.tees" wrote in message
...

"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few
years. When I turn the volume control up there's a series of loud
high pitched clicks through the speakers, a bit like LP static
discharge maybe. It was fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob

It is the volume control that needs replacing. It's a very common
problem
in most audio circuits of that age and the design of the control
doesn't
help. No need to bin the preamp, just find another volume control.
Maplin will sell something suitable for around £2-3. I would solder
it in or
get a friend who can - you will save a fortune.




I don't think that may necessarily be the case. Quad were quite good
with their circuit design, and if the volume pot interfaced to a high
impedence load then it may not be the pot as such circuits were not
prone to that type of noise.

I suspect the problem here is dried out and/or leaky electrolytic
capacitors. Clicks whilst playing are typical of capacitors that are
leaking and affecting d.c. bias conditions.

I would agree that crackles whilst playing are also typical of a volume
pot that has gone noisy, but it should not do it at minimum volume where
the pot wiper is effectively earthed.

The loss of one channel that plays when the mono button is pressed says
one pre-amp is not working. I had a Q33 which had plug-in circuit
boards: it is just possible that this unit may be of the same
construction and that the boards have become dislodged. It might be an
idea to get the lid off and see if this is the case - if it has plug-in
boards even remove them, clean the contacts if necessary and put them
back. It might just cure everything.

Otherwise I stay with the cap theory.


--
Woody

harrogate three at ntlworld dot com

Quad 34 Problem
 

h.tees wrote:
"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few years.
When I turn the volume control up there's a series of loud high pitched
clicks through the speakers, a bit like LP static discharge maybe. It was
fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob

It is the volume control that needs replacing. It's a very common problem
in most audio circuits of that age and the design of the control doesn't
help. No need to bin the preamp, just find another volume control.
Maplin will sell something suitable for around £2-3. I would solder it in
or
get a friend who can - you will save a fortune.



OK, thanks. Thing is, it looks to be quite a unique part - Alps, with a
nice feel and little indented bumps as it turns. However, I'd be pretty
certain that they're available somewhere. I don't think I'd do it
myself, and there might be a 'good money after bad' type situation
building up ...

Rob

Quad 34 Problem
 

Woody wrote:
"h.tees" wrote in message
...
"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few
years. When I turn the volume control up there's a series of loud
high pitched clicks through the speakers, a bit like LP static
discharge maybe. It was fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob
It is the volume control that needs replacing. It's a very common
problem
in most audio circuits of that age and the design of the control
doesn't
help. No need to bin the preamp, just find another volume control.
Maplin will sell something suitable for around £2-3. I would solder
it in or
get a friend who can - you will save a fortune.




I don't think that may necessarily be the case. Quad were quite good
with their circuit design, and if the volume pot interfaced to a high
impedence load then it may not be the pot as such circuits were not
prone to that type of noise.

I suspect the problem here is dried out and/or leaky electrolytic
capacitors. Clicks whilst playing are typical of capacitors that are
leaking and affecting d.c. bias conditions.

I would agree that crackles whilst playing are also typical of a volume
pot that has gone noisy, but it should not do it at minimum volume where
the pot wiper is effectively earthed.

The loss of one channel that plays when the mono button is pressed says
one pre-amp is not working. I had a Q33 which had plug-in circuit
boards: it is just possible that this unit may be of the same
construction and that the boards have become dislodged. It might be an
idea to get the lid off and see if this is the case - if it has plug-in
boards even remove them, clean the contacts if necessary and put them
back. It might just cure everything.

Otherwise I stay with the cap theory.



Thanks. Wouldn't surprise me given the age, and the fact it worked
before. Only one channel is working in stereo, with sound coming out of
both speakers in one side mono when the mono button is pressed; and,
there are no plugin boards except the phono - it happens on all inputs.
FWIW I took the top off and everything looks brand new and shiny - no
bulging/leaking caps for example.

Rob

Quad 34 Problem
 

In article , Rob
wrote:
Woody wrote:
"Rob" wrote in message
...
I've just plugged in a Quad 34 preamp that's been unused for a few
years. When I turn the volume control up there's a series of loud
high pitched clicks through the speakers, a bit like LP static
discharge maybe. It was fine last time it was used.

Does this sound like an expensive problem, or would I be better off
punting it on ebay, and buying another (about £80 it seems)?

Thanks, Rob



I think you need to go into a bit more detail - it clicks but does it
play music? Are the clicks as you move the volume control or after you
have moved it and taken your hand off?

Yep - clicks as music played, as if a connection is loose, loud crackle,
and continue once hand removed.

If the 'clicks' only occur *when* music is playing and you adjust the
volume control, then it does seem like a volume control problem. However if
you get clicks when you rotate the control without any music or input at
all, it may be a dc offset problem, not the volume control.

Slight occasional rustling noise when volume set to zero. It's been on
about 10 hours with no improvement/deterioration. To add insult only one
channel is working, with both working when the mono button is pressed.



Yes - I gather, and if it was rare/loved I'd have it serviced. But as it
is it's not of any particular significance, and is quite old (sn 3942),
although it all looks new inside/out, apart from the volume knob. I
might get £30 on ebay making repair possibly uneconomic.

Jings! I'd probably pay 30 quid for it! :-)

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