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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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15th Aug 2019, 10:47 pm | #1 |
Heptode
Join Date: Jan 2016
Location: Wolverhampton, West Midlands, UK.
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Pick up and Valve problems
Hi I bought an AKG P8ES stylus and cartridge assembly recently, and I found the left channel low on volume compared to the right hand channel. Then today I decided to do a bit of fault tracing, and the GZ32 Valve in my Quad II Amp was not working upon switching the system power on. I run a mono system, ie a Quad II and QCII Preamp. Could the low volume of the left channel be accounted for as an early symptom of the valve failure, or do you think I am dealing with two unrelated problems that just coincidentally happened at roughly the same time? I would like to hear your opinions either way, although a link appears unlikely to my uneducated mind.
Regards from Bill. |
15th Aug 2019, 10:55 pm | #2 |
Dekatron
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Re: Pick up and Valve problems
Swap the connection over from the cartridge and see if the fault follows the amp or the cartridge.
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Frank |
15th Aug 2019, 11:32 pm | #3 |
Heptode
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Re: Pick up and Valve problems
Hi Frank, none of my inputs work through the amp, there is definitely a fault there. I was about to swap channels on the pick up when the amp malfunctioned. I have sourced another valve, but currently do not have a way of checking the cartridge, this being my only amp.
Regards from Bill. |
16th Aug 2019, 7:32 am | #4 |
Dekatron
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Re: Pick up and Valve problems
Am I reading this correctly? How can the OP tell about the difference in stereo cartridge voltage outputs if he is only using a mono amplifier?
Also I can't see any possible connection between a rectifier failure and issues with a cartridge.
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Edward. |
16th Aug 2019, 8:48 am | #5 |
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Re: Pick up and Valve problems
How do you know that?
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
16th Aug 2019, 10:56 am | #6 |
Heptode
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Re: Pick up and Valve problems
Edward: my speaker is a Quad ESL, I can clearly hear the instruments on the left channel on a stereo record are not as loud as they should be. I can't see why there should be a link either, it just seemed odd that the two faults occurred in quick succession, so it made me wonder.
X: the valve doesn't warm up over time. It shows no sign of activity at all. It does seem odd that the valve failed, can I check some other component that could cause the valve to be inactive? |
16th Aug 2019, 11:14 am | #7 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
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Re: Pick up and Valve problems
If the valve does not warm up or glow over time then it has failed. A new rectifier in your Quad would be no bad thing anyway especially considering its liekly age. Easily sourced.
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Edward. |
16th Aug 2019, 11:14 am | #8 |
Dekatron
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Re: Pick up and Valve problems
The GZ32 contains two separate heaters - one for each diode. Failure of one heater, obvious by there being only one bright orange spot visible from the top of the valve (if you can see through/round the silver getter), is not uncommon. But for both heaters to fail in the same valve is rare. It can be due to a solder contact failure inside one of the pins on the valve's base. But it may also indicate a failure in the amp's wiring somewhere between the 5V secondary on the mains transformer and the GZ32 socket. If you make any measurements here do remember that this part of the wiring is connected to the GZ32 cathode which, when the valve is working, will be at about 370V DC relative to the chassis !
Cheers, GJ
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16th Aug 2019, 11:37 am | #9 |
Heptode
Join Date: Jan 2016
Location: Wolverhampton, West Midlands, UK.
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Re: Pick up and Valve problems
Thanks GJ, will have a look later on.
Bill. |
16th Aug 2019, 12:20 pm | #10 |
Rest in Peace
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Re: Pick up and Valve problems
If you are using a stereo cartridge connected to a mono amp then low sound from one channel can only come from the cartridge or the cartridge wiring.
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16th Aug 2019, 12:27 pm | #11 | |
Heptode
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Re: Pick up and Valve problems
Quote:
Bill. |
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17th Aug 2019, 3:43 pm | #12 |
Heptode
Join Date: Jan 2016
Location: Wolverhampton, West Midlands, UK.
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Re: Pick up and Valve problems
There were actually a couple of crusty bits of solder. Plugged everything back in and we have power. Will let the esl charge up for a bit and get back to you later if there's any more trouble or interesting developments. Thanks for the advice everyone.
Bill. |