yamaha c70 preamp direct disc switch noise
- Thread starter darrelb
- Start date
well the weekend is here so know i can work on it more my first c70 i recapped is dead
silent except for the mechanical noises.
the preamp still has both the noise problems the fine tuning helped some , as much as i hoped
i plan to replace the trimmers with single turn bourns and see if that helps.
as to your question about the dynavector P/U it still sounds good but i wonder if the suspension
is starting to harden i'll try my ortofon super om30.
to avoid any confusion about my posts i have more than one c70 preamps
silent except for the mechanical noises.
the preamp still has both the noise problems the fine tuning helped some , as much as i hoped
i plan to replace the trimmers with single turn bourns and see if that helps.
as to your question about the dynavector P/U it still sounds good but i wonder if the suspension
is starting to harden i'll try my ortofon super om30.
to avoid any confusion about my posts i have more than one c70 preamps
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Me too..
First verify that the relays power supply is working. All eight relays have the same power source.
Do all the push button LED's and power switch illuminate ?
What does it sound like ? Might be a burnt switch.
it sounds like a decaying noise i.e its brief bit of static thats fades to nothing both turning off and turning on its just a quick bit of noise that fades to nothing.
using a outlet strip makes no difference , this noise is more concerning because i don't
know if the noise has any high frequency content that will effect the tweeters.
the level of the noise is the same with the volume down completely but your are right i should
have started a new thread.
using a outlet strip makes no difference , this noise is more concerning because i don't
know if the noise has any high frequency content that will effect the tweeters.
the level of the noise is the same with the volume down completely but your are right i should
have started a new thread.
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This would definitely be a power supply/muting circuit issue. Doesn't sound like a capacitor issue.More of a transistor issue or maybe a diode.
What all has been replaced in this unit so far ?
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What runs hot is a combination of the power transformer and the two pass transistors on the heatsink right next to the power transformer.
i solved the power down noise , after testing all the p/s transistors and diodes and found those
good.during the recap i installed a 8 pin dip socket for the headphone amp and was using the
jrc 4560d that came with the preamp. i switched the 4560 to a AD823 and the noise stopped
completely.
the disc direct i will have to live with again many thanks for your help all really do appreciate
your help and experience.
good.during the recap i installed a 8 pin dip socket for the headphone amp and was using the
jrc 4560d that came with the preamp. i switched the 4560 to a AD823 and the noise stopped
completely.
the disc direct i will have to live with again many thanks for your help all really do appreciate
your help and experience.
Would have been nice to know..In post # 1 or 2. I was assuming the pre-amp out.
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