George also I see the woofer outward when preamp connected.
Then you have dc on poweramp out. If woofer stays out that is.
Was the AD820N in the servo DC offset of Borbely power amp.
Lucky having surviving woofers
Woofer yoga
Lucky having surviving woofers
Fortunately the woofer survive.
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Maybe silly question, but, why not put 6SN7 above input triode where it's higher gm will provide lower drive resistance ?
Would you run it at <1mA or bypass the input tube with a resistor? Or go wild and parallell 3-4 input tubes
There seems to be a 22k resistor...
Would be recalculated if so
I've built this prephono, the details is excellent.
I've used 6n2pev and 6h8c.
However I have RFI , I can hear the radio clearly. How to get rid of it?
I use ground wire running from RCA to power supply. No hum only RFI. Can grid stopper kill this RFI?
Another problem is I use one tube for both upper and lower part of the circuit. Therefore when I lift the heater around 90v . For 6h8c tube, one side will see heater-carthode around +90v another side will see around 100v.
This will shorten the life of 6h8c right?
I've used 6n2pev and 6h8c.
However I have RFI , I can hear the radio clearly. How to get rid of it?
I use ground wire running from RCA to power supply. No hum only RFI. Can grid stopper kill this RFI?
Another problem is I use one tube for both upper and lower part of the circuit. Therefore when I lift the heater around 90v . For 6h8c tube, one side will see heater-carthode around +90v another side will see around 100v.
This will shorten the life of 6h8c right?
However I have RFI , I can hear the radio clearly.
Is there a grounded metal boxing sealing the circuit?
Are the cartridge wiring twisted?
Do you use MC stepup or high level PUP?
Is there a grounded metal boxing sealing the circuit?
Are the cartridge wiring twisted?
Do you use MC stepup or high level PUP?
Signal+supply ground is float, it's woodenbox.
I use mm cartridge and wiring is twisted.
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