Stupid Filament Virtual Tap question

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someguy
Posts: 2
Joined: Sat Mar 13, 2010 4:03 pm

Stupid Filament Virtual Tap question

Post by someguy »

Here's the stupid question; if you are using a virtual ground, because the amp lacks a center tap or the 60hz hum is terrible, does it matter THAT much if its elevated or not? Couldn't you simply put a 100 ohm resistor from both heater wires to the chassis ground? I've heard of people connecting the heater pins to the cathode, but since I am doing a pcb build, thats not an option. Are there any clear problems with this?

I apologize in advance if this has already been discussed, but I couldn't find any clear cut answers.

Thanks, Brett
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FYL
Posts: 654
Joined: Fri Feb 17, 2006 1:05 am

Re: Stupid Filament Virtual Tap question

Post by FYL »

A virtual balanced ground is OK in most cases, elevating heaters helps in some amps and is required if you're close or above max heater to cathode voltages (cathode followers, etc.).
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M Fowler
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Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Stupid Filament Virtual Tap question

Post by M Fowler »

You can start with your planned to 100r to ground and see how the noise level is. Then if needed you can elevate voltage.
someguy
Posts: 2
Joined: Sat Mar 13, 2010 4:03 pm

Re: Stupid Filament Virtual Tap question

Post by someguy »

Thanks's for the responses; I guess if I get tons of hum I'll have to try elevate them, but I doubt I'll have to.
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