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Power supply Cap
http://diyaudioprojects.com/Forum/viewtopic.php?f=6&t=6170
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Author:  laurie54 [ 23 Mar 2018, 14:08 ]
Post subject:  Re: Power supply Cap

Is your 5v AC or DC. If it is 5vAC then you could rectify, filter and get the 6.3v you need for the heaters. 5vac x 1.414 = 7.07vdc. Use res to get down to 6.3vdc when loaded with heaters.

Author:  gofar99 [ 23 Mar 2018, 17:06 ]
Post subject:  Re: Power supply Cap

Hi, I always use the rated voltage on tube heaters. I have not found it to cause any issues. If the circuit is particularly sensitive to noise I raise the heater circuit to a DC potential that is higher than the heater voltage and cathode voltage combined. Typically about 1/3 of the B+ applied to the tube. This will scavange any stray electrons that don't seem to understand they need to head for the anode.

Good listening
Bruce

Author:  gwalters [ 25 Mar 2018, 14:23 ]
Post subject:  Re: Power supply Cap

Does anyone know what this high frequency stuff in on the B+ line is. The scope is set to 2mv and the frequence is set to 2uf.

Author:  Geek [ 25 Mar 2018, 14:48 ]
Post subject:  Re: Power supply Cap

Got flourescent, CFL or LED bulbs in the house? You're seeing their drivers. My bench is full of the noise >_<

Author:  gwalters [ 25 Mar 2018, 15:09 ]
Post subject:  Re: Power supply Cap

Well, I turned off every light in the house (I have floresents in the shop and some LED in the house) and my shop and the signal is still there.

Author:  gwalters [ 25 Mar 2018, 15:25 ]
Post subject:  Re: Power supply Cap

Ok, it's my Tektronix 2215 scope. Simply plugging the 2nd probe and the signal goes away. Sorry to bothered you.

Author:  Geek [ 25 Mar 2018, 16:32 ]
Post subject:  Re: Power supply Cap

Haha, as long as it's solved! :up:

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