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mahatmakanejeeves

(57,391 posts)

5. Do you have a voltmeter?

Mon Jun 27, 2016, 04:13 PM

Jun 2016

The voltages involved are pretty low. I didn't even know you could run a tube amp on 12 volts B+.

Tube hi fi equipment can be sort of scary to work on. A Dynaco Stereo 70 has 400 volts B+ and enough current to be lethal. Also you can get burned if your hand brushes up against an output tube. This headphone amp looks less hazardous to work on.

Anyway, can you read any AC voltage on the heater supplies? It looks as if maybe you have an external 12-volt power supply for this. There should be no AC there. It should be all DC.

Have you tried running this off a car or motorcycle battery? You should get no hum from that. If it works okay an a motor vehicle battery, then you have a power supply problem.

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12 replies

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Highlight:

I need a better headphone amp [View all] Aerows Jun 2016 OP

Tube-anything is generally pricier than solid state-anything. mahatmakanejeeves Jun 2016 #1

I'll pull the schematic up and post it Aerows Jun 2016 #2

Schematics Aerows Jun 2016 #3

Do you have a voltmeter? mahatmakanejeeves Jun 2016 #5

I messed around making a CMOY Aerows Jun 2016 #8

Of all the things I have Aerows Jun 2016 #10

My configuration is an ASUS DGX Aerows Jun 2016 #4

Tubes in question Aerows Jun 2016 #6

And yes, I'm aware I need a manicure Aerows Jun 2016 #7

Isolated the power supply Aerows Jun 2016 #9

Bad ground. mahatmakanejeeves Jun 2016 #11

In other words, it sucks. Aerows Jun 2016 #12