Troulbleshooting my 5e3: Bias reading 65mA

[Tom Phillips]

Noticed, with the amp on, volumes at 0, if i approach the amp with my hands, there is a humming that gets louder as i move my hands. if i touch the chassis, with one hand, the noise disappears. im guessing grounding issue?

If the chassis isn't connected to earth ground it could cause the symptom you describe. Could be a grounding problem with your wiring or and ungrounded, or mis-wired, wall outlet that you are plugged in to. Unplug the amp and measure the resistance from the round ground pin on the line cord plug to the chassis. You should read zero Ohms or close to zero.

[Jonny toetags]

If the chassis isn't connected to earth ground it could cause the symptom you describe. Could be a grounding problem with your wiring or and ungrounded, or mis-wired, wall outlet that you are plugged in to. Unplug the amp and measure the resistance from the round ground pin on the line cord plug to the chassis. You should read zero Ohms or close to zero.

Measures 00.3 ohm
Why would I not have had this before? Just because of that GRN/YEL i removed?

[Tom Phillips]

Measures 00.3 ohm
Why would I not have had this before? Just because of that GRN/YEL i removed?

I don't think so. You could try another wall outlet or use an outlet tester to verify that the house outlet is wired correctly.

[Bruce / Mission Amps]

Remove the two 100 ohm resistors from the filament supply completely and put the green/yellow wire right at the the power tube cathode's.
You can use the eyelet of the 270 ohm 5 watt resistor, where the positive end of the cathode bypass capacitor is connected too.

[Jonny toetags]

Remove the two 100 ohm resistors from the filament supply completely and put the green/yellow wire right at the the power tube cathode's.
You can use the eyelet of the 270 ohm 5 watt resistor, where the positive end of the cathode bypass capacitor is connected too.

Where else could I put it if it doesn't reach that eyelet?

[Tom Phillips]

Where else could I put it if it doesn't reach that eyelet?

At either 6V6 pin 8. Look at the schematic diagram and you will see that they are essentially the same point in the circuit. I.e. the pins 8 and the eyelet Bruce describes are all connected together with a wire.

[Jonny toetags]

Just curious....if that wire was grounded before, how come im connecting it to a positive end?

[Tom Phillips]

Just curious....if that wire was grounded before, how come im connecting it to a positive end?

You can get lots of information on the subject by goggling "heater hum reduction" and similar phrases. One good article is at The Valve Wizard

[Jonny toetags]

What's the best thing to do if the GRN/YEL won't each either pin 8's on the 6V6's.

[Bruce / Mission Amps]

What's the best thing to do if the GRN/YEL won't each either pin 8's on the 6V6's.

Solder an extension to it... or just ground it to the chassis somewhere like many other builders do.
Do just one method, not both.

[Steve A.]

Jonny:

Although not relevant to this discussion at all one really neat trick for a stock 5E3 is to turn up the other volume control when plugged in to one of the channels. I think it really expands the tonal palette available by dialing in the two volume controls while plugged into one channel or the other.

Enough for the little side trip- good luck!

Steve Ahola

[Jonny toetags]

Just wanted to report back that everything seems ok!
Amps sounds good, voltages seem to be in range, and it's a lot quieter with the GRN/YEL to ground (like I had originally done) and the removal of the 2 100ohm resistors (like Tom and others mentioned)
Thanks so much guys!
On the next build...I might just order Bruce's PT and OT (or Mercury or something). I'm not sure I feel good about the Classictones.

@ SteveA
Yeah....I love that about the circuit.

[Bruce / Mission Amps]

Just wanted to report back that everything seems ok!
Amps sounds good, voltages seem to be in range, and it's a lot quieter with the GRN/YEL to ground (like I had originally done) and the removal of the 2 100ohm resistors (like Tom and others mentioned)
Thanks so much guys!
On the next build...I might just order Bruce's PT and OT (or Mercury or something). I'm not sure I feel good about the Classictones.

@ SteveA
Yeah....I love that about the circuit.

Magnetic Component's, Classic Tone transformers are excellent!! Don't sell those things short... high grade and very reasonably priced.