loud hum

[bucketofguts]

With the  the volume at 0 on power on i get a loud hum. Turn the volume up a little the hum goes dead quiet. This is repeatable for about 30 seconds then all is right in the universe. I am going to roll some valves to check. Wonder if the powers that bee have seen this issue. So many thanks in advance.

b~

[Paul Birkeland]

How are the voltages in the kit? I would recommend posting some build photos if possible, as during power-on there's nothing conducting in the circuit, so you shouldn't hear any noises.

[bucketofguts]

I can not find my downloaded instructions for checking the voltages. thank you for getting back.
b~

[bucketofguts]

I guess now i need to find out how to get the instructions sent to me. Mine will be fun to test. I used tape and numbered it for each terminal. Then removed the tape when everything was working. I guess I thought I was Joe cool. Changing to several 6080 valves the issue is gone. It returns with my two 5998. I will try to post some pics tonight. I looked with my glass and flashlight, tugged with my tweezers nothing jumped out at me.

[Paul Birkeland]

If the noise is only there with the 5998, then the easy option is to simply use the 6080.  You can e-mail replacementparts(at)bottlehead(dot)com to ask for an additional download link.  Be sure to provide your name and pertinent information about your order so we can look you up.

-PB

[bucketofguts]

Thank you Paul. I am enjoying the 6080 WA from France in the giant white box. I sent a email to you guys about the download.

[bucketofguts]

I have the download. Thank you Team Bottlehead!

[bucketofguts]

Voltage Speedball board       DC- VOLTS 200 scale
OA  38.5
1A   62.8
B/AB  96.8
1B   62.7

OB  31.6

Speedball board w/ heat sinks   0A 98.6  OB  98.7  G  100.0   B+ 87.2.

[Paul Birkeland]

That's not a working amp.  Seeing B+ at 87V on the big board but OA/OB higher than that makes me think you have a loose black wire in the amp.  The most common spot for that is where the two black wires meet on the headphone jack, though flaky solder joints elsewhere can cause nonsensical voltage readings like this.

[bucketofguts]

Thank you! back to work.......................

[Tom-s]

Thank you Paul. I am enjoying the 6080 WA from France in the giant white box. I sent a email to you guys about the download.

Be sure to test voltages you post here with another tube.

I would recommend using a tube that you know to function perfectly in the amp.

I'd have that Thomson tube tested before use.

Especially if you've bought it via Ebay from eastern Europe.

[bucketofguts]

Will do, thank you .Pulling my hair out. The two leds on the big board will not light, Could this narrow it down some. going to put is another 6080.

[bucketofguts]

new valve lit the 4 leds on the big board

[Paul Birkeland]

If you got the 6080WA off eBay and it's labeled Thomson, those have been a tube with persistent problems for many who have used them.

[bucketofguts]

I have read that. Stock 6080 big board voltages. all leds lit both boards and socket. AO  5.7  OB  10.7  G 97  B+ 63