Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: swuuggs on March 19, 2014, 01:13:36 PM
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So I built my crack probably a week ago, and it sounds great.
First listening session I noticed a slight hum and some crackling, and switched the tube to the other one I had hanging around, and the crackling is gone, but there is still a slight hum that gets louder when the thing warms up. (think I hit the power button, and the hum fades in)
I have reflowed the solder in every joint twice now, and swapped the Black wire from 4 to 22L to 4 to 14U, no dice. Hum is still there.
I'm at a loss for what this could be.
Here are a ton of pictures:
http://imgur.com/a/P91yE
Also, this happens in both my HD555s and HD650s, using an Audioengine D1 as a DAC.
Edit: I am doing the Grounding run through sticky, and will post readings from that here, and hopefully one of you can tell me where I have it wrong.
This was in M ohms, with the black lead touching the chassis, and the tubes in their sockets, with them out of their sockets, these are both 0.
Also, all unlisted values were 0 M ohms, but many of them started at .04 to .10 and went down to 0 after a few seconds.
RCA Sleeve that your wires go into on bottom -
White - .10
Red - .09
Edit 2:
After resoldering all the grounds and plugging the amp into a grounded outlet, I have a new hum, but this one dependent on volume.
Still, as far as I can tell, only in the left ear.
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You are looking for a short. If your meter has ranges, use the lowest. Readings of M Ohms for grounds to the chassis are bad readings.
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How are your voltages?
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You are looking for a short. If your meter has ranges, use the lowest. Readings of M Ohms for grounds to the chassis are bad readings.
I switched to kilo-ohms after the first two, and after that, standard ohms, as I was unaware of what range my multimeter was capable of, but kept getting zeros, which probably has to do with reading from the chassis from the first two, which I then switched to reading from T3 after rereading the sticky.
I can remeasure tomorrow from the start.
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How are your voltages?
Just read them:
1 - 85.5
2 - 172.1
3 - 0
4 - 171.9
5 - 85.7
6 - 0
7 - 108.3
8 - 0
9 - 110.1
10 - 0
11 - 0
13 - 0
14 - 171.9
15 - Blew the fuse accidentally bridging the switch and T15 with the lead
Any shot I damaged something blowing the fuse? There was a loud pop and a white spark.
Other than the blown fuse, I'm under the impression those all check out. I of course have more to do.