Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Illy123 on November 10, 2019, 06:54:45 AM
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Hello,
I recently bought a new Crack and assembled it, using a ALPS potentiometer. When I tried to test it, I found out there is no sound coming out of the left ear on my headphones. Doubled checked with a different AMP/DAC and the RCA cable and headphone is fine.
Both the LEDs lights on.
Both Tube lights up on both side each.
I took some voltage measurements and can take some pictures if needed
1 81.9
2 167.7
3 0
4 167.7
5 83.7
6 0.7mv
7 106.7
8 0
9 108.6
10 0
11 0
12 0
13 168
14 0
15 189.2
16 0
17 0
18 89.7
19 89.4
20 0
21 210.5
A1 82.5
A2 0
A3 1.5 V
A4 0
A5 0
A6 80.7
A7 0
A8 1.5 V
A9 0
B1 80.7
B2 167.7
B3 106.0
b4 82.4
B5 167.8
B6 107.7
B7 0
B8 0
Any help is appreciated.
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Assuming your voltages are OK (I didn't crosscheck your values against those in the manual), I'd suggest posting some clear photos of the volume pot wiring and the headphone jack wiring.
cheers, Derek
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Did you buy the Alps pot from Mouser? Does it have the letters "MN" written on it and a center detent half way through the rotation?
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I got the ALPS blue RK27 from ebay. It has the right font and the indent in the middle. I took some pictures of the RCA, headphone jack, and potentiometer connections but can't link or attach them. I think it might be my soldering, but not sure which connections I should check.
Edit: I uploaded them at imgur: imgur(dot)com/a/uMPjJ7Z
Replace (dot) with a period.
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Try resizing the pics to under 2 Meg.
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Your voltages are OK and that looks like the correct pot. Can you play a 60Hz tone into the amp from your phone and turn the volume control all the way up, then measure the AC voltage between ground and each lug on the volume pot and let us know what you find?
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Hi,
I did the test with my DAC instead and got the following readings: to terminal 12.
Upper left (closest to chasis) 1.488, upper mid: 1.390 upper right: 0.008 (0?)
Bottom left: 1.480 Bottom Mid: 1.360 Bottom Right: 0.008 (0?)
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OK, sound is making it out of the pot, so that isn't as concerning as it was before. Can you post some additional photos of the build? I would be looking for things touching that shouldn't, or components not quite placed where they should be.
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I took more pictures of all the connections. Hopefully, you'll see something i don't.
imgur(dot)com/a/uIIzGWO
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That link didn't work, but from a previous post, one of your 100uF coupling caps is not where it should be.
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Looks like that was the problem! I was so sure i screwed up soldering somewhere that I didn't check the basics in detail. I guess that's what you get for wiring at 3 AM in the morning.