Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: gh0st on November 02, 2011, 07:07:39 AM
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Hi all,
This is my first BH build (and first project valves/point wiring), I'm coming from the world of AMB solid state and PCBs...
So, Crack built, straight upto Speedball so I never installed the four relevant resistors. I've checked soldering and polarities etc, but I'm getting wacky readings against the expected resistances:
* Measured with the common ground connected to terminal 12, 2x DMMs for sanity check purposes. For the higher resistances, the DMMs varied more widely, in which case I've given the reading from the Fluke (theoretically better). The number in parentheses after is just what it's supposed to be according to the manual.
1 3.6M stable (*)
2 0.7M &falling (*)
3 0
4 0.7M &falling (*)
5 3.6M stable (*)
6 2.5K stable
7 10M &rising (2.9K)
8 0
9 0 (2.9K)
10 2.49K
12 0
13 climbs14 0
20 0
22 0.5
b3 10M &rising (2.9K)
b6 0 (2.9K)
rca gnd 0
rca center 91.3K
Does anyone have an idea of what I can try next?
thanks!
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Umm, just checked the wiring to the speedball and I had 9U going to GND instead of the output. BRB <grabs soldering iron>
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9U at zero is a huge problem indeed, as is B6 being 0.
Once that wire is moved, let us know if those values straighten themselves out to be more consistent with the other channel.
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Thanks for the input! After moving the wire, the resistances balance out between the channels (still higher than the crack manual states, but I'm guessing that's the influence of the speedball circuits), and there are no longer any shorts to ground.
Anyway, I'll plug her in tomorrow and check the voltages.
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Win! Voltages checked out to within 10% of spec, so I hooked her up and...sweet music. Just warming up with my DT770 600ohm right now.
photo: http://dl.dropbox.com/u/117085/IMAG0413.jpg