Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: atom631 on July 05, 2024, 05:48:33 PM
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I just finished my Crack build. I wanted to post some pics, but it says Im not allowed to post external linkes.
Anyway, I passed all the resistance checks. When I tested the voltage, I had 3 outliers... Terminal 2 and 4 were both 211 volts and supposed to be 170. Terminal 7 is supposed to be between 90-115 and I was reading 118v.
I know on the next page it says tube tolerances can vary the voltage and to not worry about it, but i just wanted to double check.
Also - what is the break-in or burn in procedure for the Crack?
Thanks!!
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What is your incoming powerline voltage? You can upload photos directly to this forum.
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What is your incoming powerline voltage? You can upload photos directly to this forum.
Im the States, so 120v. I think thats what youre asking. :-[
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No, I mean what did you measure out of the wall? Also can you post a build photo?
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Ill have to remeasure.
here are pics of my build:
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No, I mean what did you measure out of the wall? Also can you post a build photo?
I just retook the measurements. I had it off and unplugged for about 45 minutes before I tested:
Terminal 1: 83.7
Terminal 2: 208.5
Terminal 3: .3
Terminal 4: 208.6
Terminal 5: 80
Terminal 6 .1
Terminal 7: 116.3
Terminal 8: .4
Terminal 9: 110.7
Terminal 10: .1
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I'm asking what the voltage is that you measured during the test on page 22 of the manual.
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I'm asking what the voltage is that you measured during the test on page 22 of the manual.
ah. sorry, im totally new at this. I dont recall the exact reading, but it was under 115, so I followed the directions there.
is it possible to re do the test with everything soldered up?
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I dont recall the exact reading, but it was under 115, so I followed the directions there.
I think you need to recheck this.
is it possible to re do the test with everything soldered up?
Yes, or you can set your meter to AC volts and just measure a wall outlet in your home on its own.
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I think you need to recheck this. Yes, or you can set your meter to AC volts and just measure a wall outlet in your home on its own.
So, this is probably the issue. When I test an AC outlet or reperform the test on page 22, Im getting 123.7v.
Not sure how I messed that up originally. Looks like I need to swing the red wire from N (on IEC) to 14 on transformer over to 15 on transformer. Then move the red jumper over thats on 14 to 17 to 15 to 18.
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Yes, you have the power transformer wired for less than 115V and it needs to be wired for the next range up. That will drop your DC voltages down a bit and you'll find that things look a lot better once that's done.
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Yes, you have the power transformer wired for less than 115V and it needs to be wired for the next range up. That will drop your DC voltages down a bit and you'll find that things look a lot better once that's done.
thanks!!
for my own curiosity- lets say this wasn't caught and i went about using the amp. what wouldve happened? im assuming its pushing more voltage than needed to the tubes thus making them run hotter and wear out prematurely? would there be any change in sound?
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You probably are out of spec on the the 6.3V heater winding, and that is not great for tube life. The start up DC voltage before the tubes conduct is probably a little higher than the 250V rated caps would like to see.
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You probably are out of spec on the the 6.3V heater winding, and that is not great for tube life. The start up DC voltage before the tubes conduct is probably a little higher than the 250V rated caps would like to see.
got it. thanks.
Made the changes and here are the new results. Looks like Im all good:
Terminal 1: 77.6
Terminal 2: 170.4
Terminal 3: 0
Terminal 4: 169.9
Terminal 5: 74.7
Terminal 6 0
Terminal 7: 99.6
Terminal 8: 0
Terminal 9: 95.5
Terminal 10: 0
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Terminals 2 and 4 should be identical. If you double check and see a half a volt drop between the two, I'd reflow the solder joints on the jumper wire that connects them together.
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Terminals 2 and 4 should be identical. If you double check and see a half a volt drop between the two, I'd reflow the solder joints on the jumper wire that connects them together.
so i was using the amp for a bit. then saw your message. unplugged and waited about 10-15 minutes. re-tested. terminal 2 and 4 were now identical. but they only were showing 164.8v.
disregard last comment. i tried again and got a better bite on the 12u terminal with the alligator clip and they are both now showing 170 on the nose.
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Nice looking build, both outside and in. Enjoy.
Karl