Resistance Check later followed by a voltage check :)

Johnman1116 · 5563

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Offline Laudanum

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Reply #15 on: June 25, 2012, 12:00:45 AM
Call Bottlehead, Eileen will send you a replacement LED.  Unfortunately, the LED's used arent common Radio Shack stock. 

Desmond G.


Offline Paul Joppa

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Reply #16 on: June 25, 2012, 05:30:49 AM
In that case, the diode must be damaged. Email Eileen for a replacement.

Paul Joppa


Offline Johnman1116

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Reply #17 on: July 02, 2012, 02:44:58 PM
Got to be kidding me... I think I am CURSED!  :'(



Offline Doc B.

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Reply #18 on: July 02, 2012, 02:54:19 PM
Apologies. We have a new staffer who didn't know that we ship those in padded envelopes. A new pair are headed to you tomorrow.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Johnman1116

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Reply #19 on: July 12, 2012, 09:00:55 PM
No worries, I actually was not blaming you guys at all and just thought it was a case of bad luck. Anyways the next batch of LEDs work flawlessly and all my resistance and voltages measurements checked out (nothing more that 12%).

I do still have some problems. I am getting lots of background noise which include I guess a high pitch buzzing and a lower pitch buzzing that is more "dirty" sounding; As in its sort of crackling buzz and not a smooth buzz.

I have let the amp warm up, used different sources, rca cables and power outlets but no change. I do not hear it when the volume is all the way down but as soon as i raise it, I get problems. I have not tried other headphones though...
I did check my solder joints as I was building the Crack and tested multiple times with a continuity test. I could check one more time perhaps and maybe heat up the joints again but I am fairly confident that that is not the problem.

This leads me to believe it may be a tube problem. The smaller 12au7 tube doesnt appear to light up, from what I can see, but it does get hot (yea I touched it) and I am assuming it working because the amp basically works. Maybe I could try cleaning the tube contacts but yea, I do not really know much about tubes. I have heard about noisy/faulty tubes but I do not know how frequently that happens. Could this be an issue of burn in? I dont know.

Your advice would be much appreciated.



Offline Johnman1116

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Reply #20 on: July 12, 2012, 09:05:26 PM
And THANK YOU for a great project. I got to things that I have never done such as applying finish to wood and spraying Hammertone which was really cool. It is nice to look back and feel accomplished and explaining to my friends that this is not a lamp :)
Troubleshooting is all apart of the journey and atleast I did not have to do any major desoldering and reconfiguration or get electrocuted.

Thanks again.



Offline Laudanum

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Reply #21 on: July 13, 2012, 03:25:49 AM
Johnman1116 ... The 12AU7 may have spiral filaments.  I think the EH 12AU7's do in fact.  These tubes dont glow like a lot of others.   Im not using any right now in any of my gear but from memory, I think you should probably be able to see some glow if you look down the top of the tube.  Point being, just because the tube doesnt appear to be glowing, doesnt necessarily mean it's a bad tube or the cause of your noise.   It may be the cause, glowing or not.  Or, it could be the 6080 that is noisy.   Or it may not be tube related.
Since your resistances and voltages checked out,  I would probably try swapping tubes to see if you have a noisy one.  It's quick and easy.  But you may get advice from the gurus for other things to look for.  Regardless, it's always a good idea to have a spare or two of each tube.  Even if they arent expensive, boutique tubes.  12AU7 and the 6080 (or 6AS7) tubes can be bought inexpensively.  I would consider getting a spare or two of each.  Even if it doesnt turn out to be a noisy tube, you will probably find yourself needing one of the spares at some point.  Good to have on hand for replacement without down time (waiting on a tube to be shipped to you) and quick troubleshooting.

Desmond G.


Offline Johnman1116

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Reply #22 on: July 16, 2012, 09:41:28 PM
Oh yes, I will get a spare tube of each and see if swapping them changes anything and post my findings.
Thanks,



Offline Paul Joppa

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Reply #23 on: July 17, 2012, 04:04:41 AM
From the description, the noise could be radio noise picked up from the environment. Cell phones are notorious for this, but there are increasingly many sources of radio signals - flourescent lights, light dimmers, refrigerators, computers, anything with a switching power supply, ...

Paul Joppa


Offline Johnman1116

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Reply #24 on: July 17, 2012, 08:05:26 PM
Well... regardless I bought one tube of each.    
A Sylvania 12au7a and a Raytheon 6080WB. Hopefully the problem goes away.. I am at a different location and will have to see if it changes anything.

====================
So at my new place, it is dead silent from 0 to max volume with the exact same setup.. interesting.

COOL!!!
« Last Edit: July 17, 2012, 09:50:45 PM by Johnman1116 »



Offline Laudanum

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Reply #25 on: July 18, 2012, 02:06:17 AM
Well good then.  Now you have a couple of spare tubes coming and a quiet amp.   Paul must have been right, as usual.   Must have been picking up interference from something in the old place.  Sounds like you are all set to enjoy some tunes  ;)

Desmond G.


Offline Grainger49

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Reply #26 on: July 18, 2012, 02:34:38 AM
A few posters have noise in their Crack when they startup.  Burning in gets rid of that for some, not all.  But the majority of builders get a dead quiet Crack from the get go.  And those are the words they use, "Dead Quiet."



Offline Johnman1116

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Reply #27 on: July 22, 2012, 10:06:30 AM
So I have run into they same type of buzzing again. This time I think I know where the problem is coming from. It seems like when I inset and remove the RCA, it becomes loose. I remember this happening last time as well but tightening it did not fix it.



Offline Grainger49

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Reply #28 on: July 22, 2012, 10:15:52 AM
John,

You can replace the RCA jack(s) cheaply and easily.

http://www.parts-express.com/pe/showdetl.cfm?&Partnumber=091-1120

If there is something loose, it is probably the center conductor which can get overheated easily.