Crack;Bottlehead OTL
Jan 2, 2014 at 10:23 AM Post #3,421 of 12,347
I had been watching this lot of 6080's on ebay for the last week they had been around $15 and ended up going for $358.40 which still looks a good price but more than I wanted to give to try one for rolling in the Crack
 

 
Jan 2, 2014 at 10:55 AM Post #3,422 of 12,347
  I have to admit not reading all 3500 posts in this thread...
 
Like many, I would be using this amp close to my computer.  Are there any issues with interference from lack of shielding ("gravity mounted" wooden chassis)?

 
I did get interference placing my Crack next to my Squeezebox Touch. I moved it 3 feet away and it's fine now.
 
Jan 2, 2014 at 1:02 PM Post #3,426 of 12,347
7 of them are the nice super heavy duty graphite plate tubes.....worth $50 to $80 these days if you can find them at all. :)
Wait huh? 8 6080s for $350?! Arent they like $10 each from Bottlehead?
 
Jan 2, 2014 at 2:18 PM Post #3,432 of 12,347
I posted an ad here and asked for someone to do the build. I got lots of responses. Your price is in the ballpark.

What was the range of prices you were offered? Also without the speedball upgrade got any ideas how much a second hand one goes for? 
 
Don't you think it's bit risky paying so much since I'm guessing there's no warranty?
 
Jan 2, 2014 at 2:47 PM Post #3,434 of 12,347
  Does anyone out there with a Crack and installed Speedball have any noise or hum when the volume is turned up say 75% or higher? I have a bit of noise when the volume pot is up that high and I had my buddy bring his over and he has no noise but a humming sound at that same volume level. Now I know there is no way anyone who isnt WAY hard of hearing would ever need to turn the volume up that high and yes both amps are dead silent until you get to those high volumes, I was just kinda wondering if anyone else's did the same thing. Oh and these effects were heard in multiple places around my house to eliminate the possibility of external noise, with and without a source/RCA cables plugged in and I even removed my Speedball and put the Crack back to stock on mine and it was dead silent all the way up so I know the slight noise at 80%+ volume on mine at least comes from the Speedball upgrade. All voltages and resistance checks look good with Speedball in and I have been soldering for well over 20 years so I know its not a build issue. I suppose it might be one of the components in the Speedball boards but I just wanted to ask around and see if anyone else was experiencing the same before I worry any further about it. As I mentioned its only with no music playing and the volume way higher I would EVER turn it up to.

 
OK I have some new info on this which may or may not be of help in your case but it worked for me.
 
I removed my resistors from the rca inputs to bring my BHC+Speedball back to stock my hum was still present, I messed about turning on and off equipment methodically disconnecting listening etc no joy.
 
Today I moved the Crack downstairs and had it connected up to the turntable (sounds sublime) but still had hum at way above listening levels. Later I moved the crack back upstairs connected up and the hum has changed. It was intermittent something had changed at first I thought it might be tube related but after changing a few it was not. The hum seemed more microphonic related as it started when the volume was turned up past half way but if you let go of the volume knob after a few seconds the hum decreased.
 
Here's the thing my Crack+Speedball is dead silent now at all levels.
 
The fix,
 
I twisted my rca input cables together that run from the dac to the Crack and made sure they where routed directly away from the transformer.
 
It was that simple!  I just happened to noticed when I reconnected I had a twist in the cable and as reached across to turn volume knob my elbow sometimes would move the cables. I wondered about how the internal input wiring is braided to help cancel out interference. So twisted up the connecting rca cables and no noise.
 
Hope this helps you as well
 

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