EHHA Rev A - Interest Thread
Sep 17, 2010 at 5:52 PM Post #469 of 1,752

runeight

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Hmmm. I think it is in the right orientation on the rails PS schematic. Is this the one you mean? Anode should go to ground and cathode to the -30V rail. Yes? No?
 
Sep 17, 2010 at 5:55 PM Post #471 of 1,752

runeight

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Holy cow, wait a few minutes to make a post and the finished amp appears.
 
No problems?
 
It is a nice looking set of boards.
darthsmile.gif

 
Thanks for the very fast turn.
 
If your amp is stable for a day, then I think everyone else can go ahead and build.
 
Sep 17, 2010 at 6:00 PM Post #472 of 1,752

jdkJake

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Okay, looks like we have a baseline.
 
When the sumr transformer did not look like it would make it in time, I placed an order for the Antek transformers colbaltMute so graciously found as a backup. That turned out to be a good idea, otherwise, we would be waiting. The AN-0107 is being used for the heater and the AN-0232 is being used for the +/- 30V rails. It is early, but they appear to work just fine. Both power supplies appear to be holding in regulation just fine. I have had very little heater supply drift once the tubes warm up properly. The +/-30V rails appears just as stable, but, it is early. biasing of the MOSFET's went fine. As expected, they drift with temperature, but, hold fine once everything is up at temp.
 
I ended up using the "Two Channel Alternate Wiring" hook up from the site. With the first wiring, I had a slight buzz. That cleared up with the alternate wiring. Realize, the test platform is not ideal for noise containment, but, it appears to be fine. No buzz or hum, just a slight hiss at full-open with a little bit of background noise. I suspect, a real case and careful re-orientation of the wiring (like, moving star ground from the same terminal strip as the power) should clean that up just fine. Nothing that should not clear up with a better installation.
 
At this point, I think it is safe to proceed with the rest of the beta builds. I found nothing in the build that was a real issue beyond the LED orientation for the -30V rail. That was the only component I had to pull and replace. Everything else came up first shot. No issues.
 
I need to take a break for food. I am starving. :wink:  After dinner, I will measure the DC offset at power on, see how fast it settles and also take some temperature measurements on each of the heatsinks.
 
Oh yeah, sounds great!   
dt880smile.png

 
Sep 17, 2010 at 6:05 PM Post #475 of 1,752

cobaltmute

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The -30V rail LED orientation is correct on the website.  Current flows from the most positive end to the negative end of the LED.  So from the + rail to ground or ground to the negative rail.
 
Sep 17, 2010 at 6:30 PM Post #478 of 1,752

stringgz301

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So that's what the flat black surface is for in the kitchen.  I always wondered.
 
Nice job.
 
Sep 17, 2010 at 7:37 PM Post #480 of 1,752

jdkJake

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So that's what the flat black surface is for in the kitchen.  I always wondered.


 


Nice job.





That is our new stove top. Since it is so freakin' hot, my perfectly good workbench in the garage goes unused. The stove top works well l as it cannot be damaged by heat or solder and the exhaust hood vents solder fumes. It actually works quite well, and the inside of the house is wonderful, non-humid 77degrees Fahrenheit.
 

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