EHHA Rev A - Interest Thread
Sep 18, 2010 at 10:15 AM Post #496 of 1,752

jdkJake

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Yes, excellent work...


 


The measured temp on the toroid hold down screw and washer keeps me thinking... will overspec the transformer to 400mA most likely...


51C is a lot and you have yet to case it up.





The screw itself is considerably cooler, but, the overall heat is more than I expected. That being said, if you look at the specs, there should be plenty of available current at 30V. Something like 400ma per secondary. However, the full heat dissipation of 25W is occurring at that load.

I am no transformer expert, but, I think something closer to the required voltage would probably be far more efficient. Hopefully we will find out soon and the custom sumr will show up to the party.
 
Sep 18, 2010 at 12:35 PM Post #497 of 1,752

runeight

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JDK, when you have a minute could you please measure the voltage input to the regulators? Let's see what kind of drop we're getting in the transformer. Also, measure the loaded AC voltage on the secondary.
 
Sep 18, 2010 at 4:27 PM Post #498 of 1,752

jdkJake

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JDK, when you have a minute could you please measure the voltage input to the regulators? Let's see what kind of drop we're getting in the transformer. Also, measure the loaded AC voltage on the secondary.





Loaded AC voltage on the secondary is ~28.9VAC.

Where did you want me to take the other measurement,after the rectifiers?

 
Sep 18, 2010 at 4:36 PM Post #499 of 1,752

runeight

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At the input pins to the regulators. Or, equivalently, at the +/- terminals of C1R and C2R.
 
Also, what is the spec on the transformer? Is it 30-0-30?
 
Sep 18, 2010 at 10:03 PM Post #501 of 1,752

runeight

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No necessarily. This depends in the input to regulator voltage. The anteks don't have the best regulation IIRC, so let's see what jdk is getting for the voltage first.
 
Sep 19, 2010 at 10:32 AM Post #503 of 1,752

stringgz301

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Another EHHA rev A lives.  Fairly standard build using Avel-Lindberg transformers (9+9 and 30+30).  No DC offset issues, and the bias is settling in nicely.  I may need to play with the closed loop gain because I barely turn the volume pot to 7:30 with my HF2's.
 
Sep 19, 2010 at 11:12 AM Post #505 of 1,752

jdkJake

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At the input pins to the regulators. Or, equivalently, at the +/- terminals of C1R and C2R.


 


Also, what is the spec on the transformer? Is it 30-0-30?





http://www.antekinc.com/pdf/AN-0232.pdf

Output on the secondary is ~29.5VAC

Input to the regulators (317/337) is 29.6V and -35.4V respectively.

The best part of these transformers is the price. It will be interesting to see how the other manufacture's measure.
 
Sep 19, 2010 at 11:16 AM Post #506 of 1,752

jdkJake

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What is the AC level at the socket?


If that is the Antek mentioned it should be dual 32V secondaries.


Would going to the 50VA unit AN-0532 improve things?





AC from the socket is between 121 to 122VAC depending upon what is running at the time of measure. Biggest hit is of course the HVAC, but even then, it is generally only a 0.5VAC difference.
 
Sep 19, 2010 at 2:01 PM Post #510 of 1,752

stringgz301

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Mini review of the newly built EHHA Rev A.  Not sure what I was expecting coming from my SOHA II (that sounded pretty darn good after tweaking with Mundorf SIO coupling caps and ELNA Silmic II power caps).  The EHHA is a startling upgrade, especially in transparency.  The music seems very immediate, effortless, and uncolored.  Bottom end goes way down (Nickelback (a guilty pleasure) Feelin' Way Too Damn Good - I heard bass notes I didn't recall being there) and upper end is very smooth (Jenny Lewis - Pretty Bird sounds like I'm in the studio).  I'm sitting here listening to Jeff Buckley - Grace and the hair is standing up on the back of my neck.
 
I can see why people describe the EHHA as being very musical.  Awesome.
 

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