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EHHA Rev A - Interest Thread - Page 116

post #1726 of 1733
Quote:
Originally Posted by Sathimas View Post
 

 

By "engage" I mean it switches off the outputs.

 

 

I don't quite understand your question?

 

Amp out is not connected to star ground.

 

Amp ground (next to Amp out) is directly connected to the jack from both boards.

 

 

Star ground is connected to the ground tap of the power inlet (called "IEC" in my last post).

 

 

 

yes, see the picture for the wiring, it works now.

 

 

 

 

Hope I could clarify things a bit.

Sorry, I didn't mean the Amp Out terminal. I meant the ground terminal from the Amp Out Terminal Block.  Yes, I see the picture. What is the purpose of this extra ground connection?

 

I have the Amp Out ground terminals from both amps to Star Ground.

post #1727 of 1733
Quote:
What is the purpose of this extra ground connection?
 
 I have the Amp Out ground terminals from both amps to Star Ground.

 

There is no extra ground connection, since the jack is not tied to Star ground,

but to the amp out ground terminals directly.

 

Tried this while solving my hum problems.

 

I could try the old sheme now ...


Edited by Sathimas - 6/12/16 at 9:06am
post #1728 of 1733
Quote:
Originally Posted by Sathimas View Post
 

OK. It may not matter, but weird ground eddies may be at play. Cavalli's Alternate Wiring Diagram shows the amp Out ground terminals are not connected. Instead, the amp In star ground terminals are connected to the star ground. It's worth a shot in the dark.

 

BTW, I edited my earlier post to clarify a few comments.

 

Good luck!

post #1729 of 1733
Quote:
Originally Posted by Sathimas View Post
 

 

There is no extra ground connection, since the jack is not tied to Star ground,

but to the amp out ground terminals directly.

 

Tried this while solving my hum problems.

 

I could try the old sheme now ...

OK. By "extra ground connection," I meant extra as one not shown on Cavalli's wiring diagram. No offense intended.

 

Maybe I should try your scheme to see if it helps my hum issue.

post #1730 of 1733

no offense taken.

 

Ground wiring on the EHHA is really confusing ...

post #1731 of 1733

Well, this amp is driving me absolutely mad.

 

I changed the resistor-values according to ambs website to decrease the sensivity of the e12.

 

While doing that, I changed nothing about the internal wiring of the amp.

(It was hum-free before)

 

Now after getting the e12 (half) to work (still a bit jumpy) the hum is back.

 

Changed the ground wiring to cavallis alternative wiring then with no

effect - changed to normal ground scheme and the hum was gone.

 

For some reason, the e12 cut off the outputs then and when sound came back,

the hum was there too again - without changing anything in the wiring.

 

 

I just don't get it, this is ridiculous...

post #1732 of 1733

Adding my newest observation:

 

Had the phones connected directly at turning on the amp,

had no hum when the e12 let the signal pass.

 

Got hum, starting quiet and becoming louder after a few seconds,

the hum started to "oscillate" getting loud and quiet at maybe 1 

volumen-change per second - then the e12 started to switch on and off.

 

 

Any idea where the problem might be?

post #1733 of 1733
As I see many people complaining about the hum, I will give you one tip.
Thus him is usually done by a bad tube implementation, so is the ehha.
Cut the capacitor ground, pin 9 of the tube. And directly connect it to the general ground.
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