[arteom]

Emailed Alex through the Cavalli site, he came through with a cleaner board layout. That dude rules

 
Anyway, since this is the only real build thread for this amp I thought it would be of some value to add the board layout here for anyone looking in the future.
 

 

[Jose ant.]

Hello all
 
It´s my first post and I need some help.
 
I have finished my EHHA I (MOSFET versión)) but I have an issue. R32/33 always burn. The volt. on initial checking is correct (I think):
 
R3,4= 1,5 volt
R10,14=1,5 volt
R15,17= 0,80~ 0,85 volt.
R16 & R18, R26 & R29= 0,5~0,6 volt
The voltage at pins 4 and 7 of the opamp DIP socket: +15V and -15V
Pin 6=0 volt.
 
When I turned on, the R32/33 has been burnt and I don't know what fail.
 
Where is the problem? Any idea? 
 
Thanks

 

[saur12]

Hi! Is the diagram for the original EHHA or the newer revision?

I have been gifted a non working revised model. Where can I get instructions, diagrams to troubleshoot the amp?
Any help on this will be greatly appreciated.

EDIT: Whoops did not realize that this was such an old thread. Any help will be needed.

 

[funch]

You might check with Jeff here: http://www.glassjaraudio.com/ He sells kits for both versions of the EHHA, and may be able to provide the doc's.

 

[Zulkr9]

Hi there anyone know where I can get the kits, Glassjar audio seems to be unresponsive TIA

 

[tomb]

Hi there anyone know where I can get the kits, Glassjar audio seems to be unresponsive TIA

Keep trying ... AFAIK, Jeff is still in business, just typically busy. He may travel in his day job, too.

 

[Zulkr9]

Keep trying ... AFAIK, Jeff is still in business, just typically busy. He may travel in his day job, too.

I've tried a few times already, I guess just gotta wait I guess.

 

[arteom]

Greetings everyone. So some years ago I ended up building the BJT amp boards to compliment the mosfet boards which were part of the original build that I have. On those I socketed the bits that Alex had recommended to socket for the sake of modifying open-loop and closed-loop gain, as well as the slew rate capacitors. I wanted to ask if anyone might have recommendation as to what value resistors to use for these for a headphone that is high impedance - 600ohms? Have a Beyer T1 on the way and wondering how I can optimize the EHHA for use with it.

https://web.archive.org/web/2011113...iaudio.com/diy/ehha/main.php?page=tweaks/gain
https://web.archive.org/web/2011113...audio.com/diy/ehha/main.php?page=instructions

Cheers,
-Art