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Cavalli EHHA Embedded Hybrid Headphone Amp - Page 121

post #1801 of 1817


Edited by Jose C - 11/25/13 at 12:30am
post #1802 of 1817


Edited by Jose C - 11/25/13 at 12:30am
post #1803 of 1817
The first obvious thing to do is the Setup measurements and report any measurement deviations (from expected and perhaps between channels):
Edited by cfcubed - 12/27/12 at 5:25am
post #1804 of 1817


Edited by Jose C - 11/25/13 at 12:30am
post #1805 of 1817

Was hoping someone more familiar w/the circuit might chime in...  

In the absence of real insight into this, from looking at the schematic & searching this thread for "cold" and "R21" would suspect one or more of the 8 transistors toward the center of the schematic - e.g. R21, the sand parts + resistors that influence the output transistors & the output transistors themselves.

Here's a couple diag sessions from this thread:




Good luck.

post #1806 of 1817

Sorry to drum this back up.  But I am about to start my build up and need a power supply.  Which one should I use, or at least what do I need in terms of power requirements?


I want to use an telefunken ecc 86 to start with.  I’m not sure if I need a heater power supply as well, and if so can you tell me what I would need?  If you have mouser part numbers that would be cool.  I’m about ready to make an order from them

post #1807 of 1817
post #1808 of 1817

It seems like most people are using two Avel Lindberg toroidal transformers.  I’m just not sure what model number they are using.  Also what heater transformer are people using?

post #1809 of 1817

Is the Avel Y236653 the correct one to use for the REV A?  Do I only need one if I use that one?  I also see I need a 6.3V/1A heater transformer - Any recommendations?  

post #1810 of 1817

My reply was for the original EHHA. If you are building the Rev. A, then you don't need a separate power supply, just the two transformers: one for the heaters, and

one for the amp PS.

post #1811 of 1817

Do you think the Avel Y236653 would be the correct transformer to use?  Any thoughts on a model for the heater?

post #1812 of 1817

That one is waaay over spec @ 4A. You only need 0.5A.



For the amp PS, use Avel #Y236107: 30+30V @ 0.5A.


For the heater PS, use the UF4004 diodes and use Avel #Y236101: 9+9V @ 1.67A.

post #1813 of 1817

It has been years since I had considered building one of these, life has gone up and down, left and right, I hadn't used headphones in a long while. I finally got back into the hobby. Got another pair of MS-Pro's and bought funch's EHHA from a member that had purchased it from funch couple of years ago. This thing sounds amazing! Just such an effortless presentation of sound, highly detailed, excellent instrument separation, no grain, its smooth but never syrupy. This is it folks.


The tubes on this are still the original A Frame German GE's, I have ordered a set of NOS Pope Holland 6GM8's, anxious to hear those.

post #1814 of 1817

I know this has probably been discussed (couldn't find it with search), but anyone swap capacitors? Recommended?

post #1815 of 1817

I've started getting some distortion on the board connected to my right channel, I'm trying to go through initial setup steps posted on the cavalli site but am having a hard time making out part marking on the board that is listed on the site, does anyone have alternative image. Or if anyone has a clean board and can take some pictures that show part markings, it would be well appreciated!!

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