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My EHHA-B22-o22 Build Log

post #1 of 62
Thread Starter 
So after much research, reading and planning, I have started my 3 chassis build. The build will consist of three seperate boxes: one power supply box, one balanced EHHA box, and one B22 box. Here are some overall rough details of the three units:

Power supply:
  • Dual-mono sigma22
  • 2 x Sumr 120VA fully encapsulated transformers
  • 1 x Sumr 50VA toroid transformer (heater supply)
  • 1 x Sumr 30VA toroid transformers (misc other devices)
  • Glassware H-PS-1 12.6V heater regulator
  • 2-3 e12 switch boards

EHHA:
  • 4 x EHHA boards MOSFET configuration (balanced setup)
  • Joshua Tree balanced attenuator
  • Goldpoint rotary selector switch
  • Will be able to power 6H30 tubes

B22:
  • 4 x B22 boards for balanced setup
  • Fairly standard build with few boutique parts
  • Joshua Tree balanced attenuator
  • Goldpoint rotary selector switch
  • Setup for preamp capabilities

Amphenol/Speakon umbilicals will be used between the units. And I am planning to go with Hifi2000 slim line cases with 10mm front panels (all black). At this moment I am not going to setup either the EHHA or B22 to be able to power speakers directly. I will likely use either my Rotel amp or perhaps look at the B24 or a Firstwatt DIY amp build. This is by far and away the most complex build I have done, but I am pretty excited about it.

Feel free to shoot me any advice along the way.
post #2 of 62
Thread Starter 
Here are a few pictures of the early progress:





I just received the EHHA boards this afternoon, so perhaps I'll start populating those tomorrow.
post #3 of 62
wow..this should be epic..look forward to seeing this evolve.
Both are amazing amps.

A word of advice though, i think you may want to just run the 6GM8s in the EHHA. The low plate voltage and current on the EHHA is just not ideal for the 6H30s. I've found that the amp loses its magic with the 6H30.
post #4 of 62
Nice Horio, I’m glad you started this up.

240VAC may be little excessive for a headphone only build, considering 100VAC would be adequate for 4 β22 boards, EHHA even less.
post #5 of 62
Thread Starter 
Quote:
Originally Posted by johnwmclean View Post
Nice Horio, I’m glad you started this up.

240VAC may be little excessive for a headphone only build, considering 100VAC would be adequate for 4 β22 boards, EHHA even less.
Yea, I know that leaves a ton of headroom for a headphone only build, but you never know down the road. I may change my mind in a few weeks and end up setting up the B22 to power speakers...
post #6 of 62
Thread Starter 
Quote:
Originally Posted by sachu View Post
wow..this should be epic..look forward to seeing this evolve.
Both are amazing amps.

A word of advice though, i think you may want to just run the 6GM8s in the EHHA. The low plate voltage and current on the EHHA is just not ideal for the 6H30s. I've found that the amp loses its magic with the 6H30.
Thanks for the tube tip Sachu. I wanted to setup the heater with the extra capacity so I could have the option of 6H30's. I am going to start with the 6GM8's, which are proving to be hard to come by.
post #7 of 62
your onto something huge here how about dumping a dual mono tpa buffalo in there as well :P heheh just kidding best of luck
post #8 of 62
try Glassjar audio for the tubes Sachu mentioned I got a kit from them about a month ago.....
post #9 of 62
This will be great. I love build logs!
post #10 of 62
Thread Starter 
Quote:
Originally Posted by aloksatoor View Post
your onto something huge here how about dumping a dual mono tpa buffalo in there as well :P heheh just kidding best of luck
A matching balanced TPA buffalo DAC is on the list of possible add-ons.
post #11 of 62
Sounds interesting. I'll follow your progress. Very interested in how the balanced EHHA compares with balanced B22 in term of power and cost (should be almost the same, I think).
post #12 of 62
Thread Starter 
A progress update:

I was out of town last weekend, but I started populating the EHHA boards yesterday. Waiting on a few more parts that are on backorder from Mouser, and I should be able to finish these boards (still need tubes as well). Here are a few pictures:







I also placed the order for the Sumr transformers. Once those arrive and I find some 6GM8 tubes, I should be ready to start testing. I have also decided to upgrade the heatsinks on the o22 boards so the B22 can be setup for speaker duty. I am in the process for ordering some Conrad heatsinks. The international shipping isn't cheap, but I think their flanged heatsinks are the best option for my setup.

I have a couple of e24/25 boards and all the parts, but I ran out of solder today. Will have to wait until the solder I ordered last week arrives before I can heat up the iron again.

You guys have any suggestions on hookup wire? I'm going to go with some 16ga for the power wires, and 20-22ga for the rest. I used some navships stuff in my last build, but I was thinking about trying the Belden SPC wire or something else for this build.
post #13 of 62
Looking good..be careful when you test those EHHA boards..they can be picky at times.
Make sure you have R21 turned counter clockwise before you bring up the boards.

I am listening to my own EHHA and I am rediscovering why I fell in love with this amp when i first heard it over 2 years ago.
I am convinced you will be very happy with what you hear when you have yours built up.
post #14 of 62
Thread Starter 
Thanks for the tip Sachu. I'm listening to my HD650's that the Fedex guy just dropped off. I'm thinking these phones are going to getting along nicely with the balanced EHHA in the near future.
post #15 of 62
Thread Starter 
I put together the Glassware H-PS-1 Kit today. Its a nice kit that goes together in a snap. There are several output voltages you can set the heater supply for, and I chose 12.6V for my purposes.

After a 6-month furlough, I started working again last week so progress will probably slow down. I have some 6GM8's on the way, and hopefully the Sumr transformers will ship out soon. I hope to get the chassis order in the next couple of weeks.

Here are a few pictures:





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