[johnwmclean]

Thanks gents! Really nice words,
 
Greg I’m looking forward to seeing your build completed!

 

[Horio]

I finally mailed off the panels on my CKK3/Gamma2 project, so that is almost finish finally!  After that, all my attention can go to finishing up the EHHA/o22.  I've got the EHHA boards built and the o22 running already (not cased up though).  Still need a few more parts though.  I will post some pictures on here in the next few weeks when I make some more progress.

 

[johnwmclean]

Free for anyone interested
 
 I don’t know what else to do with these so...
 



 
These panels were for my 1u 350mm Modushop chassis, they all had something that wasn’t done right from Cam.
 
The back panel was supposed to be black anodised. The front panel has the cavity for the inset volume knob dug out of the wrong side (on the other side from this photo, I was initially going to use it as is and mount the perspex on facing side it worked fine and lit up nicely, I have spare perspex rings also. I have two top panels like the one in the picture, these were drastically different from the files I had supplied CAM. The tube holes were too small and in the wrong position, the holes will still fit around a tube comfortably, but with little slip for tolerances that are out of whack with the base.
 
I have all component data sheets also, along with computer drawings.
 
All you need to pay for is shipping. First in first served

 

[primer]

Much expletives when you noticed the errors.  I'm glad everything turned out well.  Looks good.

 

[Horio]

John,
 
I might be interested in the top panel for my build.  I'm using the same chassis as you but just the 2U version.

 

[RockinCannoisseur]

how does ehha 1 compare to soha II or bijou? and why no phono stage at cavalli?   i had thought the bijou but nope?
and how does cav compare to hag?  im pretty much sold on the piccolo or bugle unless cavalli has any competition hopefully?
the hag cornet 2 also looks very nice

 

[sachu]

I prefer the EHHA over the SOHA2 or the Bijou.

 

[johnwmclean]

I’ve been following the ehha-rev-a-interest-thread closely, jdkJake measured his DC offset at power on as 1.5V even 1.7V possibly 1.9V.
I’ve measured dc offset over my four boards and I’m happy to say they are all 0mV. But I hadn’t done a dc offset test at turn on, so tried it out over the four boards of my amp to see the results.
I set my DMM (fluke 87V) to capture the highest amount, the measurements were 1.5V best result and 2.4V being the worst.
 
Virtually within a spit second these voltages drop and within 5 seconds were down to 0V.
 
Unfortunately a ε12 for me is not doable as my build is a speaker amp. I will be plugging my phones in after 10 seconds or so after power from now on.
 
Now I’m pretty sure a lot of EHHA builds will have similar readings, do you guys think this is a concern?   

 

[runeight]

2.4V for most speakers should not be a problem. For 4 ohms this would be about 600mA transient. Not enough to hurt the speaker.
 
Did you measure with or without the speakers connected.
 
Now for 32R headphones, the current would be 2.4/32 = 75mA. Some headphones might be damaged by this, I'm not sure. My guess is that most would not. Maybe none.

 

[sachu]

I almost never unplug my headphones, not something i recommend. But it helps when all your headphones are orthos that can take some serious power.

 

[johnwmclean]

Thank you guys that’s great info, measurements were made without anything connected to the outputs. HD800’s should be no problem in that case.
 
I have some some Horns Shoppe speakers on the way, I’m hoping for a great match with this amp.   
 
 
 
 
 

 

[jdkJake]

Johnwmclean,

Worse comes to worse, you could always build and install a simple hard-switched (manually-switched) relay circuit. Adding a time delay would also be pretty straight forward. No where near as sophisticated as the e12, but, certainly functional. My main receiver ( commercial) has such a circuit to keep it quiet until things settle. Just a thought.

Too bad you are so far away, I would love to hear that amp through speakers. I suspect it would be quite the treat! You are a fortunate man.

 

[rx7mark]

John,
What a great build!!    It's great to see a EHHA speaker amp up and running.
 
Would you mind summarizing the details of the build, gains, upgrades, transformers, rev to the BOM, etc. 
 
I know some of it is on this thread, but a summary post would be great.
 
Thanks in advance!
 
Mark
 

 

[johnwmclean]

Thanks Mark, I'm camping up the coast at the moment, when I'm back in a few days I'll post up some more details.

 

[adamus]

john - Are you considering speaker protection for this build? I am going to build a hybrid soon, and i just dont think i can trust a servo without protection.
 
If them amp developed a fault that meant it went to one of its rails, then i can only see one outcome... dead speaker!