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SOHA II in 2014? Looking to build an amp this summer.

post #1 of 5
Thread Starter 
So I've found myself with some time, and I was looking around for something to build when I came across the Cavalli DIY Amps. I became interested in these because they are available as kits with available PCBs and are designed and presented professionally on the Cavalli site. What I'm wondering is:

1. A lot of threads to do with the SOHA 2 are from ~2008. I doubt this amp is obsolete in any way, but has anything changed in the past 6 years to make this amp not an ideal build?

2.There are other hybrid designs on the Cavalli site, and the EHHA and the EHHA Rev A appear to have kits and PCBs available. For whatever reason I'm getting the impression that the EHHA is built more nowadays. If this is true or not, which should I build? I have no strict needs, I'm just wondering which will sound better and be a better overall experience.

I'm just getting into this but I want to build something I will want to use. I have a Fiio amp so I don't have any desire to build any lightweight or portable amps, even if something like a mint-tin amp would be easier. This should be doable if I'm careful, right?

Also: I would have put this in one of the two big old SOHA 2 threads, but they seem dead.
Edited by Crazy Sam - 6/16/14 at 8:01am
post #2 of 5

You will find my name in a couple of places in those old SOHA II threads.


Now that my SOHA II is done and solid, I have nothing bad to say about it. It has several options for building, isn't too expensive, and Glass Jar Audio will sell you a PC board for it. Mine is used daily on my desk at work. Why shouldn't I have good sounding music while I work?


Build it. You will enjoy it.


My advice for the build is:

 + Use a temperature controlled iron, good solder, and check your solder joints. Ultimately, I'm confident that the problems I had with my SOHA II were due to an incomplete joint somewhere. If I had been more careful in my initial work, I could have had several more years of enjoyment from it.

 + When you case it, leave lots of space for air flow. The good advice is "50% open". Make it so.

 + If you use Cavalli's provided PDF drill guides, confirm they have printed full sized before using them on your case. Some PDF software scales the output without warning.

 + Look over the setup steps provided on Cavalli's web site. There are a couple of places where you need to measure the voltage drop across a resistor. I really wish I had elevated those particular resistors by .1". Doing so would have let me attach my DMM with microclips while I was measuring, adjusting, and writing.

post #3 of 5
Thread Starter 
Awesome, I'm gonna go ahead and get started on this thing. Thanks for the pointers, its helpful to have input like this.
post #4 of 5

I would say go for it. In terms of current DIY hybrid tube amplifiers out there... there isn't really anything I can think of that is super recent, which I guess is a shame, but it is what it is.


With regard to options... I've built many Cavalli CTHs (Compact Tube Hybrids) -- kept 2 and use one at home and one at work. I know you're looking for kits, but this one is a great amp that is also a few years old at this point.




I'm also in the process of building an EHHA Rev A, which is even better than the SOHAII. It's quite a unique amp in that the tube is embedded into the design rather than coupled to the output stage. Thus, it's closer to a SS amp than a typical hybrid. I have the boards soldered up and waiting to be tested. I really dig Cavalli's offerings, so you can't go wrong.

post #5 of 5

I would have to agree with all of the above said. There is a reason that the design is still around to this day.  I have to give it to Alex Cavalli,  his designs are top notch.  If this is your first build than it won't be the easiest build, but do not fear, we all have to start somewhere and this a good a point as any.  Also beware, the casework will take as much time, if not longer to do than the circuitry.  My advice is take your time with the build, do not rush it, and you will have something that is very rewarding.  Lastly, above all, have fun.  


Good luck.

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