SOHA?

[blmelon]

I am looking into getting an amp and am now looking into the SOHA design. All of the threads that offer any information in the forums are about 18 months to 2 years old. Have there been any changes/improvements to the design since then? What are the standard components that would go into the build? How does this thing compare to some of the other DIYs out there? I am listening to LPs through sr225s if that helps.

 

[ericj]

Well, the SOHA board is the same. Since then, the 'jisbos' discrete buffer board has become an option as well.

Using the jisbos buffer requires that you upgrade the regulators on the soha board to the full size TO220 parts, iirc, but i don't have a jisbos. Or a preprinted SOHA board - mine is on perfboard.

Using grados, you'll probably need the jisbos. Or a pair of OPA551's on a browndog adapter.

Depending on the tube more than anything else, the SOHA is a very musical amp.

SOHA II is in the works, but the design process has been stalled for a few months due to an issue that doesn't have a solution at the moment. At any rate, SOHA II isn't likely to materialize any time soon as a viable solution for most people. At least not until some time after alex's current project is done.

 

[blmelon]

this is good stuff ericj. what are some other parts that would be good to build into the amp? any and all help is appreciated.

 

[Pars]

I am currently adding the JISBOS buffers into another user's SOHA and this is my first exposure to this amp (other than occasionally reading the design threads, etc.). Nice little amp. I would definitely recommend the JISBOS buffers. I would also recommend using one of Amb's epsilon-12 (e12) DC offset/delay boards with this amp, or at a minimum some type of delay on the output as it does take 30 seconds or so to come up and stabilize when first turned on. Otherwise, wait about 30 seconds before plugging your phones in.

 

[MrSlim]

Check out this Thread re Tube rolling (Ive got GE5963s that Im planning on using) http://www.head-fi.org/forums/f6/soh...-sound-311097/
Beyond the JISBOS, which is a major step up, from what everyone is saying, the tube has the most effect on the sound. Whether "boutique" caps in a couple of locations makes much of a difference or not seems to be up for debate (and quite hotly I'm sure).

 

[regal]

I recently built the Jisbos+SOHA. It is a fantastic amp that is a level above the Millet(not max don't have one). Although without as much bass as aDB+Millett using a GE5963 tube.

I woudn't build it without the Jisbos + gain reduction wiring scheme. For Grado's the SOHA on its own has too much gain. See the gain reduction scheme on Steinchen website.

Edit: bass issue resolved with new tube