Next project EHHA?
Jul 26, 2013 at 3:25 PM Thread Starter Post #1 of 19
Vladco

Vladco

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    On last Denver meeting I listen to EHHA and I like it very much.
1. Is it one of the best DIY amps? Or better tube or tube hybrid amps exist?
2. Is 6gm8 tubes still available? Or it possible to substitute them for different ones?
3. Which board to use EHHA, EHHA version A or wait for new version if it will be design in reasonable time?
4. Mosfet or transistor version because some transistors become obsolete
5. Power supply onboard or sigma?
6. Balanced or single end?
7. Any of other questions I should ask?

I appreciate any input from people who was able to listen to this amp.
Vlad
 
 
Jul 26, 2013 at 5:01 PM Post #3 of 19
I plan to get project under $1000. Nothing is written on stone. It can be stretched if needed and can be justified. EHHA sounded wonderful so is Blue Hawaii.
Vlad
 
Jul 26, 2013 at 5:31 PM Post #4 of 19
what headphones are you looking to drive with the EHHA. 
 
For the HD800, AKG K701/702, HD600/650 and orthos you'd be hard pressed to find a better DIY based amp. 
 
Go for the BJT version IMHO. EHHA Version A. YOu can try bypassing the power supply section and using something better like a super regulator if you want to maxx it out.
 
Balanced is not worth it unless you go for a pure balanced circuit which the EHHA isn't. Keep it single ended. 
 
 
Valvo or Phillips SQ 6GM8 tubes. 
 
Aug 5, 2013 at 7:58 PM Post #9 of 19
Quote:
mrslim said:
Care to elaborate?  
Click to expand...

 
Sorry, kind of fell asleep on this thread. For 1K you can possibly off a single ended 2A3 or 300B amp. If you use bang for buck parts, you could do it. 
 
My friend and I just finished a 350B amp fed by two 6SL7 tubes and it sounds a heck of a lot better than the EHHA. I have a little speaker amp to headphone converter and it makes my HD600s sound super warm and lush. 
 
A 300B amp would be even better, but I can not find the particular schematic that I had seen on DIY audio. A lot of other schematics have a BOM page close to 6K or ~1K for hybrid. 
 
This was a simple linear 300B all tube amp for 1.2K and I can't find it, which is not only bad for the OP, but it is also bad because I was going to play around with that design : (
 
It was very similar to this design. http://diyaudioprojects.com/Schematics/300B-SE-Tube-Amp-Schematic.htm
 
Aug 5, 2013 at 9:36 PM Post #10 of 19
Thank you guys for the responces. Also I'm looking for the complete proven project not for raw ideas because things could get complicated very fast. It's possible to work on project for very long time. It could be PCB or P2P.
 I appreciate any ideas or leads what help me to find project.
Vlad
 
Aug 6, 2013 at 4:08 PM Post #11 of 19
Finished mine about a month ago.  Love it!! I don't think you can go wrong.  Did mine from a Glass Jar Audio kit with a few upgrades.  Some pictures here: http://www.head-fi.org/t/85561/post-pics-of-your-builds/9210 and a bit of a discussion on the following page.  Also, some additional photos here : http://www.head-fi.org/t/506984/ehha-rev-a-interest-thread/1500.
Hardest part for me was doing a casing this amp deserves.
 
Jim
 
Aug 6, 2013 at 11:54 PM Post #12 of 19
Glad you enjoyed the EHHA Vlad :)
 
Personally I don't see much of a reason to get anything beyond it for my headphones and possibly an HD800 in the future. The one at the meet wasn't built by me, however I believe parts cost was around $350. The tubes in there were Pope (Phillips) 6GM8's, halo getters. It was also the mosfet versiion. I don't know about the BJT version, I have given slight consideration to socketing parts so they can be interchanged but not sure of any tuning that would need to be done after parts swap. Good luck on your next build!
 
Aug 7, 2013 at 11:38 AM Post #13 of 19
The EHHA is a fine build.  I'd put it at the Beta 22 level.  I have the EHHA I mosfet.  I'm not sure if a better power supply will help, but it certainly can't hurt.
 
300B is hit or miss, some people like them, some people don't.  The bulk of the money is in the tubes and transformers.  If I were to build a 300B amp, it would be like the Christiansen 300B with CCS loads but with different drivers.
 
Aug 7, 2013 at 12:49 PM Post #14 of 19
A 300B amp would be even better, but I can not find the particular schematic that I had seen on DIY audio.
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