DIY amp - symasym or something else?

Jump to Latest
S

solderbynumbers

Member
Joined 2021
#1
Hello forum,


I'm thinking about building a symasym amp but I think I missed the right time by 10 or 15 years or so. It still has a good reputation for sound and it doesn't look so hard to build. I'm not an expert but I'm OK with the soldering and the enclosure building. For the AC part, first powering up and trouble shooting I have some help from a friend so I should be covered at this end.


Just wondering if there are other, similar diy "open source" amps out there. To fit the shoe it should have an active community, parts should be easy to come by and of course it must sound nice. Power is not too important, symasym classic has plenty of power for what I need.

So please let me know if there are alternatives worth researching or if you have built a symasym recently (withing the last 5 years or so) and you would do it again I'd be happy to hear about that, too.




Thanks for your time
 
#3
Thanks for the hint, that is a long thread!

Apologies for the ignorance, but is the difference between the original symasym and the symasui that it's not using the big filter caps but DC servo instead? So sound wise there shouldn't be much of a difference but the offset calibration would be easier/unnecessary?


I've built quite a few boards but no hifi stuff apart from a few passive crossovers. Mainly for radio controlled vehicles - motor contoller boards, navigation and radio modules for quad copters etc. So the AC part of amplifiers is still giving me a bit of a headache. No worries - I won't touch it without supervision...
 
#4
Hello,

I have built and optimised some Symasym. I can tell you that transistor selection, as well as the inputs with JFET, are responsible for the sound quality. Since essential components -> the JFET at the input, such as Toshiba driver transistors - are no longer available, I am currently looking for a more powerful alternative.
By the way, my Symasy, which sounds excellent, only has a transformer with 2x18V. That's very little, but it also sounds very good - even if it loses bass control soon.
That's why I'm currently working on the Q17, an amplifier that has a lot of potential in theory and is a few decades younger in terms of components.
 
#5
Hi Tim,


thanks for your reply. Are the symasym parts you mentioned totally impossible to get now or can they still be found somewhere? If they're not available anymore it's probably better to find a different project. Are you documenting the development of your Q17?




Thanks
Stefan
 
#6
The JFETs are no longer available, I have not tried all the BJT variants. The 1N5551 and 1N5401 dampen considerably.
For the drivers, BJT from ON-S. is normally used, they lead to sharpness in the high tone. The Toshiba are also no longer available, I am currently testing new Toshiba. But I can't say whether this matches the circuit of the Symasym. they are not as perfect as the old ones.
The Q17 is currently under discussion. I'll report back as soon as I have the parts and ask the developer Tibi a few questions beforehand. 😀
 
#7
Very sad the parts for the Symasym are not available anymore. Looking for alternatives I found the honey badger which seems to have quite a community and the parts seem to be easy to find. I only found the boards in a US shop so far, I hope to find the gerber files or a source for the boards in the UK/EU.
 
#9
Tim1999de said:
Hello,

I have built and optimised some Symasym. I can tell you that transistor selection, as well as the inputs with JFET, are responsible for the sound quality. Since essential components -> the JFET at the input, such as Toshiba driver transistors - are no longer available, I am currently looking for a more powerful alternative.
By the way, my Symasy, which sounds excellent, only has a transformer with 2x18V. That's very little, but it also sounds very good - even if it loses bass control soon.
That's why I'm currently working on the Q17, an amplifier that has a lot of potential in theory and is a few decades younger in terms of components.
Click to expand...

Hi
As I understand, you have redesigned the input stage with JFETS? And also some other modifications?
Could you please tell some more about this?
Thanks
 
#10
solderbynumbers said:
Hello forum,
I'm thinking about building a symasym amp but I think I missed the right time by 10 or 15 years or so. It still has a good reputation for sound and it doesn't look so hard to build. I'm not an expert but I'm OK with the soldering and the enclosure building. For the AC part, first powering up and trouble shooting I have some help from a friend so I should be covered at this end.

Just wondering if there are other, similar diy "open source" amps out there. To fit the shoe it should have an active community, parts should be easy to come by and of course it must sound nice. Power is not too important, symasym classic has plenty of power for what I need.

So please let me know if there are alternatives worth researching or if you have built a symasym recently (withing the last 5 years or so) and you would do it again I'd be happy to hear about that, too.

Thanks for your time
Click to expand...

CX900mk2 PCB for sale!
 
You must log in or register to reply here.
Top Bottom