Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd October 2006, 03:08 PM   #1
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Default Troubleshooting your Symasym

This is where to find help for your Symasym if it doesn't work when you build it.

Mike and Pavel have created a fine amplifier, other members can help you get them working, or fix them after an oops.

The original thread is here.

-Chris
  Reply With Quote
Old 5th October 2006, 07:11 PM   #2
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: GŁtersloh
No one having problems ?

Mike
  Reply With Quote
Old 5th October 2006, 07:18 PM   #3
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Mike,
I'm having a problem with my Symasym. It works fine on my bench supply, but I haven't had time to build it's own supply.

-Chris
  Reply With Quote
Old 5th October 2006, 07:28 PM   #4
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: GŁtersloh
Oh... But time is an issue i can't help with... Oh, maybe i can, desolder c7, the resulting oscillation will create a time warp sphere, giving you all time you'll ever need.
But, this will only work it the outputcoil is made out of neutronium.

Mike
  Reply With Quote
Old 5th October 2006, 08:14 PM   #5
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Mike,
Darn, only the power transformer is made of neutronium.

Actively direct people from the original thread over to this one as they request help.

Not many people have had problems anyway.

-Chris
  Reply With Quote
Old 7th October 2006, 03:00 AM   #6
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
anatech,
Since you're a mod, please delete this post if you think that it is in the wrong thread or if there is a better thread for it. I didn't want to disturb the original thread, they seem to be on to something and I didn't want to disrupt their progress.

I have been messing around with symasym5.3, just testing stuff, and I found that the bias on Q13 and Q14 wasn't balanced and wondered that if I messed with the resistor values that the distortion might decrease slightly. I know that I'm not qualified to mess with this stuff but I wondered if anyone really bothers with the small stuff like that.

I have my schem in the attachment.
I increased R17 (in my schem) to decrease the bias voltage on Q14 to better match it with Q13 which made the biases around 710mV.

This is the FFT before the optimization:

Click the image to open in full size.

This is it after the optimization:

Click the image to open in full size.

NOTE: My site manager delays the time it takes for things to actually show up on the website, so if you don't see pictures, come back later

Here is my schem:
Attached Images
File Type: jpg symasm5_3optimized.jpg (86.5 KB, 1207 views)
  Reply With Quote
Old 7th October 2006, 03:38 AM   #7
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
OOP! Just saw the symasm - the sequel thread. Is there any way to move threads? If I could edit my post I would copy and paste, but my 30 minutes is up... Think you could allow me to edit my post? I frown upon such evil deeds as putting a post in the wrong thread.

BTW: mikeB, I like your sense of humor, I think you should use it more often.
  Reply With Quote
Old 7th October 2006, 02:32 PM   #8
MikeB is offline MikeB  Germany
diyAudio Member
 
MikeB's Avatar
 
Join Date: Apr 2004
Location: GŁtersloh
keantoken, i personally don't like the idea of adding an extra unbalance to compensate another. I can't see the fft-plots...
A Wilson current mirror (the 3 bjt thing) does remove the unbalance, but does not cancel the distortion.

Mike

Edit: I checked that in my sims, i would need 153ohms for your r16 to balance that out, in any case i had increased distortions. You might not fully trust in sims.
Where did you get the models for the output devices ?
How big was your unbalance ? I have unbalance of 2% (currents)
  Reply With Quote
Old 7th October 2006, 03:41 PM   #9
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi keantoken,
No need to change anything. I'm just happy you didn't post in the old one. Your question does address a troubleshooting issue as you are working with the existing design.

If you get a chance to build one, do so. It works great and it will be a very good experience for you to compare sim to real life.

-Chris
  Reply With Quote
Old 7th October 2006, 08:08 PM   #10
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
I got all my models from onsemi.
sorry, my host server is still delaying the stuff...
I will attach my images. Maybe there is something wrong with my software? (LTSpice)
Here is my FFT without the mod:
Attached Images
File Type: jpg symasm5_3r17=150.jpg (89.6 KB, 964 views)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Symasym PCB Khron Solid State 58 17th May 2012 07:18 AM
symasym 5.3 parts 406vette Parts 2 17th February 2008 07:34 PM
symasym 5_3 boards traw Swap Meet 6 11th May 2007 09:41 AM


New To Site? Need Help?

All times are GMT. The time now is 05:38 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2