♫♪ My little cheap Circlophone© ♫♪ - Page 105 - diyAudio
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 21st June 2012, 08:13 PM   #1041
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by danielwritesbac View Post
I got these values worked out from adding a resistor series to C2 to represent a lossy imperfect cap. The sim freaked out with instability as usual, whenever that resistor is present.
When you apply non-default minor parameters to a component, you should show it explicitly when you share a graphic-only attachment on the forum, Otherwise, it is completely impossible to guess (and even then, you have to look into the component in question, that's not obvious)
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 21st June 2012, 11:02 PM   #1042
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Previously indicated at post 1039, there was indeed a temporary torture test, and after achieving the higher quality of hardened centerpoint values, all parts were re-checked and shown at default prior to posting.

As shown, it does not contain any non-default minor parameters. But it will resist them.
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 21st June 2012 at 11:05 PM.
  Reply With Quote
Old 22nd June 2012, 12:44 PM   #1043
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by danielwritesbac View Post
Previously indicated at post 1039, there was indeed a temporary torture test, and after achieving the higher quality of hardened centerpoint values, all parts were re-checked and shown at default prior to posting.

As shown, it does not contain any non-default minor parameters. But it will resist them.
OK, it should be fine then.

I do not get similar results, but I use the original Circlophone parts, that's maybe what causes the divergence.

The only thing that remains to do is to validate the circuit with a physical prototype, and check the improvements do indeed materialize.
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 23rd June 2012, 02:51 PM   #1044
diyAudio Member
 
Join Date: Mar 2012
Location: ISANDO GAUTENG
Exclamation circlophone

Quote:
Originally Posted by Elvee View Post
OK, it should be fine then.

I do not get similar results, but I use the original Circlophone parts, that's maybe what causes the divergence.

The only thing that remains to do is to validate the circuit with a physical prototype, and check the improvements do indeed materialize.
This is exactly what I was thinking! Did you guys build this extremely invoved circuit or was it just theory? I discovered that the more simpler a thing the better it perform at the end. Ok I was looking for a circuit that could give me a reasonable output (20 Watts or so) for home use. How long will those little output transistors last if they get driven this hard to their maximum? Fatter transistors are not all that more expensive and WILL last a lot longer.
  Reply With Quote
Old 23rd June 2012, 11:51 PM   #1045
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by krokkenoster View Post
This is exactly what I was thinking! Did you guys build this extremely invoved circuit or was it just theory? I discovered that the more simpler a thing the better it perform at the end. Ok I was looking for a circuit that could give me a reasonable output (20 Watts or so) for home use. How long will those little output transistors last if they get driven this hard to their maximum? Fatter transistors are not all that more expensive and WILL last a lot longer.
Here's a link to the build thread.
Building Elvee's Circlophone: Documentation, Parts, Accessories, & beginner friendly

Refer to this schematic for your 20 watts (actually 27 watts):
http://www.diyaudio.com/forums/attac...e-original.gif
If this looks overly complex, try an LM1875 for good practice.

P.S.
To quickly rough estimate, with 57% of datasheet dissipation watts for AC (Music or PWM) output, I just pulled up the MJE3055 datasheet, saw 75 watts from OnSemi, used the calculator with a crude *0.57 and got ~43 watts into 8 ohms. SO, the smallest of the 3055's generously exceeds your 20w requirement by approximately 215%. A problem was where???
It is true that the MJL21194 in the simulations with 4 ohm speakers does not meet this criteria (it is "almost"); however, it is also true that some small rail pulldown (a minor volt or two) will occur at this point, thus meeting the safety estimate requirements in real life unless your capacitor bank is gigantically too big so that rail stiffness erroneously lasts longer than SOAR test timeframe, but that sort of error is rare due to the expense of causing it, so really, the MJL21194 should work fine if your rails are 35+35vdc.
The power output niche obliterated by the hi-fi LM1875 projects is why I didn't show voltage lower than 35+35vdc on the sims, and the output device selections is why I didn't show voltage higher than 35+35vdc on the sims. Of course we could do higher voltage if it was known that 8 ohm speakers are used. We're actually only using a fraction of the MJL21194's capacity.
And, the strong MJ15003 is available! These are not puny.
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 24th June 2012 at 12:15 AM.
  Reply With Quote
Old 24th June 2012, 12:45 AM   #1046
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by keantoken View Post
The compensations being applied here are becoming, shall I say, multiplicitous... Though if that ends up with a better result, I think it's pretty cool.
Well, to me it looks like none of it is an overdo (let's check that again) and all of it is better than the usual strong miller comp or similar heavy-handedness. What looks familiar is that most good hi-fi amplifiers usually have a dozen small and transparent corrections instead of a big fell swoop. Although it is important that all of the corrections are small/transparent to audio, it seems even more important that all would be different so that they can't add up to any peak in the sonic signature. What do you think?
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.
  Reply With Quote
Old 24th June 2012, 12:55 AM   #1047
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
Well in this case, the servo was out of balance. One side would be stable but the other would not. So one side had to be either sped up or slowed down.
  Reply With Quote
Old 24th June 2012, 01:05 AM   #1048
diyAudio Member
 
Join Date: Nov 2007
Location: Dallas
That was my impression, that one half presented a different Bode than the other?
I kinda deviated towards a circlopony in complimentary symmetry, as-if that were
some kinda magic bullet to make both Bode the same. Now even with perfect open
phase, both differential halfs are equally unstable in .tran . I got rid of my input pair
Miller by neutralization, and there probably lies the greater part of my folly.

Neutralizaton on the top side only works when the tail isn't messing with the class
Aness of it all from the bottom side...

Last edited by kenpeter; 24th June 2012 at 01:28 AM.
  Reply With Quote
Old 25th June 2012, 09:05 AM   #1049
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
BC556B, 2N3019, 2N5551, BD140-10, MJ15003, no other changes from the last sim, phase linear, the square is squared and 0.002608%THD
Attached Images
File Type: jpg circlo-regular-parts.jpg (164.8 KB, 182 views)
File Type: jpg circlo-regular-parts-schema.jpg (176.8 KB, 177 views)
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.
  Reply With Quote
Old 25th June 2012, 11:01 PM   #1050
diyAudio Member
 
Join Date: Nov 2007
Location: Dallas
The output cannot swing very low with that cascode in the way.
Have you considered the existing negative rail for cascode base?
You would have to provide an extra negative rail for circlophony.
But it needn't be anything elaborate since the common mode is
strongly controlled by quadrature anyway, a 5v wart might do.
  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
Need help with OB design - cheap, cheap, cheap djn Multi-Way 38 30th May 2010 06:26 AM
Scosche SPL meter: Cheap find with potential, or cheap junk? theAnonymous1 Everything Else 5 11th October 2006 03:40 AM
Alpine cda-9831 vs. 9833 vs. 9835 cbecker33 Car Audio 3 10th December 2004 12:47 PM


New To Site? Need Help?

All times are GMT. The time now is 11:44 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