♫♪ My little cheap Circlophone© ♫♪ - Page 98 - 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 26th May 2012, 04:42 PM   #971
Elvee is online now Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by danielwritesbac View Post
Can MR types be used for this?
Yes, practically any fast 1A diode will do.
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 26th May 2012, 10:21 PM   #972
abetir is offline abetir  Philippines
diyAudio Member
 
Join Date: Nov 2010
Location: Easternmost Region V
terranigma/daniel,

It's weekend here, I'll get back on my build again and see what went wrong, thank you for the help.

terranigma, I can't do measurements because D669a heats up fast, in a few seconds I figure it will explode in smoke...


I will post updates again soon.



Sir Elvee, thank you for the updates UF series is much more easier to find here than BATs, I only found one local supplier that sells BAT85. Can 1N5818-22 qualify too?

Regards!

Last edited by abetir; 26th May 2012 at 10:33 PM.
  Reply With Quote
Old 27th May 2012, 03:46 AM   #973
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by abeteer View Post
1N5818-22 qualify too?
No. The 1n5818 datasheet says rectifier type schottky with a highly variable switch on point. If at D7, those will nuke your nards. And Elvee said:
Quote:
Originally Posted by Elvee View Post
. . .Do not use schottkies!!!. . .
1N5818-22 Rectifier schottky is not a signal type.
1N5818-22 will misinform/misfire the sensor and that is not pleasant.
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 27th May 2012 at 04:09 AM.
  Reply With Quote
Old 27th May 2012, 05:00 AM   #974
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Default D7, ~1V illustration

1N4148 at D6, plus BAT86 at D7, sums up to 1V. <<-most durable example
1N4148 at D6, plus BAT85 at D7, sums up to 1V.
FR at D6, plus FR at D7, sums up to 1V (check datasheet graphs to confirm).
MR at D6, plus MR at D7, sums up to 1V (check datasheet graphs to confirm).
BY at D6, plus BY at D7, sums up to 1V (check datasheet graphs to confirm).
UF at D6, plus UF at D7, sums up to 1V (check datasheet graphs to confirm).

So, these examples are approximately 1V, at low current, in most temperature conditions.

P.S.
Conversely, 1n4148 at D6, plus 1N5819 may engage at 0.7v and cause a sensor misfire that would blow the output devices eventually, especially if the diodes are warm. And, 1N5819 at D6 plus 1N5819 at D7 will blow the output devices immediately. The 1n5819 and similar rectifier schottky have a highly variable switch on point that is very, very low voltage and thus not suitable for either D6 or D7, since random operation of the sensor wouldn't be useful.
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 27th May 2012 at 05:07 AM.
  Reply With Quote
Old 30th May 2012, 02:54 AM   #975
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Default CFP

It seems the first thing to do for going forward with the CFP. . . is to discover the maximum practical value for C5 (The standard schematic's "RF Filter" of 330p). Some people may experience rolled off/rounded treble with 3n3. I also tried 2n7, which was borderline. 2n2 looks decent. But, don't take my word for it--this needs tested because filtering depends on your source and your potentiometer. When using the 10k potentiometer, the input loss varies and that alters the filtering. SO, the first thing to do is try to find the biggest RF filter cap you can that won't dull your treble. Please help research this?

P.S.
The following links will expire/change in time: It was possible to make Standard Circlophone and visually matching CFP Circlophone schematics, and, caution, this CFP schematic is possibly not ready for prime time (the values are probably not right)--It needs proofread, simmed, checked out. Help?
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 30th May 2012 at 03:00 AM.
  Reply With Quote
Old 31st May 2012, 04:55 PM   #976
Elvee is online now Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by danielwritesbac View Post
It seems the first thing to do for going forward with the CFP. . . is to discover the maximum practical value for C5 (The standard schematic's "RF Filter" of 330p). Some people may experience rolled off/rounded treble with 3n3. I also tried 2n7, which was borderline. 2n2 looks decent. But, don't take my word for it--this needs tested because filtering depends on your source and your potentiometer. When using the 10k potentiometer, the input loss varies and that alters the filtering. SO, the first thing to do is try to find the biggest RF filter cap you can that won't dull your treble. Please help research this?
You can also keep the original 330p and increase R19 (on your schematic) to 4.7K.
Quote:
The impedance is high enough to allow for it without inconvenient.
P.S.
The following links will expire/change in time: It was possible to make Standard Circlophone and visually matching CFP Circlophone schematics, and, caution, this CFP schematic is possibly not ready for prime time (the values are probably not right)--It needs proofread, simmed, checked out. Help?
Some corrections:
C6=120p
R23=1K8
R2=47
C4=3p3
C2=390p
C12=270p
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 31st May 2012, 06:47 PM   #977
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Default The twins:

Are these good?

CFP Circlophone
(click image to enlarge)
Click the image to open in full size.


Standard Circlophone
(click image to enlarge)
Click the image to open in full size.

See how they match?
Attached Images
File Type: gif circlophone-cfp.gif (35.3 KB, 326 views)
File Type: gif circlophone-standard.gif (33.7 KB, 947 views)
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 31st May 2012 at 06:49 PM.
  Reply With Quote
Old 31st May 2012, 09:33 PM   #978
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
I am not having any overshoot issues in simulation with the CFP version. At first I was skeptical it could work with just 45uA input pair current, as the Ft at this current should theoretically be around 8MHz. But, the Ft spec in many situations isn't very useful. Just to be sure, I've increased the input pair current to over 500uA.

This version gets -3db at 5MHz. I don't see why any feedback capacitor is necessary.
Attached Images
File Type: png Circlophone_CFP_keanschem.png (120.7 KB, 193 views)
  Reply With Quote
Old 1st June 2012, 08:55 AM   #979
Elvee is online now Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by danielwritesbac View Post
Are these good?


See how they match?
Looks OK, but let us examine Keantoken's contribution before going further.

Quote:
Originally Posted by keantoken View Post
I am not having any overshoot issues in simulation with the CFP version.
........
This version gets -3db at 5MHz. I don't see why any feedback capacitor is necessary.
Yes, but the compensation components you used are very different.

This compensation strategy looks much more agressive, but if it doesn't harm the performances, it could be the way to go.
A fresh look from an outsider often brings interesting new things, and I welcome it.
I was a bit stuck with a somewhat unsatisfactory scheme, and if the issues could be solved that simply, that would be nice.
Have you looked at the slew-rates?
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 1st June 2012, 09:34 AM   #980
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
All I ever used to get compensation values was trial and error, informed by bode plots.

Here is the slew rate and an updated schematic. Redtrace is with no load, orange trace is with 6R load.

The feedback employs a capacitive divider that doesn't add any poles to the response and makes the feedback network good to the tens of MHz. This simplifies finding the right compensation values.
Attached Images
File Type: png Circlophone_CFP_keanschem_Slewing.png (112.2 KB, 87 views)
File Type: png Circlophone_CFP_keanschem_slewschem.png (121.7 KB, 77 views)

Last edited by keantoken; 1st June 2012 at 09:45 AM.
  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 02:45 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