The MONGREL (supersym II) - Page 31 - 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 15th August 2010, 10:33 PM   #301
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by AndrewT View Post
r16=4k7 for +-70Vdc????
R18=4k7?
Works perfect ...Andrew. The ones I have now are 2.7/2.7K , exact circuit , 45-0-45V. To keep the 7ma VAS standing current , the 4.7K's are needed. (See below 75-0-75VDC / 4.7k)

Edit - I see the error R17-18 are the 4.7k's

OS
Attached Images
File Type: gif BX1.1VBcurrents.gif (19.4 KB, 490 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper

Last edited by ostripper; 15th August 2010 at 10:40 PM.
  Reply With Quote
Old 17th August 2010, 09:17 AM   #302
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
At it again , after a break. (Pix 1) is the NEW PB60LP low profile for those with "IDI BIDI" amplifier cases , it will be done tomorrow. Also for tomorrow , I should have the NEW IMPROVED PB60 / PB250 done. NOTHING was wrong with the last ones.But after testing , research , and discussion... 2 ground points are the best for these boards.

And here is why .... PMA pointed out that large rail caps on the main board increase noise and foul up the star with their "filthy" current pulses. I LIKE big onboard rail caps for the simple reason that they negate the effects of the FUSE!! (yes, the fuse is a resistor) and they add a noticable "edge" to the sound. SO , why not just have their ground separate and feed that individually back to the main star of the amp's power supply. IT works , On the "supersym" , it halved my already low noise floor ... a worthwhile design change.

Andrew T. advised on "guard rings" and taking negative feedback in the most pure form back to the differential. This is now the "standard" (a shielded cable with the shield at the same potential as the NFB signal) coming direct from the inductor to the voltage boards NFB input.

And , the "biggie" Greg erksine informed me of the miswired "doug self magic resistor" on the onboard Vbe. This has been corrected. Anybody that has made the PB250/60 could just jumper (omit) that resistor anyways. BELOW are all 3 boards with all 3 "fixes". Tomorrow night they will be all ZIPPED and ready to go.

G1 and G2 - G1 is the "dirty ground" ,accepts loudspeaker return and goes back to the main PS star with 12 or 14 ga. wire. G2 is the "clean" ground , it is only a reference for the C/R/C filter - capacitance multiplier as well as the voltage board ground. IT only needs a 18 Ga. wire returned to the PS main star.

ALL BOARDS color code .. GREEN = both grounds/ RED=V+ / BLUE=V- /YELLOW= signal paths /ORANGE=positive drive / Light BLUE= neg. drive...

ALSO , next to come is the PB200M , which will be a quasi MOSFET 4 device masterpiece to round out the power board lineup. (last pix)

OS
Attached Images
File Type: gif PB60LP_overview.gif (79.5 KB, 433 views)
File Type: gif PB60_overview.gif (144.0 KB, 422 views)
File Type: gif PB250_PCB_overview.gif (113.4 KB, 407 views)
File Type: gif PB200M.gif (24.1 KB, 411 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 17th August 2010, 09:30 AM   #303
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
post302,
careful with the use of "magic" for that extra Vbe multiplier resistor.

There is another paper (can't remember the Author) on introducing a "magic" resistor into the topology to improve the sound quality. It is quite different from the multiplier's extra resistor.

R80 is still in the wrong place.
The driver is tapped into the bottom of R80 adjacent to the Vbe transistor's collector.
As a result the capacitor must now be moved to the VAS side of the multiplier. C86 connects the collector of Q8 (VAS) to the collector of Q10 (CCS)
__________________
regards Andrew T.

Last edited by AndrewT; 17th August 2010 at 09:35 AM.
  Reply With Quote
Old 17th August 2010, 09:55 AM   #304
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
What is C85 for?

- keantoken
  Reply With Quote
Old 17th August 2010, 10:10 AM   #305
diyAudio Member
 
keantoken's Avatar
 
Join Date: Aug 2006
Location: Texas
Blog Entries: 2
And to help compensate for the capacitance of the lower outputs, how about trying a small cap parallel to R88, equal to the capacitance seen by Q99?

Also the MJE3x0 drivers seem a little low-Fi...? Especially since everything else is high-tech japanese devices?

- keantoken
  Reply With Quote
Old 17th August 2010, 12:26 PM   #306
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by AndrewT View Post
post302,
careful with the use of "magic" for that extra Vbe multiplier resistor.

There is another paper (can't remember the Author) on introducing a "magic" resistor into the topology to improve the sound quality. It is quite different from the multiplier's extra resistor.

R80 is still in the wrong place.
The driver is tapped into the bottom of R80 adjacent to the Vbe transistor's collector.
As a result the capacitor must now be moved to the VAS side of the multiplier. C86 connects the collector of Q8 (VAS) to the collector of Q10 (CCS)
I did not update the schema , the boards reflect the change, although. I get the hard part first (the boards), then go back do "cleanup" (match BOM , schema, parts overview...). Also , I reuse previous simulator builds to make new ones...

"Magic resistor" AHHHH 1

I almost forgot, To eliminate or reduce the "memory effect" the french dude put them between active and cascode trannies. (a GX amp update ). Link is here : Memory Distortion Philosophies - Part 5 : Circuits, continued

Quote:
By keentoken - And to help compensate for the capacitance of the lower outputs, how about trying a small cap parallel to R88, equal to the capacitance seen by Q99?

Also the MJE3x0 drivers seem a little low-Fi...? Especially since everything else is high-tech japanese devices?

You don't like MJE340/350's .... those poor , poor devices , nobody likes them .. except tube guys Would you suggest the KSA/KSC's , so the IRF's could "sing" better at 4 mhz ?? I will try Q99..


OS
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 17th August 2010, 12:31 PM   #307
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
you're forgiven.
Nobody can do everything at the same time.
__________________
regards Andrew T.
  Reply With Quote
Old 17th August 2010, 12:32 PM   #308
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by keantoken View Post
What is C85 for?

- keantoken
At 20k , C85 improves stability of the Vbe , reducing Xover point deviation to under 1mV on all the PB's. Still researching WHY?
OS
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 17th August 2010, 12:36 PM   #309
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by AndrewT View Post
you're forgiven.
Nobody can do everything at the same time.
Just to lay it to rest.. is this (pix) the correct way. (reflects the boards)

OS
Attached Images
File Type: gif correction.gif (4.0 KB, 201 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 17th August 2010, 12:38 PM   #310
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
c89 is in the wrong place.
It should be between the VAS and it's load (the CCS or bootstrap)

I wonder if that accounts for the very high current in the cap when the sim modeled behaviour?
__________________
regards Andrew T.

Last edited by AndrewT; 17th August 2010 at 12:41 PM.
  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 - the next generation (supersym) ostripper Solid State 260 26th June 2014 09:23 PM
Supersym patent Rescue Toaster Pass Labs 6 22nd January 2008 09:49 PM


New To Site? Need Help?

All times are GMT. The time now is 03:13 AM.


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