diyAB Amp - The "Honey Badger" - Page 6 - 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 July 2011, 03:05 AM   #51
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Default DONE at last !!

Woahhhh ! There actually was a lot to pack in there.

I was extreme in my layout of the circuit traces to what would actually be seen , (signal-wise). I am aiming for the least "cross contamination" between sections. 50mm separated by the rail trace should keep my input stage rather isolated from the bad, bad output inductor.

Below is the labeled PCB (attachment) , the .ZIP file has the BOM , schematic draft , and PCB draft. I have SPLAN , to make a "pretty" schematic , but would like to know whether there are any better cad's out there.

What shall we name it ?? (The amp)

Quote:
Hi,

In my experience the Vcc and Vee entry points to the pcb should be kept as close as possible so that the supply wires can be twisted together. This will reduce EM radiation which is likely to swamp the distortion of the circuit.

Trust me, the routing of the power supply leads is absolutely critical. It is something that has to be seen to be believed. I only discovered it when I bought an AP520 and built a blameless amplifier (with my own pcb layout). The loop area between Vcc and Vee has to be kept as small as possible. Bob Cordell in his book, even advocated interspersing the output devices - N,P,N,P etc, in order to keep the area between the + and - supply tracks as small as possible.

I'm sorry if you already knew this, but as you are putting in so much effort, I thought I would mention it. Layout of psu wiring is and positioning of the power entry points on the pcb (and the associated tracking) is critical - as is the -ve feedback take off point (Self's book at least makes this point clear).

I hope this is of of some use,
Cheers, Ian
Yes, center NFB takeoff I agree with. The close rail-trace/ wire twisting has been "demystified" - read this , --- Enduring Class B layout mythology ----

I've yet to see an OEM that runs parallel rail traces on a single amp PCB , although some HT amps run parallel copper bus bars to feed the 5-7 channels on one PCB , but adcom , luxman, nikko - just run the rails from each side. I have seen a silicon chip layout with the parallel traces , but no alternating (V+/V-/V+) output scheme. For diya's heatsinks (If I had 2) , I would of designed a flat- opposing OP 3-4 pair layout. BTW , none of those OEM's twist their wires.

OS
Attached Images
File Type: gif DIYA_linamp_PCB.GIF (71.5 KB, 2018 views)
Attached Files
File Type: zip DIYA_linamp.zip (116.5 KB, 581 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 15th July 2011, 04:44 AM   #52
Variac is offline Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
Quote:
Originally Posted by AKSA View Post
Great project, Pete!
A credit to you that you were chosen for this design.....
Good to see you using a nice EF2, proven front end.
DIYaudio rules!

Hugh
Quote:
Originally Posted by ostripper View Post
Woahhhh ! There actually was a lot to pack in there.

What shall we name it ?? (The amp)
OS
Boy, OS tore right through this! Proves he was the right guy for the job.
Maybe we should have a little naming contest with a set of boards as the prize...

Mark
  Reply With Quote
Old 15th July 2011, 05:21 AM   #53
Banned
 
Join Date: Jan 2005
How about DAFAmp1 (DiyAudio Forum Amplifier 1) ?
  Reply With Quote
Old 15th July 2011, 10:23 AM   #54
ihan is offline ihan  England
diyAudio Member
 
Join Date: Mar 2008
Location: Stockport, UK
Quote:
Originally Posted by ostripper View Post

Yes, center NFB takeoff I agree with. The close rail-trace/ wire twisting has been "demystified" - read this , --- Enduring Class B layout mythology ----

I've yet to see an OEM that runs parallel rail traces on a single amp PCB , although some HT amps run parallel copper bus bars to feed the 5-7 channels on one PCB , but adcom , luxman, nikko - just run the rails from each side. I have seen a silicon chip layout with the parallel traces , but no alternating (V+/V-/V+) output scheme. For diya's heatsinks (If I had 2) , I would of designed a flat- opposing OP 3-4 pair layout. BTW , none of those OEM's twist their wires.

OS
Thanks for the link. I maintain that it is still sensible to keep the supply loop area as small as possible, so that equal amounts of +ve and -ve currents are injected into sensitive areas. In my opinion, this is best achieved by having the psu entry points close together in the middle of the board, so that twisted supply cabling can be used.

Bob's post here - Bob Cordell's Power amplifier book sums up my views and agrees with my pratical experience with a distortion analyser.
  Reply With Quote
Old 15th July 2011, 10:28 AM   #55
ihan is offline ihan  England
diyAudio Member
 
Join Date: Mar 2008
Location: Stockport, UK
Hi OS,

You may want to think about increasing the value of R25. As it stands, the collector current through Q9 at positive clipping will be rather large!

Regards,
Ian
  Reply With Quote
Old 15th July 2011, 03:39 PM   #56
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by ihan View Post
Hi OS,

You may want to think about increasing the value of R25. As it stands, the collector current through Q9 at positive clipping will be rather large!

Regards,
Ian
I agree , carlos (DX) blew a few beta enhancer's here... I only achieved a warm ksa992 with hours of clipping with 45v rails. 470R or more would not affect performance one bit.

I segmented the whole design (below) ....

A=IPS - the "universal" input stage. You could omit/ jumper out the C-E of Q3/4, omit C6/R18-19 for the simple 2 device input pair. you could also not do this and use a low noise {ECB} input pair...

.. most of mouser's low Vceo- low noise to-92's (BC-xxx) are EBC.
(please comment on this !!! )


FET's are more problematic , some are "unobtainium" , have different DGS pinouts ..... it would be best to go the SOT23 way with a micro PCB. In this way, whatever BJT pads are chosen the SOT's can be routed (BF862 X2)
on the "micro PCB" .

B=The current sources , tried and true .... this will even minimize turn-on "thump". The real amps will stay 8.82ma VAS from 0C - 40C , no change.

C=VAS Changing R25 , no issue ... mje340/350 for Q10-12 , it will work. Jumper C8 - omit R24 , you have simple miller compensation. I also left capacitor pads on the negative feedback path for a little lead compensation (next to R6 on PCB) , i'll label it "LC".

D= The output stage , use anything ON NJW/MJL x302/x281, Toshiba 5200/1943 - any 200w+ 200v+ 80Hfe + TO-264/TO-3p output device.
Driver , the same MJE - 2sa/c - to-220.


I'm going to finalize the whole thing , right down to the mil spacing for the component leads , so I need a final comments on input pair or any other component choices. I tried to make it as DIY "friendly" as possible (larger pads , no special parts or form factors). Thanks ...


OS
Attached Images
File Type: gif DIYA_linamp_schema-draft-edit.gif (55.4 KB, 1912 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 15th July 2011, 04:05 PM   #57
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by Variac View Post
Boy, OS tore right through this! Proves he was the right guy for the job.
Maybe we should have a little naming contest with a set of boards as the prize...

Mark
Thank you , Mark ...
But there are those small details to "sweat" now. The reason for this thread.

Visually , the board will be "pretty" (VERY visually appealing) and exactly 252 X 76 mm , the whole 25mm area above the output "line" (the E - J holes) will be gone , they were just for alignment.

I did this from "mind" ( no auto-routing) , for this is a "artform" (like a painting).

This has 99.999% chance of working the first time as it is , should we prototype it first ?? , as to not go down the road of the GOLDMUND , with all of it's mod's and shortcomings. BTW , that was not Alex MM's fault , they should of built it first - then went to production ( look at AKSA's latest fetzilla project).

I will edit the BOM text to perfection , and write the "book" too. I have photo's of my AX , which is the first version of this amp ..exact same VAS/OP. Your call as to what format to do this in. PM me.

OS
Attached Images
File Type: gif another draft.GIF (68.8 KB, 1886 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper

Last edited by ostripper; 15th July 2011 at 04:14 PM.
  Reply With Quote
Old 15th July 2011, 05:38 PM   #58
Bigun is offline Bigun  Canada
diyAudio Member
 
Bigun's Avatar
 
Join Date: Jan 2009
Blog Entries: 2
Quote:
Originally Posted by ostripper View Post
Visually , the board will be "pretty", for this is a "artform" (like a painting).
this is exactly the right approach


it has to be technically good, but that's just a ticket to enter the game, to be the best it has to look and feel like somebody really cared when it was designed.
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.
  Reply With Quote
Old 15th July 2011, 05:48 PM   #59
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Quote:
Originally Posted by ihan View Post
Thanks for the link. I maintain that it is still sensible to keep the supply loop area as small as possible, so that equal amounts of +ve and -ve currents are injected into sensitive areas. In my opinion, this is best achieved by having the psu entry points close together in the middle of the board, so that twisted supply cabling can be used.

Bob's post here - Bob Cordell's Power amplifier book sums up my views and agrees with my pratical experience with a distortion analyser.
I agree that is slightly more ideal ,

Consider this - this amp has the supply onboard , rectified, unfiltered DC will be entering the fuses , no typical DC lines running from an external PS. The charging pulses will return to the main earth/CT near the edge of the board , the second set of thinner returns (CCS's/VAS/input ground's) will have far less "garbage' on them and shield the small signal area. This amps loop area is just 100mm total (C13/17 to the first outputs- 50mm X 2).

Now... with traces going down the PCB center , you would either have to jumper the circuit across the rails , or place most of the circuit on either side.
One would be a bad choice and one would waste real estate.

On another design (below) , it could be brought out one step further than what you see. Not only put the rails right together down the center , but split the P and N channel return traces to meet dead center at the end of the board.
I had to compromise for this application while still trying to retain the performance. My best guess , is that the amp will stay PPM up till 1/3 - 1/2 power , then slightly degrade to .005-.01%+ at high power levels/load. This is unavoidable with just the fact that we have a EF2.

This is why MY amp will be triple op / below layout. Not to say this will make a bit of difference in the sonics , but this also would be subjective. Lacking an AP , I did see the effect of loop area / cable inductance on the slew of a heavily loaded square wave on my present version of this amp.

OS
Attached Images
File Type: gif optimal.gif (42.5 KB, 1798 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  Reply With Quote
Old 15th July 2011, 07:27 PM   #60
diyAudio Member
 
ostripper's Avatar
 
Join Date: May 2008
Location: Albany , NY (smallbany)
Default looking for BUGS....

Voltages -( picture 1 ) and a real world layout (picture 2) .. this is the only way to push 99.999% to 100%. ps- red is V+, blue is V-, yellow= signal , greens are ground....

Still waiting for component/general suggestions before I "lock down" the design.
At $30-35 a pair (or whatever is the price) , I wish this was available when I started DIY.

OS
Attached Images
File Type: gif voltages2.gif (55.1 KB, 1749 views)
File Type: jpg real world.jpg (199.2 KB, 1160 views)
__________________
Mongrel website , always current and updated :
http://www.fidelityforce.com/ostripper
  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
diyAB Amp The "Honey Badger" build thread Variac Solid State 1190 4th September 2014 02:15 PM
Honey, I smoked the Weller 8200 jackinnj Equipment & Tools 5 25th April 2011 06:07 AM
Badger Badger Badger..... Mushroom !! 5th element Everything Else 15 20th September 2003 03:16 PM


New To Site? Need Help?

All times are GMT. The time now is 01:16 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