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Old 25th July 2013, 10:19 PM   #381
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I've identified from the forum some minor issues with layout.

Outlined in red circles below - (first pix)

#1 - D4-5 (D8-9) - output snubber diodes. Read that the fit is tight ...Badger holes are 1mm
I checked MR856G http://www.onsemi.com/pub_link/Collateral/MR850-D.PDF ...
1.3mm diameter ... oops.

#2 - "CRZ" jumper is masked.

#3 - C18-19 pads are masked.

#4 - jumperless design. The print side of the board shows jumpers , but these are actually plated through holes and run on the back layer (physically it is jumperless) ...easy fix ! I would however suggest real jumpers for the V+ trace as the plated through holes might be a current "bottleneck"(V2.2). A more permanent solution would be to increase the number of holes on the 2 points where the V+ trace crosses other traces. Sort of like the power and ground planes on a computer motherboard.

An example is below (pix 2).

These "bugs" are very minor and the version 2.3 board works and is even reviewed (no effect on proper operation). Just cosmetic and ease of construction updates.
Any other version 2.4 suggestions are welcome !!

OS
Attached Images
File Type: jpg badger revision.jpg (133.2 KB, 371 views)
File Type: jpg throughhole.jpg (36.5 KB, 360 views)
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Old 25th July 2013, 10:20 PM   #382
pthep is offline pthep  Canada
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While on the subject of the AB amp bom, may I be allowed to take the discussion a couple of rungs further down the electronic evolutionary ladder. I noticed that the digikey address for R23 and R27 brings up 1/4 watt while the bom is calling for 1/2 watt. Is that an oversight or is it a non issue. Remember you are dealing with a strictly plug and play guy here.
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Old 25th July 2013, 11:09 PM   #383
mattmcl is offline mattmcl  United States
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I'm finding the holes for Q10, 11 and 12 to be too small as well.
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Old 25th July 2013, 11:30 PM   #384
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Quote:
Originally Posted by pthep View Post
While on the subject of the AB amp bom, may I be allowed to take the discussion a couple of rungs further down the electronic evolutionary ladder. I noticed that the digikey address for R23 and R27 brings up 1/4 watt while the bom is calling for 1/2 watt. Is that an oversight or is it a non issue. Remember you are dealing with a strictly plug and play guy here.
At rest , the VAS ( derived from P = E squared/R) = pulls just .005 watt through R23-27. Most OEM's (commercial amps) use 1/4w to 1/2w - overkill !! If the drivers (Q14-15)are loaded these resistors might see a little more. 1/4w will do !

I specified 1/4 watt for almost the whole Badger's small resistors as they are most common (radio shack - e waste), but 1/8w will do for most. I will refine the BOM with more choices. 1/8 watt devices might even look/fit better on the small signal stages (LTP/mirror). 1/4 watt's fit but slightly cover the screen printing .
R32-33 ,R36-50, and R53-54 are the only resistors that see .25w(1/4w) + ....
observe these ratings!!!

PS - R18/19 (the cascode divider ) sees .02w , most of the input stage LPT.mirror only .001 - .002w or less. We are QUITE derated !!

OS
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Old 26th July 2013, 12:14 AM   #385
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Quote:
Originally Posted by mattmcl View Post
I'm finding the holes for Q10, 11 and 12 to be too small as well.
What version board (2.3?) I just fit a 2sc3503 , it's even loose !

In fact , the to-220 (slightly larger pins)even fits Q10-12 and Q13-15 .. all the medium sized transistor holes.
The only device that has a larger collector pin is the mje340/350 pair. For these ,I could use a sewing needle for the Q10 middle hole.

picture below shows everything.

OS
Attached Images
File Type: jpg holes.jpg (174.2 KB, 344 views)
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Last edited by ostripper; 26th July 2013 at 12:17 AM.
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Old 26th July 2013, 02:41 AM   #386
mattmcl is offline mattmcl  United States
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Quote:
Originally Posted by ostripper View Post
What version board (2.3?) I just fit a 2sc3503 , it's even loose !

In fact , the to-220 (slightly larger pins)even fits Q10-12 and Q13-15 .. all the medium sized transistor holes.
The only device that has a larger collector pin is the mje340/350 pair. For these ,I could use a sewing needle for the Q10 middle hole.

picture below shows everything.

OS
V 2.2
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Old 26th July 2013, 03:18 AM   #387
mattmcl is offline mattmcl  United States
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First pic shows Mouser PN 512-KSA1381ESTU inserted, with original board holes drilled out to 1.5 mm. (I don't have a "before" pic.)

Second pic shows in red what size the original holes were (though the solder plates were visible.) In blue it shows the size they needed to be to fit this component.
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File Type: jpg IMG_20130725_210916.jpg (800.0 KB, 291 views)
File Type: jpg IMG_20130725_210903.jpg (869.3 KB, 274 views)
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Old 26th July 2013, 04:41 AM   #388
Variac is offline Variac  United States
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looks like the pitch (how far apart the holes are) might be the problem, but OS's fit just fine.. ?
Maybe we'll make these in red so people know that they're the latest. .

It would be nice to have a Digi-key BOM too at some point. I deal with them a lot. Not a big deal though
Athough if the BOM is in the right spreadsheet format the whole order just sliiiiiides in..

Although Mouser prob has the same thing?

Last edited by Variac; 26th July 2013 at 04:45 AM.
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Old 26th July 2013, 04:46 AM   #389
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wow 1.5mm !! That's big diode territory !

http://www.classiccmp.org/rtellason/...ta/ksa1381.pdf

States .75mm , I set the V2.2 to .82mm for all the to-126's (below 1). I do not know how this happened as I submitted the correct drilling size. I don't know how they got to V2.3 (the holes are right on these) , but (at least)on the V2.2 sprint file , it was right. STRANGE !!

Just about have V2.4 done (below 2). I'm using parts on hand,a V2.3 board, and datasheets to tweak the holes.

OS
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File Type: jpg to-126drill.jpg (10.4 KB, 121 views)
File Type: jpg V2.4badger.jpg (126.7 KB, 107 views)
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Old 26th July 2013, 04:57 AM   #390
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Yes , Mouser has the spreadsheet BOM conversion ... http://www.mouser.com/BOMHelp/

Variac , If you could give the mounting hole spacings and any other requests
(Maybe a real badger on the board) .

I'm doing this on the build thread as this is where the information is (builders -holes - spacings - problems?).

On the discussion thread - component options , smaller input stage resistors (1/8 watt) , fets !! I'll do that before the final BOM update - spreadsheet stage.

OS
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