gar381

garAM10BC build thread
« on: March 14, 2018, 07:44:34 PM »


The garAM10BC DOA will work from +/- 15V  thru +/-24V so it is a
Happy camper on any VPR or 51X standard.


INFORMATION COMMON TO BUILDING ANY gar DOA....


PLEASE ALWAYS REFURE TO THE APPROPRIATE ASSEMBLY MANUAL WHEN ASSEMBLING gar DOAs.  Either print it out or have the pdf open on your desktop. This will help both the novice and ProTech alike from accidentally making assembly errors.

Note that the OUTPUT transistors are NOT the same.  One is a NPN and the other is a PNP.  Make sure that they are in the correct positions and facing the correct direction
As shown in the assembly manual.

Note the BLUE Murata caps are all different values.  Make sure you got the correct
cap in the correct positions as shown in the assembly manual.

Note that the DIODES are polarized.  Make sure that the black band on the diode is in
The hole with the circle.  Note the diode pads on the PCB are square shaped.  They are the ONLY square pads on the PCB.

All  BC560C transistors are on tape.  ( Except for the Match Pair in the gar918BC kit.  Those are  in a little bag with the Millmax pins) The pads on the PCB are in a straight line for The BC560Cs and only for these, so that they will not be confused with the BC550C pads.   Make sure they are facing the correct way as shown on the silkscreen.

All  BC550Cs transistors are in little bags.  One of the bags is for the MATCHED input pair (except for the gar918BC kit) and this bag will also include the Millmax pins.  Do not remove the transistors from this bag until installing them so they do not get mixed up with the other BC550C transistors in the kit.  All BC550C pads on the pcb are in a triangle formation so as not to be confused with the straight line BC560C pads.  Make sure they are facing the correct way as shown on the silkscreen.

Measure all RESISTOR values at installation and install according to the manual.  Be careful when measuring values above 100k so you will not be including your skin resistance in the measurement.

Before testing your fresh assembled DOA,  double check for unwanted solder bridges as shown In the manual and make sure that no component leads on the component side of the PCB are touching each other.

As these are all the most common assembly errors.  Following this basic informational
Guide should result in a successful build and your new DOA should work first time out of the box.


When inserting your new DOA into the millmax sockets of a module, Please insert straight down and not at an angle.
DO NOT push down on the component parts but use the edges of the DOAs PCB.  Remove DOAs the same way. 
Pull straight up from the edges of the PCB and not at an angle. Never insert a DOA or a module with the power on.



Note on part substitutions in kits .....

Occasionally the parts listed in the BOM of each kit maybe temporarily unavailable from my parts supplier.  A substitution
Part will be included in the kit.  These parts will be of the same value, tolerance And quality of the part listed in the BOM.   

For you folks sourcing your own parts For your builds,   All the ¼ watt resistors use any major brand 1% metal film.
The ½ watt resistors can be any major brand carbon film or metal film 5% or better.
The Murata caps can be 50v or 100v 5%.  Any major brand npo/cog 5% with the lead spacing of .1” or 2.5mm can be used if necessary.  Output transistors can be ON semi, Fairchild or ST micro transistors.  Note that the ST micro transistors have a slightly different  Package but will drop right in the PCB just fine.


 

« Last Edit: April 29, 2018, 07:53:19 PM by gar381 »
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html


gar381

Re: garAM10BC build thread
« Reply #1 on: March 14, 2018, 07:49:05 PM »





THE garAM10BC  DOA
« Last Edit: April 29, 2018, 07:54:46 PM by gar381 »
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

john12ax7

Re: The NEW gar(xxxx) build guide (KITS COMING SOON)
« Reply #2 on: March 14, 2018, 08:30:10 PM »
Is this a new design,  or inspired by an older classic?

Any tips for soldering the millmax pins to get them all perfectly perpendicular to the pcb?

EmRR

Re: The NEW gar(xxxx) build guide (KITS COMING SOON)
« Reply #3 on: March 14, 2018, 08:59:41 PM »
Q6 Q7 Q9....just guessing.......interpret code.....
« Last Edit: March 14, 2018, 10:34:03 PM by emrr »
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

gar381

Re: The NEW gar(xxxx) build guide (KITS COMING SOON)
« Reply #4 on: March 14, 2018, 10:26:15 PM »
Is this a new design,  or inspired by an older classic?

Any tips for soldering the millmax pins to get them all perfectly perpendicular to the pcb?

John...   the pins should fit pretty darn close these days if you have the DOA level in a small vise when soldering.

The new DOA  is my version of an old 70s classic but using modern parts and converted to a 2520 pin out.
It is a bit of a different color and nicely very vintage  sounding.   It's also a new color option for 51x use !!

GARY
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

mjrippe

Re: The NEW gar(xxxx) build guide (KITS COMING SOON)
« Reply #5 on: March 15, 2018, 09:40:07 AM »
Q6 Q7 Q9....just guessing.......interpret code.....

Doug, I count ten transistors so I think you are correct.  Plus the 24v rails...

Potato Cakes

Re: garAM10BC build thread
« Reply #6 on: May 08, 2018, 11:41:05 PM »
Gary,

I'm putting together the parts for the 30 boards I have, and I wanted to check on a couple of things before I get on with the soldering madness.

For R5, I have a pile of 1.54k but no 1.5k. Will the approximately 3% deviation impact the electrons make a noticeable difference (audio or heat generation)? I believe that it won't, but wanted to double check just in case so I don't have to desolder parts from tiny PCBs.

Is there any audible or significantly measurable difference in using 1N4148 vs 1N914? If there isn't I was going to use all the ones I have of both types to use up what I have on hand.

I'm going to use these for a console mod I am hoping to be finished by the end of this year.

Thanks!

Paul


Potato Cakes

Re: The NEW gar(xxxx) build guide (KITS COMING SOON)
« Reply #7 on: May 08, 2018, 11:45:19 PM »
Any tips for soldering the millmax pins to get them all perfectly perpendicular to the pcb?

I've been using chunger's method (I believe it was his) of inserting pins into sockets already installed in a PCBs that uses DOAs and then put the DOA board on top of that and then solder the pins in place. If you have a build that uses multiple DOAs then even better.

Thanks!

Paul

gar381

Re: garAM10BC build thread
« Reply #8 on: May 13, 2018, 09:25:20 PM »
Gary,

I'm putting together the parts for the 30 boards I have, and I wanted to check on a couple of things before I get on with the soldering madness.

For R5, I have a pile of 1.54k but no 1.5k. Will the approximately 3% deviation impact the electrons make a noticeable difference (audio or heat generation)? I believe that it won't, but wanted to double check just in case so I don't have to desolder parts from tiny PCBs.

Is there any audible or significantly measurable difference in using 1N4148 vs 1N914? If there isn't I was going to use all the ones I have of both types to use up what I have on hand.

I'm going to use these for a console mod I am hoping to be finished by the end of this year.

Thanks!

Paul

Paul..

You are golden !! ;)

Gary
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

JW

Re: garAM10BC build thread
« Reply #9 on: May 17, 2018, 12:22:34 PM »
Oh My God. Perfect. Timing. Yamaha PM2000!

You think they'd work in both mic pre and line amp DOA's in this application? (see schematic)


JW

Re: garAM10BC build thread
« Reply #10 on: May 17, 2018, 12:23:21 PM »
Line Amp

gar381

Re: garAM10BC build thread
« Reply #11 on: May 17, 2018, 09:34:45 PM »
JW...

Give it a shot.  Don't see why it wouldn't work.

GARY
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

Potato Cakes

Re: garAM10BC build thread
« Reply #12 on: May 30, 2018, 03:04:31 AM »
10 finished, 20 to go...

10 seems to be the number I can do in an 8 hour setting. On the second to last one, I managed to put in the BD140 backwards. It was like 1am though.

I've tested them to make sure they work but don't know how they sound.

Thanks!

Paul

Potato Cakes

Re: garAM10BC build thread
« Reply #13 on: May 30, 2018, 06:43:48 PM »
Well this is embarrassing, and possibly also very lucky...

When I did the first batch of 10, my eyes told my brain that D6 and 7 were to be mounted parallel with D8, alternating the placement of the black stripe on the diode, even though the instruction are clear and there is even a picture to make comparisons. I picked up on this today when I started working on the next batch. Unbelievable! However, as shared earlier, they all seem to work. I put them in a VP25 and they all responded correctly to gain changes when applying tone nor was there any magic smoke or excessive heat from the power transistors. I haven't measured distortion or been able to listen for any differences, so I don't know if the ones with the error operate the same as a properly built one. Maybe Gary can chime in and check this against the schematic and see if I get a pass this time or if I get to enjoy some quality op amp repairing.

Thanks!

Paul

Potato Cakes

Re: garAM10BC build thread
« Reply #14 on: May 31, 2018, 12:17:23 PM »
It seems the gain functions between the correctly built ones and the ones with an error are exactly the same. So pending any new information i think I'll leave the misplaced diodes for now.

Thanks!

Paul

gar381

Re: garAM10BC build thread
« Reply #15 on: May 31, 2018, 10:59:10 PM »
Paul

D6 and D7 are series bias diode string.  What you have done
is now you only have one of these diodes in the string
changing the operating point somewhat.  This will work but your
clean headroom will change somewhat.  I would get your
hakko 808 or simliar out and fix this.

Best

GARY
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

Potato Cakes

Re: garAM10BC build thread
« Reply #16 on: May 31, 2018, 11:52:38 PM »
Thanks for the info, Gary.

I was hoping that this one time I would have gotten a pass. It seems I have a date with some solder wick when I get home.

I had made another mistake on the second batch where I had put the 150R resistors where 1k5 went, so I had the pleasure of removing those guys. I think I was having one of those days where I couldn't help but make dumb mistakes. It was frustrating and also hilarious.

Thanks!

Paul

living sounds

Re: garAM10BC build thread
« Reply #17 on: June 09, 2018, 11:33:02 AM »
I also put D6 and D7 in the wrong way in my first one. Maybe you can update the manual to make it a little clearer?

The result was higher distortion, easily audible versus a correctly working channel in the inverted mix.

I really like the sound of this op amp on the mix bus. It's got heft to it without the usual dirt.

So far I have built 2. The second one shows slightly higher distortion and sounds less clear. However, I cannot find any fault in the built. I've cleaned it, checked the connections etc., but makes no difference. Got 2 more kits to build and see if they turn out differently.

Thanks for a great product!

Re: garAM10BC build thread
« Reply #18 on: June 14, 2018, 02:36:12 PM »
Hey guys, I've been racking my brain over what I did wrong with these AM10 DOAs. I've tripled checked that all the resistors, caps, transistors, and diodes are in the correct places, they are all polarized correctly, and there are no solder bridges on top or bottom of this build (except where recommended). I'm an experienced builder and was careful not to overheat components. They both pass signal but have the same high frequency distortion. It sounds like there's no headroom. Has anyone experienced this? Unfortunately my phone takes too high res photos to post here... Thanks!

jsteiger

Re: garAM10BC build thread
« Reply #19 on: June 14, 2018, 03:56:30 PM »
Hey guys, I've been racking my brain over what I did wrong with these AM10 DOAs. I've tripled checked that all the resistors, caps, transistors, and diodes are in the correct places, they are all polarized correctly, and there are no solder bridges on top or bottom of this build (except where recommended). I'm an experienced builder and was careful not to overheat components. They both pass signal but have the same high frequency distortion. It sounds like there's no headroom. Has anyone experienced this? Unfortunately my phone takes too high res photos to post here... Thanks!
It would be best to see them somehow. What about the 620k resistor question?

Gary, Antonio thinks he received 620k R's instead of the 62k's. Can you shed some light on this?
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