gar2520 build thread

[Hoop Crambone]

http://www.groupdiy.com/index.php?topic=41741.0    Should have all info you need.

 

[tonycamp]

just for the record, although chungers build thread is spectacular, this does NOT show the values of the blue ceramic caps(the 2 yellows don't matter, are of equal value), you NEED the build doc's to orient those parts correctly on the 2520 and 1731, you need to ask for them at purchase.

T

 

[fluxofpinkindians]

I just built a GAR2520. I am a bit concerned that I have solder bridges between caps CD1, CD2 and the mill max pins for +V, C, -V and O.  They are so close together!!

I remember reading somewhere that this is not important and I just wanted to ask anyone who knows if this is true.

I tested the op-amp in a previously built VP26 and it worked. Should I worry ?

 

[gar381]

Should be fine..

GARY

 

[fluxofpinkindians]

Many thanks

 

[Thanatopsis]

Hi, I'm building my first gar2520 and have a little problem. How do I determine which pine of Q5 go in which holes? From looking at pictures I'm pretty sure the way it goes but want to be positive. Thanks.

 

[gar381]

chungers great photo work will show you exactly.

check the pictures from this thread..


http://www.groupdiy.com/index.php?topic=41741.msg530177#msg530177


best of luck and have fun..

GARY

 

[Thanatopsis]

Thank you very much Gary. Those higher resolution pics(vs the ones in the PDF) help a lot. Much appreciated.

A short while later, I'm done. Gotta do one more and then the VP28 will be complete.

 

[malenkytolchock]

Hi there,

i recently built 4 of the gar2520s and successfully built 3 however my 4th is giving me some issues. I stupidly managed to mix up q7 and q8 and also r3 and r2 (long night soldering). After unsuccessfully testing it i realised my mistake and rectified it. After testing again r11 and r12 have burnt out.

Any ideas as to what could be causing the issue (other than my stupidity)

Regards,

Joe

 

[gar381]

Hi Joe... welcome to DIY

Don't feel stupid.. this is a very common mistake.  You are not the first
and won't be the last.

The output transistors don't like to be reversed and draw lots of current thru R11,12 when they are.
If you got Q7,8 back in the right holes try a new set of R11,12 and  you just might luck out.
4 times out of 5 this is all you need to do.

Best of luck

GARY

 

[malenkytolchock]

Many thanks for the reply Gary, i'll swap them out and give it another shot. I have some some of your 1731s on the way from capi. I'll make sure to triple check the components this time 

 

[Fuccimain]

may have a solder bridge btwn r12 and tyhe outmill max.... are they supposed to be connected?

thx

s

 

[kante1603]

may have a solder bridge btwn r12 and tyhe outmill max.... are they supposed to be connected?

thx

s

Yes,there's a trace you can see on the bottom side of the unpopulated pcb in the build manual,all good.

Best regards,

Udo..

 

[BudCarroll]

Hey guys,

Just built a vp26 and a gar2525,...inserted into my lunch box and pfft smoke.  Powered down looked at the op amp and R11 and R12 are burnt looking.  Admittedly this is my first kit, but I was extremely careful and triple checked my work,...any ideas?

 

[kante1603]

Hey guys,

Just built a vp26 and a gar2525,...inserted into my lunch box and pfft smoke.  Powered down looked at the op amp and R11 and R12 are burnt looking.  Admittedly this is my first kit, but I was extremely careful and triple checked my work,...any ideas?

Hmmmmm......maybe look 4 posts back (#149)?

Udo

P.S.:Welcome to the forum!

 

[BudCarroll]

Hey guys,

Just built a vp26 and a gar2525,...inserted into my lunch box and pfft smoke.  Powered down looked at the op amp and R11 and R12 are burnt looking.  Admittedly this is my first kit, but I was extremely careful and triple checked my work,...any ideas?

Hmmmmm......maybe look 4 posts back (#149)?

Udo

P.S.:Welcome to the forum!

Face palm,...switched the transistors and r11,12 still metered well,.......put it back in and whammo, my first Api pre amp kit sounds thick and meaty and awesome.  Looks like I've got a new addiction.

Cheers and glad to be here.  Thanks or the help.

 

[kante1603]

Most of us did funny things when we started to diy.
Cool you got it sorted.
Best to swap out the both resistors too,even if measuring o.k. at the moment they might go bad one day once they look burnt.
Just a precaution and easy to reach.

Best regards and have fun,

Udo.

 

[gar381]

Hey guys,

Just built a vp26 and a gar2525,...inserted into my lunch box and pfft smoke.  Powered down looked at the op amp and R11 and R12 are burnt looking.  Admittedly this is my first kit, but I was extremely careful and triple checked my work,...any ideas?

Hmmmmm......maybe look 4 posts back (#149)?

Udo

P.S.:Welcome to the forum!

Face palm,...switched the transistors and r11,12 still metered well,.......put it back in and whammo, my first Api pre amp kit sounds thick and meaty and awesome.  Looks like I've got a new addiction.

Cheers and glad to be here.  Thanks or the help.

Bud..  Glad you got her working!!  Enjoy

BTW... This is one of the reasons that R11,12 are 1/2 watters

 

[Trench Recordings]

I killed two gar2520. Accidentally sent -16V to the out pin. What should I check first ? Replace the output transistor Q number ? Or check the diodes ?

 

[mitsos]

You still will want to check all the transistors and diodes. Google "transistor diode check" or something along those lines and you'll find instructions on how to check them with your DMM.  I've managed to save a couple of DIY2520s like this, found the damaged transistors without having to remove them first.