gar1731 build thread

[blackbird]

Hi guys..

I messed up a little, and didn't use the matched pair of 550c's in Q1 and Q2.
What potential issues can arise from my stupidity? Still has 550c's in them, just not the matched pair from the bag.

Should I order a new matched pair, or see how it goes.

Thanks
Dave

 

[gar381]

Give it a shot Dave.. see how it sounds.  Can't hurt anything.
You might get lucky as they are all from the same batch of 550cs
Quite often random ones from the same batch are close enough
but not always.

You can always order an new matched pair from Jeff
if necessary.

Best..

GARY

 

[blackbird]

Give it a shot Dave.. see how it sounds.  Can't hurt anything.
You might get lucky as they are all from the same batch of 550cs
Quite often random ones from the same batch are close enough
but not always.

You can always order an new matched pair from Jeff
if necessary.

Best..

GARY

Thanks Gary..
What would happen sonically if they aren't a good enough match?

Cheers
Dave

 

[berkleystudios]

two things real quick,

1) I accidentally ordered 1/8 watt resisters in the R3 R4, and R13 positions, will these still work?

2) is it possible to solder the les on after the componets are on the boards, I kind of built It backwards. and by it I mean 6 of them...

 

[gar381]

two things real quick,

1) I accidentally ordered 1/8 watt resisters in the R3 R4, and R13 positions, will these still work?

2) is it possible to solder the les on after the componets are on the boards, I kind of built It backwards. and by it I mean 6 of them...

Hi Adam

1)  Order the correct ones from the BOM.

2)  If you mean the Millmax pins the answer is yes.  Pre-tin them and solder them from the bottom only.
    Make Shure the PCB is LEVEL in a bench or Pana vice and you should have no trouble.

Best..

GARY

 

[Elcapitan]

Howdy folks, new to the board, and just did a couple of VP26/gar1731s, and they went really well.  The opamps were a challenge due to size, but after the first one, which works fine but ain’t pretty, I found the second one to be quite easy, or so I thought.  The DMM tests on it went fine, however, when I stuck it in a pre and powered it up, R14 burned up and heated a few other components.  At first I was sure they were toasted too, but they actually don't look too bad now that I have the bad resistors unsoldered. 

I went through this thread and checked all of the  issues spotted; wrong transistors, diodes in the wrong spots, none of that is the case. 

It appears that the issue is that I didn’t trim back the soldered lead far enough, and so a short was created when I seated the opamp in the sockets, because that lead touches the socket.  So, before I go about getting another opamp kit, or purchasing a built opamp, I want to make sure this doesn’t indicate some other problem.  I would just swap the good opamp and see if the pre works, but I want to hedge my bets a little and see what you think first before I risk roasting that one.  Even though it’s only $18, I spent a bunch of time on it!

The DMM tests on the preamp went just fine, and having terminated many device PCBs during my time in the AI shop at Pro Co sound, I’m confident I put them together correctly.  Seems like a simple, careless mistake.  Here is a pic.  I can't get a good closeup of the component lead.  Any help is appreciated!

R14 is complete toast:

 

[Elcapitan]

Bump

 

[gar381]

Hi Elcapitan

You will get a little me height and room if you insert the millmax pins from the solder
side of the PCB  instead of the component side as well as trimming the component  leads short.

Best of luck..

GARY

 

[PeteJE]

Without schematic, I need to know if a possible bridge or connection is correct - does pin 2 of Q6 connect to one side of C3 and R10?

 

[PeteJE]

 

[gar381]

Without schematic, I need to know if a possible bridge or connection is correct - does pin 2 of Q6 connect to one side of C3 and R10?

YES that is the net..  Q4 pin 3, Q6 pin2, C3 and R10

 

[Deepdark]

Hi guys

quick one. I had to swap 2 resistor that I misplaced first. One of them had a little bit on coating left on the bottom of the resistor. Is it that dramatic or I can left it on the board and it will works. Thanks guys

 

[alexc]

Hi All

Where can I get the gar1731 build guide? I have a bunch I purchased from CAPI a few years back and I seem to have misplaced the doc.

Thanks
AlexC

 

[jsteiger]

Send me an email thru the store and I'll reply with the info 

 

[alexc]

Hi Jeff -  emailed your store.

Thanks kindly

Alex

 

[smokinpcb]

I've heard there is a good op amo test procedure in the build pdf, can some message me a copy? currently building some 2520's and having some problems

 

[AudioHak]

Hey everyone,

Needing some help here. I have purchased 2 of these 1731's and Jeff never sent me the BOM. Unfortunately, Jeff is off for the holiday. I have also emailed Gary from this site, but I am not sure how long it will take for him to respond. Any help here? Got 2 kits here begging to be built over this weekend while I'm off work. Would hate to lose this time. Thanks in advance.

 

[jsteiger]

They might be in your spam? That happens often. I do have a handful of orders to send docs out for yet. I will be getting to those within the hour.

 

[AudioHak]

Hey Jeff!

I checked there already...

I sent you an email about it through the store.

Edit: Jeff is the greatest. Thanks for the help. Excellent customer service.

 

[jgmille]

Howdy folks, new to the board, and just did a couple of VP26/gar1731s, and they went really well.  The opamps were a challenge due to size, but after the first one, which works fine but ain’t pretty, I found the second one to be quite easy, or so I thought.  The DMM tests on it went fine, however, when I stuck it in a pre and powered it up, R14 burned up and heated a few other components.  At first I was sure they were toasted too, but they actually don't look too bad now that I have the bad resistors unsoldered. 

I went through this thread and checked all of the  issues spotted; wrong transistors, diodes in the wrong spots, none of that is the case. 

It appears that the issue is that I didn’t trim back the soldered lead far enough, and so a short was created when I seated the opamp in the sockets, because that lead touches the socket.  So, before I go about getting another opamp kit, or purchasing a built opamp, I want to make sure this doesn’t indicate some other problem.  I would just swap the good opamp and see if the pre works, but I want to hedge my bets a little and see what you think first before I risk roasting that one.  Even though it’s only $18, I spent a bunch of time on it!

The DMM tests on the preamp went just fine, and having terminated many device PCBs during my time in the AI shop at Pro Co sound, I’m confident I put them together correctly.  Seems like a simple, careless mistake.  Here is a pic.  I can't get a good closeup of the component lead.  Any help is appreciated!

R14 is complete toast:

I just had the same issue with my gar1731.  R14 burned up on me.  Inspected a little closer and saw I had created a short with some poor soldering on the next door point.  Ordered a replacement 10R and hopefully I can clean it up and get it to work. 

Did yours turn out?

Jason