[BUILD] 1176 Rev A - Back to the beginning...

[benlindell]

Figured it out, had the output transformer wired up wrong, I was following the hook up diagram that's up a few pages back and they are in the wrong order, checked mnats pdf and now it's not burning, time to calibrate.

 

[phishman13]

Yeah, I did the same thing.  Followed the diagram, BURN.  Followed the PDF, no burn.  Now do I need to replace that resistor?  I checked it in circuit with my meter and it read around 36 ohms.  Seems still alright.  Now that I got mine hooked up, I tried passing audio through it and it does pass, but it sounds weird.  No low end at all and it doesn't seem as loud as it should be. Definitely not what its supposed to sound like.  No Gain reduction on my meter (the +4 and +8 are working though), and the 12:1 position is VERY loud and distorted.  It does compress though I think.  I'm able to hear the release pot working, i THINK i can hear the attack pot work, and the input and output pots do what they are supposed to, but since it sounds low in level, i cant tell for sure.  Does the GR not working have anything to do with not even trying to calibrate?  I will try calibrating it tomorrow.  I will try to poke around and figure out why that one ratio is way different than the others, but do you guys have any ideas about the weird sound of it?  My power supply voltages are what they should be btw. 

 

[ilfungo]

hello phishman13
I had also had problems with the output transformer ...
Follow the directions on the main board, worked for me.
I suggest you change the resistance for safety
12:1 ratio with regard to trying to see this link (http://www.groupdiy.com/index.php?topic=34502.40) modifications to be done and that worked for me
I hope I have been helpful

 

[stereokillah]

R32 still burning, i checked the wiring diagram 100 times do new stuuf on all point checked th resitor value , try with an another output tx.

Lost!!!

 

[danjpiscina]

R32 still burning, i checked the wiring diagram 100 times do new stuuf on all point checked th resitor value , try with an another output tx.

Lost!!!

i wouldn't try another o/p transformer. i had a similar problem with my rev. F. R36 (100 ohms) kept frying. it was a bad transistor. once i replaced all the transistors (and R36) it worked fine. i suggest you do that. good luck

DP.

 

[stereokillah]

thank you i will try it.

 

[Ringwraith]

Does anyone have the mouser part number for the 3 pin norm short thingie??

Thanks
Sean

 

[phishman13]

I believe this is what you are looking for?

http://www.mouser.com/Search/ProductDetail.aspx?R=22-28-4037virtualkey53810000virtualkey538-22-28-4037

 

[Ringwraith]

That looks like it would work. I wounder if it comes in a row of 6 like the pic or are they individual?
Also do you know what the piece is that you put on to short it?

Thanks!
Sean

 

[phishman13]

It definitely works!  That's the one I ordered and installed.  It shows more but hidden in the part description is 3P for 3 pin.

Here's the little shorting connector:

http://www.mouser.com/Search/ProductDetail.aspx?R=15-29-1024virtualkey53810000virtualkey538-15-29-1024

If you have any other part questions, check out this post earlier in this thread:

http://www.groupdiy.com/index.php?topic=29981.msg410331#msg410331

He has a full parts list at mouser (all except for the on board PSU and there are a few different parts if you are using the push buttons, etc...)

 

[ilfungo]

hello guys
I finished calibrating 2 blue stripe
in one of two I can not have 000 V between PT10 and PT 11 (I have 011v)
what components can I check?
both the meter easily lose the 0 in GR mode it's normal?
which pot can i use as audio taper  for 0 adjust?
Thanks...

 

[Ringwraith]

Thanks Phishman13, that's awesome!!  ;D

Sean

 

[phatmateo]

ilfungo, I had the same problem.  I swapped my 3708's in the meter section to matched 5088's and the voltage went to 0.00v.  Hopefully this will work for you

 

[ilfungo]

hello and thanks Phatmateo
The strange thing is that I used 2N3708 metched for both machines, even metched between them ...
This is good for the calibration procedure? http://nimbleswitch.com/diy/1176_revD/index.php?page=calibration
Thanks ..

 

[phatmateo]

yes, that guide is the same, except for the distortion trim.  Try finding another set of matching 3708's if you are concerned with both units having all the same components.  Or just replace all the 3708's in the meter sections(Q12 and Q13 only) with 5088's.  I'm guessing having the same Hfe doesn't always mean they are the same, performance-wise.  Perhaps someone else can explain this.   

 

[phishman13]

I'm guessing having the same Hfe doesn't always mean they are the same, performance-wise.  Perhaps someone else can explain this.   

I second that!  I'm interested in what it takes to really "match" transistors.  would matching hfe get you close enough for most purposes or are there other tests to do to get closer?

 

[SaMpLeGoD]

Hello! I've finished my 1176 Rev A! No problems at all, sounds awesome! just a little bit of "SShhhhh" noise floor than my Rev D! of course 'cause it's not a "LN" unit
I used the resistor's changes for the pushbutton's board and one in the main (resolving the plosive issue), I didn't need swapping the 2K, "0" set pot, by the 5K one as some people did because I had no problems at all regulating it!
Mako, it's an awesome project, I must say! thanks all of you from supporting this forum!!
Cheers,

Eddie

 

[stereokillah]

hello danjpiscina,
it was the bad transisator like you said, thanx
i coldn't know cause my multimeter give a good value for it.

after your post i tried a new time on multimeter and always good value , after i 've put a 5088on good place instead of the 3707 and ihave the good value.

i will change my multimeter or just the battery.

 

[stereokillah]

ok it was bad 3707 NPN EBC instead of ECB like it's wwrite on the datasheets if i put it in a same place of the 5088 give a good voltage

???????????

 

[danjpiscina]

hello danjpiscina,
it was the bad transisator like you said, thanx
i coldn't know cause my multimeter give a good value for it.

after your post i tried a new time on multimeter and always good value , after i 've put a 5088on good place instead of the 3707 and ihave the good value.

i will change my multimeter or just the battery.

great! i thought that's what it was. i just changed them all because it didn't take too long and i always buy extras.

all the best,

Dan P.