[BUILD] 1176LN Rev D DIY

[jplebre]

forgot to say Re: o/p pot. I have swapped it for the bournes one as per recommendations.

 

[mnats]

Re: noise - any way I can provide you with info to see if this issue can be narrowed down (future generations of DIY'ers

I had the issue happening with the unit plugged in the in/out of a DIGI192, DIGI96, RME ADI8DS and RME UFX.
I usually use the hardware as "hardware interfaces" in Protools.

Will try and put it on the insert of a NEVE shortly will let you know if problem persists.

Try this: connect the input of your 1176 to the output of one of your interfaces. Connect the output of the 1176 to the input of a different interface. Does the problem persist?

Or put another device that can deliver 40ish dB gain in place of the oscillating 1176 and crank it. Do you get a similar kind of feedback?

 

[jplebre]

outputting from RME Adi8 to RME UFX - problem persists. Turn the output pot to the marking "6" on the hairball enclosure and you get oscilating noise, quite fast. Recorded a bit of it is it possible to post audio in this website?

Also, few hours in today the ratio pot stopped working. All voltages are pretty close (+- 0.5v) from your schematic with voltages for revision D (pcb 2.2 latest one).
Replaced resistor and capacitor because the capacitor looked a bit bumped on the top. these are WIMA 0.022 rated at 100v

FDH333 diodes are testing fine, all voltages on the board measure fine. Unclicking the ratio pot does turn on compression I would say towards the fast-ish but there's no difference whatsoever.

Tested pot for resistance and it's fine (0ish to 24.7 ish kohms)

tested both r54 and C27 - all good.

did I miss something that can affect the attack speed?

Unit was calibrated following the method shown in the video.

Thanks

 

[chipss36]

hate to do this but I am stumped, I have a new built 1176 d , all works well, sounds great, and have calibrated bias adjustment, however setting setting the gain reduction meter I get no where, If I press gr button, the meter is pegged left, and no adjusting of  r72 or r75 has any effect, the meter works in +8 and +4 modes, but will not zero?
wonder what mistake I have make here, anyone offer a clue as to where to look?

I FOUND IT, whole meter board wired bass accwords.....dough...after two days of looking, zooming in on pictures of the new wiring pages, cant belive it worked so well wired all wrong like that...
fully calibrated, and working....now to finish #2...

 

[jplebre]

Nice one chipps. The unit does work amazing.

Hey guys, I was STUPID! I still have the attack speed problem, but the unit is as slow as it could be - is simply not getting faster.

I've made my own little board for the cap and resistor (both of them brand new) and rewired that section (new solder, etc.) making sure there's no cold joints. Both pots measure what they should (5M on release, 25k on attack).

Had a chance to compare it to the real thing attack all the way left, before the switch, it sounds SPOT ON with the old stuff, better (to me, as I like clean and a wider bandwidth, and louder).

Any ideas with the attack speed? (see above posts for all that I did).

Thanks all! it's a great work all of you done!

(and yes, the unit is faster, was being a dork though that the slowest setting should be slower - no, the faster needs to be faster

João

 

[chipss36]

#2 is done and calibrated, pretty sure my attenuator is bad, it has one spot that gets scratchy and the volume level drops, from 48 to 36 on the input is unusable,  have to fix it when I get back from offshore...gotta pay the bills.


3 black faces, and no names....lol

 

[jplebre]

Troubleshooting diary Part 3:
Main issues: attack pot not working, o/p pot scratchy 6-0 area only when O/p is present (balanced)

- Fixed: O/p transformer red and blue where inverted (damn habit of calling pin 2 "hot" in some countries, red being hot, blue being cold
Now it's all good, but changed nothing


- Reworked the O/p pot. Tested the value, doublechecked cable for continuity from pot to the next component and is ok. Pot Still scratchy from "6" to "0"
Question: I've noticed the O/p pot measures only 120k across when wired to the Ratio board ????????? is this normal?
- Pot only scratchy when an o/p load present. Unplugging the plug and it's fine. Outside world cables are fine and the unit is a modern UFX or ADI8DS (only ones I have here ATM)

SUCCESS! I forgot to ground the board! Clean as a whistle now!!!!! Little hookup wire from C25 negative side to the O/p transformer chassis (which conducts to the chassis)
When I get home going to start from the beginning again - voltages and what not.

If I could have some help with the attack pot would be great
- With a scope and a sine, should I only see half a wave? should I only see DC? What am I looking for here?

- Voltages across the board when unit on for a while - 90% of them spot on, some of them 0.03-0.1 volts difference, worst case scenario a 1v variation from MNATS "schematic + typical voltages"

- Spoke with mata_haze, which suggested me to look for cold joints and test continuity, specially around the ratio board area/pot hookups.

- Checked all the pots for values. All ok
- reworked ALL the connections from the pots, replaced resistors and caps (as per above post)

- Double checked all values for Ratio Board resistors as per hairball guideline. All OK. reflowed solder points

- Checked continuity for attack pot (from FDH333 to pot, from pot to release and pot to ratio board), all OK.

- Same with Release, but here something caught my eye, not sure if normal: I can get continuity between the lug that should reach QBias wiper and ground????? (regardless which way you twist the trim pot)

- REading this post, already at page 36

The unit is compressing, sounds amazing , but stuck at a rather useless attack setting for most sources

 

[jplebre]

updated above "diary"

 

[jplebre]

reading this thread from the beginning forum I am now confused about the wiring.

Skylar has this on this website http://equinoxsystems.net/wp-content/uploads/2011/07/SG-1176-RevD-Wiring_ALLv3.pdf where release pot lug connects to pad 7 (which is not really what's on the schems) and he was successful.

That's the oposite of mnats guide and the schematics.

Did I miss something?


Did some more homework. In red are the voltages that deviate more from normal now that the PCB has been grounded and the o/p pot oscillation fixed:
PSU R87 = 29.7v
PSU Zener = -8.7v

I/p section:
Q2 b=1.05v c=1.79v e=0.54v
Q3 c=11.48v e=1.18v
Q14 c=29.7v (power rail) e= 10.87v

O/p section:
Q4 b= 1v c= 4.7v e=0.42v
Q5 b=3.24 c=24.6 e=2.71
Q6 c=27.2 e=2.2

meter:
Fet 13.3v
Q12 b=-0.65 c= 12.51 e= -1.23
Q13 b= -0.74 c=12.76 e= -1.3
(have not calibrated the meter since placing the ground

GR section:
Q7 b=4.5 c=14.7 e= 3.95
Q8 e= 14.09
Q9 b=3.49 c=17.09 e= 2.87
Q10 e= 16.52

I don't just want to get this unit working, also want to udnrstand what's causing this.
My attack/release pot as wired per mnats, not Skylar.

 

[jplebre]

If I disconnect the return from ratio board and release pot (pad 18) the negative rail goes back to -9.7 ish.
I've rebuilt and rewired the entire of the ratio board and attack/release pot section. Tested for continuity, etc.

if I was to look at the main board (gr control) could I have a bad R39, R60 or R35? Is this likely to be the cause?

Any help would be great probed this bad boy up and above 1000 times by now

 

[Echo North]

If I disconnect the return from ratio board and release pot (pad 18) the negative rail goes back to -9.7 ish.
I've rebuilt and rewired the entire of the ratio board and attack/release pot section. Tested for continuity, etc.

if I was to look at the main board (gr control) could I have a bad R39, R60 or R35? Is this likely to be the cause?

Any help would be great probed this bad boy up and above 1000 times by now

Is the 10M resistor on the ratio PCB ok?  Correct value?  Shorted?

 

[jplebre]

Hi Echo

Thanks for the reply.
10M ok, doesn't seem it's shorting anywhere.

I had a look through the forum and found your posts dealing with someone that had an issue when ratio and release board connected, the -10 rail dropped to about -8 which is what's happening to me.

That prompted me to redo that entire section just to be sure, but problem is still there. Tested all the components before going in.

The whole of the CR control part works fine (you can see in a scope acting like the ones in this website http://www.axtsystems.com/index.php?option=com_content&view=article&id=57:1176lnproblems&catid=34:1176ln&Itemid=62 - last few of them are for GR control) and the tantalum caps are doing their job.

Replaced C21 as it links with 0 so could be giving some issues. Nothing changed.

According to your reply in page 153(ish), even with the Attack/release/ratio pot section on, the voltage on the negative rail should be -10 ish, -8.5 would be to low?
I have compression. Release changes more the attack than the attack pot itself, but I have it. It has the same character as the original (less dirt though)

 

[jplebre]

Sharing some pictures. Maybe a fresh set of eyes will do

GR control section

Ratio board redone

Ratio board redone solder points

The solder bridge you see there was because I accidentally lifted one of the pads, so I used a solder bridge instead

Time constant pots and wiring

Time constant pots and wiring close up attack/release

 

[mnats]

- 4:1, 8:1, 12:1 seem to respond ok, but when pressing 20:1 it indicates no gain reduction

But is it limiting the signal when set to 20:1? If not, you'll want to see if any signal is making it to the G.R. Control Amp at that setting.

One more thing:  on the final calibration step we never could get it to go to the -10db drop without increasing the input up almost all the way and the output almost all the way down.

The output control should not affect the threshold in any way. What level was the signal you were feeding it?

 

[jplebre]

Mike or Mnats where can I find an overlay of your ratio board?
Just want to make sure I'm not missing anything (cut trace or something).

Mike has the meter board overlay on his wiring document, could you add the ratio board to that document for reference only please?

J

 

[Echo North]

Mike or Mnats where can I find an overlay of your ratio board?
Just want to make sure I'm not missing anything (cut trace or something).

Mike has the meter board overlay on his wiring document, could you add the ratio board to that document for reference only please?

J

Right here:
http://www.groupdiy.com/index.php?topic=29981.msg621280#msg621280

 

[jplebre]

thank you Mike!
I probably should read Rev.A and Rev Jakob (ehehe) posts but these 160pages were much of a headache already.

Specially those pages and pages arguing about slacking or going back to gearslutz Urgh

Anyway looking forward for my next free w-end to do some more troubleshooting. This will help completely put the ratio board out of the equation.

 

[Dvaughn]

Hey all,

I've just finished my first 1176 Rev D build, was the biggest diy project i've tackled yet (not fully tackled or I wouldn't be posting)  I'm pretty noob level when it comes to most of this stuff so my question probably has some basic solutions.  I stuffed the power supply first as suggested by the hairball site, tested the rails and everything was fine. Then I stuffed the rest of the board as carefully as possible and followed all of the wiring instructions on mnats site. 

Upon first power up nothing smoked or caught fire so I was pretty happy at first, i set the meter to gain reduction and used the zero meter pot to adjust, that worked.  I connected the unit to my digi 003 and brought up a signal generator to start calibrating and wasn't getting anything to pass thru the unit, I immediatly started swaping cables because I didn't trust the ones I was using, still nothing.  So i decided to just run a mic->mic-pre->input of the 1176 to see if I could see a signal of any sort and when I went to power the unit on it lit up for a split second and then DEAD.  I tried powering up a few more times, nothing, switched AC cables, nothing.  I checked the fuse and it looked fine, swaped fuses still nothing.  I checked to see if maybe it was just the vu lamp that had went and maybe it just looked off, checked the voltage at the power rails, nothing there, I prodded at the secondaries of the power transformer and wasn't getting anything there either.  I checked the continuity of the power switch and everything seems fine there. 

Anyone have any suggestions of places I should measure (and how,  me = noob) to further narrow down my issue.


Greatly appreciate any help thanks!!





UPDATE, I adjusted the wire leads in the barrier strip (I have a slightly larger one than needed I think) unit powers on now.  Must have been faultly connection. Now to get some audio going thru it.

 

[jplebre]

Don't take this badly, but I've done the same mistake many times:
you said tested the rails - nothing
then tested the trafo secondary and nothing. Did you change your DMM to when you tested the secondary side? get's me everytime.

Not anything on the secondary (+-20v if I remember) means there's something wrong between the wall socket and the transformer primary, or if you have something loading down the circuit terribly, but I'm pretty sure some smoke would be involved.

Check usual suspects orientation of caps, the zener, the voltage reg IC.

I would also disconnect the lamp circuit completely to make it simpler.

 

[Dvaughn]

That is something i'm completely capable of  ;D.  Turned out to be shotty connection from transformer to the board.

Thanks man