[BUILD] 1176LN Rev D DIY

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Stagefright13 said:
There is no problem with the meter scales. The meter CAN drift up somewhat after extended use as said in the original 1176 manual. That is normal. I calibrate after the unit has been on a few hours. Just follow the video calibration procedures. Then insert R44. then trim the meter as follows:

(This was posted earlier in the thread by another member but explains it better than I can)

So when you're sure about your Qbias, and have then done the Zero meter, 0volts across R74 step....
Here's an outline of my tracking adjust method...maybe it will help:


R44 in
GRmode(20:1)
Your controls set for the 10db swing(10db of GR)
Your source signal coming through...being compressed.

Now, adjust your meter needle to -10VU using the R44 "tracking adjust" trimmer(reflecting the 10db of reduction).

Now, mute your source signal(or short pad 22 to ground), and adjust the needle back up to 0VU using the "0 Set"(R71) trimmer.

Now un-mute your source signal again(or un-short pad 22), and readjust R44 trimmer so the meter needle again shows the 10db of gain reduction(-10VU).

Mute the source signal(or short the 22 pad), and again use the "0 Set"(R71) trimmer to adjust the meter needle back to 0VU.


You should see a slight bit of change(for the better) after each adjustment cycle.

So, repeat this back and forth adjustment procedure until the meter finally holds it's adjustments...
i.e., the meter needle will eventually hold at -10VU when you have the source signal present, and then go back to 0VU when you mute the source signal(or short pad 22 to ground).
Getting to this point usually requires many repetitions of that adjustment cycle.
Click to expand...

That's precisely what I did - since the tracking and zero adjust interact so much, I almost used them to achieve the others intent with pretty good results. But it still only reads -6db on the meter. If you switch from 20:1 to 4:1 without touching the other controls should you see more gain reduction at the output? 

Thanks for responding SF


 
When you switch ratios the input pot needs to be adjusted to get the same gain reduction. Sounds like you may have an incorrect resistor value somewhere. I would check that. It's easy to swap a K for an R so to speak.

I'm wiring my rev D right now. Wish me luck! ;)
 
Can someone help-me wiring the EA-5002 Output transformer?

According to the mnats info:
"The EA-5002 will also fit right into a 1U rack case without any modifications. The color code is the same as the Cinemag except for the output secondaries. The EA-5002 has two secondary output windings - four wires like the original - that are ordinarily connected in series. The Cinemag is connected internally, so it has only two wires at the output."

After connecting the wires to the board (easy since the colors are identified on the board) there are four wires remaining to connect, As far as I understand, 2 are going to the output pot, and the other 2 should be connected together.
Can you tell me what wires are going to the output pot?

There is also a ground wire. Where should be this wire connected? Anywhere on the chassis or should I solder it together with the other ground cables in a "star ground scheme"?


I´m also having trouble with the Atran input TX, even having red the explanation mnats gave in this thread due to my poor English understand, can you help me with the links/jumpers that this transformer need to be soldered?
Thank you,
Luis
 
luis said:
Can someone help-me wiring the EA-5002 Output transformer?

According to the mnats info:
"The EA-5002 will also fit right into a 1U rack case without any modifications. The color code is the same as the Cinemag except for the output secondaries. The EA-5002 has two secondary output windings - four wires like the original - that are ordinarily connected in series. The Cinemag is connected internally, so it has only two wires at the output."

After connecting the wires to the board (easy since the colors are identified on the board) there are four wires remaining to connect, As far as I understand, 2 are going to the output pot, and the other 2 should be connected together.
Can you tell me what wires are going to the output pot?

There is also a ground wire. Where should be this wire connected? Anywhere on the chassis or should I solder it together with the other ground cables in a "star ground scheme"?


I´m also having trouble with the Atran input TX, even having red the explanation mnats gave in this thread due to my poor English understand, can you help me with the links/jumpers that this transformer need to be soldered?
Thank you,
Luis
Click to expand...

Sorry Luis-

I don't have the schematic or my unit in front of me.  did you see Skylar's wiring guide?

http://www.equinoxsystems.net/DIY/SG-1176-RevD-Wiring_ALLv3.pdf

Hope it helps

Good luck SF!!

Josh
 
On the 5002 connect the orange and yellow together (by themselves not connected to board or anything). Then connect the red and blue to your output. The schematic for that transformer is here http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-1176LNmanual.pdf

I didn't even hook the ground wire up but I guess you can hook it to star ground if you want. Or circuit ground.

It's just like the original wires. Mnats mentions this on his Rev D page toward the bottom.

Mines in the rack done and squeezing. :) finished it yesterday morning. Sounds exactly like my first one. Gonna rig up an 1176SA stereo adapter and see what they sound like on drum overheads. And may match up a pair of Q1's for them.

John
 
Thank for all your help!

I have Skylar files, but he used the cinemag output tx, not EA-5002.

John: I was reading the manual, but i didn´t finish.. so I tought that was just the manual without any schematic.. I´m so dumb! :-[

Thank you all, once again!
Luis
 
Yeah it's a great idea to read the entire original manual. Lots of cool stuff in there and original scanned historical stuff. It's a great read. And there is a TON of other tests you can do if you have the equipment.

John
 
Has anyone tried, or does anyone have an opinion on running the 1176 from a JLM 48V supply?

Any comments? I've not used the JLM supply, but I assume it should be decent enough if it is used for mic preamps too.
 
rodabod said:
Has anyone tried, or does anyone have an opinion on running the 1176 from a JLM 48V supply?

Any comments? I've not used the JLM supply, but I assume it should be decent enough if it is used for mic preamps too.
Click to expand...

Bump. Has anyone tried this? Or have any reason to doubt it? I will try, but if anyone has any opinions, I'd be glad to hear them.

Roddy
 
I´m finish my pushbutton version, but I can´t find a 25K Linear Pot with SPDT here. The more close I could buy was a 22k but it has 6 solder lugs instead of 3 like the recommended one.

Can someone confirm if this would work, and if possible, help wiring it?

Thank you all,
Luis
 
It should work.  Sounds like you have a DPDT.

You need to know how the 6 lugs are connected. If they are lined up like the pushbutton switches the 2 middle lugs are probably common.  In that case, refer to the part in my instructions where I show how to wire the bypass to the the pushbutton switch.  You'll want to use the continuity tester on your multimeter to figure out which lugs the common is connected to in which position.  Or refer to a datasheet if you have one.

Thanks,

Mike
 
Echo North said:
It should work.  Sounds like you have a DPDT.

You need to know how the 6 lugs are connected. If they are lined up like the pushbutton switches the 2 middle lugs are probably common.  In that case, refer to the part in my instructions where I show how to wire the bypass to the the pushbutton switch.  You'll want to use the continuity tester on your multimeter to figure out which lugs the common is connected to in which position.  Or refer to a datasheet if you have one.

Thanks,

Mike
Click to expand...

Thanks Mike,

I think I will not use this pot that i bought. It just feels cheap and I cannot find the datasheet.  Does anyone have a spare one of these switch that could sell-me? It seems impossbile to find in Europe, and to buy from mouser, its really expensive (Switch + shipping + Possible Customs).

Regarding the pushbuttons, I don´t understand how the power button (in the Pushbutton version) is wired. Can someone help-me? For what I understand the hot wire is runnign in the button? Looks dangerous! ;D
 
Hello Luis ;)

The OFF pushbuttom is wired the way to put the unit off when pressed, so when you press another buttom like GR buttom, the unit power on! and only power off when you press the OFF buttom? can you see that? the 4 buttoms function in oposition, get it?
About the 25K with SPDT... I really bought mine from Mouser... here in Portugal... forget it.

Cheers,

Eddie ;D
 
rodabod why would you want to use a JLM supply? I would save that for another project. everything is on board ya just need a toroid. And will be whisper quiet.

jakearoo I'm not sure what ya mean by pad 4 of the meter. Do you have push button or rotary switches? I never made a rotary one.

And yeah the original had full AC wired to the front panel. I put switched and fused IEC jacks on the back panel and use the "off" button on the front panel to turn off gain reduction. I didn't use the attack pot with switch on all mine cause I didn't know where to get one at the time. Now I like it that way.  ;D

Mike from Hairball gives instructions for that and other options in his great instruction kit that comes with the switch boards.

My only problem was I was short 2 1176's tracking a couple weeks ago! It never ends does it??!!

John
 
Jakearoo,

I connected Pad 4 on the Meter board to Pad 4 on the Ratio board on mine.  I think that is correct - mine seems to work anyway... except...

My Ratio switch seems to work backwards - has anyone experienced this?  Going clockwise I get 20:1, 12:1, 8:1, 4:1, 1:1, 1:1...  I'm using the rotary switch from Kato's parts list with Mnat's board.

I re-checked my wiring and everything seems to be correct.  Am I missing something? 

Thanks.
 
spica said:
My Ratio switch seems to work backwards - has anyone experienced this?  Going clockwise I get 20:1, 12:1, 8:1, 4:1, 1:1, 1:1...  I'm using the rotary switch from Kato's parts list with Mnat's board.
Click to expand...

How are you determining ratio's? 

If you're just looking at the GR on a meter, lower ratios (4:1) tend to show more GR on a meter then higher ratios (20:1).  The amount of GR is not the same as the GR ratio.  If you haven't yet, check out gwans fabulous page on measuring GR ratios:
http://www.axtsystems.com/index.php?view=article&catid=34%3A1176ln&id=54%3A1176lnratios&option=com_content&Itemid=62

If you already know all this, my apologies in advance ;)

Mike

 
Thanks, Mike.

My thinking on the GR was wrong - didn't occur to me that the threshold changes with each ratio although it is something I know I've read in the thread before.  It's been a long day of breathing solder fumes:)

Has anyone implemented Slam Mode with the Lorin switch?  Not sure there is an easy way to do it, might have to use the Alpha per Mnat's pictorial instead.  Looks like that will be tomorrow's project.



 
Stagefright13 said:
rodabod why would you want to use a JLM supply? I would save that for another project. everything is on board ya just need a toroid. And will be whisper quiet.
Click to expand...

Thanks. I just thought it would keep things simple as I probably won't use my BAs at the same time as the 1176. I could skip most of the PSU section bar a bit of filtering.

But you probably have a point... I maybe should just go with a standard design.
 
hello,
I have just powered my unit up.
I got the BEAUTIFUL KIT from hairball audio: Trafos, ratio switches Input PAD.
the attack pot is the suggest one from moused with DPDT.
I have wired my unit according to SKYLAR instructions (apart from output trafo which the color coding doesn not match what I have here) and used hairball instructions on how to wire the attack pot up.
i get (even before line up) 46dB of gain before it peaks, i am monitoring using a Neutrik A1 meter (nice piece of kit)
everything seems to be working fine BUT...
I get gain reduction even when the attack pot is on "OFF"
I have checked the usual suspects : wiring, loose connections, dry joints... even if I have left the kattle on....(sorry kinda english humor)

what else am I missing?

any tips will be much appreciated.


Best,
Mattia.
 

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