[BUILD] 1176LN Rev D DIY

[astrovic]

Hey guys - don't post here often but have got some valuable info from this thread and the Rev A thread while building this is baby, a dual 1176 with a Rev A and a Rev D:

Front (you can see the dual G1176 I built a couple of years back in the background):

Rev A on the left, Rev D on the right:

Rev A:

Rev D:

Due to the tight space, I mounted the ratio boards in the floor and ran jumpers to the ratio switch.  This made front panel work easier, but added a lot of wiring!

I managed to keep the nuffiness to a minimum - just a couple of stupid mistakes that IO slowly cottoned on to.  I've been building long enough now to know that there's a 98% chance of human error causing the problems, so I just keep searching until I find the mistake!  Works nearly every time.

I'm down to 2 issues:

1. Calibrating the meter in GR mode is proving a challenge on both units.  I'm burned out on this build, so I'm going to park that issue for a while and come back to it later when the head is refreshed

2. I only ordered one bloody To-5 heatsink for the output transformer.  Dag-nammit!  You can see that the 2n3053 in the Rev A has the Flying Nun outfit on, but the Rev D is a nude dude. If any Aussies out there happen to have a TO-5 style heatsink that is surplus to requirements, I happily grab it Otherwise it's a special order to Futurlec or Ebay or whatever, which is fine and will happen if necessary but a bit of a pain as I'm not planning on ordering anything else.

What can I say about this fella?  Mnats, you are a champion.  This board is an absolute delight to work with, a real work of art.  The effect you've put in leaves me speechless.  And both units sound unbelievable - you haven't heard how rich and warm a 1kHz sine wave can sound until you've put one through these puppies!

 

[trancedental]

I'm still having problems working out what is exactly wrong with my 1176D build.

I have audio coming through the unit controls pots working fine without distortion but don't appear to have any compression nor   the VU meter indicating anything at all. I have rechecked  all the wiring & connections

My board input voltages are 29.6 / -9.5 within range I assume?

So I have started to check voltages (Updated readings with all switch buttons out & Input / Output Pots @ 12'O'Clock)

Q1 2N5457 GSD   -0.9 / 0 / 0

Q2 2N3391 ECB   0.2 /1.5/ 0.7
Q3      "               "       0.8 /4.8 /1.5
Q14    "            "     4.2 /29.6 /4.8

Q4 2N3391    "       0.4 /5.2 /1.0
Q5 2N3037 ECB   2.7 /13.3 /3.2

Q7 2N3707    "       3.2 /12.4 /3.7
Q8       "           "       11.2 /29.6 /12.4
Q9       "           "       9.2 /9.6 /10.0
Q10     "           "              9.1 /29.6 /9.6

Q11 2N5457 GSD -0.8 /0.1 /10.6
Q12  2N3707 ECB -1.7 /8.9 /-1.1
Q14 2N3391    " 4.2 /29.6/ 4.8

Q1 Q11 (Both socketed but changing to a different 2N5457 makes no difference)

Has anyone got any details on what voltages I should be getting around the board, I have searched & read all the 1176 threads & only found voltage information / details for the G1176 builds which don't appear to have Q1 transistor

Meanwhile I'm waiting for a signal generator in the post first!

However A voltage chart from a working build would be very helpful!!!!!

Cheers JK

 

[Stagefright13]

Try passing a signal thru it and turn the input knob up really high like 3/4 and listen for audible compression. (Obviously turning the output down low) If nothing something is wrong. Does the meter work in +4 and +8? The meter gets its signal in output mode directly from the xlr outs. If the meter doesn't work in output mode then the problem is the xlr connection to the meter board or the meter board wiring. Got any pics sometimes someone can look and see a simple mistake. Especially with somew close ups.

Cool Job Astrovic! 2 in one is a great idea. Hope you like it!

John

 

[dmp]

Astrovic: I had problems with the GR calibration step and I had to make the tracking adj trimmer larger (r44). I put a 5k in for the 2k. If you go through the process in Mnat's video, but the trimmer turns all the way to the end before the needle gets to 10, you need a bigger one. 

 

[dmp]

Wanted to see what the new 1176revD was doing, so I measured the signal in and the signal out.
The dashed lines are the expected curves based on the ratios...

 

[dmp]

Added a 120k where the T&C is in the original schematic and looked at how it changed the compression curves. Didn't effect ratio, but lowered threshold. Anyone know about what this would have been, and what it would have been used to test & check?

 

[Stagefright13]

I used a 2k trimmer in all 4 of my rev D compressors and they all calibrated fine. Even with the different rev of the boards. All you are doing in the GR tracking calibration is matching what the compressor is doing verses the meter. If you think of it that way it is pretty easy. And Mnat's video I saw for this is awesome! Just watch it a few times. He really put "A LOT" of time into making it easy for everyone. Especially with the videos.

Not to say it didn't confounded me at first! LOL

John

 

[dmp]

I ended up with a very large resistor in the T&C spot. From what I've been able to figure out, it is almost unnecessary. Does keep the grid of the GR circuit connected even with all buttons out. Speaking of which, running this compressor without the 'compression' engaged, seems to quickly distort, due to low negative headroom in the preamp. I'm curious about this.

 

[pearldrum944]

I have spent the last few nights reading and searching for how to wire up a couple of 1176's I'm building.  Boards are stuffed and I will be ordering 2 hairball kits in a week or two.  This project is a lot more complicated in terms of wiring compared to the gssl I recently finished!  I have been working my way around how to wire the unit, and have spent some time drawing a wiring diagram for visual reference but have a couple of questions in which I can not find clear answers too.

How is the meter pot wiring done with the hairball pot?  Just wires soldered to the r71 slot? is the center hole on the pcb the wiper?

Input shielding.  Is this correct?  Pin 1 of XLR goes to ground, also connects to the shield. which follows the input (jumpering around the attenuator and input transformer) up to the main PCB input and is not connected on that end.

From what I have seen from pictures, there seem to be more grounds than I am aware of.  Input xlr, output xlr, IEC, and ground connection on main pcb (also the shield for blk/grn wires).  What am I missing?

Also, I have a .jpg called "wireCheck3" that is a little confusing since the hairball manual says not to use the optional 22,grn.black on the meter board.  The correct wiring is single conductor wire from 22 to common on bypass switch.  The shield grounded and hooked to the blk connection on the ratio pcb and switch?  Then the shield for the grn wire hooked to that shield as well?

Does the shield for pad 7 need to be grounded? ???

I think one of the reasons for some of my confusion is that I don't really have any of the parts other than the main PCB sitting in front of me. 

Thanks in advance.

 

[dmp]

Hi PearlDrum
Welcome to a great project! I just finished wiring up a pair of 1176s and it is a lot of fun. I'm thinking of a GSSL next so glad to know you liked that project.
I ran wires from the r71 out to the pot on the front panel to zero the meter. Having this on the front panel is really nice. The Hairball cases are awesome.
After I first wired up my units, I had problems with oscillations when I turned up the output pot. After reading all through the forums and finding some good references on audio shielding, I changed the way the shielding is connected. First, I connected the signal ground (on the PCB) to the chassis ground at only one place. Then connected all the shields at one end, plus the xlr, and IEC just to the chassis ground. I had problems with noise at first because I connected shields to the audio ground. I think Mnats referenced a document  on audio grounding earlier in the tread from the Rane website that was really helpful.
I think I did shield the pin7 -> release pot, but I am not sure how important it is here since it is acarrying a DC voltage back to the FET.  All shields should be connected to chassis groundat one end.
After improving the grounding, my 1176s are quiet and work great. I used them for the first time this weekend on vocals and they sounded outstanding.

 

[dmp]

Sidechain link using the Hairball/Mnats/PurpleAudio stereo link kit by lifting R205. Needs a second switch to chose from stereo link, sidechain link in addition to a link switch. About to try it and see if it works...
(interesting note: the MC77 does a sidechain link by making balanced send/returns... but by using the buffer on the stereo link board, it should be *ok* to send unbalanced? i.e. noise cannot go backwards into the output pot & audio signal)

 

[pearldrum944]

Hi PearlDrum
Welcome to a great project! I just finished wiring up a pair of 1176s and it is a lot of fun. I'm thinking of a GSSL next so glad to know you liked that project.
I ran wires from the r71 out to the pot on the front panel to zero the meter. Having this on the front panel is really nice. The Hairball cases are awesome.
After I first wired up my units, I had problems with oscillations when I turned up the output pot. After reading all through the forums and finding some good references on audio shielding, I changed the way the shielding is connected. First, I connected the signal ground (on the PCB) to the chassis ground at only one place. Then connected all the shields at one end, plus the xlr, and IEC just to the chassis ground. I had problems with noise at first because I connected shields to the audio ground. I think Mnats referenced a document  on audio grounding earlier in the tread from the Rane website that was really helpful.
I think I did shield the pin7 -> release pot, but I am not sure how important it is here since it is acarrying a DC voltage back to the FET.  All shields should be connected to chassis groundat one end.
After improving the grounding, my 1176s are quiet and work great. I used them for the first time this weekend on vocals and they sounded outstanding.

Thanks.  I think I am getting my head around shielding and grounding inside the unit.  I'm sure I'll have more questions when I begin assembly.

 

[astrovic]

Astrovic: I had problems with the GR calibration step and I had to make the tracking adj trimmer larger (r44). I put a 5k in for the 2k. If you go through the process in Mnat's video, but the trimmer turns all the way to the end before the needle gets to 10, you need a bigger one. 

Thanks mate.  I've suspected I might need to look into that, but for now it's passing audio, compressing, sounding great and the needle is is dancing.  Whether it is dancing precisely in relation to the dB's getting chopped off will be for another time...

 

[T-rex]

Is there an audible difference between using the 2N5088 and the 2N3037s?  I have a set of both and was going to maybe socket the board this time so I could switch between them but before I do that is there enough of a difference to matter? 

In case anyone is interested I did my second 1176 with 2n5088's.  I couldn't find a good sockets so I said screw it and soldered them in.  I do not have "golden ears" by any stretch of the imagination, but I can say after several hours of use I don't hear any noticeable difference.  I need to go back and calibrate my first unit again because I thought I understood the process, but when I did the second unit everything clicked.  Anyway, I ordered all of the parts for both at the same time so the only difference between the two besides basic tolerances are the transistors and I can't hear any perceptible difference.  I used them on a stereo drum buss for a mix yesterday and they sounded great together.

 

[bdubya]

Cool, thanks for sharing your observations

Is there an audible difference between using the 2N5088 and the 2N3037s?  I have a set of both and was going to maybe socket the board this time so I could switch between them but before I do that is there enough of a difference to matter? 

In case anyone is interested I did my second 1176 with 2n5088's.  I couldn't find a good sockets so I said screw it and soldered them in.  I do not have "golden ears" by any stretch of the imagination, but I can say after several hours of use I don't hear any noticeable difference.  I need to go back and calibrate my first unit again because I thought I understood the process, but when I did the second unit everything clicked.  Anyway, I ordered all of the parts for both at the same time so the only difference between the two besides basic tolerances are the transistors and I can't hear any perceptible difference.  I used them on a stereo drum buss for a mix yesterday and they sounded great together.

 

[guitarguy12387]

Hey guys,

Building my first rev d. with hairball kit.

I'm a little confused about the input transformer/attenuator wiring... is the thing balanced? Is there any posts/documents that explain the wiring a bit? I have searched the thread and the forums, but can't find too much info.

Thanks!

 

[Stagefright13]

It has balanced input and output. After the transformer it's just 2 wires to the input on the board. There is a diagram in this thread for the attenuator. And Skylar has a nice flow chart in here for the wiring. Just make sure you wire the output transformer correctly. The newer boards have a different color code to the circuit board than the diagram.

Have fun!

John

Edit: Page 13 of the rev A thread has a flow chart also. They are wired the same as the D.

 

[jyrki3101]

Hi, I started building a rotary version- dual 1176LN revD with mnats pcb's(ver.2.2).
The problem is, I can't find info how to wire the mnats external PSU board->main board . What parts to leave out from the main pcb etc..
There are also two extra wires(yellow and orange) in Hairball audio's output transformer(UA5002). I can't see them in Skylar's layout?
Ratio board(w/rot.switch) has pinouts for a trimpot, but I don't know the resistance value, no documents on that.
I'd like to order rest of the parts from mouser but there's no sense of ordering wrong or unneccessary parts.
Does the T-attenuator from hairball replace the input level pot? Just want to make sure before I drill a bigger hole for that.The case is from Purusha. I would greatly appreciate If someone could help me with this?
With best Regards, Jyrki Telila

email:  jyrki.telila(at)gmail.com

 

[Kingston]

Terve,

http://mnats.net/psu.html
http://mnats.net/1176_revision_d.html

Wiring was found using the forum search:
http://geocities.com/m_natsume/files/MNATS1176REVD.pdf
http://mnats.net/files/DIY1176LNREVD_V2.pdf

 

[Stagefright13]

The T-Pad IS the input pot. And yellow and orange get soldered together. And not connected to anything else. Don't worry about the trimpot. It's not needed. If your doing a Parusha case with push buttons you won't even use the rotary boards.

And make sure the trimmers on the main board are orientated correctly. That's a fairly common mistake when assembling the pcb. Have fun!!

John