[BUILD] 1176LN Rev D DIY

[Delta Sigma]

Well I'm assuming that if I look at frequencies above the tone I inject that I should be able to tell if my THD is increasing or decreasing with adjustments.

Hopefully I can get one of these programs to work on XP on my Mac. I don't use XP often and I'm worried about hardware problems.

 

[tomcat]

Faber Acoustics have some very nice OS X analyzers & tools!

 

[ShandonSound]

270k. (check the schematic... it really does have a lot of answers but you have to poke at it a bit)

Thank you

Could anybody help clarify something else. I've been following the wiring guide for the hairball case on the mnats site, this shows connections being made to the 'a','b' and 'c' lugs of the attack pot spdt switch. This seems to disagree with the wiring diagram I have from hairball which doesn't show any such connections. Which should I be following? So far I have followed the mnats guide and I have unit which passes clean audio but the metering doesn't work! Any help would be very welcome.

Best,

Steve

 

[MicDaddy]

Hi Steve,

I finished up a Rev A last night, followed exclusively the Mnats wiring guide..  terminated wires to each of the 'a', 'b', and 'c' lugs on the attack pot just like in the wiring guide.

Metering was screwy until 'Q' bias was set, prior while in GR the meter would peg all the way in the red..   now everything works great!!

 

[ShandonSound]

Metering was screwy until 'Q' bias was set, prior while in GR the meter would peg all the way in the red..   now everything works great!!

Sadly my meter isn't doing anything, so I've obviously got something else wrong! Thanks anyway!

Steve

 

[ShandonSound]

Hi Steve,

I finished up a Rev A last night, followed exclusively the Mnats wiring guide..  terminated wires to each of the 'a', 'b', and 'c' lugs on the attack pot just like in the wiring guide.

Metering was screwy until 'Q' bias was set, prior while in GR the meter would peg all the way in the red..   now everything works great!!

Hi again,
When I followed the mnats guide I ended up with 3 pads on the meter board unused; 'GRN', '22' & 'BLK' is that correct or have I misunderstood something?

Thanks in advance.
Steve

 

[MicDaddy]

If I understand you correctly, the pads are right behind the +4 pushbutton?

If so that is correct, no wires will terminate at these pads.  

Both 8.2K and 3.6K should be populated, there should be 6 conductors terminated to the top-side of the meter board, where it says V X 28 29 VU VU.

 

[Echo North]

Those 3 pads allow for the option of using a pushbutton as the GR Off if you don't want it on the attack knob.  You have to cut traces to make it work.  If you're doing a classic 1176 w/ the GR on the attack just leave those empty.

Explained here:
http://www.hairballaudio.com/docs/FET%20Compressor%20PCB%20Board%20Info%20V3.pdf

 

[ShandonSound]

Those 3 pads allow for the option of using a pushbutton as the GR Off if you don't want it on the attack knob.  You have to cut traces to make it work.  If you're doing a classic 1176 w/ the GR on the attack just leave those empty.

Explained here:
http://www.hairballaudio.com/docs/FET%20Compressor%20PCB%20Board%20Info%20V3.pdf

Yes that's how I have it!
I've been through my wiring again and everything seems to be correct but the meter is still dead even when I select GR the needle doesn't move to 0VU.
I can measure volts at the VU terminals which vary as I adjust the input pot (0-around 1.3v, does that sound right?)

In the wiring guide (bottom of Attack and Release Pot page) it says "Solder the yellow wire from the ratio board plug to pad 19" is that the yellow wire from the attack pot, as far as I can see there is no yellow wire from the ratio board?
Also on the "meter circuit" page third para from end it says "Twist together the blue and red wires from the ratio board connector" presumably they mean the meter board, as there are no blue or reds from the ratio board?

Beyond that I'm struggling to find where I have strayed from the guide, and would really appreciate any suggestions anyone can offer.
The last thing I want to do is waste anyone's time so I apologise in advance if my lack of knowledge has led me to ask some stupid questions, but I'd be really glad if anyone could point me in the right direction.

Thanks again!

Steve

 

[Echo North]

Yes that's how I have it!
I've been through my wiring again and everything seems to be correct but the meter is still dead even when I select GR the needle doesn't move to 0VU.
I can measure volts at the VU terminals which vary as I adjust the input pot (0-around 1.3v, does that sound right?)

In the wiring guide (bottom of Attack and Release Pot page) it says "Solder the yellow wire from the ratio board plug to pad 19" is that the yellow wire from the attack pot, as far as I can see there is no yellow wire from the ratio board?
Also on the "meter circuit" page third para from end it says "Twist together the blue and red wires from the ratio board connector" presumably they mean the meter board, as there are no blue or reds from the ratio board?

Yes yellow wire from the attack pot goes to pad 19.

Yes red and blue from meter board.

Beyond that I'm struggling to find where I have strayed from the guide, and would really appreciate any suggestions anyone can offer.
The last thing I want to do is waste anyone's time so I apologise in advance if my lack of knowledge has led me to ask some stupid questions, but I'd be really glad if anyone could point me in the right direction.

Is the meter working in +4/+8 mode when passing signal?  If not feed 1V ac directly into it and see if it moves.  If neither of these work the meter may be dead.  Let me know if it is.  Make sure you're using the meter connections not the lamp.

Also make sure you calibrate the unit first.

Mike

 

[ShandonSound]

Is the meter working in +4/+8 mode when passing signal?  If not feed 1V ac directly into it and see if it moves.  If neither of these work the meter may be dead.  Let me know if it is.  Make sure you're using the meter connections not the lamp.

Also make sure you calibrate the unit first.

Mike

Hi Mike,
No the meter doesn't do anything with the switches in any position.
I have applied a 1khz sine wave (which I boosted to read around 1V ac) directly to the meter and the needle didn't move at all.
However I'm not sure what you mean by calibrating it first? Do you just mean the screw adjustment on the front of the meter, or is there something else I need to do?

Thanks,

Steve

 

[Echo North]

That sounds like a broken meter.

If it's mine, email me to get a replacement.

info at hairballaudio dot com

 

[Marcocet]

Hey, just wanted to post that I just built mine and it worked perfect right off the bat. Thanks for all the work you guys put into designing and testing the hell out of this thing! Used it on a session all day and it sounds fantastic.

 

[electron monkey]

I have a revision D 2.2

I have a problem where the 2 resistors and 1 capacitor that go over the Attack/Release potentiometers are hard to locate on the BOM.  I need to know their values.  I have a Hairball Rev D kit + enclosure for this project if that helps.

I am also wondering about rotary knob/pushbutton versions, is this a major issue and what will I have to look out for? I thought they were all pretty much the same.

Just wondering what these values are, I can see them on the MNATS schematic hosted on his website, but I don't know if they will suit my revision/version!

TIA

 

[Echo North]

They are the same, just hooked up a little different.  I believe for the rotary version, the attack/release resistor and cap are on the PCB.  If you are building from my kit just follow the MNATS wiring guide.

Look at the schematic:
http://mnats.net/files/DIY1176LNREVD_V2.pdf

At the bottom you can see the resistor and cap attached to R55(attack) and the resistor on R56 (release).

Mike

 

[blackwaterstudios]

Hi all - just finished up fixing a hairball rev-d I sent off to someone to get wired up, calibrated and finished.  It did not go well so I'm trying to fix it.

Started the calibration per the videos and the q-bias went fine, as did the meter tracking.  My problem comes when I'm trying to do the gain reduction meter adjustment and when I short 22 to ground and do the adjustments, when I remove the jumper to get the gain reduction reading nothing happens.  I should state I'm using the pushbutton model not the rotary switch and the attack does have the off switch but I haven't a clue if it's wired up or not so I always do the jumper from 22 to ground leaving the attack knob alone.

Any clue where I should start looking?  I didn't wire this thing and the guy that did mucked it up pretty bad although he said it did calibrate.

Any help would be appreciated - just let me know if I need to give you more info.

Thanks in advance!

 

[blackwaterstudios]

As a followup I got pissed and went to the work area to do the calibration again.  Removed jumper from 22 and nothing happened.  Then I just started pushing ratio buttons at random and lo and behold with in ANY mode but 20:1 it SEEMS to behave correctly.  Weird.  Not sure what to do now...  Also when I go to VU mode I assume I use +4 and not +8 correct?

 

[Echo North]

As a followup I got pissed and went to the work area to do the calibration again.  Removed jumper from 22 and nothing happened.  Then I just started pushing ratio buttons at random and lo and behold with in ANY mode but 20:1 it SEEMS to behave correctly.  Weird.  Not sure what to do now...  Also when I go to VU mode I assume I use +4 and not +8 correct?

The "not working in 20" is a problem a few people here have had and fixed.  It's a simple wiring error that I can not remember off the top off my head.  Try printing and searching the 1176 threads or maybe someone who remembers can chime in. 

You can use +4 or +8 for metering, what ever is appropriate for your signal level.

 

[blackwaterstudios]

Ok one post led me in maybe the right direction.  Checked the ratio board and it looks like his solder technique was to stand back and throw globs of solder at it as hard as he could.  Freekin solder whiskers EVERYWHERE, globs dripping down off of wires onto other wires.  Jesus!

 

[Echo North]

Bad times.

Want me to toss an extra ratio board in your current order?