[BUILD] 1176LN Rev D DIY

[Chryst]

Thanks! I don't know what the tolerance should be. This are my measured voltages. They seem ok or am I missing something?

AC pad 22

20 0.34
12 0.21
8 0.13
4 0.58

DC 21

20 -6.79
12 -3.77
8 -2.64
4 -1.69

DC 19
all -1.10

Any suggestions are greatly appreciated. Thanks!

 

[dudeitsree]

I'm having issues with my power supply on a Hairball Rev D kit.  I've populated the PS properly checked polarity on components, double checked power transformer, mains and switch wiring.

I have no reading at the 30v point.  So I checked the mains again, after replacing the fuse all good there, as well as the switch.  But, when I checked the secondary I got incorrect readings with it disconnected form the PCB.  I got:  37.6v / 17.4 on CT / 7.6 direct from secondary outputs.  What might be the issue?  Is the power transformer okay? 

 

[AKopp]

Hello, sorry to bring up another issue here, but has anyone had dead input transformers? I made an audio trace tool and I have signal at the input of the transformer but nothing coming out. It's installed correctly and the two leads are correct on either side. Ground is also good. The headers are okay as well. Kind of stinks when you are on step one of calibration and you can't even pass signal through the unit. Thanks for any help. One other thing, the input knob seems to make no change on my level at the input of the trans. I'm off to bad start here.

 

[Echo North]

Hello, sorry to bring up another issue here, but has anyone had dead input transformers? I made an audio trace tool and I have signal at the input of the transformer but nothing coming out. It's installed correctly and the two leads are correct on either side. Ground is also good. The headers are okay as well. Kind of stinks when you are on step one of calibration and you can't even pass signal through the unit. Thanks for any help. One other thing, the input knob seems to make no change on my level at the input of the trans. I'm off to bad start here.

Rare, but it can happen.

Disconnect your the wires at the headers.  With your Ω meter test the DC resistance between the header connectors on the primary and secondary side.  Should be a few ohms (like 4 and 16) on each side and infinity or over load between pads on either the secondary or the primary.

 

[Echo North]

I'm having issues with my power supply on a Hairball Rev D kit.  I've populated the PS properly checked polarity on components, double checked power transformer, mains and switch wiring.

I have no reading at the 30v point.  So I checked the mains again, after replacing the fuse all good there, as well as the switch.  But, when I checked the secondary I got incorrect readings with it disconnected form the PCB.  I got:  37.6v / 17.4 on CT / 7.6 direct from secondary outputs.  What might be the issue?  Is the power transformer okay?

Keep your transformer wired to the PCB.  You want it "loaded".

Are you testing for DC at the 30V test point?  In reference to the CT?  What is your -10V DC reading?

Mike

 

[Echo North]

Thanks! I don't know what the tolerance should be. This are my measured voltages. They seem ok or am I missing something?

AC pad 22

20 0.34
12 0.21
8 0.13
4 0.58

DC 21

20 -6.79
12 -3.77
8 -2.64
4 -1.69

DC 19
all -1.10

Any suggestions are greatly appreciated. Thanks!

Your pad 22 seems backwards and weird.  What if your AC at the ANODE of CR2 for each ratio??

 

[dudeitsree]

Keep your transformer wired to the PCB.  You want it "loaded".

Are you testing for DC at the 30V test point?  In reference to the CT?  What is your -10V DC reading?

Mike
[/quote]


Thanks Mike, I have it sorted out.  I was testing incorrectly. 

 

[Bowie]

Question; I just picked up a couple of cases on a whim and I need to figure out what board I should be using.  I have an unused Mnats Rev H but I see mention of Rev J and am wondering if it's worth buying the newer board instead.  I already have a fully built Hairball Rev D and my goal with one of these new 1176s is to build a Rev D 1176ln with vintage transformers, carbon comps, etc.  If there is a board that allows a bigger resistor resistor footprint, that would be great.  Please help point me in the right direction, thanks!

 

[AKopp]

Hello, sorry to bring up another issue here, but has anyone had dead input transformers? I made an audio trace tool and I have signal at the input of the transformer but nothing coming out. It's installed correctly and the two leads are correct on either side. Ground is also good. The headers are okay as well. Kind of stinks when you are on step one of calibration and you can't even pass signal through the unit. Thanks for any help. One other thing, the input knob seems to make no change on my level at the input of the trans. I'm off to bad start here.

Rare, but it can happen.

Disconnect your the wires at the headers.  With your Ω meter test the DC resistance between the header connectors on the primary and secondary side.  Should be a few ohms (like 4 and 16) on each side and infinity or over load between pads on either the secondary or the primary.

Update: I have no resistance between headers. No readings at all from any points. So I guess I need to order a new IT and pcb. 

Can anyone verify the range of resistance on the input pot? I'm coming up with 625 ohms at zero (full CCW) and 1.172k at full CW. I'm measuring between the input + and outout +. Are these accurate values? I just found it odd that my signal never really changed when testing after the input pot. Should I order one of these as well? Thank you.

 

[deejaywhite]

Hey Guys,

I have a problem with the calibration (hairball method) as follows:


Set output control for 0dBu (0.775 VAC) at the output. DONE

Set attack full CCW (off position). Set input control for +10dBu (2.44 VAC) at your output XLR. DONE

Turn the attack control ON (Fully CW) and readjust the output level control for “0dBu” if necessary.
Now lets set the meter to display this 10dBu drop.  When the attack is “off” (full CCW) and you see +10dBu at the output, set the meter to 0 by using the front panel zero adjust trimmer. FAILURE
--> When I set the attack knob back to OFF, nothing happens...

What should I do?

Many Thanks,
Jens

 

[Echo North]

Hello, sorry to bring up another issue here, but has anyone had dead input transformers? I made an audio trace tool and I have signal at the input of the transformer but nothing coming out. It's installed correctly and the two leads are correct on either side. Ground is also good. The headers are okay as well. Kind of stinks when you are on step one of calibration and you can't even pass signal through the unit. Thanks for any help. One other thing, the input knob seems to make no change on my level at the input of the trans. I'm off to bad start here.

Rare, but it can happen.

Disconnect your the wires at the headers.  With your Ω meter test the DC resistance between the header connectors on the primary and secondary side.  Should be a few ohms (like 4 and 16) on each side and infinity or over load between pads on either the secondary or the primary.

Update: I have no resistance between headers. No readings at all from any points. So I guess I need to order a new IT and pcb. 

Can anyone verify the range of resistance on the input pot? I'm coming up with 625 ohms at zero (full CCW) and 1.172k at full CW. I'm measuring between the input + and outout +. Are these accurate values? I just found it odd that my signal never really changed when testing after the input pot. Should I order one of these as well? Thank you.

You need to measure between the + and -.

If your transformer is defect email me.

Mike

 

[Echo North]

Hey Guys,

I have a problem with the calibration (hairball method) as follows:


Set output control for 0dBu (0.775 VAC) at the output. DONE

Set attack full CCW (off position). Set input control for +10dBu (2.44 VAC) at your output XLR. DONE

Turn the attack control ON (Fully CW) and readjust the output level control for “0dBu” if necessary.
Now lets set the meter to display this 10dBu drop.  When the attack is “off” (full CCW) and you see +10dBu at the output, set the meter to 0 by using the front panel zero adjust trimmer. FAILURE
--> When I set the attack knob back to OFF, nothing happens...

What should I do?

Many Thanks,
Jens

Is your bias set correctly?

Do you get any drop on the output?

Mike

 

[deejaywhite]

Hey Guys,

I have a problem with the calibration (hairball method) as follows:


Set output control for 0dBu (0.775 VAC) at the output. DONE

Set attack full CCW (off position). Set input control for +10dBu (2.44 VAC) at your output XLR. DONE

Turn the attack control ON (Fully CW) and readjust the output level control for “0dBu” if necessary.
Now lets set the meter to display this 10dBu drop.  When the attack is “off” (full CCW) and you see +10dBu at the output, set the meter to 0 by using the front panel zero adjust trimmer. FAILURE
--> When I set the attack knob back to OFF, nothing happens...

What should I do?

Many Thanks,
Jens

Is your bias set correctly?

Do you get any drop on the output?

Mike

Hi Mike,

Thanks for everything!
I found out what the problem was...
Rarely enough, the tracking variable resistor was too extreme set what brought the r71 to it's max so I couldn't get to 0 on my meter!
So the next step couldn't be done!

Do you have any explanation for this?
I have to implement it into my major project!

My compressor is working properly and I like this build a lot!

Thanks for everything!

 

[John Peacock]

I'm dusting off this old project...  I purchased the original Mnats rev D board back in 2007.  My board is stuffed and I am partially through hooking up the wires in a Hairball case, which has brought me to a few questions.

1. On the original board there is no ground terminal next to pad 7, as shown on the current hook-up instructions provided by Mnats and Hairball Audio.  I have found some old connection guides that suggest not bothering to connect the shield to ground from the main wire attached to pad 7.  Another guide suggests connecting the shield from the wire at pad 7 to the shield/ground from the wire attached to pad 22.  However, I would think connecting it to the non-connected shield from the input transformer may be easier (as it's closer), if that would work.  Or is there any real trade-off to leaving the pad 7 shield not connected to ground?

2. I am using the Cinemag CM-96731 output transformer.  As stated on Mnats guide about halfway down the following link in the section marked "Output transformer options:"
http://mnats.net/1176_revision_d.html
the output of the transformer can be terminated into a 619ohm resistor.  Where exactly do I place the resistor in terms of the circuit (between ? and ?).  Also, I read that some folks put this resistor on a switch as mentioned in the second to last post in the following link:
http://groupdiy.com/index.php?topic=18209.msg212586;topicseen#msg212586
How exactly can I wire the resistor on a switch.  Meaning, what kind of toggle switch do I need to buy (number of poles?, etc.), and any specifics on the wiring of the switch/resistor would be greatly appreciated.

3. Finally, when I started this project there was no Hairball Audio to make this process, especially the sourcing, much easier.  I bought expensive push-button assemblies directly from UA.  Mike at Hairball has a post here:
http://groupdiy.com/index.php?topic=26998.msg326843#msg326843
where he very clearly explains the connections from the UA ratio board.  He attempts to explain the meter board hookup in the next few posts, but I don't follow.  There are 7 terminals on the UA meter board rather than the 6 found on every diagram I can find (new or old) from Hairball's push-button boards or those old green ones from Mnats (I actually have a set of those, too).  The 7th is for +8 metering?  If this is the case, what does the +8 button do on the modern Hairball/Mnats units?  If someone is able to refer me to a diagram or simply tell me which connections to make from the UA meter board to the Mnats board, that would be great.  Or would I be better off biting the bullet and just buying new meter boards and push-button assemblies from Hairball to make it easier to follow the current wiring diagrams?  Any links, diagrams, insight, etc. would be greatly appreciated.

Thank you!

 

[Mr.Franky]

Quick question: Is there any type of solder you guys would recommend?

 

[Bowie]

Quick question: Is there any type of solder you guys would recommend?

There's a wide number of good types.  I personally love Wonder solder because it melts at a low temp and flows really well, meaning less chance of component damage (and, it's made of good materials).  I've used it for 15 years and have yet to have a joint go bad.  WBT melts even faster and flows better but the flux smoke coming off it makes me ill in the lungs so I no longer use it.  Both of those are expensive but you don't have to spend a lot.
  I avoid lead-free because I've heard of (and seen) too many long-term reliability issues, though that seems to vary based on the formula.

 

[Mr.Franky]

Quick question: Is there any type of solder you guys would recommend?

There's a wide number of good types.  I personally love Wonder solder because it melts at a low temp and flows really well, meaning less chance of component damage (and, it's made of good materials).  I've used it for 15 years and have yet to have a joint go bad.  WBT melts even faster and flows better but the flux smoke coming off it makes me ill in the lungs so I no longer use it.  Both of those are expensive but you don't have to spend a lot.
  I avoid lead-free because I've heard of (and seen) too many long-term reliability issues, though that seems to vary based on the formula.

Hey, thanks for the reply. Unfortunately I live in Europe, where leaded solder is "illegal" because of "health" laws. They look pretty promising though. I'll try and get my hands on them if I can!

Greets,

 

[weiss]

Hey guys, i could need some help on my 1176 Rev D. So far everything works fine except the meter, which won't move at all.
I sent the 1kHz signal through the input to calibrate my device but the meter won't make a single move while turning the calibration trim pots. All wires have been soldered clean and correct: Two cables from the meter to the first two solder points on the ratio board and two for the light. Trim pot on the front plate directly goes to the pcb. I think it is no hardware issue. As far as i tested, there is no voltage coming out of the meter board.

weiss

 

[Echo North]

Hey guys, i could need some help on my 1176 Rev D. So far everything works fine except the meter, which won't move at all.
I sent the 1kHz signal through the input to calibrate my device but the meter won't make a single move while turning the calibration trim pots. All wires have been soldered clean and correct: Two cables from the meter to the first two solder points on the ratio board and two for the light. Trim pot on the front plate directly goes to the pcb. I think it is no hardware issue. As far as i tested, there is no voltage coming out of the meter board.

weiss

feed a 0dBu 1K signal directly into the meter terminals.  Does the needle react?

 

[Scheff]

I got an issue with the output pots on two Rev D I built recently. When I turn the pot up, a low rumbling is audible that gets louder at approxamitely 12 o'clock and then sounds like touching the needle on a record player. Besides that the compressor is behaving like it should and voltages seem to be right.
I already installed a Bournes output pot on one unit, tripple checked all component values, wiring etc especially in the line amp stage. It's strange that it happens on both units, which makes me think it has to be my mistake. On the other hand I didn't encounter anyhting like this on the 4 Rev A I built so far, and I really don't know what I did differently...  Any hints where to look for mistakes/faulty components?
Thanks for your help!