[BUILD] 1176LN Rev D DIY

[babaorum]

Hello, I built a rev D mnats/Hairball 1176 (first channel of a stereo one)
and I need help because my measures are very stranges ...
I'm in france so 240V/24V for the input transformer.

It seems to be ok for the Gr and power supply.
But for preamp and amp line I have :

Q1 == G: -0.1V /S: 0V / D: 0V
Q2 == E: 1.3V /C: 14.4V /B 0V
Q3 == E: 27.8V /C: 27.8V /B 14.4V
Q14 == E: 28V /C: 29.1V /B 27.8V

R10 bounds : 0V
R11 bounds : 1.1V 27.8V
R14 bounds : 27.8V 28.9V
R17 bounds : 28.8V 29.1V
R18 bounds : 1.3V 0.7V

Could you tell me if you see what component could give these wrong values

(I can't calibrate the comp and I have no sound in the output)

Thanks

Regards
Jérôme

 

[ArnauTS]

I've built a dual 1176 rev D for a friend. Done a few rev J but this was the first rev d.
It's a diy racked case wich it will be nice to have a bit more depth and i don't like the omniversal words but well my friend choose that case ;D
Matched resistors, HFE transistors and i'm glad i did.
Fired up first try without problems and stereo compression it's great +-0.5dB so very close.

I forgot to order the stereo link boards but will add that later

 

[babaorum]

Cool I saw that case but I prefered choose this one from Dan :

 

[dbonin]

Hello, I built a rev D mnats/Hairball 1176 (first channel of a stereo one)
and I need help because my measures are very stranges ...
I'm in france so 240V/24V for the input transformer.

It seems to be ok for the Gr and power supply.
But for preamp and amp line I have :

Q1 == G: -0.1V /S: 0V / D: 0V
Q2 == E: 1.3V /C: 14.4V /B 0V
Q3 == E: 27.8V /C: 27.8V /B 14.4V
Q14 == E: 28V /C: 29.1V /B 27.8V

R10 bounds : 0V
R11 bounds : 1.1V 27.8V
R14 bounds : 27.8V 28.9V
R17 bounds : 28.8V 29.1V
R18 bounds : 1.3V 0.7V

Could you tell me if you see what component could give these wrong values

(I can't calibrate the comp and I have no sound in the output)

Thanks

Regards
Jérôme

I know you may get a LOT of this type of response, but here goes:

Before you check anything else, did you triple check that everything is oriented on the board correctly?
Everything is soldered to the PCB and there are no solder bridges?
If you used terminal blocks, double check that each wire is seated nicely in the terminal?

Do you have the box completely wired?
If so, and you have checked all that, start at the INPUT and trace an input signal with your DMM set to AC.  Do you get a signal where the input transformer connects to the PCB?
Once you have done all that,  skip Q1 for now and check the other voltages against the REV D reference voltages posted on MNATS pages.

 

[Riinehart]

Immense thanks to Mnats and Mike at Hairball for all their work and info. And also thanks to everyone else who has posted here, following up on the solutions to their problems, etc. I just finished a Rev D and, although it was a steep learning curve, it pretty much all went perfectly thanks to all the info here.

I hadn't done any electronics projects prior to this (with the exception of some very simple soldering -- cables and contact mics) but decided to cautiously take this on with the hope of learning and doing more similar projects in the future (I'd never be able to afford the retail versions of these things).

Some miscellany, especially for first-time builders (since I was really unsure if I'd be able to tackle this when starting out):

If you can take your time and follow directions well, this is difficult but certainly possible. If you have trouble with either of those things, it would probably be best to avoid this project.

Read everything you can in advance, especially all of the directions from Hairball and Mnats. Also read this thread all the way through. It was so helpful to know of potential snags before running into them in reality, and reading the whole thread also helps a beginner like me get more of a sense of why things go together the way they do. I kept thinking I'd have to beg for help somewhere along the way, but I kept finding the answers to my questions here before I had to ask.

If you're a total beginner like me, you'll also end up having to spend a lot of time researching different elements of the electronics world in order to know how to proceed. For instance, learning about what tools you'll need and why, how to read/measure the different components, how to solder well, etc.

Speaking of which, follow Hairball's advice and measure every single component before you install it. Knowing almost nothing about electronics going into this, I knew that I really wanted to avoid a lot of troubleshooting, so I tried to get everything done right the first time and was happy to do this. Also, for the same reasons, be very careful with your soldering -- resolder if you're not confident. (Another thankful note: I decided to get the complete Hairball kit so that I could be sure I didn't forget some part or other, or have to figure out a replacement for something that's not in stock, etc., and the kit was absolutely perfect. Every component was spot-on, everything was nicely packed and organized, just perfect. Thanks Mike!)

Obviously this all takes time. I remember, before I started, reading that it generally takes people 6-10 hours to complete this. But in my case, accounting for all the researching, stopping to watch tutorials, and so on, it was probably somewhere closer to 25 hours or so. Well worth it if you use the tools and knowledge for similar projects in the future.

Thanks everyone!

 

[Spadehead]

Thanks for the link - interesting point but my problem is that my units seem to be compressing more than they should - almost like there isn't as much input attenuation happening.

Most folks tend to agree on a starting point of 12/12 and driving more for more compression, leaving quite a lot of wiggle room for high levels of compression (dropping the output pot).

I can't get to that level with a 0VU average input level on the console without having the in and out pots at 9am - meaning that if I push the levels they get FAR too loud and useless- raising the noise floor etc - the only option is dropping the input level on the console - not something I should have to do.

It feels like the input needs to attenuate more so that I need to boost the input pot so compensate if that figures? Or am I going crazy??

Thanks in advance....

I think this is a really great thing to understand and now that you pose the question I would like to know and understand this better myself - if i understand you correctly,  you want to be able to crank the input to get lots of compression WITHOUT clipping or distorting downstream, but you can't do this with a 0VU input into the 1176 - doing so causes you to have either the INPUT or OUTPUT on the 1176 almost OFF in order not to over saturate the next stage in the signal path?

Just for grins, when you measure the input signal you are using going into the 1176 coming from your console, what do you measure on your DMM for AC volts? 

What is the ideal do you think?    So if i feed my units .775 volts (0 dbu) signal, and i set my input/output to 12/12 on the dials (or somewhere near that) I'm looking for something near  .775 volts on the output?  In other words, we're looking for where unity gain occurs, in relation to the position of the I/O knobs?

I'm still unsure about this. I checked through my build again. Voltages ok. Calibration okay. Wiring ok.

In the 1176 manual it states unity is with both input and output pots at 12 o'clock but I can only get unity at 0VU on the meter when my signal generator on the input is at -10dBU. When racked up and in the patchbay, every input seems to be too loud for the unit - when in +4 mode I can only zero the meter when in/out pots are at 9am!

This renders the unit slightly unusable as I have to either pad the input 10dBs or have the output pot almost off. Most folks tend to agree on starting at midday on both pots and turning them against each other for more/less compression.

I found another post describing a similar problem where David Kulka was suggesting a 1.8k at R12 and I thought I'd finally solved the issue as this would lower headroom and mean at were kept at 9am so I quickly checked my build but I already have the 1.8k pots installed so I'm back to square one.

Is no-one else experiencing what I'm talking about or am I going nuts? I have the same issue with both Rev D's and a Rev A and don't have these issues with any other comps in the studio.......

Anyone??

 

[dmnieto]

12' o'clock both input/output is around +12dB for me too...

 

[Echo North]

Thanks for the link - interesting point but my problem is that my units seem to be compressing more than they should - almost like there isn't as much input attenuation happening.

Most folks tend to agree on a starting point of 12/12 and driving more for more compression, leaving quite a lot of wiggle room for high levels of compression (dropping the output pot).

I can't get to that level with a 0VU average input level on the console without having the in and out pots at 9am - meaning that if I push the levels they get FAR too loud and useless- raising the noise floor etc - the only option is dropping the input level on the console - not something I should have to do.

It feels like the input needs to attenuate more so that I need to boost the input pot so compensate if that figures? Or am I going crazy??

Thanks in advance....

I think this is a really great thing to understand and now that you pose the question I would like to know and understand this better myself - if i understand you correctly,  you want to be able to crank the input to get lots of compression WITHOUT clipping or distorting downstream, but you can't do this with a 0VU input into the 1176 - doing so causes you to have either the INPUT or OUTPUT on the 1176 almost OFF in order not to over saturate the next stage in the signal path?

Just for grins, when you measure the input signal you are using going into the 1176 coming from your console, what do you measure on your DMM for AC volts? 

What is the ideal do you think?    So if i feed my units .775 volts (0 dbu) signal, and i set my input/output to 12/12 on the dials (or somewhere near that) I'm looking for something near  .775 volts on the output?  In other words, we're looking for where unity gain occurs, in relation to the position of the I/O knobs?

I'm still unsure about this. I checked through my build again. Voltages ok. Calibration okay. Wiring ok.

In the 1176 manual it states unity is with both input and output pots at 12 o'clock but I can only get unity at 0VU on the meter when my signal generator on the input is at -10dBU. When racked up and in the patchbay, every input seems to be too loud for the unit - when in +4 mode I can only zero the meter when in/out pots are at 9am!

This renders the unit slightly unusable as I have to either pad the input 10dBs or have the output pot almost off. Most folks tend to agree on starting at midday on both pots and turning them against each other for more/less compression.

I found another post describing a similar problem where David Kulka was suggesting a 1.8k at R12 and I thought I'd finally solved the issue as this would lower headroom and mean at were kept at 9am so I quickly checked my build but I already have the 1.8k pots installed so I'm back to square one.

Is no-one else experiencing what I'm talking about or am I going nuts? I have the same issue with both Rev D's and a Rev A and don't have these issues with any other comps in the studio.......

Anyone??

I assume you mean in bypass mode (GR off) 12 an 12 should equal unity?

 

[Spadehead]

Yeah, not even compressing the unit seems to be too loud! I've seen a similar post on the recent pages of the Rev A build saying the same thing and someone suggests putting a resister is series over Pad 22 but is this necessary - I've never compared to a classic unit as I don't have any but it seems the input is too loud so I constantly have the pots at 9am......

 

[dmnieto]

Yeah, not even compressing the unit seems to be too loud! I've seen a similar post on the recent pages of the Rev A build saying the same thing and someone suggests putting a resister is series over Pad 22 but is this necessary - I've never compared to a classic unit as I don't have any but it seems the input is too loud so I constantly have the pots at 9am......

Spade, do you know what is the output level in dBu for -20dbFS  in your interface? Maybe you are running it too hot. If you still need to drop the threshold of your setup you need to change the voltage divider in the board... changing R22 for a higher value..

 

[Spadehead]

Yeah, not even compressing the unit seems to be too loud! I've seen a similar post on the recent pages of the Rev A build saying the same thing and someone suggests putting a resister is series over Pad 22 but is this necessary - I've never compared to a classic unit as I don't have any but it seems the input is too loud so I constantly have the pots at 9am......

Spade, do you know what is the output level in dBu for -20dbFS  in your interface? Maybe you are running it too hot. If you still need to drop the threshold of your setup you need to change the voltage divider in the board... changing R22 for a higher value..

I use rosettas whic are calibrated to 0VU = +4dBU = -20dBFS

I have problems just running through inserts on the way in though as well as when mixing. I dont use hot levels. Sometimes the mic pre needs trimming down a ridiculous amount just to not squash the life out of it when using the 1176 - not a problem on other units....

 

[dbonin]

Hey Spadehead,

can you send us a pic of your input transformer as you have it mounted/wired on the PCB?

 

[electron monkey]

Hello, I looked on both hairball and mnats pages

There is no sign of any wiring guide for the output transformers!

Where could I get one?

 

[electron monkey]

Hello, I looked on both hairball and mnats pages

There is no sign of any wiring guide for the output transformers!

Where could I get one?

im following the colour scheme in fact on the board, problem is, which white  and black does it mean, it doesn't say which primary or secondary windings to use.  the hairball page speaks of a guide, but I can't see one anywhere

 

[dbonin]

Hello, I looked on both hairball and mnats pages

There is no sign of any wiring guide for the output transformers!

Where could I get one?

There really isn't one - for most revs the output transformer in the hairball kits has color coded wires that match the PCB silkscreen - there is no question where each wire should go.

 

[electron monkey]

just realised one of the wires is black AND white


Time to put the glasses on I guess.

 

[therichieray]

I recently made an effort to build a Rev D, but cannot get the power supply to work.  I've done a ton of trouble shooting, but can't figure it out.  I'd gotten slammed at my studio and have no free time to continue.  Is there any one reputable on here that may be able to fix/complete the build for me?

 

[sr1200]

Where are you located?

 

[jeff s.]

Hello all,

I built two 1176 rev d's and having a couple of issues with both.

At first I could not calibrate either unit even though they both powered on and clean tone went through. I found that I had C19 switched the wrong way on both so I switched them around. Now one does calibrate with one issue I will get to in a moment. The other powered on for about 5 minutes but while trying to calibrate it switched off and isn't coming on any more. I checked the fuse and it is not blown. Any suggestions of where to start looking for the problem? C19 isn't in the power supply so wouldn't it be strange that me switching the capacitor around did something?

On the unit that is still functioning I am having a issue with the second step of calibration. I am able to get both the VU and the multimeter to be at zero but once I put R44 back into the circuit I can't get R71("0" set) to move the Vu all the way back to zero. Seems like I need a few more turns but the pot stops completely before reaching zero.

Thanks in advance for any suggestions or help anyone can give me.
Jeff

 

[joe-electro]

Check to make sure all transistors are inserted properly. That is, the emitter is in the proper hole, etc. Check the data sheets for the actual brand of transistor you're using for the correct pinouts. They may vary from brand to brand.

--Joe

Hello all,

I built two 1176 rev d's and having a couple of issues with both.

At first I could not calibrate either unit even though they both powered on and clean tone went through. I found that I had C19 switched the wrong way on both so I switched them around. Now one does calibrate with one issue I will get to in a moment. The other powered on for about 5 minutes but while trying to calibrate it switched off and isn't coming on any more. I checked the fuse and it is not blown. Any suggestions of where to start looking for the problem? C19 isn't in the power supply so wouldn't it be strange that me switching the capacitor around did something?

On the unit that is still functioning I am having a issue with the second step of calibration. I am able to get both the VU and the multimeter to be at zero but once I put R44 back into the circuit I can't get R71("0" set) to move the Vu all the way back to zero. Seems like I need a few more turns but the pot stops completely before reaching zero.

Thanks in advance for any suggestions or help anyone can give me.
Jeff