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Project Specific Discussions => Dynamic Processors => Topic started by: Hairball Audio on October 04, 2009, 01:33:24 PM

Title: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 04, 2009, 01:33:24 PM
(http://hairballaudio.com/diy_images/PCB_White.jpg)
A few months ago I started thinking about offering a stereo link option for the 1176.  My initial thought was that the “Pad 7” (direct connect) method was not a great solution so I started down the path of offering a version of the 1176SA circuit.

I asked Ed Andreson if he had any advice on the topic and he shared an insightful analysis of the linking options.

----------
To get two 1176s tracking in stereo, you'd want the GR FETs on both to get the same DC signal.  So lets say we tie the point at the output of both sidechains together (Pad 7 meathod).  Now the outputs of the sidechains are in parallel.  A side effect is that now both the attack/release networks are also in parallel, which means the minimum attack time is doubled.  Another side effect is that the controls interact.  You can read about it in the manual, but it does make the settings a bit trickier.  If the FETs are perfectly matched, then the DC control voltage at zero compression should be the same on both units.  But what if they aren't the same?  Then there is a DC potential between the two FET control lines, and current will flow from one unit to the other, which is a problem.

If you look at the 1176SA adapter as shown in the urei 1176 manual, you can see that it is basically a battery and a pot.  This is the solution... the battery is a floating (not referenced to any power supply in either unit) voltage that you can stick in between the two FET control lines to bridge any difference in DC voltage, so that there is no current flow.  The pot allows you to adjust the voltage to exactly match the difference between the two units.  The problem with the "solution" (apart from the side effect of doubled min attack and control interactivity) is that while the FETs may be matched at no GR, it make take a different amount of DC to make each FET do, say 10db of gain reduction as an example.  You can trim those differences out in the meter circuit to make the meter FET track the GR FET, but you'd have to introduce a more complex adjustment to get the two GR FETs to track each other reliably over a wide range.  In the 1178 urei went with a matched FET pair chip, which is basically unavailable today.

The purple solution, which you can see on the MC77 schem, is to take the audio from the output of the first stage on each unit, buffer and sum it together, and then feed the summed audio to both sidechains. so the sidechains in both units hear the summed program material, and they don't have to really be paralleled, so there are no side-effects

----------

After considering Ed’s thoughts, I decided the best option would be to offer a project that utilized the Purple Audio summing option.  Purple Audio graciously gave me permission to offer the circuit and mnats kindly offered his PCB layout skills.

The 1176 stereo linking boards are offered as a kit or PCB’s only here:
http://hairballaudio.com/shop/product_info.php?cPath=22&products_id=50 (http://hairballaudio.com/shop/product_info.php?cPath=22&products_id=50)

Two boards are required to link to units.  Wiring instructions can be found here:
http://library.hairballaudio.com/datasheets/Stereo_Link_Wiring_Guide.pdf (http://library.hairballaudio.com/datasheets/Stereo_Link_Wiring_Guide.pdf)

For proper stereo operation the units should use the came control settings and have reasonably matched GR FETs.  Hairball Audio only accepts FETs with curves within a specific range.  Any two pairs of matched FETs purchased through Hairball Audio should provide stereo linking within 1db up to 10db of gain reduction.

Support questions can be posted in this thread.
Ordering questions should be posted in the Hairball Audio White Market thread located here:
http://www.groupdiy.com/index.php?topic=28923.0 (http://www.groupdiy.com/index.php?topic=28923.0)

Thank you to mnats, Purple Audio and Ed Anderson.

Mike
Hairball Audio
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: regularjohn on October 04, 2009, 08:26:47 PM
Very cool mod board!

So for stereo 1176's built with stereo matched FET's from Hairball, do still recommend using this board?

Also, since you're summing the L/R image and sending that to both sidechains, are there any compression artifact issues caused by this?  Particularly with bass-heavy center panned tracks like kick and/or bass gtr?  I'm asking because the GSSL sums the L/R which can cause compression artifacts, and that was the reason the turbo board came about for that comp.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 05, 2009, 03:06:11 AM
I must admit I'm not too familiar with the compression artifact issues in the GSSL.

Most of my testing involved the function of the PCB layout as the design itself has existed in a commercial product (MC77) for a while.  I have not personally heard of any issues with artifacts in the MC77.

My guess would be that if there were any issues it would be at high ratios with high amounts compression, but I'd have to research it more.  I may get a chance to ask the guys from Purple next weekend at AES. 

I think it's a great mod and it's really not that much more work then wiring the "pin 7" method.  I'm not offering stereo matched FETs anymore because they simple required way too much time.  This kit with an 2 sets of FETs I sell (or anything you reasonably match) will work a lot better and will cost less money.

If you do a lot of stereo compressing I would suggest this project.

Thanks!

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on January 11, 2010, 01:51:51 PM
What revs of the 1176 does this stereo link theory/kit apply to? I'm building the rev D.
Thanks
Dan
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: emrr on January 11, 2010, 01:53:18 PM
all
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on January 11, 2010, 06:40:26 PM
Cool thanks. What a great deal for $9
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on January 11, 2010, 06:48:12 PM
Screaming good deal  ;D

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: kilmister on January 18, 2010, 06:41:48 PM
Hi all!

I suppose I can use this thread for next one.

I didn't notice in time of my order for trafos and etc. from Hairball there is stero link boards so I found self etch files from lovely Mr. Nats site.
I stuffed couple of boards today I noticed there is no holes and soldering taps for C301. In check plot they are so they are missing only in etch picture.
Not really a problem there's space enoght to drill couple of holes and bend cap legs over the track.

Obviosly refering to the picture in first message of thread there is these holes and taps in Hairball's boards.

All best,
Paavo
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on January 19, 2010, 03:34:55 AM
I've been holding off mentioning the page as it is still in draft form (though linked from my index page). I've fixed the files - thanks for pointing out the error.

Can't imagine that many people would choose to self-etch when the Hairball kit is so cheap but I think it is good DIY etiquette to allow those who prefer to etch at home to do so or who don't have the wherewithal to purchase from Hairball. Later I'll do some test results and some hook up explanations and/or photos as time allows...

Oh - here's the link to the new document: http://mnats.net/files/STLNK1.1DOC.pdf
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on February 20, 2010, 07:44:05 PM
I may have gone off the deep end trying to understand this 1176 circuit to make a well matched pair of 1176 revD compressors. I would say getting two units to work well with the stereo link is very difficult. Even building a matched mono set is difficult. I bought 10 FETs and matched the best 4 into pairs. Built the two units. Both work well, and calibrate correctly. First test is swap the two FETs in the individual 1176s to see how closely the GR meter matches the actual circuit GR. One 1176 is nearly perfect, one it about 2-3 dB off. Next test, hook up the stereo link. Two units, when fed the same signal, are not even close. about 4-5 dB off. The GR curves match very closely however (I posted the graphs in the rev D thread). The response of the FET to changes in voltage, however are significant. I think the FETs need to be matched VERY closely. Maybe I'll save up and order 100 from mouser. 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on February 20, 2010, 08:01:16 PM
The FETs vary WIDELY.  It's actual very shocking.

I buy FETs 2000 at a time.  probably 60% end up in the rejected bin because they are way off the ideal curve. If you want 4 FETs matched within 5 or 10% and also have them close to an ideal curve you will need a lot more than 10 FETs.

I've started to get very tight with my matching tolerances.  The stereo link kit and 2 pairs of matched FETs from my store should get you within a dB.

If you're using the pin 7 method for linking, that is a whole different story.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on February 20, 2010, 09:11:08 PM
Well, 2000 FETs would cost $260 at $0.13 a piece... but the loss of my sanity checking them would be even steeper ;)
I used the awesome Hairball stereo link kit, of course.
I actually thought the FETs matched very closely. I built the test jig described on this forum, and had  voltages 1.79/1.50, 1.81/1.54, 1.73/1.47, 1.78/1.51. The later two were the pair that showed the difference in one of the units.
Mine were probably way off the ideal curve because I needed a 5k trimmer to get the GR calibration to work.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on April 16, 2010, 07:25:23 PM
Hi,

I am actually finishing the wiring of my dual 1176 rev J.
I would like to add the two Stereo link boards but, I do not know how  ???
I read the instructions, but I am not really sure...

I made a quick schematic
Is it the right wiring? :


(http://sounddiy.free.fr/images/1176/stereo%20linking.jpg)


thanks a lot
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: canidoit on April 16, 2010, 07:51:18 PM
Hi,

I am actually finishing the wiring of my dual 1176 rev J.
I would like to add the two Stereo link boards but, I do not know how  ???
I read the instructions, but I am not really sure...

I made a quick schematic
Is it the right wiring? :


(http://sounddiy.free.fr/images/1176/stereo%20linking.jpg)
Great diagram mate, would be helpful to newbies. It be good if you shows which pins on the in and outs the wiring goes to? Is that the XLR ins and outs for unit A and B?


thanks a lot

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on April 16, 2010, 08:06:02 PM
Looks good to me.  Give it a try!

canidoit "in" and "out" are not connected to the board they are connected to interconnects (rca...1/4 inch...).

Read here:
http://hairballaudio.com/guides/Stereo_Link_Wiring_Guide.pdf

mathflan if you have a dual unit you can just hard wire in to out and out to in.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: canidoit on April 16, 2010, 08:23:44 PM
Well done on the documentation Mike. It really helps people out and makes it easier for the build process!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on April 17, 2010, 03:57:20 AM
Mike

You wrote :
Quote
mathflan if you have a dual unit you can just hard wire in to out and out to in.

So,  not need a TRS connector?

IS it Right?
(http://sounddiy.free.fr/images/1176/stereo%20linking2.jpg)


thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on April 17, 2010, 06:31:01 PM

A better picture  :


(http://sounddiy.free.fr/images/1176/stereo%20linking3.jpg)

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on April 17, 2010, 08:59:39 PM

IS it Right?


Wire it up and you will have your answer.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: canarion on April 24, 2010, 08:16:39 AM
Hello. Someone could help me with the wiring to a D version with rotary switches, I've tried several ways and it doesn't work.
Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on May 02, 2010, 05:35:25 AM
I finished to wire the stereo link but It doesn't work  :(
I check all voltages and wiring, All seems OK.

Do I miss something?


 thanks

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on May 03, 2010, 03:32:22 PM
Did you add it to a previously working build or is it a new build?

What is the issue?

Also make sure you are familiar with how the circuit works.  It's different then the UA 1176 link box.


Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ethervalve on May 04, 2010, 11:13:48 AM
Hi Mike,
Do you have a finished unit with the Stereo Linking board installed?
If so, and if it's not too much trouble, would you mind uploading a photo of the innards at some point?
I'm a bit stuck troubleshooting an oscillation issue with a rev D with the stereo board (I think it's a somewhat common issue: the oscillation occurs when the output pot is near maximum).
I'd just like to see a photo of a successful build to get a better idea of where i should run the wires.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on May 04, 2010, 11:40:43 AM
I built two revD units with the stereo link boards. I ran into the same problem with oscillations as the output pot was turned up (actually before I even added the link boards) and it was a shielding / grounding issue. Run shielded wire to the link board and the output pot and connect the shield at one end to the chassis ground, not the audio ground. At first I soldered the shield to the pcb ground, which is audio ground, and got oscillation like you are describing.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ethervalve on May 04, 2010, 12:19:28 PM
Thanks for sharing that dmp.
I'm at work so I'm just going by memory, but I believe I also connected the shields to the pcb ground. I'll try switching up the shield connections ASAP.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ethervalve on June 01, 2010, 04:25:08 PM
Hi all,
I think you were right dmp. Re-wired it and the oscillation went away. Thanks!

Now, I'm still unable to get the stereo matching to work perfectly though. At slowest attack/fastest release i'm getting about a 3 dB discrepancy in gain reduction between units whenever I got beyond about 5dB or 6dB in GR.
A couple things I'm wondering about:
1) there seems to be a great deal of Gain reduction interaction when I adjust the release pot on either unit--would switching to tighter tolerance release pots be worth attempting? I'm currently using 20% alphas. (I noticed this older post from Gswan that suggested checking the 5meg pot when attempting the "connect pad 7" style stereo match: http://www.groupdiy.com/index.php?topic=646.msg439565#msg439565 )
2) I had to drop in a 4.7k trimmer to complete the tracking adjust calibration for one of the units (the other had enough range with the standard 2k trimmer). Does this suggest anything fishy? Both units seem to behave identically outside of the stereo link mode when fed the same programme.

 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: TheJames on June 02, 2010, 09:26:29 AM
I've been pondering stereo-linking FET compressors lately.  This circuit makes alot of sense, tap off both inputs, sum them together, then feed the output to both side-chains.  However, as mentioned, you've got to get both side-chains' controls matched for it to behave the same.

I'm not too familiar with the intricacies of the 1176, however strictly audio speaking....Assuming you have matched GR FETs, summing the inputs, feeding one side-chain, and then buffering that output and feeding both GR FET gates should provide the best stereo tracking and only one set of attack/release controls to deal with.  I'm probably missing something, but that seems more elegant to me.  There might be some issue with GR meter tracking on the "slave" unit...But it would seem this would at least get the audio signals tracking right.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Soeren_DK on July 01, 2010, 03:41:04 AM
Is this correct? ;) ;) ???

Cheers
Søren

EDIT: Picture not correct
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 01, 2010, 09:51:33 AM
Is this correct? ;) ;) ???

Cheers
Søren

Yes.

Edit: No.

See posts below.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on July 01, 2010, 01:24:31 PM
Ethervalve,
I haven't gotten my units to match very well either, so I can't be too much help... IF your units are matched well at fast  attack / slow release, you are doing better than I am.
But, at slow attack / fast release, your 5Meg pot is not dominating the circuit because the wiper is turned such that R57 is in parallel with the pot resistance. If R57 is matched very well, it is in parallel with 5meg+/-20%, which reduces to 256k +/- ~1% (if my math is right). So I would not think the 5meg pot is the likeliest suspect. Similarly for the attack pot, be sure that R54/C27 are matched very well.  Is discrepancy in GR measured at the input/output signal, or is it a apparent difference from the meters?
About the tracking adj trimmer - I *think* that a large resistance indicates Q12/Q13 are not matched very well for hfe and the larger trimmer is necessary to compensate for this. I don't think it would affect operation if you are able to get the GR meter calibrated correctly. 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ricothetroll on July 08, 2010, 03:03:32 PM
Hi !

I tried to make my Stereo Link work, but for the moment it doesn't... I wired it the way shown on the picture posted by Soeren_DK on the current thread.

I drew a principle schematic in order to have a better understanding of how the circuit works. You'll find it here :

http://www.wuala.com/ricothetroll/public/Stereo-Link.gif (sorry for the ugly hand-drawing)

My interpretation was based on the schematic on page 4 of that pdf :

http://mnats.net/files/STLNK1.1DOC.pdf

I might be wrong but it appears to me that Soeren_DK's wiring doesn't make sense : pad 15 of the main board mustn't be connected directly to pad 15 of the ratio board as it used to without the stereo link. Pad 15 of the ratio board is where the signal enters the sidechain, connecting it to pad 15 of the main board means that when the link is activated, both the output of the preamp AND the sum (L+R) goes to the sidechain.

I suggest this wiring :
http://www.wuala.com/ricothetroll/public/Stereo-Link_wiring.gif

Is it right ?

Best regards.

Eric
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: craigg on July 11, 2010, 04:05:56 PM
HI there.  I have two mnats 1176s.  One is a Rev A, and one Rev D (with hairball kits).  work great.  Sound great.  Got the stereo linking kit and put it together.  Not sure if the stereo linking works yet because I'm having a problem powering the stereo link pcb in the Rev A.  The Rev D seems fine.  When I try to power the SL pcb on the 30v test point in the Rev A, my audio level drops, the compression goes away (turning the compression on or off makes no difference, and my 30v test point reads about 26v and my -10v test point (which read about -8.5v) goes to -12v.  Unhook the 30v power from the SL pcb and the unit works fine - compression, all switches, etc.  Anybody have any idea?  I hooked up this pcb to the rev d that I have and it worked fine (didn't have this problem), so I feel confident that the SL pcb isn't the culprit.  Thanks everyone.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 12, 2010, 07:17:53 PM
HI there.  I have two mnats 1176s.  One is a Rev A, and one Rev D (with hairball kits).  work great.  Sound great.  Got the stereo linking kit and put it together.  Not sure if the stereo linking works yet because I'm having a problem powering the stereo link pcb in the Rev A.  The Rev D seems fine.  When I try to power the SL pcb on the 30v test point in the Rev A, my audio level drops, the compression goes away (turning the compression on or off makes no difference, and my 30v test point reads about 26v and my -10v test point (which read about -8.5v) goes to -12v.  Unhook the 30v power from the SL pcb and the unit works fine - compression, all switches, etc.  Anybody have any idea?  I hooked up this pcb to the rev d that I have and it worked fine (didn't have this problem), so I feel confident that the SL pcb isn't the culprit.  Thanks everyone.

Did you triple check all the components on the PCB (resistor values specifically)?

Seems odd.  I would start there.  Also check the TL071 to see if you are getting +15V at the output.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 12, 2010, 07:52:29 PM
I might be wrong but it appears to me that Soeren_DK's wiring doesn't make sense : pad 15 of the main board mustn't be connected directly to pad 15 of the ratio board as it used to without the stereo link. Pad 15 of the ratio board is where the signal enters the sidechain, connecting it to pad 15 of the main board means that when the link is activated, both the output of the preamp AND the sum (L+R) goes to the sidechain.

I must admit I know little about the ROTARY ratio board wiring. 

If you look at the PCB traces on the ROTARY ratio board Pad 15 is directly connected to the CW lug (left lug from the back) of the output pot.  So if you follow the Purple schematic, pad 15 of the main board (Pre Amp Output) connects to the output pot lug and is then wired to the "loop" terminal.

I guess what I'm trying to say is even though the ROTARY ratio board shows pad 15 connected to the main board pad 15, it's only traced to the output pot and not the actual ratio circuitry (by looking at).

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 12, 2010, 07:58:03 PM
Hi all,
I think you were right dmp. Re-wired it and the oscillation went away. Thanks!

Now, I'm still unable to get the stereo matching to work perfectly though. At slowest attack/fastest release i'm getting about a 3 dB discrepancy in gain reduction between units whenever I got beyond about 5dB or 6dB in GR.
A couple things I'm wondering about:
1) there seems to be a great deal of Gain reduction interaction when I adjust the release pot on either unit--would switching to tighter tolerance release pots be worth attempting? I'm currently using 20% alphas. (I noticed this older post from Gswan that suggested checking the 5meg pot when attempting the "connect pad 7" style stereo match: http://www.groupdiy.com/index.php?topic=646.msg439565#msg439565 )
2) I had to drop in a 4.7k trimmer to complete the tracking adjust calibration for one of the units (the other had enough range with the standard 2k trimmer). Does this suggest anything fishy? Both units seem to behave identically outside of the stereo link mode when fed the same programme.

 

Definitely what DMP said.  The parallel resistor on each pot is dominating the over all resistance.

Maybe your fets are out?  Did you get them from me? In the past you could order 2 sets of FETs from me and they would give you stereo linking withing 1db up to about 10db GR.  UNLESS you were unlucky enough to get the two that were at either extreme of my matching window.  I've since addressed and fixed this issue.  If you got FETs from me and think they may be the issue let me know and I'll send you new sets.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ricothetroll on July 13, 2010, 03:34:19 AM
Hi Mike,

Thanx for your answer !

I'm using the Gyraf Audio version, maybe that's the reason why we have those differences.
http://gyraf.dk/gy_pd/1176/1176.pdf
If you take a look at the ratio board on the first page (superimposed view), you see that pin 15 feeds on the one side the pot, and on the other side the sidechain (rotary switch) through the top left 56k resistor.
I'll try my wiring and let you know the result !
Best regards.
Eric
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 13, 2010, 10:36:15 AM
Hi Mike,

Thanx for your answer !

I'm using the Gyraf Audio version, maybe that's the reason why we have those differences.
http://gyraf.dk/gy_pd/1176/1176.pdf
If you take a look at the ratio board on the first page (superimposed view), you see that pin 15 feeds on the one side the pot, and on the other side the sidechain (rotary switch) through the top left 56k resistor.
I'll try my wiring and let you know the result !
Best regards.
Eric

I see what you are saying and see the issue.

Yes you want wire the switch between the pot and the sidechain, so some creative wiring needs to happen on the rotary boards.  As you stated earlier you'll probably just want to wire pad 15 from the main board directly to the pot and keep it away from the ratio board.

You have it figured out, I'll stop confusing things ;)

Mike

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on July 13, 2010, 04:44:01 PM
Hi,


thank ricothetroll,

your wiring works greats. :)
I know now why it did not work before.


Thanks echo north for the PCBs


MAth
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 13, 2010, 05:13:21 PM
Thanks echo north for the PCBs

Don't forget confusion.  I provided this thread with a lot of confusion.   ;) ;D

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ethervalve on July 14, 2010, 12:02:50 PM


Definitely what DMP said.  The parallel resistor on each pot is dominating the over all resistance.

Maybe your fets are out?  Did you get them from me? In the past you could order 2 sets of FETs from me and they would give you stereo linking withing 1db up to about 10db GR.  UNLESS you were unlucky enough to get the two that were at either extreme of my matching window.  I've since addressed and fixed this issue.  If you got FETs from me and think they may be the issue let me know and I'll send you new sets.

Mike

Yes I did use a couple sets of fets i bought from you.
I was actually planning on ordering another two sets of fets plus another stereo matching board set to add stereo capabilities to the pair of rev As I built last year.
If it's not too much trouble, I would very much appreciate it if you could throw in another couple sets of fets when i place the order. Thanks so much for the offer!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 14, 2010, 02:07:00 PM
Yes I did use a couple sets of fets i bought from you.
I was actually planning on ordering another two sets of fets plus another stereo matching board set to add stereo capabilities to the pair of rev As I built last year.
If it's not too much trouble, I would very much appreciate it if you could throw in another couple sets of fets when i place the order. Thanks so much for the offer!

No problem.

Thanks,

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ricothetroll on July 19, 2010, 04:18:34 AM
Quote
thank ricothetroll,

your wiring works greats. Smiley
I know now why it did not work before.

Thanx for testing it !  ;D As I wasn't too sure of my modification and - as I had a lot of weird issues with one of the units - quite fed up with "debugging 1176", I just let the project in stand-by, waiting to have more opinions about it.

Quote
I see what you are saying and see the issue.

Yes you want wire the switch between the pot and the sidechain, so some creative wiring needs to happen on the rotary boards.  As you stated earlier you'll probably just want to wire pad 15 from the main board directly to the pot and keep it away from the ratio board.

You have it figured out, I'll stop confusing things Wink

Mike

Right !

Best regards.

Eric
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Josiah on August 08, 2010, 01:32:25 PM
Hello everyone,

I have 2 working 1176 Rev D units and I am trying to connect them with the stereo link option. I have the stereo link boards in and I am wondering what I should be expecting from the "front panel" operation. Does one input/output control both units? and do the attack release pots remain separate?

I'm trying to figure out what is normal so I can be certain this is done right...

Here is where I am at:
My voltage is right at +30VDC
Resistors have all been verified a few times
IC's are in the right position with the circle on the chip matching the board dot position
Caps are in the correct direction
Wired according to the Hairball schematic

Any help here would be greatly appreciated...

Josiah
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: regularjohn on August 08, 2010, 01:43:22 PM
you'll still need to control input, output, ratio, etc seperately on both units, however you may notice some interaction of the controls.

The stereo link connects the sidechain signal of both comps, but does not affect front panel operation.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Josiah on August 08, 2010, 02:07:43 PM
Thank you John your reply is greatly appreciated...I got them working in proper order then.

Josiah Zamora


P.S. Studio owner Rich Ayres says thank you as well!

www.rivercityrecording.com
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: evilcat on September 06, 2010, 04:19:04 AM
Hi guys !

I'm wondering where I will take the +30V...
Mike suggestes to take it near R87, a "+30V test point". But if you look at the schem, it make me think that you can take it near the output transformer's black wire. It would be much more simple : a molex to molex connection !
My question is : will I mess with the audio signal if I take some power supply here ?

Thanks for your inputs.

Ben.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on September 06, 2010, 02:22:52 PM
Hi Ben,

The +30VDC test point is directly connected to the BLK output wire so it SHOULD work fine.

I'd give it a try and let me know.  I'll update the documentation.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: evilcat on September 07, 2010, 03:19:56 AM
Thanks Mike, I'll try.

Best,

Ben.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on October 03, 2010, 10:24:34 AM
Hi,

Although my dual 1176 working with stereo linking, I noticed a huge Voltage problem.
I have 28 Volt DC between Ground and earth!
I noticed that It because I wired the ground of the stereo link board to Earth.
I measured 4.6 K ohm between GND( Stereo link board) and +30 V ( stereo link board)
SO I think there is a problem somewhere...  ???

Is it normal?

Thanks a lot

Math
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: evilcat on October 03, 2010, 01:41:09 PM
I think I've the same problem. I don't have time to look further yet, I wait to have my case finished... Maybe you'll find the solution before me ;D !
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on October 03, 2010, 05:33:25 PM
It is really strange because, although I noticed that the Ground of the linking board were not connected to Main ground  I have 28 volt between Ground (Stereo link board) and +30 (Stereo link board).

Mike any ideas  ???

thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 03, 2010, 08:39:19 PM
I'm not sure what you are saying?

You have +28V between ground and the +30V on the stereo link board?  That should be normal.

Audio ground and chassis ground should be connected via the chassis.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on October 04, 2010, 02:35:03 AM
Sorry, I Made a mistake. :-[

I have 28 volt DC between GRound of the stereo link board and main ground of 1176 boards.


Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 04, 2010, 09:57:47 AM
Ground on the stereo link PCB should be wired to the main PCB ground, which would make a voltage differential impossible.

Unless I'm missing something?

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mathflan on October 04, 2010, 03:20:11 PM
I am so ashamed  ! :-[

Yes, the Ground of the stereo link board was not connected to main ground... so that like you said would make a voltage differential impossible.

Sorry for that, Sometimes I am little stupid.... sometimes  ;)

thanks mike.

Works perfectly!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 04, 2010, 03:27:54 PM
No need to feel shame!

We've all had our "moments".  ;D
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: abechap024 on October 18, 2010, 07:03:28 PM
I've been looking this over...and at the expense of being called daft...does the audio actually get run through the board??  I know the sidechain audio must be put through the board but not the actual audio?
Am I even making sense!
Thanks

AC
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on November 16, 2010, 12:59:44 PM
I've been looking this over...and at the expense of being called daft...does the audio actually get run through the board??  I know the sidechain audio must be put through the board but not the actual audio?
Am I even making sense!
Thanks

AC

You are correct, it's "sidechain audio" not the actual audio at the output.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: [email protected] on January 15, 2011, 10:59:50 PM
I would like to get a recommendation on the optimal placement of the Hairball Stereo Link PCB in the Hairball Blue Stripe enclosure. Also, if you are setting up a TRS link between 2 units, does anyone of have images of their set up and wiring?

Thanks 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Randyman... on January 16, 2011, 01:53:13 AM
If the blue-stripe chassis is the same as the black chassis, here is a pic of mine:

(http://img840.imageshack.us/img840/4384/10008190.jpg)

I used two standoffs and mounted it from one side.  I only had to drill one small hole for each enclosure (use the last pre-existing hole and drilled the other).

On the TRS - simply swap the T and R connections on ONE of the unit's TRS jacks and use a straight-thru TRS cable to patch them together.

I put the link switch on the front panel.  That kept the additional wiring to a minimal length - not that this has primary audio on it - but you still want to keep the sidechain audio clean...


8)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: KasperNyhus on January 16, 2011, 11:28:34 AM
Hi guys

I've build myself a stereo 1176 with mnats rev.J pcb and hairball stereo link.
I just can't figure out how to wire them properly?
The way I've done it now, the "dual mono" mode works fine but when I switch on the "stereo" mode one channel sort of sucks the audio and it takes a while before it stops fully attenuating the signal.

Has anybody experienced this behavior?

Also I would really like if one of you guys could point out the right wiring for me.

Thanks,
Kasper
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: [email protected] on January 17, 2011, 10:31:35 AM
Thanks Randyman,
That pic cleared the fog in my brain. A few more questions:
-Anyone see a problem with having the link toggle switch on the back panel(wire length)?
-Since the original wire between ratio pad 15 and the pot are shielded, should I be shielding the entire set up?

Cheers
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: NorthernLight on March 11, 2011, 04:54:41 PM
Hi,

I'm building a Dual 1176 Gyraf style with a Purusha case (the one with the rotaries). I'm still in the planning fase (waiting for some parts to arrive to finish populating the PCBs) and want to stereo link the two PCBs in a decent fashion. I also want to power the boards with a decent PSU - not using the on board PSU section. All that is easy enough with ready made PCBs available and all but it's no fun to run wires to and from two small PCBs - so I took it a step further; I threw together the schematics of mnats PSU and 2 of your Stereo Link modules, and replaced the big electrolytics of the PSU with the CRC filter of the GSSL - don't know if that will do anything for the unit but it surely won't hurt. I even managed to lay everything out on a single sided board of decent dimensions.

Question is: are you ok with me throwing that out on the public domain? Of course I also wouldn't mind at all if the design would end up in your shop one way or another. I've made everything in Eagle Light, but I can export to pictures too of course.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on March 11, 2011, 04:59:35 PM
Well the link design belongs to purple audio.

Honestly, if you mean posting self etch files of your design I think that would cool and I don't think anyone would take issue with it.  It's DIY!  :D

Mike

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: NorthernLight on March 11, 2011, 06:54:01 PM
OK, here it comes:


(http://www.virtualogic.nl/diy/1176_crc_link_schematic.png)

(http://www.virtualogic.nl/diy/1176_crc_link_board.png)



Eagle files can be downloaded as well: http://www.virtualogic.nl/diy/1176_crc_link.sch (http://www.virtualogic.nl/diy/1176_crc_link.sch) and http://www.virtualogic.nl/diy/1176_crc_link.brd (http://www.virtualogic.nl/diy/1176_crc_link.brd)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ricothetroll on March 16, 2011, 12:09:31 PM
Hi,
I have two G1176 in an enclosure in order to have a dual/stereo compressor. Each compressor works well apart and are closely matched (I measured Vin/Vout on each unit in order to have both transfer curve and they are matched at about 0.2V). I have Hairball's stereo link PCBs and Hairball's HB8037 meters. I wired the stereo link PCBs as showed in my previous post and can be found page 2 of this thread (Mathflan said that he used my wiring successfully).

My problem is when I switch it to be stereo, I have a the 2nd unit that has a (measured) gain reduction of about 2dB more than the first unit. My test procedure is : in dual mode, both channels are fed with the same signal (ch1 from the L output of my soundcard and ch2 from the right one), I scoped both signals at test point 2 - right after the input gain pot - to make sure both compressors are fed with the same signal, I then set the out pot in bypass mode to have unity gain in both units. Then I switch both units to GR and measure both outputs, and see that both gain reduction is the same. When I switch the link switch to link mode, I measure a 2dB difference between ch1 and ch2, that is to say there is a 2dB difference in gain reduction. Meters also display a 2dB difference between the two channels.

I double checked every resistor on both stereo link PCBs, every voltages (on opamps), I only noticed a difference of about 1V between the two +30V rails (respectively measured 29V and 30V). That difference also appears on the main boards (each stereo link PCB is supplied by its corresponding main boards 30V test point). Stereo link PCB's grounds are taken from the star grounding connected to the enclosure, bear the power transformer.

When I scope the signal that comes from each stereo link PCB ("link" test point), they have the same amplitude.

Any help would be appreciated ! Thanx in advance.

Best regards.

Eric
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: benlindell on March 16, 2011, 01:29:28 PM
Hey guys, quick check to see if anyone else has gotten this. When I switch the stereo link on my units, the audio level gets really low and sounds high passes. I assume I messed up the wiring somewhere, anyone had this happen and know maybe what exactly I did? I gotta pull them out of the rack and tweak this.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: pacemaker on May 24, 2011, 06:10:52 PM
Hi !
i'm building a stereo 1176 with mants rev D PCB ,
and i was wondering if it's better to use the available PSU based on LM317 and 337,
or use the onboard PSU ?
i have the parts for 2 onboard PSU so cost is not a problem,
just looking for the best solution regarding noise etc...
regards,
Francois
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dashbad on July 12, 2011, 09:23:31 AM
I have an issue with one of my channels in a 2-1176.

For some reason when I activate stereo link the input buffer of the left stereo link pcb fails to buffer the signal.

Referencing the schematic the audio signal is present at the input of the first opamp - A201a pin 3 but I get 0V at pin 2 and pin 1. I've disconnected this PCB from the other link PCB and get the same results.

This led me to believe that there was something wrong with the link PCB components and wiring. I've checked all capacitors and swapped out the opamps but get the same behavior. Measuring DC voltages I get 15V (above signal/chassis ground) at the input (pin 3) but again, 0V at pin 1 and 2.

The other channel's link works fine.

Can anyone help?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on July 12, 2011, 10:19:25 AM
Maybe a dumb question, but you have the shorting wire installed on both board correct?  They go on the line by the PCB info.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dashbad on July 12, 2011, 10:25:28 AM
Yes, this is in place.

Edit: I took a closer look at the board and it appears that one of the legs of one of the Caps had detached from the bottom of the board taking the solder pad with it. i tried to patch this break to the nearest component with a small piece of wire but it hasn't changed anything. Perhaps it has created a short to the ground plane? I think I might need a new PCB so have ordered one to try
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dandeurloo on August 29, 2011, 01:42:55 AM
Dash did you figure it out?  I'm having a few issues as well.  I am trying to wire it this way but it doesn't seem to work.

http://www.wuala.com/ricothetroll/public/Stereo-Link_wiring.gif

Can you confirm this wiring to work?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 25, 2011, 11:24:57 PM
Hi All,

If you have any issues with wiring you can reference the Purple Audio MC77 schematic.  The stereo link circuit is from the MC77:

http://www.purpleaudio.com/product/mc77more.html
(bottom of page).

One other thing to clarify is that this circuit is not the same as the tradition link circuit sold as a separate box by UA.  That has a different functionality (this one is better IMO).  I believe with the UA one unit controls both sets of controls.

This circuit simply sums the audio from both side chains.  That way both compressors are seeing the same peak levels in the side chain.  All the controls should be set the same on both units.  Because the pots can have 10-20% tolerances and slight differences in FETs and biasing, you will need to trim the input and output on one unit to get them perfect.

Thanks!

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: abechap024 on October 26, 2011, 04:20:49 PM
Yes.

Got my first unit hooked up with this implementation. It seems to work fairly well, but it doesn't connect the DC control voltage at all, so getting the release and attack times exactly perfect on both units is....interesting! It does take a bit of fiddling to get them to dance together. But it works!

Thanks Mike!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 26, 2011, 04:29:07 PM
Yes.

Got my first unit hooked up with this implementation. It seems to work fairly well, but it doesn't connect the DC control voltage at all, so getting the release and attack times exactly perfect on both units is....interesting! It does take a bit of fiddling to get them to dance together. But it works!

Thanks Mike!

But remember when you connect the control voltages like UA link, you double the attack and release times.  So with that system it's impossible to get fast attack or release times in stereo mode.

Great work!

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ilfungo on December 13, 2011, 09:07:48 AM
Sorry for the stupid question
for 2 x 1176 in the same box, I have to use one or two stereo link PCBs?
Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Nele on December 13, 2011, 09:53:47 AM
two:  one for each 1176
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ilfungo on December 15, 2011, 11:13:51 AM
sorry
I am building 2 x 1176 rev D in the same box.
I would like to add 2 links PCBs, but just do not understand .....
Looking at this diagram:
To - In the second of the unit?
To - Out of the second unit?
Is there anyone who did it and can help
thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: abechap024 on December 15, 2011, 11:17:12 AM
sorry
I am building 2 x 1176 rev D in the same box.
I would like to add 2 links PCBs, but just do not understand .....
Looking at this diagram:
To - In the second of the unit?
To - Out of the second unit?
Is there anyone who did it and can help
thanks

At the risk of sounding not very empathetic: it seems confusing at first, but really its not. Just sit down with the picture and wire it up. Step by step. Once you do it its not that hard. Good Luck!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ilfungo on December 15, 2011, 11:21:31 AM
thanks abechap024
was just trying not to make mistakes....
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: abechap024 on December 15, 2011, 11:46:24 AM
I totally hear you...it IS confusing at first, but I don't think anyone could really make it easier than the pictures around here....just trust yourself, your not going to permanently destroy anything if you hook it up wrong. You may be surprised what you can do!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: atticmike on December 21, 2011, 10:13:36 AM
Can anybody please confirm whether the link boards truly work or not?

There is plenty of information on how possibly the best approach'd be but rarely anyone saying that they're totally satisfied with its function / purpose.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: buildafriend on December 21, 2011, 11:59:29 AM
Hm.. I think im finally going to get  around to trying to get this working this weekend. I have 2 working Rev F hairball 1176's and this kit. I just have not linked them yet. Has anyone every tried linked 1176's on their master buss?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: buildafriend on December 21, 2011, 12:02:19 PM
Can anybody please confirm whether the link boards truly work or not?

There is plenty of information on how possibly the best approach'd be but rarely anyone saying that they're totally satisfied with its function / purpose.

I don't think mike would put these out unless they worked.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: atticmike on December 21, 2011, 12:15:54 PM
Can anybody please confirm whether the link boards truly work or not?

There is plenty of information on how possibly the best approach'd be but rarely anyone saying that they're totally satisfied with its function / purpose.

I don't think mike would put these out unless they worked.

good because i don't see a problem in the provided pfd, wiring the boards up.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on December 21, 2011, 12:22:58 PM
Lots of people, including me, have them up and running.  It's the exact same circuit used in the MC77.  A lot of confusion comes from the fact that the stereo linking works in a very different way from the original 1176 linking "circuit".  It's also a bit of a tricky concept to understand.

I believe this way is better. Not perfect, but better.  They key is that you still have to play with your settings a bit on each channel to get them tracking in stereo.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmp on December 21, 2011, 04:58:38 PM
I used these in 2 revD builds. The wiring can be confusing but if done correctly these work as intended.

I found that I had to match the FETs in both units very closely to get a pair of mono units to track correctly (i.e. a matched QUAD of FETs)
I believe I bought 50 FETs and carefully traced there curves to get four that matched closely. Now my pair off 1176s respond correctly either dual mono or linked stereo.   
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ethervalve on December 21, 2011, 05:36:18 PM
As Mike (echo north) said, you sometimes need to play around with your settings a slight bit to everything tracking properly (in my case, the release pot especially). But after you take 15 seconds to get it up and running--it sounds great! I use my Rev Ds in stereo linked mode all the time.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: buildafriend on December 21, 2011, 06:04:32 PM
I have a lot of faith in mikes designs.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on December 21, 2011, 06:08:53 PM
I have a lot of faith in mikes designs.

It's a Purple Audio design/MNATs layout  ;)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: buildafriend on December 21, 2011, 07:53:37 PM
hahaha my bad. I will re phrase; "I trust what mike sells."
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: robertbonello on February 07, 2012, 01:50:50 PM
Hi guys,

I really tried hard to be a good noob and read and read and search but I can't quite get my head around using the meter +8 switch(pushbutton) to put the stereo link in on my two rev a builds. Could anyone point me at a definitive set of instructions?
A couple of photos of the wiring on the meter board would be really appreciated.

Thanks, Rob
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: atticmike on February 07, 2012, 02:09:34 PM
Hi guys,

I really tried hard to be a good noob and read and read and search but I can't quite get my head around using the meter +8 switch(pushbutton) to put the stereo link in on my two rev a builds. Could anyone point me at a definitive set of instructions?
A couple of photos of the wiring on the meter board would be really appreciated.

Thanks, Rob

I'd call myself quite the noob amongst those geniuses and had no trouble going by the official wiring document. All the wiring illustrations from board users were rather confusing than anything else.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on February 10, 2012, 06:37:59 AM
hi guys :)

I just finished a 1176LN mono with hairball kit. I'm so happy ! :) Thanks again EchoNorth and all the guys helping me ! I'd like to build a stereo 1176 (revD) right now with this frontpanel :
(http://www.diy-racked.com/DIY/DUAL1176UA-B.jpg)

1 - Do you have some Mouser reference for the Power LED and mono/link - ON/OFF - Bypass/Comp switches ?
2 - Do you know where I can find knobs looking as the originals UA knobs ?
3 - Someone can post some pictures of the inside finished unit please ?

Thanks :)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Autophase on February 21, 2012, 09:08:44 AM
Hi guys I have decided to build a stereo 1176, well 2 actually one for me and one for a friend.
I obviously intend to use the stereo link kit and I will get matched pairs from hairball, but I have 2 questions.
1: can I easily make the stereo compressor use a single set of controls as opposed to having 2 sets of mono controls, or.would you suggest it's better to have them both available to help with adjustments for tracking differences?
2: which revision is best if I intend to stereo link? I see a lot of you using revision D. Does it make a difference?
Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Brotastic on February 24, 2012, 12:18:43 AM
Hello everyone, this is my first post.  I have been on the site for awhile just reading and absorbing all the information on here.  I have been searching and searching and I have the same problem as germoju does.  If anyone has any information about the: 
1 - Mouser reference for the Power LED and mono/link - ON/OFF - Bypass/Comp switches ?
2 - Where I can find knobs looking as the originals UA knobs ?
3 - Someone can post some pictures of the inside finished unit please ?

Thanks.

Dan
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: CapRock on February 27, 2012, 02:24:36 PM
Hey guys.  Does anyone have a list of voltages I should be reading at tl071 and tl072?  I am getting proper 30vdc to the 30v pad.  My 2 rev D's work perfectly in mono but when I flip the switch to stereo I get no gain reduction.  The meters do not show any reduction and there is no "actual" gain reduction.  In stereo mode i still get sound from both units just no reduction.  I wired it up exactly as on the hairball diagram, with the exception of mounting my switch in an exernal enclosure.  I used a dpdt instead of 2 spdt's and connected a TRS cable from each mono comp to the external enclosure, as well as jumping the 2 comps together with a TRS cable as proposed in the diagram. Other than the voltages if anyone has any ideas please chime in, thanks...
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: useme2305 on February 27, 2012, 02:57:37 PM

3 - Someone can post some pictures of the inside finished unit please ?

check out crisotop's thread (http://www.groupdiy.com/index.php?topic=29854.0) for dual 1176 gutshots.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Brotastic on February 28, 2012, 06:23:24 PM
Thanks for posting that, but the link doesn't work for me.  I did find it searching the boards:

http://www.groupdiy.com/index.php?topic=29854.0
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Brotastic on March 01, 2012, 01:02:36 PM
For the bypass do i need something else.....ie another board or anything? 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: CapRock on March 01, 2012, 02:03:05 PM
you do not need another board for bypass.   If you look at the wiring diagram you will need 1 SPDT switch per unit as well as one stereo link pcb per unit, or you could run both units to a single DPDT switch.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on March 01, 2012, 04:28:09 PM
For the bypass do i need something else.....ie another board or anything?

What do you mean by "bypass".  The 1176 doesn't have a true bypass, just a GR off.  The GR off is usually placed as a switch on the attack pot.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Brotastic on March 01, 2012, 04:59:12 PM
ok, cool.  I apologize if that was a newb question....but well I am a newb.   :o  Someone told me that I needed a board to hook up the toggle up to for the comp/bypass for the stereo 1176.  Thank you guys for clarifying this for me. 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Brotastic on March 01, 2012, 05:01:24 PM
For the bypass do i need something else.....ie another board or anything?

What do you mean by "bypass".  The 1176 doesn't have a true bypass, just a GR off.  The GR off is usually placed as a switch on the attack pot.

so, on the front panel of the 2-1176 it has a place for a bypass.......is that not a true bypass?  I apologize for my ignorance. 
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: CapRock on March 08, 2012, 09:53:40 AM
I posted the following about a week ago can anyone lend some sugestions....

Hey guys.  Does anyone have a list of voltages I should be reading at tl071 and tl072?  I am getting proper 30vdc to the 30v pad.  My 2 rev D's work perfectly in mono but when I flip the switch to stereo I get no gain reduction.  The meters do not show any reduction and there is no "actual" gain reduction.  In stereo mode i still get sound from both units just no reduction.  I wired it up exactly as on the hairball diagram, with the exception of mounting my switch in an exernal enclosure.  I used a dpdt instead of 2 spdt's and connected a TRS cable from each mono comp to the external enclosure.  I jumped the 2 comps together with a TRS cable as proposed in the diagram. Other than the voltages if anyone has any ideas please chime in, thanks...
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: speakerface on March 12, 2012, 01:40:29 PM
For the bypass do i need something else.....ie another board or anything?

What do you mean by "bypass".  The 1176 doesn't have a true bypass, just a GR off.  The GR off is usually placed as a switch on the attack pot.

so, on the front panel of the 2-1176 it has a place for a bypass.......is that not a true bypass?  I apologize for my ignorance.

This reply would probably be more at home on a different thread, but the short answer is that the mnats boards kit does not have a true bypass.  However you do have some options for using that space depending on your needs.

If you're just looking for something to plug the hole so to speak, you could easily wire what is supposed to go the the SPDT switch on the attack pot (from both channels) to a DPDT on the front panel...you'd still get all the coloration of the input/output transformers with no gain reduction.  Turning it on and off wouldn't truly show how the unit is affecting your sound.

If you want true bypass and don't mind a back panel switch, you could easily add a DPDT to each channel (or a 4PDT for both channels) of the compressor sending the input signal to either the input pot or directly to the output.

If you want true bypass from a front panel switch, the only good way to go is some sort of a relay set up.  (You could also do the back panel method, but I assume too much noise would be induced on a run that long).  Igor makes some bypass PCBs available in a couple of different sizes (check white market section), but I don't believe either of them fit Dan's case perfectly (anybody feel free to correct me here).  These are set up for board mounted XLR connections and you'd need to wire power to the board in addition to the front panel switch.  If your XLR spacing isn't correct you could use these boards, but wire them to the XLRs instead of board mounting.   

I am currently building one as well and plan on doing a relay bypass on perfboard with a front panel switch (after I get the thing working without bypass) as well as having the attack pot SPDTs.

Hope that helps.     
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Brotastic on March 12, 2012, 02:14:22 PM
Thanks for the reply.  It does help.  Yeah, I thought that maybe I could rig it to the stereo board, but I guess not.  Let us know how you do the bypass.  I would love to see it.  Thanks again. 

Dan
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: a zombie on April 03, 2012, 04:53:17 PM
Just finished mine and I'm not sure if it's working propery... :-\

Should the meters on both 1176s move even if only one is being fed audio?

When I engage the stereo link I get less GR, is that normal?


I have +30 on the +30 pin, around +15 on the in's and out's.

The ground connection on the SL board is directly connected to my star ground.  The link and loop wires are shielded, with the shield connected on the switch end to the audio ground.  The in/out's are connected to a TRS jack via a shielded cable, with the shield only connected to chassis ground on the TRS jack.

EDIT:  I attached a drawing of how I wired it, sorry about the crapiness of it.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on April 05, 2012, 12:57:29 PM
Well the way you have it linking would be engaged with the switch in the down position.

Do you have the onboard wire jumper installed?  it's net to the info text on the PCB.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on April 05, 2012, 01:04:45 PM
You should see summed audio coming out of the "link" pad.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: a zombie on April 05, 2012, 06:20:24 PM
Well the way you have it linking would be engaged with the switch in the down position.

Do you have the onboard wire jumper installed?  it's net to the info text on the PCB.

It is wired to a push/pull output pot, so pulling it out engages the link.

You should see summed audio coming out of the "link" pad.

Turns out I forgot to install the jumper on the St. Link board.  Now it works REALLY GOOD.  tracking is damn near perfect with two hairball/mnats rev D's.  Probably due to the excellent FET matching that Mike does.


...so if you're in the process of stuffing the stereo link board

MAKE SURE YOU INSTALL THE JUMPER!!! IT IS EASY TO MISS!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Autophase on April 13, 2012, 10:07:10 AM
Hi guys I have decided to build a stereo 1176, well 2 actually one for me and one for a friend.
I obviously intend to use the stereo link kit and I will get matched pairs from hairball, but I have 2 questions.
1: can I easily make the stereo compressor use a single set of controls as opposed to having 2 sets of mono controls, or.would you suggest it's better to have them both available to help with adjustments for tracking differences?
2: which revision is best if I intend to stereo link? I see a lot of you using revision D. Does it make a difference?
Thanks

Sorry for self bump, can anyone answer my questions above, id appreciate any advice RE: Building stereo units, I'm intending to buy my boards and components soon.

Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on April 13, 2012, 04:12:02 PM
1: can I easily make the stereo compressor use a single set of controls as opposed to having 2 sets of mono controls, or.would you suggest it's better to have them both available to help with adjustments for tracking differences?

Can you easily find a dual T pad with a single shaft?

2: which revision is best if I intend to stereo link? I see a lot of you using revision D. Does it make a difference?

I can't answer that question based on any personal experience but there's nothing intrinsic about the revisions that would make one specific rev perform better in a stereo link configuration than another. What might make a difference is that the G uses only a single pot for the input control; finding a dual pot should be a lot easier than finding the dual T pad.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on April 19, 2012, 04:30:08 PM
hi guys,

i'm linking my units with the stereo kit BUT ... (!!??!!) i got questions :) !

1-  for the sidechain, I have to use a mono jack ? or stereo jack ? or nevermind ?

2 - On the stereo card, the ground goes to ground of the jack, right ?

3 - the +30V test point goes to +30V on main PCB R87 ?

 4 -the IN goes to one pin of the jack ? And OUT goes to the other, right?

Sorry , I read all documentation but I too novice !
Please can ou help me with that ?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: a zombie on April 19, 2012, 05:02:08 PM
1- either 2 mono jacks or 1 stereo jack.  The two units need to connect in to out and out to in, so if you use single stereo jacks on each 1176 then they will need to be wired opposite to accomplish this.  If you use 2 mono jacks on each, then you will wire the 'in' to one jack and the 'out' to the other jack.  To interconnect the two 1176's you would connect them in to out, and out to in.

2- On the stereo card the 'ground' terminal goes to chassis ground. 

3- yep

4- Yep, all you are trying to accomplish is to connect the two st. link pcb's in to out, and out to in.  There are multiple ways to do this as stated above.  but if you've only got 2 1176s, single TRS jacks wired inversely is the easiest, cheapest, and most convenient.

Also, be sure and use shielded wire for all the audio paths.  Connect the shields on one end only to prevent a ground loop.  For instance: on the connection between the st.link board and the jack, you should connect the shield to the sleeve/chassis connection on the jack only.

hi guys,

i'm linking my units with the stereo kit BUT ... (!!??!!) i got questions :) !

1-  for the sidechain, I have to use a mono jack ? or stereo jack ? or nevermind ?

2 - On the stereo card, the ground goes to ground of the jack, right ?

3 - the +30V test point goes to +30V on main PCB R87 ?

 4 -the IN goes to one pin of the jack ? And OUT goes to the other, right?

Sorry , I read all documentation but I too novice !
Please can ou help me with that ?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on April 19, 2012, 05:39:23 PM
thanks for your help :)
tomorrow I will do a draw tomorrow ;)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: emrr on April 19, 2012, 10:21:30 PM
Can you easily find a dual T pad with a single shaft?

Yes, vintage Daven on ebay, but it's gonna cost you around $400. 

Or buy a Goldpoint, also really expensive. 

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on April 20, 2012, 10:37:25 AM
hi,

I did a draw ! :)
i will use 2 mono jack, IN and OUT.
But I dont know where solder the wire on the female jack.
See my draw :
(http://nsm05.casimages.com/img/2012/04/20//120420044603420669743718.jpg)

I read on the hairball documentation that I can use the +8 button to remplace the link switch...
Do you know how to do that ?

(http://nsm05.casimages.com/img/2012/04/20//120420044604420669743719.jpg)

;)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on April 20, 2012, 04:58:18 PM
Can you easily find a dual T pad with a single shaft?

Yes, vintage Daven on ebay, but it's gonna cost you around $400. 

Or buy a Goldpoint, also really expensive.

At least the tracking will be good so that's one problem solved.

You building one too Doug?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on June 16, 2012, 04:34:43 AM
hi guys...

i just have a question about this stereo link PCB...

i have to solder a piece of resistor between the 2 points near the "hairball" logo ?
When I look at the circuit i think : "Yes, do it ! it makes sense !"
but I would like a PRO confirmation :) Can you tell me please ?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on June 16, 2012, 01:02:20 PM
Yes do it.

You need to connect those points with a piece of wire or cut component leg.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on June 16, 2012, 10:09:50 PM
Yes do it.

You need to connect those points with a piece of wire or cut component leg.

;) Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: late on June 18, 2012, 03:44:29 PM
Have some grounding problem. Get noise when turn output pot and hum when wire IEC to chassis. Now i have wired output pot leg 1 and stereo link ground to chassis. Not have wired main pcb ground to chassis. But when i get touch to chassis then noise is gone.

Is my grounding right?

Used this diagram
http://www.wuala.com/ricothetroll/public/Stereo-Link_wiring.gif
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: late on June 20, 2012, 09:46:53 AM
Do i need connect output pot directly to chassis or how? And it give noise only when output pot body get contact from chassis.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on June 20, 2012, 11:09:24 AM
Do i need connect output pot directly to chassis or how? And it give noise only when output pot body get contact from chassis.

Stereo link must be wire to chassis Ground...
Output pot to main board 16 - 15 - 17
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: late on June 20, 2012, 12:08:34 PM
Do i need connect output pot directly to chassis or how? And it give noise only when output pot body get contact from chassis.

Stereo link must be wire to chassis Ground...
Output pot to main board 16 - 15 - 17

Still same problem. I think that my wiring is right. Because it work well if get touch from the case. Some grounding issue.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on June 20, 2012, 02:14:18 PM
Do i need connect output pot directly to chassis or how? And it give noise only when output pot body get contact from chassis.

Stereo link must be wire to chassis Ground...
Output pot to main board 16 - 15 - 17

Still same problem. I think that my wiring is right. Because it work well if get touch from the case. Some grounding issue.

maybe you got pictures ??
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: NorthernLight on August 03, 2012, 10:13:27 AM
Quick question: how important are the 25K resistors? I don't have them, but I have plenty of 24K 1%. The kit that Hairball sells includes 25K 1% resistors but I could not find from the schematic or other sources if they have to be 1%; if 5% is just as fine then substituting them for 24K 1% is not a big issue I guess.

Nevertheless, I would like to hear from someone with a bit more experience than me  ;D
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dryman on August 06, 2012, 02:24:55 PM
i want to build a stereo Rev J 1176, with Stereo-Link from hairball. I would like use the alternate PSU, but i don't find any info, how to wire and what parts i don't need on the main-pcb.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: ricothetroll on August 07, 2012, 01:43:23 AM
Hi,

Just a little post here to share my experience with the stereo link : I just couldn't make it work until I removed the sockets I put the fets into. Now it's working just fine !
Sometimes I just keep looking in the wrong direction...
See my post here :
http://www.groupdiy.com/index.php?topic=646.msg625439#msg625439
Hope this helps.
Best regards.
Eric
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on September 30, 2012, 07:23:13 AM
Hi,

i'm building a dual 1176 and before I want to be sure of my wiring. Do you see any error on my drawn ?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on October 01, 2012, 11:39:36 AM
I also have a question about PSU wiring...
I'm not sure to be good on that... I did a draw too :)

Someone can tell me if I'm ok please ?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Harpo on October 02, 2012, 10:02:13 AM
I also have a question about PSU wiring...
I'm not sure to be good on that... I did a draw too :)

Someone can tell me if I'm ok please ?
PSU will NOT work.
Depending on type of your PSU, the voltage regulators and some polarized caps either will blow up or might be protected by some diodes that prevent damage when reverse powered.
Mains transformer primary winding(s) receive AC voltage from the wall outlet and transforms this up/down to a -for usual- different AC voltage at whatever ratio. This transformer secondary winding(s) is feeding the AC input of your PSU pcb. The PSU then rectifies, smoothes and regulates this received AC voltage to one or more constant DC voltage(s).
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dryman on October 02, 2012, 10:16:30 AM
I also have a question about PSU wiring...
I'm not sure to be good on that... I did a draw too :)

Someone can tell me if I'm ok please ?

If you use the alternate PSU, you connect the transformer to the PSU on AC-CT-AC. Pos-Gnd-Neg should be connected to both of the boards. But you have to leave out some parts on the 1176-boards and add some wires. It is all described on mnats page http://mnats.net/psu.html (http://mnats.net/psu.html). I wired my 1176 with this description and everything works well.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on October 02, 2012, 10:53:42 AM
hummm thanks :)

if I understand I have to wire it like that ?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: late on November 10, 2012, 07:15:31 PM
I wondering how to get matched attack and release times. Do i need match all transistors? I already have matched 5457 on both channels. Is it normal that every channel have a little bit different attack/release time? Or do i have some issue on my build.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: earthsled on November 13, 2012, 09:41:40 AM
Hi all,

I'm having issues using the stereo link kit with the ROTARY switch boards.

My first attempt was to follow the PDF posted at Hairball Audio.
When I switch into stereo link, my output level drops to almost nothing and sounds thin.
 
Earlier in this topic, ricothetroll provided a link to an alternative wiring diagram (attached).
Has this approach been successful?

Thanks for your help!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on November 14, 2012, 02:23:46 AM
Hi all,

I'm having issues using the stereo link kit with the ROTARY switch boards.

My first attempt was to follow the PDF posted at Hairball Audio.
When I switch into stereo link, my output level drops to almost nothing and sounds thin.
 
Earlier in this topic, ricothetroll provided a link to an alternative wiring diagram (attached).
Has this approach been successful?

Thanks for your help!

hi, I wire my unit like this and it works well...
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: earthsled on November 14, 2012, 09:49:54 PM
Quote
hi, I wire my unit like this and it works well...

Thank you germoju! I will give this a try...
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Janzoulou on November 24, 2012, 07:01:03 AM
Quote
hi, I wire my unit like this and it works well...

Thank you germoju! I will give this a try...

Hi there.. Did it work? Thanks a lot!  8)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: earthsled on November 28, 2012, 05:54:25 PM
Quote
Hi there.. Did it work? Thanks a lot! 

Yes, this wiring worked for me.

I also found that my unit needed a connection between audio ground and the chassis to function properly.

Cheers!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: JamesW on December 03, 2012, 09:06:51 PM
Hi all  working my way through a dual build. Can the stereo link boards be powered direct from the power supply board? This will make a much neater wiring job.

Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Janzoulou on December 04, 2012, 01:49:01 PM
@earthsled: Thanks !  8)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on February 28, 2013, 05:44:33 AM
Hi,

My problem is when I switch it to be stereo, I have a the 2nd unit that has a (measured) gain reduction of about 2dB more than the first unit. My test procedure is : in dual mode, both channels are fed with the same signal (ch1 from the L output of my soundcard and ch2 from the right one), I scoped both signals at test point 2 - right after the input gain pot - to make sure both compressors are fed with the same signal, I then set the out pot in bypass mode to have unity gain in both units. Then I switch both units to GR and measure both outputs, and see that both gain reduction is the same. When I switch the link switch to link mode, I measure a 2dB difference between ch1 and ch2, that is to say there is a 2dB difference in gain reduction. Meters also display a 2dB difference between the two channels.


HI guys,

I got the same problem. I builded a Stereo Revision D. When I'm in Dual mode, the 2 compressors have the same compression.... But when switch to link mode, one of the copmpressor has a difference about 2 or 3 dB of compression...

Somebody has the same ? Somebody has fixed this already ?$

Thanks !!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: lowend on February 28, 2013, 08:07:38 AM
Hello,

I finished 2x 1176 Revision A with the stereo link PCB. But I cant understand what happen. When I'm in Dual Mono mode, all is fine. Compression is normal etc.... But when I switch to stereo, Compression is very heavy !
I've made a video, please take a look : http://youtu.be/lybZ44KPct0 (http://youtu.be/lybZ44KPct0)

I hope someone has the same problem to get an issue ! :) Cause I really dont understand... I check all wires, voltage etc...

Thanks
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: rainton on February 28, 2013, 10:02:22 AM
sorry I can't help you but how did you get the UA Logo onto the frontpanel?
Looks really good and authentic!  8)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on February 28, 2013, 11:41:54 PM
Hello,

I finished 2x 1176 Revision A with the stereo link PCB. But I cant understand what happen. When I'm in Dual Mono mode, all is fine. Compression is normal etc.... But when I switch to stereo, Compression is very heavy !
I've made a video, please take a look : http://youtu.be/lybZ44KPct0 (http://youtu.be/lybZ44KPct0)

I hope someone has the same problem to get an issue ! :) Cause I really dont understand... I check all wires, voltage etc...

Thanks

Clean builds!

Do you have the link wire by the PCB link board writing installed?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: lowend on March 01, 2013, 03:57:34 AM
Hello,

I finished 2x 1176 Revision A with the stereo link PCB. But I cant understand what happen. When I'm in Dual Mono mode, all is fine. Compression is normal etc.... But when I switch to stereo, Compression is very heavy !
I've made a video, please take a look : http://youtu.be/lybZ44KPct0 (http://youtu.be/lybZ44KPct0)

I hope someone has the same problem to get an issue ! :) Cause I really dont understand... I check all wires, voltage etc...

Thanks

Clean builds!

Do you have the link wire by the PCB link board writing installed?

Hi,

Sorry I dont really understand your question ... :)
To explain : I got a wire from Stereo PCB "link" to my switch.
I followed the instructions. When Stereo mode : "link" is connected to ratio pad 15, when dual mono : ratio pad 15 is connected to output pot.
I hope you can see , sorry for the picture quality...
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: earthsled on March 01, 2013, 11:08:52 AM
lowend: double check the orientation of the op-amps on your stereo PCBs -- these are easy to get backwards.  :)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: lowend on March 01, 2013, 04:11:06 PM
lowend: double check the orientation of the op-amps on your stereo PCBs -- these are easy to get backwards.  :)

Thanks, but orientations are good :)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on March 01, 2013, 05:35:34 PM
You've followed this?

http://hairballaudio.com/guides/Stereo_Link_Wiring_Guide.pdf

your ins are connected to your outs?

Check that your PCB has +30 at the pad and voltages at the op-amp supply pins.  Make sure you have continuity to ground at the GND pad.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: lowend on March 05, 2013, 08:15:05 AM
You've followed this?

http://hairballaudio.com/guides/Stereo_Link_Wiring_Guide.pdf

your ins are connected to your outs?

Check that your PCB has +30 at the pad and voltages at the op-amp supply pins.  Make sure you have continuity to ground at the GND pad.

Mike

Hi,

yes I followed the doc... Before I builded 2 pairs of Rev D with the same stereo link and it works :)
So I tested the stereo links cards with an oscilloscope and 1 kHz... I got a bad wave at some points...
As the TL071 and TL072 are plug with sockets pins,... I unplug them and test them with oscilloscope and 1 kHz... My TL071 has good wave... but TL072 has an uncorrected wave response.
So I think it's the problem.
I send my 1kHz in the card without TL072 and I good wave response everywhere...

So ! I have an other stereo link board kit, I change it and it works now. The issue was a bad TL072 :(
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on March 05, 2013, 10:01:19 AM
Send me an email and I'll get a replacement out to you.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: lowend on March 06, 2013, 09:13:09 AM
Send me an email and I'll get a replacement out to you.

Mike
Done !
Thanks ;)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on March 08, 2013, 07:05:19 PM
Hi !

I builded a Stereo Revision D. When I'm in Dual mode, the 2 compressors have the same compression response.... But when switch to link mode, channel A has a difference about 2 or 3 dB of compression... and it's a little difference when I change the ratios...

Stereo link PCBs wiring is OK... IN of one go to OUT of the other etc. My 5457 are matched pair from HairballAudio...

Somebody had the same ? Somebody has fixed this already ?

Thanks !!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Janzoulou on March 12, 2013, 08:08:47 AM
Hello everybody... I am wiring now the Stereo-link board inside my dual 1176 REV A. One (maybe silly) question:

Referring to the graphic from ricothetroll on ratio-board pad17 and output-pot - pads staying empty??

Cheers and excuse if this question is stupid.. just want to be safe.
:-)


Ok... this one is solved. Now i got the same problem like germoju posted above... GR changes on one side around 2-3dB when the sidchain is linked via the Stereo-boards.. Anybody got an idea?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on March 13, 2013, 04:07:15 PM
Hello everybody... I am wiring now the Stereo-link board inside my dual 1176 REV A. One (maybe silly) question:

Referring to the graphic from ricothetroll on ratio-board pad17 and output-pot - pads staying empty??

Cheers and excuse if this question is stupid.. just want to be safe.
:-)


Ok... this one is solved. Now i got the same problem like germoju posted above... GR changes on one side around 2-3dB when the sidchain is linked via the Stereo-boards.. Anybody got an idea?


The link boards sum the side chain audio so both side chains see the same peaks.

You need to set both compressors to the same controls (input, output, ratio) then because of some tolerances with components you may need to tweak a control or two.  If they are way off if might be because you bought FETs a different times.  If you bought your FETs on the same order they should be reasonably matched.  You may want to send a test signal into one unit and test that you see the summed test signal in each unit.

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Janzoulou on March 13, 2013, 05:23:46 PM
Thanks a lot for the response, Mike!

Yeah, you are absolutely right, i think. My 309 FET´s I actually did not buy in your shop.. i just forgot to order them and had to find them in a different place in Germany. Of course not matched ones... All the other parts were ordered in your store and mouser at once.... I will anyway order shortly a REV F kit at your place and then exchange the J309 with yours. :-)

I tweaked around with the settings of course and reduced the output from on side at the end. The result is not accurate but for now I guess I have to live with that. I will also check the resistor - values in the corresponding area on the ratio and main board. Maybe there is some tolerance to get rid off?

Cheers again! Thanks again for the great support and everything else, making it possible to get those amazing kits Mike!!

Fredi

btw: when setting them up im stereo i do the following: I set everything in Dual-mode with the signal i want to compress, then put a 1kHz tone to check the compression etc is the same on both sides. then i link them. thats where I get a 2-3dB drop on one side.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on March 15, 2013, 03:26:22 AM
Hi,

Yes I got 2x rev D inside and i buyed the Stereo kit on hairballlaudio. So I think FETS are matched by Hairball...
When I send a signal in one board, i can find it on stereo board but one is louder than the other.
The response is not the same between all ratio. Maybe i got a problem on my ratio boards ? But I dont think so,  cause in mono the response are the same with pots at same position etc.
The only components i'm not sure are the 3391 and 3708... Maybe they are not matched as it should.Thanks for your help Mike ! :)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Axelerator on May 14, 2013, 12:52:42 PM
just a short q....is the stereo summing board out of the cuircuit while in dual mono mode  ?
(that is how i read the drawings here)
thank you
axel
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: germoju on May 17, 2013, 02:47:28 AM
Hi,

Yes I got 2x rev D inside and i buyed the Stereo kit on hairballlaudio. So I think FETS are matched by Hairball...
When I send a signal in one board, i can find it on stereo board but one is louder than the other.
The response is not the same between all ratio. Maybe i got a problem on my ratio boards ? But I dont think so,  cause in mono the response are the same with pots at same position etc.
The only components i'm not sure are the 3391 and 3708... Maybe they are not matched as it should.Thanks for your help Mike ! :)

OK !!! I changed all the 3708 on both cards and replace with matched 3708 ! It works great !! same response in stereo mode now :) So happy :) :) :)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mrerdat on June 25, 2013, 03:45:04 PM
OK !!! I changed all the 3708 on both cards and replace with matched 3708 ! It works great !! same response in stereo mode now :) So happy :) :) :)

I did the same yesterday and the stereo response is MUCH better now.  I bought a junk $5 multimeter that had a hFE test because I didn't have that functionality on the other one that I used for my build last month. 

Before, I was getting good stereo response at 4:1 or 8:1, but it got worse after that and was totally unusable in all-buttons-in mode.  It sounded very lopsided and kind of cool actually, but wasn't very usable for many things.  It was bad to the point where I had a better stereo response by putting the unit in dual mono mode when going 20:1 or all-buttons-in.   

Now after matching 3708s with the batch of 20 or so I had left, the tracking works great for all ratios! Now I think I have only a very, very slight deviation.... like a dB or less in all-buttons-in mode because I couldn't be super picky with matching the limited amount of FETs I had lying around.  Nothing that the slight tweak of a knob won't fix. Also very happy   ;D

One thing I should mention is that after replacing the 3708s is that one of my channels had a very low level and wouldn't work well until I passed a loud signal through it.  That fixed it completely and it felt like there were audio cobwebs in the transistors or something...
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: 100WChris on September 12, 2013, 06:13:12 AM
Hi!
Finished my Stereo-1176 with mnats Rev-D boards and hairball Stereo Linking.
(http://www.chrisreiss.de/DIY/2-1176.jpg)
looks wild, but the unit is totally quiet
(http://www.chrisreiss.de/DIY/2-1176_innen.jpg)
transformer and link-boards are under the main-pcbs
(http://www.chrisreiss.de/DIY/2-1176_innen2.jpg)
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: 100WChris on September 18, 2013, 12:53:36 PM
Hi!
OK, because Mnats had mentioned it in Hairball/Mnats-Stereo-Support thread i have to ask:
Whats the best grounding scheme for a Stereo-1176 unit?
In my build i have done the following:
- All XLRs are grounded to chassis via Pin1
- IEC, all (four) boards, and PSU are grounded individually to the starground-point near IEC
- three LEDs are grounded via PSU-ground-terminal to the start ground.
Can this be improved? Unit works and is really quiet, but if it can be done better... :-)
Cheers
Chris
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on September 19, 2013, 08:51:28 PM
Hi!
OK, because Mnats had mentioned it in Hairball/Mnats-Stereo-Support thread i have to ask:
Whats the best grounding scheme for a Stereo-1176 unit?
In my build i have done the following:
- All XLRs are grounded to chassis via Pin1
- IEC, all (four) boards, and PSU are grounded individually to the starground-point near IEC
- three LEDs are grounded via PSU-ground-terminal to the start ground.
Can this be improved? Unit works and is really quiet, but if it can be done better... :-)
Cheers
Chris

My comment in the other thread was about the XLR grounding. As mentioned by Neil Muncy et. al. pin one should go directly to the chassis rather than to a wire connected to the star ground. I think that is what you are describing above.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: morls on September 21, 2013, 05:06:16 AM
Hello,

I'm having a hard time getting the stereo link to work. I have 2 revision D units, and both work great in dual mono. However, when I link them there is no gain reduction happening. A signal is still passing through, and the meters work in VU mode, but no compression takes place.

I've got a couple of questions regarding the wiring, which might be where I've gone wrong...

1. The TRS female sockets I'm using have the terminals marked as 1, 2 and 3. I'm grounding 1 to chassis, and using the other 2 for input/output and output/input respectively. Is this correct?

2. When I'm connecting the loop terminal to the output pot, using a single core shielded cable, do I need to attach the shield to the pot as well?

Can anyone offer any advice please?

Thanks

Stephen
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: morls on September 22, 2013, 02:53:33 AM
So, I have an update, with progress of sorts...

I've been tracing the audio through the compressors. There is only a signal at the 'link' pad, coming from the output pot. Tracing this through the stereo link PCB, there is something I'm not sure of at R202 and R203. There is no signal crossing these two resistors - it's there on the 'link' pad side but not the other. This is the case on both stereo PCB's so I don't think it's bad resistors...

Can anyone please help?

Thanks

Stephen

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on September 22, 2013, 06:33:55 AM
1. The TRS female sockets I'm using have the terminals marked as 1, 2 and 3. I'm grounding 1 to chassis, and using the other 2 for input/output and output/input respectively. Is this correct?

A search fails to turn up any standard numbering system for these connectors. Please specify tip, ring and sleeve, a manufacturer's data sheet or how those numbers relate to the agreed upon terms.

I've been tracing the audio through the compressors. There is only a signal at the 'link' pad, coming from the output pot. Tracing this through the stereo link PCB, there is something I'm not sure of at R202 and R203. There is no signal crossing these two resistors - it's there on the 'link' pad side but not the other. This is the case on both stereo PCB's so I don't think it's bad resistors...

Not sure what you mean by crossing, but if there is a signal coming from the link pad (which is, after all, the output of the Stereo Link Board circuit) then something must be going in either from one or the other units that feed the simple mixer based around A201b. If the signal there makes it through the link switch to the input of the ratio board (R78 on the Rev D) then I can't see why it shouldn't be working.

Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: morls on September 22, 2013, 07:27:22 AM
Hi mnats, and thanks for the great 1176 PCB's!

As far as the TRS connectors, 1 is sleeve, 2 is tip and 3 is ring.

I've also made a mistake in my earlier post - I get a signal only at the "loop" pad, and none of the other pads. Sorry for the confusion.

As far as my trace, I'll try to be more specific:

I'm running audio through the 1176, using the signal tracing probe from Mark Burnley's site http://web.archive.org/web/20050310014839/http://www.diyfactory.com/data/mbsignaltracing.htm

Here's where I get audio:
"loop pad"
into R201
out of R201
into C201
out of C201
into R202, but NONE out of R202 - ground point, so maybe all ok?
into R203, but NONE out of R203
into R204
out of R204
lastly, pin 3 of A201a

this seems to be the case on both stereo link PCB's.

I think my next step will be to check R203 on both boards. I verified and tested all resistors when I put the boards together, but I'll check again.

If you can help in any way I'd be very grateful. It's very generous of you to offer this support already, so many thanks.

Stephen
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on September 22, 2013, 04:35:19 PM
Hi mnats, and thanks for the great 1176 PCB's!

As far as the TRS connectors, 1 is sleeve, 2 is tip and 3 is ring.

I've also made a mistake in my earlier post - I get a signal only at the "loop" pad, and none of the other pads. Sorry for the confusion.

As far as my trace, I'll try to be more specific:

I'm running audio through the 1176, using the signal tracing probe from Mark Burnley's site http://web.archive.org/web/20050310014839/http://www.diyfactory.com/data/mbsignaltracing.htm

Here's where I get audio:
"loop pad"
into R201
out of R201
into C201
out of C201
into R202, but NONE out of R202 - ground point, so maybe all ok?
into R203, but NONE out of R203
into R204
out of R204
lastly, pin 3 of A201a

this seems to be the case on both stereo link PCB's.

I think my next step will be to check R203 on both boards. I verified and tested all resistors when I put the boards together, but I'll check again.

If you can help in any way I'd be very grateful. It's very generous of you to offer this support already, so many thanks.

Stephen

You stopped at the crucial moment. So no output from the first buffer? Is it the correct IC (dual rather than single)?

Measure the DC voltages of A201 at pins 8 and 4 using the virtual ground as reference at the junction C301/302.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: morls on September 22, 2013, 06:24:26 PM
Thanks,

I have identified the problem. I have incorrectly installed A201 and A302 on both boards, they need to be swapped. An inevitable mistake I think given my level of (in)experience.

Your help is much appreciated. I'll let you know how I go once I correct this problem.

Stephen
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: morls on October 12, 2013, 05:44:54 AM
OK, I'm very happy to report success. I ordered a new stereo link kit, and have just installed both the stereo link boards. It all seems to work very nicely.

Thanks again for the help, I really appreciate it.

Stephen
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: DUDE GUY on December 13, 2013, 06:10:27 AM
Hello,

 I just installed the link PCB's in two mono hairball 1176 kits. Both compressors work fine on their own, however, when linked, I'm having a similar problem that Boris (Stephen) mentioned previously:

Both compressors continue to pass signal (and meter fine in VU), but I see no gain reduction on my meters when in GR mode. I can turn up the level of the audio passing through the compressors, using either the input or output controls, but no compression occurs (no GR on the meter, no audible compression). I've triple checked the components on my link PCB's and I'm pretty sure everything is in order.

I believe I have used proper shielding techniques. The signal leads are shielded up to link PCB's and the ratio PCB's. I tied together all shields at the SPDT switches (but floating, not connected to the switches) and connected the shields to the right pin of the output pot (looking from the back), which then connects to GND at pad 16 on the main PCB, in the signal preamp area. I'm not having any noise issues, which would seem to imply that my shielding is good. Yes? No?

I'm using an SPDT switch in each unit (on the front panel) to minimize cable lengths. Thins means I have to engage the stereo link on both compressors, as opposed to using a DPDT switch installed in one compressor to engage the stereo link. I'm using the TRS link method described in the hairball stereo link guide, with tip and ring swapped at the link PCB's. I have the jumpers installed and my IC's are in the correct positions.

I'm grounding the link PCB's to one of the bolts on the output transformer, which is grounded to the chassis. I connected the +30 pad on the link PCB's to the +30 VDC test point on the main PCB. I'm measuring 29.72 VDC across  the +30 pad and chassis ground.

Any help is appreciated. I'm stumped. Please let me know if you need additional info.

Thanks very much.

-Kevin
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on December 14, 2013, 01:57:35 PM
Both compressors work fine on their own, however, when linked, I'm having a similar problem that Boris (Stephen) mentioned previously:
...
Any help is appreciated. I'm stumped.

So did you try signal tracing like moris did?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: DUDE GUY on December 15, 2013, 02:06:08 AM
Good call. Thanks, mnats. I'll build that and see what I find.

Thanks for the boards, btw.

-Kevin
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmnieto on December 15, 2013, 04:18:58 PM
transformer and link-boards are under the main-pcbs

Hi Chris, I have one question... where do you find those L-shaped hinges (where you mount the output transformer)? I am trying to build my dual stereo board witha similar configuration as yours, but I have no clue about where to find that
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: 100WChris on December 15, 2013, 08:46:55 PM
transformer and link-boards are under the main-pcbs

Hi Chris, I have one question... where do you find those L-shaped hinges (where you mount the output transformer)? I am trying to build my dual stereo board witha similar configuration as yours, but I have no clue about where to find that

Hi!
I found them at the local hardware store, nothing special...
Chris
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: dmnieto on December 15, 2013, 10:59:48 PM
My local store sucks them :( do they have a particular name?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: 100WChris on December 16, 2013, 04:12:12 AM
My local store sucks them :( do they have a particular name?

sorry, i dont´n know if they have a dedicated name... i´d call them aluminium L-profile or L-brackets. i found them in length of 1 meters at the hardware store and just cut of two small brackets to mount the transformers.
Chris
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: DUDE GUY on January 05, 2014, 08:57:01 PM
Both compressors work fine on their own, however, when linked, I'm having a similar problem that Boris (Stephen) mentioned previously:
...
Any help is appreciated. I'm stumped.

So did you try signal tracing like moris did?

I tried signal tracing and it seemed to be an issue with one of my SPDT switches. I swapped out the switch and the problem persisted. Before I try anything else, I want to make absolutely sure my wiring is correct. Please see the attached diagram. I included the MAIN PCB wiring (pads 16, 15, 17) that are connected to the output pot. All of the green "boxes" around the red lines represent the shield. Hopefully you can see how all the shields are connected. Please let me know if this looks correct or if I'm way off.

Thanks very much.

-Kevin
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mnats on January 06, 2014, 07:01:45 PM
I tried signal tracing and it seemed to be an issue with one of my SPDT switches. I swapped out the switch and the problem persisted.

You drew a conclusion that proved to be incorrect. It would be more helpful if you posted the results of your measurements like moris did.

Before I try anything else, I want to make absolutely sure my wiring is correct. Please see the attached diagram.

Compare yours to the wiring shown in the Hairball document to confirm.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: DUDE GUY on January 14, 2014, 03:06:20 AM
I tried signal tracing and it seemed to be an issue with one of my SPDT switches. I swapped out the switch and the problem persisted.

You drew a conclusion that proved to be incorrect. It would be more helpful if you posted the results of your measurements like moris did.

Before I try anything else, I want to make absolutely sure my wiring is correct. Please see the attached diagram.

Compare yours to the wiring shown in the Hairball document to confirm.

Hello again, mnats

I finally had a chance to do some measurements. I also triple checked my wiring and it is wired according to the Hairball document.

So just a reminder of where I'm at:

When I have both units linked with the TRS cable and both link switches enabled, unit 2 continues to show gain reduction and has audible compression, while unit 1 shows no gain reduction and has no audible compression. When I remove the TRS cable and leave the link switches enabled, I see gain reduction and hear compression on both units. I've tried three different TRS cables, but no change.

I hear audio at:

OUT
LOOP
IN
R201 (IN+OUT)
R202 (IN only)
R203 (IN only)
R204 (IN+OUT)
R205 (IN+OUT)
R206 (IN+OUT)
R208 (IN only)
C201 (IN+OUT)
C202 (IN+OUT)
A201 PIN1
A201 PIN2
A201 PIN3
A201 PIN6

I do not hear audio at:

LINK (when I remove the TRS link cable, I hear audio at LINK)
R207
R209
R316
R317
C301
C302
C203
A201 PIN4
A201 PIN5
A201 PIN7
A201 PIN8
A302 (ALL PINS)


Thanks for your help and I appreciate your patience.

-Kevin
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Piotr on January 20, 2014, 07:53:47 AM
Hi to all of you !

Having built a stereo rotary version of the 1176 (Mnats boards) and trying to fit it with Hairball's stereo linking pcbs, I've run in the exact same issues stated by Ricothetroll. Stereo switch engaged nulled the ouput to almost nothing...

I've successfully rewired my unit using his drawing so big thanks to him for pointing me in the right direction and helping me understand the issue.

Here's the unit which still needs a little cosmetic work, but is calibrated and works as it should !

Thanks Rico !!!

Piotr.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: DUDE GUY on January 26, 2014, 10:27:01 PM


I finally had a chance to do some measurements. I also triple checked my wiring and it is wired according to the Hairball document.

So just a reminder of where I'm at:

When I have both units linked with the TRS cable and both link switches enabled, unit 2 continues to show gain reduction and has audible compression, while unit 1 shows no gain reduction and has no audible compression. When I remove the TRS cable and leave the link switches enabled, I see gain reduction and hear compression on both units. I've tried three different TRS cables, but no change.

I hear audio at:

OUT
LOOP
IN
R201 (IN+OUT)
R202 (IN only)
R203 (IN only)
R204 (IN+OUT)
R205 (IN+OUT)
R206 (IN+OUT)
R208 (IN only)
C201 (IN+OUT)
C202 (IN+OUT)
A201 PIN1
A201 PIN2
A201 PIN3
A201 PIN6

I do not hear audio at:

LINK (when I remove the TRS link cable, I hear audio at LINK)
R207
R209
R316
R317
C301
C302
C203
A201 PIN4
A201 PIN5
A201 PIN7
A201 PIN8
A302 (ALL PINS)


Thanks for your help and I appreciate your patience.

-Kevin

Hello,

I'm really stumped here. Would someone mind helping me out?

I described my problem in the quote above and I provided a list of PCB pads where I heard and did not hear audio with my audio probe.

To add to that, I measured voltages across the pins of the IC's and ground.

Unit One (the 1176 with the issue):

--TL072
PIN1: 26.9V
PIN2: 26.9V
PIN3: 26.6V
PIN4: 0V
PIN5: 26.9V
PIN6: 22V
PIN7: 28.9V
PIN8: 29.6V

--TL071
PIN1: 158mV
PIN2: 26.9V
PIN3: 26.9V
PIN4: 1.3mV
PIN5: 158mV
PIN6: 26.9V
PIN7: 28.6V
PIN8: ??? (voltage continues to increase)

Unit Two (the 1176 that works fine):

--TL072
PIN1: 14.8V
PIN2: 14.8V
PIN3: 14.8V
PIN4: 0V
PIN5: 14.8V
PIN6: 14.8V
PIN7: 6.9V
PIN8: 29.7V

--TL071
PIN1: 155mV
PIN2: 14.8V
PIN3: 14.8V
PIN4: 0V
PIN5: 155mV
PIN6: 14.8V
PIN7: 29.7V
PIN8: ??? (voltage continues to increase)

From what I've read in the other posts in this thread, Unit Two seems to have the correct voltages (around 15V), while Unit One has an issue.

Any help would be greatly appreciated. Thanks very much, everyone.

-Kevin
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: DUDE GUY on January 26, 2014, 11:33:02 PM
OK, figured it out. I accidentally installed a 1k resistor where a 10k should be and vice versa (DUH). I'll proceed to kick myself for the rest of the night, although I am relieved. Thanks anyway everyone, always very helpful.

-Kevin
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: jonathanmorbin on December 17, 2014, 08:10:53 AM
Hi,

If there is anyone out there still looking at this thread i have a small problem i can't figure out. I have wired the boards as per the diagram and have all the correct voltages. I don't seem to be getting any audio where R206 and R205 Meet. The first buffer stage seems fine. I have audio in and out. But i have no input on the second buffer stage as mentioned. When i increase the input of one unit i get gain reduction on both units but as i move the other units input up it decrease the gain reduction on both. It doesn't seem to be summing the Control voltage correctly. I have tried new stereo link boards and still no joy. Can anyone give me any ideas?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Janalex on January 19, 2015, 11:03:33 PM
Quick question.  Which if any cables on the stereo link boards need shielding? I'm assuming in and out do. How about link and loop?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: robertoray on February 21, 2015, 07:44:12 PM
Hi.
Really, i didn't understand how works the stereo linking PCB.
I will try to  the Ricothetroll wiring scheme that i've found in this thread.
But i'd like to place an external/internal sidechain switch, if it's possible.
And a stereo jack for ext. sidechain input.
Could someone tell me if I have attached a working wiring scheme?
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: robertoray on February 24, 2015, 12:11:59 AM
Quick question.  Which if any cables on the stereo link boards need shielding? I'm assuming in and out do. How about link and loop?

Hi Janalex,
I've the same questions.
But before i tried to understand the stereo link and compressor schematics because i can't found detailed info.
If i say something wrong, please correct me.
LOOP is an input where are connected the out of compressor-1(main board pad 15) bufferized and sent to OUT (for IN to the 2nd stereo link)
LOOP and IN(compressor-2 buffered out) are mixed together and sent to LINK
-------------------------------------
Switching in dual mode, looking at the Ricothetroll wiring scheme, we have the original connection, except LOOP it still connected to main board pad 15 and out pot.
I'm asking if will be better to disconnect this too when not used because we have 25k + 25 Kohm in the link board connecting the audio signal to the ground and the out pot is 250k ohm to the ground (250:50)
Has anyone observed signal lost adding this board, in particular connecting the loop wire?
In case, i will try.
In link mode the original audio signal from the out pot. to ratio pcb pad15 (then cross trough the gain reduction amp to control the output gain like sidechain) will be replaced by the mix (the common sidechain for both compressors)

This PCB is for LINK MODE, because we have a sidechain mix. But if we need for a general external sidechain?

A) we can use the link pcb buffer:  LOOP for ext. return and OUT to ratio pad 15.

B) the mixer like a buffer (obviously disconnecting theLOOP), using the IN like ext. return and LINK to ratio pad 15.
More simple if we would have the link  and ext sidechain features together, in this case we have one DPDT (dual/link) and one 3PDT (ext-int) switch.
And the ext. sidechain works only if the link switch is activated, but we have also dual or link mode in ext. sidechain, depend if we have mono or stereo ext. return.
in addition with this 3PDT switch we can disconnect the LOOP for ext. sidechain but also for the link switch when in dual mode position, if this could be a problem.

C) we don't need to have an input stage and we can connect the ext. sidechain return directly to ratio pad 15.
Any suggestion?

In the revD scheme, both Pad 15 and 17 to the output pot. have to be shielded.
So i think we need to shield this wires used just for sidechain, but connected directly to the pad 15:
-from output pot. to link switch
-from link switch to (ratio board) pad 15
-from LOOP to output pot.
-from LINK to link switch, i don't think, but by the way..
I was thinking to use 2 wires separately shielded for both LOOP and reduce possible crosstalk.
For LINK i think that connecting two LINK together or use one for two, it never mind, but only we don't need stereo ext. sidechain.
Seems that we have a mixer extra if we place the link boards in the same chassis.
We need the second board just for the input buffer.
However, near the link switch we can cut all grounds for avoid ground loops.
IN and OUT i think doesn't need to be shielded, it used just for sidechain... but by the way...

I would ask if it should be better connect the stereo link GND to c25 negative pole too or in any ground of the main PCB where we take the +30v rather than connect it to the IEC chassis ground.
And if i can take +30v from the blk output transformer pad, looks better.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Jazzyseb on March 14, 2015, 01:18:01 AM
Hello,

I finished 2x 1176 Revision A with the stereo link PCB. But I cant understand what happen. When I'm in Dual Mono mode, all is fine. Compression is normal etc.... But when I switch to stereo, Compression is very heavy !
I've made a video, please take a look : http://youtu.be/lybZ44KPct0 (http://youtu.be/lybZ44KPct0)

I hope someone has the same problem to get an issue ! :) Cause I really dont understand... I check all wires, voltage etc...

Thanks

Hi  everybody!
I've just finished my 2 Rev D builts with stereo link and the same  problems occuring to me, as to lowend about 2 years ago!
Dual Mono : everything works as it should!
Switch to Stereo: way too much compression is happening! :-(
Could this be the same issue? ( broken Opamp? )
I haven't an  osciloscope so i can't test it like lowend did...
Any other suggestions how to make sure the Opamps are the problem?
I'm quiet  sure i got all the wires right!
We'll i think i'm just going to order a 2nd pair of link Pcb's and see ...

Greetz
Jazzyseb
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: weiss on October 18, 2015, 02:35:06 PM
i wanted to add, that the link to the wiring guide is not working anymore
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on October 20, 2015, 12:53:02 PM
i wanted to add, that the link to the wiring guide is not working anymore

Updated.

http://library.hairballaudio.com/datasheets/Stereo_Link_Wiring_Guide.pdf
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Fandangoita on April 11, 2016, 09:06:04 AM
Hi, Mike, Hi mnats,  hi guys. Probably nothing new here, but i have built a stereo version of LN1176 rev J (Gyraf) rotary switch version and trying to link them using Hairball/Mnats stereo link pcbs. The limiters work perfectly in dual mode but not at atll when i switch to link. I trple checked the wiring dozen times and..nothing. No sound out except for a sort of almost silence distorted sound. Any advice? I am getting mad! Thanks!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Hairball Audio on April 11, 2016, 12:27:20 PM
Hi, Mike, Hi mnats,  hi guys. Probably nothing new here, but i have built a stereo version of LN1176 rev J (Gyraf) rotary switch version and trying to link them using Hairball/Mnats stereo link pcbs. The limiters work perfectly in dual mode but not at atll when i switch to link. I trple checked the wiring dozen times and..nothing. No sound out except for a sort of almost silence distorted sound. Any advice? I am getting mad! Thanks!

Are they getting proper voltage?

Do you have the small link wire in place on the PCB by the labeling?

Mike
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Fandangoita on April 11, 2016, 01:11:53 PM
Hi Mike. Yes on both questions. I've checked some previous posts here and it seems that there is an issue about connecting point 15 to volume pot streight from the main pcb and not from ratio pcb. Is that the solution?
Thank you
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: Fandangoita on April 12, 2016, 09:57:05 AM
Done! It works perfectly. Now i am looking forward to receive your matched four fets for a perfect stereo performance. Congrats to Mnats and Purple for the project and thanks Hairball for the totally killer deal selling this stereo link PCB  kit.
Just to make it clear, if you build a stereo 1176 clone rev J  (Gyraf project),  rotary ratio board, adding the  Hairball stereo link PCB,  you must consider that  lug1 volume pot must be connected streight to point 15 on main pcb and not on ratio pcb, just like on the draw found on this tread that i reposted in my previous post.
Happy stereo compressing!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: TheJetTek on April 14, 2016, 10:42:12 AM
Anyone have insight on installing this kit on a Warm Audio WA76?? I've got everything wired up except I'm stuck on the whole "link to ratio pad 15" part… I have no idea where to make that connection on my units…. Any help, especially with a drawing, would be hugely appreciated.

Thanks guys!!!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: midwayfair on May 30, 2016, 05:31:40 PM
TheJetTek: Use the picture Fandangoita posted.

I can't tell if the link document on Hairball's site is assuming that you're using the rotary PCB (which has pads for the output pot already on it) or just assuming that everyone would leave the connection from the output pot to the PCB in the wiring instructions, but the gist is that their diagram presumes that you're adding this to an existing build and not removing anything or touching any wires except the ones shown. It could probably be clearer in that document, though.
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: elskardio on June 20, 2016, 02:35:11 PM
Hi,

I've been trying to make the stereo link works for the past week and it's driving me crazy!
I have 2 perfectly working mono channels with 4 matched fets from Hairball Audio.
If I use the Pad 7 method to link, I get readings of +\- 1dB. So the fets looks pretty well matched. When I link using the Stereo Link PCB the readings are way off! +\- 8dB
My wiring is good and I read every post I could find on the forum but I can't find the solution and would really appreciated some help.  :-\
Here's a video of what happens when I link using the PCB.
https://vid.me/t24T

Thanks!
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: darkus on June 28, 2016, 05:36:03 AM
Hi all! Just installed the stereo link kit on my mnats rev D´s. Both sound great in dual mono, but when link engaged i get massive distortion and no compression! I guess the distortion is the output trafo saturating cause the output gets a dozen dB´s louder, but i cant get any gain reduction even if i crank the input all the way.

Dual mono, -5dB of gain reduction and output to daw is something like -12dB. When i engage link, no gain reduction and output to daw is +20 and distorted.

Anyone with a similar problem or solution, Mike perhaps?

EDIT: Problem solved, it was the cable connecting the units, so silly, works perfectly now.

-Markus
Title: Re: Hairball Audio: 1176 Stereo Linking PCBs Support Thread
Post by: mhuss on July 08, 2016, 11:40:01 PM
Just (finally!) finished my dual mnats 1176 with the Hairball red link cards . Both channels seem to work fine in dual mode. When in linked mode, sufficient input on channel 1 causes both channel meters to indicate GR as I would expect. However, the same input on channel 2 causes that channel to show /more/ GR while the channel 1 meter doesn't move.

All the connections and voltages on the red cards look good. However, I noticed that when I put in in dual mode, the input to the link switch (coming from pad 15 on the ch. 1 ratio board) goes flat - the signal stops. This happens even when the wire is disconnected at the red board (loop) end!  :o

I checked the DPDT switch and wires carefully with an ohmmeter and the switch seems to be working fine, and nothing is shorted to ground.

Any ideas what I should look at next?