[BUILD] 1176LN Rev D DIY

[blackwaterstudios]

Please do and thanks!  LEt me know the paypal amount and I'll shoot it to you right now.

 

[Echo North]

I'll toss it in for free, no need for payment.

 

[electron monkey]

Ok, I'll try and get this thing fixed up in a few weeks!

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

Did that effect functionality? 

 

[blackwaterstudios]

Well - if by functionality you mean "The Freekin Thing Don't Work" then yeah - pretty much so. 

I'm now trying to figure out if there's supposed to be a wire on the ratio board that attaches to a resistor beside it via a large ass teardrop shaped solder blob and if any of the other wires attached to the ratio board should be touching the ones next to it... ???

I'm  being an ass, I'm sure they don't.

 

[Marcocet]

Hahaha. Guess who burned up the power xformer on his second one by accidentally putting one of the 12v lamp bulbs in instead of a fuse and then plugging in to some bad power?

Note for others: those things in the kit are not fuses

 

[MicDaddy]

Hahaha. Guess who burned up the power xformer on his second one by accidentally putting one of the 12v lamp bulbs in instead of a fuse and then plugging in to some bad power?

Note for others: those things in the kit are not fuses

;D  Hey don't feel bad  

 

[blackwaterstudios]

Well I have resoldered all the connections on the ratio board - well actually I mean I reheated the solder connections then slung the board to get the solder blobs off of it and everything seems to LOOK ok now but I still cannot get the thing to do the gain reduction meter calibration.  All other calbrations went fine.

I * think* the guy that wired this lifted a pad on the ratio board while doing his "very drunk ninja on qualuudes" soldering technique and that's why the solder blob to connect one of the input wires to the resistor below it but damned if I can find a pic of the ratio board and I *know* I saw either a pic of a schemo for it around somewhere - but I would like to confirm this.

Anyway - with R44 in circuit it 0's fine with R71.  Short pad 22 to ground and add tone and adjust output to "0" goes fine.  Removing the wire to see the gain reduction and nothing.  It just sits there.  I went on with the next calibration step thinking maybe that's just where it lands and adjust input till I see -10 on the meter and that goes fine but when I reconnect pad 22 to ground - meter doesn't move.  It's passing signal or at least I can hear tone in my headphones but I can't tell if it's compressing it.

I'm SO close to finishing this but have been trying to figure this one last thing and it's killing me!

 

[blackwaterstudios]

No one eh?

 

[Delta Sigma]

Did you follow this? http://www.groupdiy.com/index.php?topic=20058.msg323325;topicseen#msg323325

If you bought the Hairball kit and its bill of materials ignore the part about using a decade box. The 2k trimmer should work fine. I think the key to this one is to use an external meter (if you have one available) to measure the 10dB drop on the output (when I did mine I terminated the 1176 output on my ADC and measured using a meter in bridged {hi Z} mode). Once I had my 10dB drop, I jumpered in R44 (which I had set to a minimum) and adjusted it until I saw the drop. I then had to set R75 & R71 to zero and adjust R44 multiple times until it was dead on.

Now if you don't get the a drop on your actual output when you engage gain reduction then have some troubleshooting to do. If you don't have a level meter to put on the output just use a DVM. Make sure you have a good signal going in (like +4dBm) to make sure that gain reduction will occur. I think +4dBm would be around 1 1/4 V (RMS) on your DVM or try Googling for conversions (http://www.sengpielaudio.com/calculator-volt.htm).

You can also use an Ohmmeter to check continuity between connections if you have to gain reduction and you're stuck. Just don't probe your solder joints. Pick a point on either side of each soldered connection you want to test (pick a point on the meter board and the main board that is directly connected to the points you want to test then check you schematic to see if your test points make sense). Don't worry about impedances from other components when checking continuity. You should read 0.2 Ohms or something like that depending on your meter and leads.

Also, if you cannot see as large of a voltage on the output as you have on the input (by reducing your input attenuation {CW on the input knob} and turning up your output gain {CW} then you have problems in your audio stages and not the gain reduction sidechain. I had this problem on one of my units from some poor wiring loading the input transformer. I cleaned that up and I was sailing.

Also, taking a break and watching the NHL All Star week-end might help....

 

[Stagefright13]

Actually after setting the first calibration the compressor should work fine. Irregardless of what the meter says. Put a track into it and turn the input up high. It should smoosh. Just listen. When you select a different ratio you have to adjust the input level to compensate. It's not like a DBX style compressor. IF it is smooshing then maybe the calibration steps are confusing to you. If it is not smooshing the signal then it's troubleshoot time.

The first time calibrating one of these can be confusing.

John

 

[marshman]

Hey hey,

Just wanted to give a shout out to Mnats and Mike from Hairball. I just finished a couple of rev D's I started WAY long ago.

They both came on line with no problems what so ever thanks to the excellent doco that was provided. No I am sorry I procrastinated so long! Great boxes!

Thanks again for a great project!!

mm

 

[blackwaterstudios]

I wish I had an external meter but I don't.  I'm tempted to rip out all the wiring the guy did and re-do it myself to see if that helps - the only thing stopping me is i'm thinking it's something stupid I'm not seeing.  I redid all the calibration steps again just to be sure and the q-bias and meter went fine so the thing IS working and passing signal - just going belly up on the GR meter tracking.

I'd surely paypal someone that knows what they're doing for some phone support!      Beer money anyone?  It's gotta be something stupid...

Oh well - back to checking all the wiring...

 

[Delta Sigma]

Is your unit compressing? Ignore the meter and listen to something through it and try to squish it. You should be able to hear it.

If it is compressing don't assume it's your wiring. The calibration is not easy and your meter won't track (in GR) until you've calibrated it.

Did you try using your DVM for levels? It is not precise but it would work.

Can you generate some sort of tone? Even a plugin should be able to generate some sort of sine wave (1k if possible) at a hot level. As long as you can do that and measure at certain points with a DVM and make calculations to convert dBV to mV. It won't be as exact as using measurement equipment but it'll be good enough to make the thing usable.

Are the instructions confusing? I've calibrated a lot of complicated control systems and still found the instructions confusing (I didn't watch the videos though so I can't comment on them).

If you get stuck just walk away and try to explain (on here) where you're getting stuck. I'm sure someone here will respond fairly quickly.

 

[blackwaterstudios]

Ok - here's what I have now.  I took it up to the studio and ran a bass guitar track thru it and it DOES seem to be compressing and the meter IS showing gain reduction although I dunno if it's correct and I assume not but I'm ok with that for now - at least it's showing SOMETHING and it appears close maybe.  Sounds fantastic too!

So I wonder what the deal with the GR calibration is?  I'm inputting a +4 1k square wave tone and following the video step by step and as I said earlier it does fine until turning off the attack to set the 10db GR drop and I'm seeing no drop in the meter at all.

Weird.  Closer though - and thanks to all that have helped so far - just this one last thing and it's in the rack and on to the other 3 and hopefully you won't hear anything from me on those other than "Another one done and sounding great!!" 

 

[kosty]

So I wonder what the deal with the GR calibration is?  I'm inputting a +4 1k square wave tone and following the video step by step and as I said earlier it does fine until turning off the attack to set the 10db GR drop and I'm seeing no drop in the meter at all.

You should use a SINE wave not a square wave !

---------

I've got some hum / noise issues after doing some changes on the board and I just can't find what is causing this.
The unit was fine before.
So what I did is :

I removed the sockets for Q1, Q11, Q12, Q13 and soldered them back directly on the board in the same position.
I did the same for R59 (Q-Bias pot) after placing a socket there because of a faulty pot previously.
I resoldered XLR in / Out (just cut out the end of the previous cable and resoldered it in a cleaner way then before).
Grounded the input transformer board, as the tutorial of mnats suggests.

The problem now is that I have noise (ssshhhhhhhhh) going to the output if I turn the output level above 9 o'clock and some hum is added above the 12 o'clock position.

It appears that it's not related to the Input or the input att / tranny, because this problem remains after removing the wires to the input section of the board.

The strange thing about the hum is, that it gets louder when I hold my hand close to the pcb board (approx 2-3cm).

Is it possible that I can get these symptoms when Q1, Q11, Q12 or Q13 are not soldered correctly or the pins are shorted  ?

 

[Delta Sigma]

When I did mine, I adjusted in/out to get a 10dB drop then thought of the 0 adjust, null and meter adjust as one big step with two parts.

Part A: Turn off gain reduction (attack pot) then tweak the 0 adjust pot (R71) and null pot (R75) for 0 on the meter and 0V on R? (I can't remember which resister you measure across) respectively.
Part B: Turn on gain reduction (attack pot) and adjust meter tracking pot (R44) to -10dB on the meter.

Part B will throw off you 0-ing so repeat part A then repeat part B until neither throws the other off.

Again, I didn't watch the calibration video so there may be a better way but this worked for me.

Hope that helps.

 

[[email protected]]

I had the same issue on m first attempt at GR Meter Calibration. Turns out that I had to start the calbration process with the input level set to 16 instead of in the middle. I found that when you are performing this calibration, if the input level is not  near the final setting you will not see the meter drop at all.
Try playing with the stating input level
Good luck

 

[blackwaterstudios]

Ah!  Nice one Bruce - I'll try that!  Thanks! 

I believe a square wave will work just fine will it not??

 

[[email protected]]

Three more questions:
What are you using to generate the square wave and how are you measuring it's amplitude (voltage)?
Are you using the Stereo Link option from hairball?

Cheers

 

[Biasrocks]

I believe a square wave will work just fine will it not??

No, use a sine wave.

Mark