[BUILD] 1176LN Rev D DIY

[mrtomcat]

Thanks Mike!

 

[dbonin]

Hello everyone,

I got my potentiometers today (thank you Mike!) and finished my build, all working great . Calibration wasn't as awkward as I expected!

Sounds lovely, exactly what you want from an 1176 and reacts almost identically to how I remember the ones that I've used. Such low noise as well, kudos for all the wiring tips.

What is the best way to verify the ratios are working as they should? It all sounds right to me but wouldn't mind having a look. My DMM is useless at low VAC, but I can work with test tones and record them back in etc..

Thanks again to Mike, mnats and everyone else involved in putting this together. Was a lot of fun to build and learnt a lot.

What to build next?  8)

That's the distortion trim - just leave it alone.

 

[johnbroadb]

Hello,

I just completed my first 1176 rev D build, massive props to mnats and hairball, great work!
Everything works as it should and I have calibrated the unit, it passes signal fine and the compression is working.

I am finding i have a heap of extra noise, starts off as more of a buzz which gets louder the more you turn the output up until the last little bit when i turns into more of a hiss. The signal i run through it is fine, theres just all this extra noise. When i turn the unit off, it still has a buzz when i have it plugged into the speaker. its alot quieter but still there.

I'm thinking its a shielding/ground issue? i'm fairly new to this so any help steering me in the right direction would be much appreciated.

 

[mrtomcat]

Hello,

I just completed my first 1176 rev D build, massive props to mnats and hairball, great work!
Everything works as it should and I have calibrated the unit, it passes signal fine and the compression is working.

I am finding i have a heap of extra noise, starts off as more of a buzz which gets louder the more you turn the output up until the last little bit when i turns into more of a hiss. The signal i run through it is fine, theres just all this extra noise. When i turn the unit off, it still has a buzz when i have it plugged into the speaker. its alot quieter but still there.

I'm thinking its a shielding/ground issue? i'm fairly new to this so any help steering me in the right direction would be much appreciated.

make sure all your audio wires are out of the way off the PCB, you twisted the wires where stated, use the casing as additional shielding where ever possible

 

[dbonin]

Hello,

I just completed my first 1176 rev D build, massive props to mnats and hairball, great work!
Everything works as it should and I have calibrated the unit, it passes signal fine and the compression is working.

I am finding i have a heap of extra noise, starts off as more of a buzz which gets louder the more you turn the output up until the last little bit when i turns into more of a hiss. The signal i run through it is fine, theres just all this extra noise. When i turn the unit off, it still has a buzz when i have it plugged into the speaker. its alot quieter but still there.

I'm thinking its a shielding/ground issue? i'm fairly new to this so any help steering me in the right direction would be much appreciated.

make sure all your audio wires are out of the way off the PCB, you twisted the wires where stated, use the casing as additional shielding where ever possible

Tomcat is right and it is 100% necessary to make sure you have a  good electrical connection between all panels of the case (I do that before adding a single wire).  You should have continuity from the ground screw in the back to both sides and the front of the case.  If you have that, this is very likely a wiring issue.

 

[Echo North]

Make sure you don't have wires hanging across the PCB either.  Particularly near high impedance sections of the PCB.  Keep long runs of wire off to the sides of the enclosure.

 

[mrtomcat]

One more thing...I mention this because that's what happened to me and it cost me countless hours of headache:
Make sure that the signal that you're sending in is clean... I had forgotten to change the sample rate on my converter and it created a nasty noise that I thought was because of my wiring...so check the signal coming in prior to sending it into the unit first

 

[johnbroadb]

Thanks guys,

I'll get on to that tonight after work, my wiring is a tad messy at the moment, i hadn't tied them up yet just incase i did have a problem.
I have twisted the wires where stated, i couple of the long ones haven't been moved to the side yet.

Thanks again! i'll let you know how it goes

 

[mitsos]

Thanks for the confirmation... working fine now.. I did have a toggle switch for the link, and it worked fine, but something was not right about the unit.  It actually worked fine at my place, but I had it at my friend's for a few months and it would act up there.  Once in a while the VU would go from 0 to about -3 and sort of fluctuate back forth a bit (like between -2.5 and -3.5 or so). This was with the meter in GR (of course) with or without signal, sort of like -3 was the new 0.  In the end, I think it was compressing, I'm waiting for my friend to send me a vocal he ran through this unit where it happened in the middle of it.

Anyway, I can't say for sure that it was the link circuit, but with so many wires in this box (2 channels in 2U), one less thing will at least make it easier to troubleshoot if it happens again.  So far though it's been on for a couple of hours and needles are set at 0. Fingers crossed.

thanks!

OK, left the unit at "friend A's" studio for a few days. That's where it was having the problem. Presented the VU issue after a couple of days, I picked it up and left it at Friend B's studio to rule out studio/power issues because he's had some PSU problems in a couple of other pieces of gear.  Anyway, here again, it was working fine for a couple of days, then, yesterday, while I was there, I glanced down, and the needles were at -3... This is with VU in GR mode, no input, controls have no affect.  I opened it up as quickly as possible to take some voltages, and proceeded to check the PSU first.  As soon as I touched my DMM probe to the -10V output (mnats PSU), the needles went back to 0...  all transistor voltages were in line with voltage chart... but I expected as much because the VUs were already back to normal.

I'm at a loss how to proceed with this, I guess next time it does it I'll measure the GR Fet voltages first...  Anyone have an idea?

thanks!

I think I finally got this cleared up... I had the FETs on sockets from the beginning and left them like that.. Well turns out the right channel meter FET had a bad socket that was going intermittent... I took out the sockets and it's been on for 3 days now without a glitch.. I had started to suspect them, but it was mnat's idea of poking with a stick until it the problem manifested itself that made me check them.  so thanks to mnats!

Moral of the story? Don't use sockets? Maybe use better sockets? the old 1176's had sockets, as does a lot of other gear, so maybe there's no moral at all. 

I'm just glad to have it working..

cheers!

 

[mrtomcat]

All done building...calibrating tomorrow...wish me luck

 

[mrtomcat]

Calibration worked first time around...the rev D proudly took place next to the rev A

 

[rjd2rjd2]

Hi all-I'm hoping you can help me.

The output transformer that came with my hairball kit has wiring that does not match the color coding on my rev D PCB. there is a blue, red, gray, and brown wire, but none of the wires are colored "white/red" or white w/ stripe.

i have been around and around both the mnats and hairball sites, and cannot for the life of me find ANY docs relating to this. can anyone point me in the right direction as to what pads these go to? thanks alot-rj

 

[Echo North]

Hi all-I'm hoping you can help me.

The output transformer that came with my hairball kit has wiring that does not match the color coding on my rev D PCB. there is a blue, red, gray, and brown wire, but none of the wires are colored "white/red" or white w/ stripe.

i have been around and around both the mnats and hairball sites, and cannot for the life of me find ANY docs relating to this. can anyone point me in the right direction as to what pads these go to? thanks alot-rj

What?!?!  That weird.  Did you get the kit direct from me? 

Did you get a Rev F/G output transformer?  Does it say B11148 on it?

Send me an email (info at hairballaudio dot com).

 

[johnbroadb]

Hi Guys,

Just wanted to let you know i fixed the problem and it all works perfectly! yay for me!
It was exactly as you guys said, i hadn't gotten rid of the powdercoat underneath the output transformer, so i wasnt getting any connection between the transformer and the chassis. once i fixed that there was no more buzz or hiss.
Man it feels good to have built my own fully working 1176! Thanks hairball aduio and mnats!!!

I'm just slightly excited!

 

[rjd2rjd2]

yea, it says B11148 on it.

 

[schepbo]

Hey! I just finished my build of the rev D 1176. It turns on and passes audio fine, but when i turn the output knob to about 1/4 the meter pins straight to the right. When the output knob is almost open, the needle drops to zero again. I have an oscilloscope and i can see a high frequent signal coming out when the meter pins to the right, even when no input is present. I also listened, and i can't hear any kind of compression, regardless of the settings.
I checked the wiring, and everything is connected as it should be. Soldering joints are all very neat. Voltages from the power supply are perfect and stable.
I'm very confused right now.. I hope there is someone who can help me!

Bart

P.s.: Sorry for my bad English.

 

[dbonin]

I'm sure you already checked this, but for the record...

make sure all your polarized caps are positioned the right way, transistors are seated correctly and the right transistor values are where they need to be.

High freg oscillation?  All your wiring is shielded and or twisted as it should be, routed around the board?  did you check to make sure chassis ground is good all around the case?

Hey! I just finished my build of the rev D 1176. It turns on and passes audio fine, but when i turn the output knob to about 1/4 the meter pins straight to the right. When the output knob is almost open, the needle drops to zero again. I have an oscilloscope and i can see a high frequent signal coming out when the meter pins to the right, even when no input is present. I also listened, and i can't hear any kind of compression, regardless of the settings.
I checked the wiring, and everything is connected as it should be. Soldering joints are all very neat. Voltages from the power supply are perfect and stable.
I'm very confused right now.. I hope there is someone who can help me!

Bart

P.s.: Sorry for my bad English.

 

[dbonin]

also, confirm your output transformer wiring is correct both to the board and to the xlr - also, check that output transformer ground wire is good.

Hey! I just finished my build of the rev D 1176. It turns on and passes audio fine, but when i turn the output knob to about 1/4 the meter pins straight to the right. When the output knob is almost open, the needle drops to zero again. I have an oscilloscope and i can see a high frequent signal coming out when the meter pins to the right, even when no input is present. I also listened, and i can't hear any kind of compression, regardless of the settings.
I checked the wiring, and everything is connected as it should be. Soldering joints are all very neat. Voltages from the power supply are perfect and stable.
I'm very confused right now.. I hope there is someone who can help me!

Bart

P.s.: Sorry for my bad English.

 

[Sillen]

Hi
Wont the tracking adjustment trimmer work unless you also install the shorting thing (which i've lost)? Or is it just bad connection of the trimmer?

 

[dbonin]

Regardless of calibration, the shorting pin is required for normal operation - you could rig up a piece of wire to connect the pins until you get a replacement.
Rig something up and complete the calibration as mnats shows in his videos and you'll be good.

Hi
Wont the tracking adjustment trimmer work unless you also install the shorting thing (which i've lost)? Or is it just bad connection of the trimmer?