[BUILD] 1176LN Rev D DIY

[mnats]

Yes, the R12 thing was for College who may have missed that on the site  :

the BOM I had downloaded and printed from the site about a week ago is now different than the one that is coming up today... very odd.  The one I looked at last week had R15 as a 7.5k, and only had R34 and R76 as 8.2k (was missing R77) unless there are 2 different 1176LN_REVD_V2.2_DOC.pdf files on your server it looks correct now. 

The only other thing would be the 5W resistor for the hailball VU. 
Sorry about the confusion is there was any.

The BOM hasn't been altered since David Kulka pointed out the error with R12.

There's no way of knowing what type or number of light(s) each builder will use - if any - with their VU meter so adding a dropping resistor to the BOM would be irresponsible unless a specific bulb/LED was also added. Note that the original schematic shows two bulbs in series with no resistor. There are simply too many options available and no good reason to limit DIYers to one rigid standardized build.

 

[college101]

Well I order'd some more parts, cant wait to get started...cleared off my bench last night in order to get ready...

Building an EQ after this build for my next class project in school...

 

[zorg]

I'm actually building  1176 rev D with Mnats 2,2 pcb version.
just one question,about the 5002 output transformer cables: Mike wrote on the forum: "Yes orange and yellow.  Tie them together and nothing else"
Do you guys mean I have to connect the orange with the yellow cable or just tie (roll them) without soldering?
would you send me a pic? a clear explanation.
I'm on 220v country
Thx a lot.

 

[sr1200]

being that this an audio transformer, i dont think the supply voltage has anything to do with it (i could be wrong), but if you're using the hairball transformer that came in the kit, solder them together, and insulate the solder joint so it doesnt hit anything and ground out. 


The POWER transformer is a different stowry all togevva... i had to beat them to deff wit their own shoes...

 

[zorg]

Thanks to SR1200 and Mike "Echo North" for your answers.
The unit is finished, kudos to my father who did most of the building and measurement  , I was his humble assistant.

we're going to calibrate the baby following the Mnats videos, is it difficult? any advices or issues?
Merry Christmas to all  the forum members.

 

[zorg]

Does the wiring seems correct on my 1176 pic?
Thx guys

 

[sr1200]

looks about right to me... only thing i can add as far as tips to calibrate (the mnats video's are pretty good, just be ready to pause them a lot while you catch up, as a lot of things are done sped up to runtime sake for the vid)

if you read page 105 of this thread there was discussion about this:

I've found it more useful to start the input at 50% and the output at 0.  Once you apply the signal (with attack OFF), bring up the OUTPUT till you get to 0.  (you will barely have to turn it up to get the needle to fly over, this is ok)

Turn ON the attack (you should see the drop)
Adjust the OUTPUT till you get to -10
Turn the attack OFF (the needle will fly up past 0)
Adjust your INPUT (down) till you get back to 0
Turn the attack ON and you should be REALLY close to getting it 0 to -10.

 

[zorg]

Thx for your advices sr1200
cheers from France

 

[awall22]

What value are the resistors and capacitor that go on the attack and release potentiometers?

1176(D Rev) 

 

[Majestic12]

you just have to look in the schematic.....


Attack    470R +  22nF
Release  270K

 

[college101]

I am sure, everhyone is aware of some recent updates at Hairball audio! Have you been to site lately? I like the new look!

I recently read the new post at Hairball about completing the 1176 build,  I decided to test my power supply first and then go forward..

I assembled the power supply, connected the ground wire to the power cap(c25) and then fired her up...good news.. I got +30 volts and -9.98 first try this time! I am excited and back on track! 

Just thought I would give  updated report with my build

 

[sr1200]

Hey College, I feel your pain on the previous issue man...

I just finished my 2nd (well, 3rd, but this is my second that im keeping) and am having all sorts of problems with it lol.  The thing powers up just fine, but I cant calibrate it for anything, the pots run out of room way before coming close to what they need to be set to, so im going to get some new multi-turn trimmers and see what happens, the unit is passing audio just fine, but theres no compressionthe GR needle just sits there acting sort of assish.  Im gonna open my working unit up tonight and compare the 2 to see what I messed up.

 

[zorg]

Same issue here audio ok but no compression,
In GR mode, the needle is locked on the left side in the meter.

In +4 meter mode the imput modulate on the meter.
Imput and output are ok.

any ideas why compression doesn't work?
Thanks

 

[sr1200]

deleted cause im a dumba$$------

 

[sr1200]

The prob im having is during step 3 of the calibration... when switching the attack from off to on there is NO drop of the needle at all, just wiggles for a split sec then goes back to 0.  sound familiar?

 

[sr1200]

Gaaaaaahhh!!!  found the prob!  the wire going to pad 22 was reversed on the attack switch! DOH!  works fine now....

 

[zorg]

What are the things I have to check to find the compression problem?
When I push the GR button, the needle stay on the left side, and even the GR meter doesn't move , the unit doesn't compress.
How to check the Q bias trim pot/ Pannel attack button? Is the circuit is all set on off by a wiring mistake or a fet componet is dead?
`How can I check the fet transitors?
Thanking you guys for helping a French Newbie.

 

[sr1200]

I was having some REALLY odd issues because the tracking adjust trimmer was all the way to one side (similar to what you're going through right now)  I would say, go over the entire wiring diagram again from the beginning and double check your wiring (thats how i found mine)  Also, make sure you put the jumper back on to put the R44 back into circuit before trying to compress otherwise nothing works right.  If you can take some pics of both the switch connectors and pots/switches, maybe there is something wrong there, if you really think its a fet issue, make sure all the fets are mounted properly first, then check this
http://mnats.net/files/1176REVD_VOLTS.pdf and check against the voltages listed on there to further troubleshoot.  Good luck!  This is an AWESOME!!!!! project, you're gonna love it once its up and running!

 

[thesystem]

Hi guys, I'm wiring my 1176 right now and everything is going well. I'm about to wire the T attenuator to the input tx but I want to use an original UTC 012 which I bought on ebay. How do I connect the wires?? And is there also a nice way to mount the 012 to the chassis cause it doesn't fit the hairball pcb. thanks!

EDIT: 2nd question: how do I mount the attack and release pots? There's a ring attached to the pots but they should stay behind the case on the pot right? Also, how do you attach the knob to the pot?

 

[skidmorebay]

Everybody,
I completed a Rev D 1176 recently. It's been working great except that I get quite a bit of noise that is dependent on what level the output pot is set at. There a lot of broadband hiss and occasional crackling. I re-soldered the pot, and then replaced it with the upgrade suggested in the MNATS bom. Each time it seems to solve the problem, but it comes back - I think it make actually start making noise after running for a while/heating up. None of the other controls have any effect on the noise. All the solder connections to all the pots seem sound. Any ideas on where/how I should start looking? Any help is appreciated.
thanks,
JS