[BUILD] 1176 Rev A - Back to the beginning...

[Rob Flinn]

I don't know where you guys are getting your 2N3707's from, but out of a total of 40 I had 24 above 250, 12 between 200-250, & only 4 below 200(all 4 were close to 200).

 

[ethervalve]

i got mine at mouser. central semiconductor was the brand, if i recall correctly.

 

[orangerec]

Mouser here also...Central Semi

 

[phatmateo]

ha, same here.  Mouser/central semiconductor.  Where did you get yours?

 

[Rob Flinn]

I got them from ebay seller : razzzzzor
Item number: 270287553123

I've dealt with them before, they are reasonably priced & send the goods really quickly.

I had actually populated the board with some 2N3707 that I had previously bought form the same guy, but had not checked the Hfe.  As I didn't have any spares, & listening to the experiences you guys were having I thought I'd buy a few more.  However only 2 of the ones I took out were out of spec.

 

[RedNoise]

May I ask if it's important  : should those Fet be JFet or RF JFet ????
I dunno if this matter...
Thanks.

 

[orangerec]

Yes, thank you stagefright13, I replaced R75 with the 5k trim pot and bingo, 0.00 vDC. I do remember reading that, thanks for the reminder. The other issue with my release control was a wrong value resistor, a 270ohm instead of a 270kohm across the 5M pot.  :-[ I have way too many projects going on at the same time: 2 SSL comp, 4 pultecs, another G1176 and the RevA. woooooooo ;D
For those of you building this, I highly recommend installing the FETs on sockets, it's a huge time saver if troubleshooting is needed.

 

[Stagefright13]

Hey cool I helped someone! I always wanted to, cause I got so much help here from other people.

My REV A is coming along rapidly but I am so tired right now. I have so much respect for Purple etc. now that make these things at that price point.

 

[Stagefright13]

Woohoo the rev A is alive! Worked perfect right away! Thanks to Mike's switch boards and Skylar's wiring diagram it was a piece of cake. Thanks Mnats! Once again you rock!! My first rev D I did the switches point to point and wired it all from the schematic... Took me a while.

Sounds great and VERY different from my rev D. Seems to have a harder knee and a brighter sound. Definitely cool to have. It's a totally different sound. I have a band coming in later this week so I will see how it sounds on stuff.

I did spend an hour tho rechecking all my wiring because the meter didn't work in GR mode. But it turned out the trimmers were set beyond the meter's threshold... I still have to tidy it up but here's a couple pics:

 

[Stagefright13]

Also use the testpoints for calibration, the voltage across R74 is constant. Different than the video if you are using that. Make sure ya solder in a couple pins to clip your test leads to. The test points are the same as the R74 test point on the rev D.

Starting to sound more rounded after a couple hours of burn in. Let ya know. I like a couple days of burn in before I say anything. I jumped the gun cause I am anxious. Has a smooth sound and seems to mate with a U87 vocal track perfectly. Or maybe I have heard this sound before...

 

[Echo North]

Nice work!  ;D

 

[orangerec]

Great Stagefright13, someone else who is done. I agree with you about the sound, different from the revD, as it should be. I really dig this compressor. Have you tried the "all buttons in" (actually, all you have to do is push in 4:1 and 20:1)yet? This is the only issue I'm having. After all the calibrations and burn in, I love it but it is not responding well with the nuke mode. I love this on snare drum and occasionally on a mono drum room mic. My revA distorts, not in a nice way with the the effect.

I don't have mine in a rack case yet, refuse to load it in 'til everything is perfect. Love the pics, any shots of the front? Frontal!!! 

 

[Stagefright13]

Yeah the all buttons in has a slight issue. Mine sounds like nuke but I get some pops on plosives. But I think there is a reason for that lemme look back... Something to do with the resistor on the ratio board I think. I may be totally wrong but I think that is the issue.

Mine got alot mellower after a few hours burn in. Still different but I can hear the old style transistor sound. Hard to explain.

 

[orangerec]

Yes, exactly! Plosives is a perfect way of describing it. Sorry for that, but at least I know it's just not me...gonna keep investigating. Anyone else?

 

[Stagefright13]

I'm busy as hell forget the weak economy. It is a resistor. Too tired to do it right now but will tomorrow. But is listed in the rev D thread... I think. Skylar asked questions about it if I remember correctly.

 

[Stagefright13]

I'm guessing here but it may have something to do with the position and value of R45. I tried reading the schematic here: http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-1176LNmanual.pdf but the image is fuzzy at best lol. I don't ever use the all buttons in anyway. I don't often need the "Wall of sound" effect.

I'm pretty sure Ed Anderson said something about R45 is there to prevent the compressor from going crazy in nuke mode. Over the years it appears in different spots. But I'm just an amateur so don't go by me. But I try hard lol. I'm sure it can be fixed fairly easily. 

And this thing sounds frickin' great. I've run several dozen different tracks thru it and has been compressing a loop for almost 24 hours. Not sure if it is the carbon resistors or the orange drops or the circuit itself. But it has that really cool brightness the 1176 is known for. It's bright but not brittle or grainy. And doesn't cause any sibilance. Cool effect. Even with the GR off. Certain tracks sound better just running thru it period. Even uncompressed. I should be wiring my rev D right now but I can't leave it alone lol!

Just when I thought I was done building for a while I may just have to make another of these...

John

 

[orangerec]

I believe this is what we're looking for. I pulled it out of the Rev D thread. It is in reference to R46, the 10M resistor. Now, I'm gonna try and make sense of it. Any help would be appreciated. 

http://www.groupdiy.com/index.php?topic=20058.msg259614#msg259614

 

[Stagefright13]

Yeah the 10 meg R45. It's on the 20:1 side on my rev D's. However the Rev A was manufactured BEFORE someone figured out how to "Nuke" it and later they positioned that resistor to keep it stable. Dunno just guessing. Like I said just an amateur. But seems a likely culprit.

I am calibrating my rev D right now but intend to fully experiment with my rev A. But will be busy this week. I have $400 worth of cables and a new rack arriving tomorrow. So I might not be able to try anything after tomorrow. At least 'till next week. But Mnats and Ed Anderson are the kings on this 1176 thing. And thankfully they both post here!

I still can't believe Mnats squeezed 2 1176's into such a small case!

John

 

[Siegfried Meier]

I've got a complete BOM that I will post once I go back through and check a couple items.
I have seen it mentioned that electro's should be rated close to operating voltage instead of over-rated. Does this matter? Ie; using a 100V electro in a position that will not exceed 35V (better to use an electro rated closer to 35 + a couple)?

Thx,
Jonathan

[EDIT]
Here is a BOM I put together to help myself understand all of the components:

http://diy.dbfsforge.com/mnats_d1176/mnats_1176_revA_BOM_DUAL_jonathan-burtner.xls

I referred both to the schematics, the boards, and various other threads.

Please be sure to check that these components are adequate for your particular needs before ordering.

Shoot me an email or PM if you find there is anything worth changing and I will update the list with a new version.

Cheers,
jonathan

Anyone ordered from this yet, and have noticed any issues?

Thanks!
Sig

 

[Stagefright13]

Well I am doing a full CD project right now. And after 3 snares and 2 compressors on snare... Guess what? the REV A is ruling the show! Thanks MNATS! It's sounds great. And I get to use it again in the mix. Awesome compressors both rev D and A.

Appreciate the work you did to make these possible.

John