[BUILD] 1176LN Rev D DIY

[okgb]

It's good to have the v.u. option , as sometimes the levels can creep up
before you notice switching to the meter to see that's where the level is pegging in the chain .

An off position is not bad either if the slam mode gets too disturbing
pinning the needle .

 

[Stagefright13]

True. But I am using Protools and my converters will be slammed long before the 1176

 

[okgb]

I'd still do it myself considering the black version had an attenuator before the input xfmr to give you an idea of what's going on in the unit ,
but true most people just leave it on G.R.

 

[Stagefright13]

Wow Tommypiper robes and a straw hut. You guys musta been on some serious stuff!!

 

[tommypiper]

John, and ok, thanks for the info, very helpful! Do you happen to know where the connection point "4" is on the main pcb? It is supposed to connect to the meter switch, AFAIK. There are other numbers on the meter switch board which correlate to connection points on the main PCB, but there is no "4" on the main PCB. Just in case you have your notes handy. Overall looks like I'll have to follow traces like you did, I guess.

Would have been so easy to just label things originally, but oh well. Can't have an easy build, no matter what. There must be some hidden logic to the odd numbering scheme. Not related to part numbers? Not related to a grid? Mmm.

Yes, put me in a robe in a straw hut with my hand on a woman's knee any time. Just get that photographer out of here. Or was it CJ?

cheers,
-"Tommy"

 

[Stagefright13]

Yes the Photographer was CJ lol

Truthfully I traced the board at every connection and checked it off on a printout I had.

It's not a walkthru type of project. You will have to learn some stuff to make it. But was and IS one of the best sounding projects ever.

I didn't go by numbers I went from schematic. So can't help you on that. I didn't even have the rotary boards.

 

[Stagefright13]

Actually I prolly have the rotary boards here somewhere. So if someone needs a set lemme know. I will dig them up.

 

[mnats]

[quote author="tommypiper"]Do you happen to know where the connection point "4" is on the main pcb? It is supposed to connect to the meter switch, AFAIK. There are other numbers on the meter switch board which correlate to connection points on the main PCB, but there is no "4" on the main PCB. [/quote]
There is no "4" on the main PCB. The other "4" is on the Ratio Swich rotary board, just as in Jakob's original 1176 rotary switch design. Wiring the rotary switches is explained on my rotary switch wiring page.

Connect a wire to pad 4 on the meter board. Note that the designation "4" doesn't show up anywhere on the 1176 schematic, it's a marker unique to the clone...Wire the other end to pad 4 on the ratio board, right next to where the output pot wires go.

[quote author="tommypiper"]Would have been so easy to just label things originally, but oh well.[/quote]
Really? What would you call an unlabeled connection from the schematic on the PCBs?

I thought Jakob's numbering scheme was fine - the number 4 isn't duplicated elsewhere on the schematic and it can't be mistaken for anything other than a connection between the two rotary boards.

[quote author="tommypiper"] Can't have an easy build, no matter what.[/quote]
Right. When I decided to offer PCBs of this build, I included this caveat in the first post:

Please note that this is not a "G1176" type project. You must be able to read a schematic, have the patience to read about and locate difficult to find parts and be prepared to think for yourself. If you have any doubts, start with a Revision F/G type project.

I wasn't being condescending, I was just trying to make it clear that it doesn't make a good one-evening project or a way to get a "cheap 1176".

 

[Stagefright13]

MNATS is right. But Damn it if it doesn't make a beautiful sounding compressor!! And a good learning experience too. At least for me. Thanks MNATS for the great design. And if I may say so I am very proud of my work and what I learned in the process. I am sure others will agree. It wasn't easy but was extremely rewarding. I reap the benefits every day. :thumb: I WISH I could assemble the parts to make another.

Thank You!

 

[tommypiper]

I'm sure it sounds great. That was apparent right away to me. In fact I am going the extra mile to use quality parts and do things to maximize its potential the best I can.

Nice to hear from Mnats. I don't think anyone is expecting a G1176, whatever that means. Just basic documentation. It's just the Rev D documentation is incomplete. Yes, how can we know what connection point is what? It's not on the schematic. Seems odd not to put it there when it's on the PCBs, right? :wink:

Wow. I had never seen that switch page, it's quite amazing, thanks. It's not the Rev D project, so I never came across it. We would never have known. And we're supposed to reference Jacob's G1176 to understand how the Rev D is wired? I never would have known that either.

OK. Thanks for telling us. I'm sorry, I thought they were different projects. I've never built a G1176 and I thought the point was to make the Rev D, not a G1176 (as you mentioned).

I know I'm not the only one who has been scratching my head on these points. Yes, of course I would figure it out on my own, following the traces, whatever, as John did, but why not ask if there is some logic behind the numbering scheme and other mysteries along the way? Obviously there had to be, but it was not apparent. How are we supposed to know that we are to look at Jacob's schematic for the Rev D? Jacob didn't design the Rev D, the boards, nor a schematic for it.

You know we love this project and we all appreciate the PCBs. Don't come down on people for asking questions. This is the first 1176 for many of us and we therefore have never seen Jacob's numbering scheme.

 

[mnats]

[quote author="tommypiper"]It's just the Rev D documentation is incomplete. Yes, how can we know what connection point is what? It's not on the schematic.[/quote]
The point is that all connections required to get a working 1176 are on the 1176 schematic linked from the first post of this thread. My schematic (from which the netlist was created) exists as the basis for the main PCB. I included it in my document as a courtesy mainly to show the differences between the original and my clone. The differences are noted on my schematic.

Due to time constraints and limitations of the software I used to draw the schematic it does not accurately represent every aspect of the circuit. The input circuit, for which there are many options, is not included at all (but exists on the JBL and Purple schematics also linked from the first post of this thread). But believe it or not, the connection represented by point "4" is there! Point "4" on the rotary boards feeds the connection made to the GR Control Amp when the GR Disable switch is "off", meaning Gain Reduction is "on".

To be honest, the rotary boards were a bit of an afterthought (I did not use them myself) but I figured since many people have built Jakob's G1176 rotary version it made sense to include boards for the Lorlins. I could have just left it completely up to the builder to wire up the external controls themselves since it seems as though many people have gone with a pushbutton option.

[quote author="tommypiper"]And we're supposed to reference Jacob's G1176 to understand how the Rev D is wired? I never would have known that either. [/quote]
If you put the schematics side by side (they are conveniently close on the JBL document) you'll see that the ratio and metering switching is nearly identical between the Rev D and the Rev F (upon which Jakob's G1176 is largely based). The major differences are in the output circuit and the metering circuit (Class A vs Class A/B; Discrete vs IC). The rotary switch meter boards were designed to accommodate the discrete circuit (reference: third paragraph on my Rev D main page). That paragraph begins with the sentence "Generally, wiring the Revision D is the same as wiring a rotary version of the G1176."

As I've mentioned before in this thread, I can't force you to read my Rev D page. But I would suggest that you read it. It is also linked from the first post in this thread.

[quote author="tommypiper"]OK. Thanks for telling us. I'm sorry, I thought they were different projects. I've never built a G1176 and I thought the point was to make the Rev D, not a G1176 (as you mentioned). [/quote]
My mention of the G1176 was simply in reference to the complexity of the build. If you take a look at the genius of Jakob's design, you'll see that most parts, including the input and output transformers, just drop onto the main PCB. This one ain't that easy.

[quote author="tommypiper"]Jacob didn't design the Rev D, the boards, nor a schematic for it.[/quote]
I didn't design the Rev D or the schematic either. I only made PCBs based on the original schematics that have been publicly available for a while now.

[quote author="tommypiper"]Don't come down on people for asking questions. [/quote]
I was baited by statements like

[quote author="tommypiper"](Where is the documenation, hello?)

I don't think anyone is expecting a G1176, whatever that means. Just basic documentation. [/quote]
...and the first statement quoted at the top of this post. So just to make it crystal clear: everything you need to build an 1176LN Rev D is on the original schematic. I have tried to document my PCB and project as best I can. If you think you can do better, by all means feel free to make your own page as others have already done. Thank you for taking the time to read this post.

 

[okgb]

thanks for making the boards in the first place and this threads reminders
[ like ALL threads ] to read through carefully

[ only have my D version half started , gotta get there ]

regards Greg

 

[Stagefright13]

If you go back about 20 pages you will see my completed REV D. I was able to build it all with the info in MNATS post number 1. So it ain't THAT hard. I'm not genius boy lol. You'll get it done soon TP!

And would also like to voice how cool it was for MNATS to make such a nice board for this. And he DOES link enough info in post one to get it done. I am living proof! :thumb:

 

[tommypiper]

Thanks guys, thanks Mnats. Sorry, I was just wondering aloud and didn't understand the methodology to the documentation. Speaking for myself (and I'm sure others) I appreciate all the effort and time which has gone into making the boards and docs and web pages. A selfless, and mostly thankless effort.
:guiness:

I still don't quite understand the thinking behind the documentation, and maybe I'm seeing something different on my web browser in that first post and your Rev D page (because I'm using a very old browser with no Java, etc), or whatever, because I never saw some of those pages and don't see links or mention of them (like the rotary switch page or the PSU page or any reference to the number scheme from Jackob). But obviously this has been covered now and we should all get back to build related posts.

It's not that I'm unable to figure things out (by following traces and reverse engineering it with my own drawings, etc, albeit slowly) -- I just didn't understand the organizational aproach or the method behind it, and wondered why, and what was going on.

Onward and upward. I'm glad to be working on these again after a crazy year and now I know where to find the missing pad numbers and we can reference the other build projects, other webpages besides the Rev D (this was not logical to me), and Jackob's G1176, and the historical 1176 docs as needed, as well as the rotary boards page and PSU page. I think those are all the necessary references now to complete the picture. Thanks for sharing info in the DIY spirit to all.

 

[Underthebigtree]

Thanks to Tommypiper, Stagefright, and Mnats for explicitly getting all this info together in this section of the thread. I'm just getting to the wiring phase of my units, and having all this in one place will make it easier for sure.

I think that in the case of this particular project, all the information is available, but in disparate places across the net. Tying it all together here will help a lot of us who have not built the 1176 (in any flavor) before.

:thumb:

 

[JdJ]

This might sound like a stupid question, but as I haven't really had the opportunity to use an 1176 other than the dual rev D I have built (and software versions). So disclaimer aside- do those who have built this version find it pretty gritty (especially on higher gain settings)? Don't get me wrong- I dig it, I just don't have anything to compare it to, and I want to make sure I haven't screwed something up...

Cheers!

J

 

[tommypiper]

J, sounds like something is wrong. How's your gain staging?

I hope to contribute more about my own build soon. Underthebigtree and I are trying to finish ours by Christmas. However I've been slammed with family and other work recently.

 

[Underthebigtree]

Looks like Christmas is coming early, TommyP! I just powered up my first unit, and it pretty much all worked perfectly the first time. :shock: :shock: :shock:

It sounds HUGE. Absolutely whisper quiet until I crank the output knob near full, at which time it craps out - I first hear some noise, then some crackling, as the signal disappears. My guess is some sort of RF noise is feeding back and taking over - but what the hell do I know? I was terribly careful with grounding and wiring, and except in edge case situations, it is just fine.

Onward to calibration and figuring out how to mount the damn meter in the hole - maybe epoxy.

 

[Underthebigtree]

So it appears that I was highly optimistic as to my success.

The unit is generating an incredible amount of output - like 21V with the output knob set to halfway. I've gone through the whole thing carefully, replaced Q4 (see below), checked for shorts, and so on. I just can't figure out what's going on.

To start with, here are my test settings:
Input signal: 260Hz sin wave at 0.69Vp-p (-10dBu, 0.448Vac)
Input knob set to 10 (on 0-10 scale), output 0, attack and release fully CW, ratio 1:4, meter knob: bypass

Now here are my readings going through the signal chain to the main board:
Input: 0.448Vac
Hi output of T600: 0.448Vac
(Hi output of T600 at midway setting of T600: .221Vac)
Hi input to Mnats input card: .447Vac
Either output of input trafo (Lundahl LL1540 on Mnats input card): 1.786Vac

So first of all, should the input signal be more than tripled in voltage coming out of the input transformer?

Now here are the readings at my transistors through the signal chain, with the output signal set at zero:

Signal preamp section:
Q1: G=1.62V, D=1.78V, S=1.78V
All the rest are in the order B, C, E:
Q2: 1.78V, 1.78V, 1.78V
Q3: 1.78V, 2.07V, 1.78V
Q14: 2.07V, 1.78V, 2.07

Signal line section:
Q4: 1.79V, 1.79V, 1.79V
Q5: 1.79V, 1.79V, 1.79V
Q6: (didn't measure - has to be done from underside of board)

Now if I set the output knob to 20%:
Q1: 2.6, 3.4, 2.9
Q2: 3.4, 1.7, 2.8
Q3: 1.7, 2.7, 3.0
Q14: 2.6, 3.0, 2.6
Q4: *** (80V?), 1.8, 1.8)
Q5: 1.8, 3.1, 2.1

*** at this setting, Q4 is off the charts when I touch the test probe to the Base pin, and I start to hear a buzzing, ticking sound in my output transformer, which makes me remove the test probe rapidly. WTF?

Now if I set the output knob to 50%:
Q1: 18.5, 21, 20
Q2: 21.6, 1.8, 21
Q3: 1.8, 19.6, 20.7
Q14: 20, 20.7, 19.1
Q4: ***, 14.8, 18
Q5: 16.3, 20.8, 3.6

The first thing I did after taking these measurements was to swap out Q4. No change.

In addition, as soon as I get the output up to about 20%, the sin wave starts distorting asymmetrically on my scope.

Here are the corresponding output voltages, measured at pin 2 of the output XLR, between my unit and a UA 1176 reissue:

Output knob My unit 1176 reissue
0 .001V .001V
2 2.8V .068V
5 21V .425V


Any help would be greatly appreciated. I've been banging my head against this for a couple of weeks, and don't know where to look next.

-Nick

 

[tommypiper]

After a cursory glance at your post. Sounds to me like you have something wrong at the input. I don't have the docs in front of me and can't remember off top of my head, but I don't think it's a 1:3 input ratio. Sounds to me there is something wrong with the T-Pad and input transformer wiring. The distortion you're getting is because the signal is too hot through the circuit.

We should get together. Call me.