[BUILD] 1176LN Rev D DIY

[usekgb]

I'm very interested to know this...perhaps that's why I can't bias this thing to save my life. Maybe my ratio switches are backwards. That'll be fun to take out... :?

That's exactly why I want to find this out before soldering. And what a nightmare to remove these once soldered!

Cheers,
Zach

 

[Stagefright13]

I would just use a continuity checker on the switch and check it verses the schematic to confirm the orientation. Then you'll know for sure.

 

[ap123]

Stagefright13, did you finish calibration on yours? I'd be interested to know any of your comments on calibration. I still get no limiting on certain positions of the ratio switch all dependent on the bias adjustment. I just can't seem to get it to work once I follow the bias procedure. I'm going to check the switch continuity when I get home. Inside the switch is two half moons and I believe they cannot be oriented incorrectly...but it's time I test that because, like I said before, I simply cannot calibrate the unit. It also seems like the function of the limiter is dependent on the meter calibration itself -- and I've read some say "zero the meter before you bias" but the bias effects the meter zero. I'm going to go back to where I should've left out R44 and start from there.

 

[Stagefright13]

I did the first 2 steps of calibration then just adjusted the other pots to get the meter to work ok at -10 and -3 gain reduction for now. I still have to install an input transformer and a step down resistor for the meter lamp. So I figure i'll remove r44 at that point and finish it all at once. With a more precise calibration. I rather calibrate it in it's final configuration.
But it works fine at all GR settings and output settings. And confirmed audibly. It actually sounds surprisingly good "as is" on some stuff.

Plus it's always nice to burn something in a while first...

 

[Stagefright13]

Just turn the q bias all the way up past the point where the meter climbs... Then set your zero at +1. Then turn bias down till your meter reads 0. You should do this with an external meter. But I did mine with the internal one for now.

Are ya having any luck yet?

John

 

[ap123]

After reading some other 1176 threads I grounded input to the chassis and two things happened: 1) the noise disappeared and 2) all aspects of the unit became much more stable. Now I've done the calibration and the world makes sense again. Between my germanium and this I sound a lot more talented than I actually am and that is a mission I will never escape :grin: I have one channel done but I'm waiting on the PECs to ship to finish my second....surely my hakko will enjoy the break.

I pulled R44 out of both my boards and decided to pop in a socket for my feeble mind's sake. I simply bought a 6 pin socket and snipped it in half. This way I can pull R44 out if I need to mess with the meter section again (without killing the pads). This has ended up being a bit of a classroom in a box for me...so sockets are good.

 

[nerd]

Any word on the Altrans?

I picked up some cool tamuras that should work ok but I will still like to get the 'real deal', well... almost 'real deal'.

 

[edanderson]

[quote author="nerd"]Any word on the Altrans?
[/quote]

[quote author="Skylar"]Is anyone currently trying to get a hold of Cinemag CM-96731 output transformers? [/quote]

i should have a page up with both the altran input and the cinemag output for sale next week sometime. they will not be limited to 1 per person this time. i am waiting for mnats input transformer pcb to arrive so that everyone who buys an input transformer can get a pcb also.

ed

 

[okgb]

Perfect Ed , thanks

i can already tell you i'll need one output & two in's ,
but i'll wait , great idea to add the in boards

regards Greg

 

[kazper]

good deal..

I'm down for two inputs for sure.

 

[usekgb]

I'm interested in two input and two output.

Cheers,
Zach

 

[Skylar]

Thanks for offering this Ed! I'll definitely be grabbing an in & out.

 

[Stagefright13]

Wow that's great news! Thanks once again for helping everyone Edanderson! Most of this stuff would be impossible without this board and a team effort. And the people like Ed and Mnats that make things like this possible. I hope I can contribute as much in the future. I am however new to the board but have some things to offer I hope.

:grin:

 

[edanderson]

hey everybody. i'm glad to be helping out as best i can. i know it can be hard to get ahold of obscure transformers in one or two piece qtys.

so that we don't clutter up this thread, please don't reply here with how many of what that you want. and please don't PM me or email me. i'm not taking reservations -- there should be plenty for everyone. the order page will be up next week.

ed

 

[mnats]

Click to enlarge

As mentioned previously, I have had some transformer boards made up for this project.
These will fit the Altran O-12 clone that will soon be offered by Ed. Ed will be providing boards with each input transformer.

They will also fit the following transformers:

CMMI-2PCA - Cinemag's version of the O-12
CMLI-15/15B[PC] - as used in some of the UA reissues
Lundahl LL1540 - for a G1176-style input but wired 2:1 stepdown
OEP A262A2C - wired reversed for 2:1 stepdown

Other transformers that use a standard pinout could also possibly be adapted to use this board.

The Lundahl and OEP will work with the board as-is. The Altran and Cinemags require wire links configured to adapt to each unique pin assignment. Pads are just under the transformer footprint and a guide is printed on the screen layer of the board. You can use short pieces of tinned bare wire under the board or insulated wire through the holes.

There are footprints for constructing an H-pad described by W O'B and used on some of the UA reissues. Use this option if you are not using a T-Pad.

Self-etch files have been posted on my Rev D page.

I will also post information on how to get just the board soon.

 

[Stagefright13]

AP123 great Idea with the dip socket! I just fixed my R44 the same way. The trimmer fits in nice and snug. Highly recommended. It's a real pain to flip the board to calibrate. This solves the problem easily.

For the record I ended up using a 220 ohm 5 watt resistor to fire the 12 volt lamp from 34 volts ac. Final voltage 11.78.

Thanks for sharing!

John

 

[Stagefright13]

I finally did a full calibration on mine tonight. However I have 1 issue. I did qbias again no problem this time with my external bomb factory meter in pro tools. Then did gain reduction meter tracking purple style. Got both 0 VU on meter and 0 volts (touchy) across R74. Then it says to reinstall R44 wich I did and I get a 3 DB drop almost on the GR meter. Even with R44 set at 1.8 ohms. (The lowest it will go)

It seems everything works perfectly and my meter is accurate finally. In gain reduction and actual output level. Until I install R44. I am ready to omit R44 altogether. My unit is perfectly stable and accurate without it. Or am I missing something?

 

[ap123]

I had the same exact issue with R44. Curious to hear about this one.

 

[Stagefright13]

Well it could very well be that using a 1:1 input transformer could be the problem... I will redo it when I get the new transformer. The 1k tone is actually going in alot hotter than the typical 2:1 transformer would do. Just a thought.

One reason I wasn't gonna do a full on calibration without the correct and final parts installed.

But I have been having alot of fun playing with mine today just the same...
:green:

John

 

[ap123]

I have the R44 issue with a UTC O-12, too. (eh em...yes, I was dumb enough to buy an O-12 for one billion us dollars)