[BUILD] 1176LN Rev D DIY

[Arrigotti]

All right.......I guess this is just my personal DIY troubleshooting BLOG, but I fixed it. It works perfectly now.

Sometimes I guess it just helps to write it out so that you can get your head outside of it and see it from a different perspective.

So what was the issue?

The wiring from the main board to the ratio board to the output pot was a little mixed up.

I realized that that was were the problem was after I posted my problem and thought about that section of the circuit.

Thanks for being my cyber-sounding board.

Maybe this will help someone else in the future.

Thanks!! :green:

 

[Siegfried Meier]

Hey guys,

I need to purchase a pair of T-Pads for my Rev D's. Andrew at Purple has 2 different kinds:

Clarostat J series, two decks - $76 each
Clarostat 70 Series, three decks - $60 each

Does anyone know which one would be the best to use? I'll probably be using Cinemag ins and outs.

Thanks,
Sig

 

[codered]

Check Leeds ..they had the Mallory for $40 a couple of weeks back

 

[sysexguy]

so I bought 25 2n3707's and...well if we were in baseball, it would be 9th inning, 1 out with a perfect game - no hitter (hfe speaking)....none are up to the task.

Can I try a substitute, if so, what and are there any things that must then be accounted for (other than the calibration) 2n3711? the 5088's(?) that purple uses?

Thanks,

Andy

 

[plexirob]

Hi, leeds where can I find them? I'm also in the T600 hunt!

Thanks,

 

[codered]

[quote author="plexirob"]Hi, leeds where can I find them? I'm also in the T600 hunt!

Thanks,[/quote]

http://www.leedsradio.com/parts-resistors.html#potentiometers

and a kind request( for everybody) please dont buy a whole lot for hoarding..that's what happened the last time he got a bunch.

 

[Bri]

Andy, go with the 2N3708's as a direct, "no worries" replacement.
They should be fine, in regards to the necessary HFe.
But measure them anyway.

--Brian

 

[sysexguy]

Thanks Brian....they're showing b/o at mouser so luckily I have 70 other projects on the go :roll:

Andy

 

[Neeno]

Hi guys !
I'm finally building my 1176 rev D
But i'm having some troubles figure out how this thing should be connected...

I'm using the PEC Bridged-T Attenuator, Mnats Trannie PCB sruffed with the altran C3837-1 going to the 1176 board.

Does anyone have a wiring diagram for this ?

 

[Stagefright13]

That info is in this thread back a ways.

 

[Neeno]

I've found the following diagrams:

and this

but honestly i can't get them ?!?!

So I followed the schematic and i came to this:

Now the question is... wich one is the right one ?

I'm trying to test it using my signal generator and the oscilloscope, but the level one the altran output is not changing...

Yesterday i was trying to cablibrate my unit, i completely removed t-attenuator and the trannies and i fed a signale directly to the input of the 1176 board. It looks like the unit is compressing and there is GR (shown also by the VU meter) but in GR the meter behaves in a strange way.

It looks like the ballistics are bad, even if the meter is right, i'll try to explain but it's not easy and my english should be even worse...

I set the compressor for 10dB gain reduction (shown on the meter), then i switch off my signal generator, the gauge goes back to 0dB (GR) but it oscillates for some seconds, that happens even when i change the ratio...

What could it be ? A wrong component ? Wrong wiring ?
I triple checked everything but i can't get it right...


Can anyone help me ?

 

[Neeno]

It looks like I solved the T-Attenuator problem...
I'll check it out again tonight...

Now it looks like i can't solve the GR meter problem...
I calibrated the unit properly, following the JBL manual, i did the repetitive steps more than 5 times to be sure but my meter is still WOBBLY when in GR mode... even during the -10dB calibration, when i mute the signal it goes back to 0dB but it swings for 2-3 seconds before stop...

Is it right ?
Am I missing something ?

 

[Stagefright13]

Your meter swings back and forth or takes a bit to settle? And what meter are you using? Maybe it is on slow release? I have the 3 deck Mallory so I couldn't help you with the PEC sorry bout that. Also the meter on mine tends to rise after prolonged use. Also stated in the Urie manual. A max of +1 tho.

Does it sound good? After the bias adjust it is all just meter anyway. Mine calibrated fine after hours of learning... But in use the needle is flying around. It is a fast compressor. I really don't look at the meter as much as I did at first. But when I do glance over sometimes it does quick peaks to 20db reduction. But is just the sound I want.

And the 3708's I got ALL tested good hfe. And sounds great. My Mallory is scratchy now tho I may have to replace it with something.

 

[Stagefright13]

Andy email me with your address and I can send you the 3708's I have a dozen left. No charge. And I will test them first also.

 

[pH]

Well I finally have mine together in a nice case from Tat. I'm using a Lundahl Y236105 which gives 22VAC, I fired it up and I'm only getting 28.7VDC on the rail. Should I worry about this being too low? I was able to go through all the other calibration steps successfully, and it still sounds GREAT.

The other thing is that my ratios are backwards!?! I wired a rotary slam switch following Mnats picture guide and thought I had it right, but to my ear clearly 4=20 and 20=4. Slam is still all the way to the right, but the meter pegs all the way past the red when no GR is happening. Ideas?

 

[gevermil]

Yep , I wired mine as shown and I have backward ratio as well :wink:
Sounds good though

 

[Bri]

Hey guys.

On my build, my ratios also seemed backward...to my ear, and meter.
I had no previous experience with the specific characteristics of the 1176's ratios, thresholds, etc.

I came across a post from squib which was very helpful.
Using his method, I ultimately found that my ratios were actually correct.

I'm still a newb, so forgive me if you're aware of this already or if it doesn't pertain to you at all.

Here's his post:

"forget the meter for now
you need to set up a jig to test the ratios
ensure that as you test each ratio that you push the unit into 3dB of GR, then up the input level by exactly 10dB without touching any of the 1176 controls and measure the change in output level. For 20:1, you should see about 0.5dB increase, for 4:1 you see about 2.5dB increase etc etc.

You need to prove the sidechain / ratio circuit first before investigating the meter. Make sure you reset the unit for the 3dB of GR when testing each ratio."

Cheers,
Brian

 

[pH]

I admit it can be tricky to tell 4:1 vs. 20:1 compression when the output volume changes, but I'm still not convinced all is right.

I'm running a mono drum mix through at 4:1 and it sounds pretty crushed. When I step up towards 20:1 (without changing input or output volume) it gets increasingly LOUDER with more transient peaks, much less compression happening. Others on the G1176 thread have said volume will go down with increased compression ratio (as it should), but the opposite is happening here. Does the whole input gain structure change with the ratio switch?

Slam is working fine, but in this mode my meter still pegs to the right with no signal, moves left with gain reduction. Meter seems to work fine in other modes.

Hmmm... :?

 

[Neeno]

Your meter is right...
That happends also in the original units...
When you swich all 4 buttons in (or to the slam mode on the rotary) the meter pegs all to the right !

 

[edanderson]

on the 1176, changing the ratio changes the threshold. the higher ratios have a higher threshold.

ed