All things G1176 - the new "repost" thread.

[gswan]

Remove the GR FET and repeat the gain test on the faulty channel. The FET may be faulty, have too much bias applied to it or be inserted wrongly. If the gains check out OK with the FET removed then replace the FET or examine the orientation/Qbias. With the FET out you can perform a simple check on it to get its characteristics.

 

[3nity]

I used the Nuke mod on my 2 x 1176 ....
one of them works very nice VU meters completely to the right when engaged...

On the other i just drop to -7Db and dont compress at all..it works fine when Nuke off.

when i compared the mods on both boards impossible to trace??
I might be a little tired...

Any hint please?

 

[btproductionsaustralia]

Hey All,
I'm nearing copletion on my first 1176 build, and am now about to attached the potentiometers to the chassis, but it's occured to me It's now actually clear which is which, that is I have...
R5
R27
R77
R78

But not sure which is for the input, which the attack etc... ???

Also, I've tried attaching the sitches as a trial, but no matter how tight I tighten them onto the chassis, when I put the knobs on and try turning them, eventually the whole switch comes loose and spins...do you guys ever glue them, or attach in another way, or is it just my puny hand muscles??

THanks for the help

Ben  ;D

 

[gswan]

The values on them are a good clue.
R5 = 10K log = Input
R27 = 100K log = Output
R77 = 25K lin/log switched = Attack
R78 = 5M lin/log = Release

Rotary switches and pots also have a little locating pin/tab on them that usually sits in a blind hole at the back of the panel through which they are being fitted. This prevents them spinning, however you need to use a shakeproof washer (spring, compression or star) to prevent them coming loose under normal use as well.

 

[btproductionsaustralia]

Thanks once again for your help G swan...first rate!!

 

[ChrioN]

Did anyone try to use a opamp output instead of an output transformer? How to?

 

[3nity]

you mean electronic balanced out?
you can use the THAT 1646...i tried it on one of 1176's but you have a lot more gain!

Anyone read my question above?

 

[ChrioN]

Did you build an external +/- psu to power the that chip output with?
Sorry, don't know what the problem with your unit is.

 

[btproductionsaustralia]

Hey All,

I'm currently wiring everything up on my 1176, and need to clarify this...

Mnats site says to wire the earth on the input xlr to the chassis, and that this is the only place the mains of the circuit will be connected to the chassis, but I THINK I should also wire the earth of the mains from the mains plug to the chassis...is this wrong?

would this be wiring the earth to the chassis twice? or are they considered seperate?

I'm sure this is real dumb, but hey I'm a newb...

Thanks

Ben

 

[mnats]

Mnats site says to wire the earth on the input xlr to the chassis, and that this is the only place the mains of the circuit will be connected to the chassis, but I THINK I should also wire the earth of the mains from the mains plug to the chassis...is this wrong?

Read carefully. My site actually says "This will become the one and only point at which the electrical ground of the main circuit board connects to the chassis of your unit." (Emphasis added) I think originally I based this on instructions on Jakob's site but that's not how I currently do it, even though in that unit it worked well. You can find lots of information on ground wiring by doing a search of this site.

 

[3nity]

Anyone with the Slam mod by Gyraf having troubles?
I installed the mod to 2 units but one has IC input works fine  and the non working has OEP input?
I checked the wiring and seems fine..??

Any ideas will be apreciated?

Thanks.

 

[btproductionsaustralia]

Hey all, a painfully basic question I'm afraid...

How do I stop the pcb from touching the chassis and hence potentially shorting??
Is this an issue, and if so, do I put rubber underneath like with the toroidal? or do I just mount it with large nuts so it sits off the bottom?

Thanks for all the help guys, I'm nearly there!!!

BT

 

[casrec]

They are called standoffs and yes, you use them to lift the pcb off of the chassis to ensure no shorting.

 

[btproductionsaustralia]

Great thanks!!  ;D

 

[JW]

Hey guys,

I'm curious to know whether a 1dB VU slip is normal for the zero adjust after calibration is complete and the unit has been used only a handful of times. I have a dual unit and the other channel hasn't changed at all.

 

[Echo North]

It can be.

I never touch my 0 adjust until the unit has been powered on for at least 45 minutes.

Mike

 

[btproductionsaustralia]

Hey All, just just finished my first build, a 1176!!
Was stoked until I powered it up to calibrate and discovered the following issues:

1.When I have my preamp plugged in and have the 1176 powered up, the 1176 picks up frequencies from it, like hissing and random high frequency noise...how might I stop this?

2. with the preamp off, the unit still makes a soft clicking sound on the audio, it's a consistent ticking...any thoughts on what could cause this and a cure? a power issue?

3. When I turn the VU meter from bypass to GR or VU measure, there is a VERY loud hum/whirring noise...any ideas?

4. Finally, the unit passes audio( I ran a test signal) but it adds various artefacts/noises, and radio style hum...
The attack and release sound like they are doing what they are meant to, at least to my ears, and the input and output knobs both work fine...

Any help would be GREATLY appreciated, as I'm desperate to get this unit working smoothly!!!
If it would help, I have recorded audio samples of the various noises, and could email them if some kind soul would help me out?

Yours desperately

BT 

 

[gswan]

Have you performed the steady-state DC bias tests?
Have you performed the gain check tests?
Have you performed the calibration?

 

[btproductionsaustralia]

Have you performed the steady-state DC bias tests?
Have you performed the gain check tests?
Have you performed the calibration?

Hey Gswan,

I was trying to calibrate, but my in experience coupled with these noises have made it difficult. I'm not sure if these are noises that could be cured by calibration...

I'm not sure what either a steady-state DC bias test or a gain check test are? how do I perform these? Note* my only "tech" equipment is a multimeter...

Thanks for the help
ben

 

[gswan]

Ben,

You will need to read the DC voltage on the leg of each transistor with no input signal and check them against a table such as this:
http://www.axtsystems.com/index.php?view=article&catid=34%3A1176ln&id=57%3A1176lnproblems&option=com_content&Itemid=27

If you find any that are off then it is likely that you have a component or construction error.