[BUILD] 1176LN Rev D DIY

[eadgbytc]

Hey all,
I am not getting any compression. Unit is passing signal. All of the voltages are correct against the mnats schematic.  Could someone please post their voltages for q1 and q11? Any help/ other suggestions would be greatly appreciated. 

 

[weiss]

is it normal that i hear more higher frequencies when the output knob is turned all the way down?

 

[Echo North]

Hey all,
I am not getting any compression. Unit is passing signal. All of the voltages are correct against the mnats schematic.  Could someone please post their voltages for q1 and q11? Any help/ other suggestions would be greatly appreciated.

We're you able to set the Qbias?  That controls compression.

 

[dbonin]

is it normal that i hear more higher frequencies when the output knob is turned all the way down?

Can you please elaborate a little - is this with a test tone or music?

If your output is "all the way down"  you should hear nothing on the output.

 

[weiss]

is it normal that i hear more higher frequencies when the output knob is turned all the way down?

Can you please elaborate a little - is this with a test tone or music?

If your output is "all the way down"  you should hear nothing on the output.

1. both knobs on mid position
2. i play music through the device
3. now i turn my input knob "up" to 75%
4. i turn the output knob "down" to 25 % to compensate gain
5. i see and hear a lot more higher frequencies in the frequency analyzer
6. is that normal?

thanks

 

[dbonin]

1. both knobs on mid position
2. i play music through the device
3. now i turn my input knob "up" to 75%
4. i turn the output knob "down" to 25 % to compensate gain
5. i see and hear a lot more higher frequencies in the frequency analyzer
6. is that normal?

thanks

If the unit is compressing you will definitely be hearing and measuring an increase in the amplitude of those frequencies - even though you lower the output, the input signal is being compressed and it's raising the noise floor making those high frequencies stand out.  The input transformer alone will have some slight color effect on the tone - check it in bypass mode (not compressing) and see if you can hear/measure it there as well.

Anyone else want to chime in on this one? 

 

[EmptyMusicBox1]

hello everybody i have just finish a 1176LN revD on 1U





work great but i have a problem with the INPUT :

when i use a Frequence generator Unblalanced : no problem i have good level !

But when i use a Balanced Signal : i have the Pin 3 of the XLR to the ground !!!???  and i don't have a good level for work !!!! I think i have a wire input probleme no ?

thanks for your help

Done !  it was the soundcard output was unbalanded wired

Work perfectly now !!

Just a question about the Slam mode it's the same as British mode ?

Audio extension kit exist ? HPF on sidechain ? dry & wet ? Or other thing ?


thanks

 

[weiss]

Yes, also called four button trick or notoriously British Mode.

weiss

 

[Alexwfm]

Hello everyone, I just finished my 1176 Rev D Rotary poor man's edition.
Some people might not like this way of doing things but yes, I recycled an old sony tape player chassis!

Thanks mnats and Hairball audio for making this possible. Each step in the assembly process is extremely well documented.

It worked at first shot, and sounds amazing!

I may need a help from the ones of you that know the schematic a little bit better:
It may be beacuse I used a different Vu meter, but at the time of calibration - expecially R44 tracking adj) I happened to set the trimmers quite near to the end of their range.

Example: R44, tracking adjustment calibration.    I succesfully make the vu meter drop exactly -10dB on the display at the time I engage compression, but when I set the meter to gain reduction, I'm not able to adjust the Vumeter arrow drop lower than -3dB. adjusting R44 actually brings it to +6dB when turned fully CW.
It looks like the meter shows right output levels but is not sensible to GR movements.

Voltages wise, I notice that my voltages at the Vumeter's Q12 Q13 collectors are around 6V when monitoring GR. A bit lower than schematic, but I noticed this changes drastically when using R71 to adjust the 0db point.

Any help would be immensely appreciated!

Cheers,
Alex

 

[Alexwfm]

I also noticed that the ratios seem odd. I get the most compression when 4:1 is engaged.

I was also wondering why the ratio selector switch was dual in the schematic, now as far as I know the switch bank on the left changes the ratio and the one on the right the Threshold.
Right?

 

[weiss]

I also noticed that the ratios seem odd. I get the most compression when 4:1 is engaged.

I was also wondering why the ratio selector switch was dual in the schematic, now as far as I know the switch bank on the left changes the ratio and the one on the right the Threshold.
Right?

threshold is changed with the ratio buttons, this is correct...

 

[ericfergus]

Audible tones can happen when the output is loud enough.

No Compression, but passing signal:

Something is wrong with your side chain.  Things that can cause this:

- Improper QBias adjustment.
- Component error on the Ratio PCB
- Component error on the Attack/Release Pot
- Component error on the side chain section of the PCB
- Wiring between all of those parts.

After checking all of that troubleshoot.

Troubleshooting:
Feed a 1K 0dB signal into the compressor.  In/Out/Att/Rel all set half way. Confirm that you see 0.775 VAC between input pin 2 and 3.

Post your AC voltage between pad 22 and ground for:
20:1 -
12:1 -
8:1 -
4:1 -

Post your DC voltage between pad 21 and ground for:
20:1 -
12:1 -
8:1 -
4:1 -

Post your DC voltage between pad 19 and ground for:
20:1 -
12:1 -
8:1 -
4:1 -

Mike

Hello!  This is my first post here.  I have built a Rev D and it is passing signal.  I do not appear to have any compression through and although the Q bias and Discrete Meter Circuit/Null Adjust seem to calibrate fine, I get no compression when following the "Gain Reduction Meter Tracking Adjustment" steps.  Turing on/off the attack does nothing.

If done my best to check everything.  Connections look fine.  I double checked all resistor codes and cap value stencils.  I haven't found a short.  I also checked the voltage values of all transistors to the MNATS troubleshooting schematic.  Although not perfectly the same, all were close and were proportional between pins.

I did check the HFE on a pile of 708s when stuffing the board and they are closely matched.  Although I purchased a complete kit, I failed to check the HFEs when first stuffing the board, so I purchased a bunch of 708s after the fact and made a matched pair.  If I recall, they measured around 320.

As suggested in Mike's post several months ago, I took the following measurements.

Thanks to anyone who is willing to help!

Eric


Post your AC voltage between pad 22 and ground for:
20:1 13.9mv
12:1 12.5mv
8:1 11.5mv
4:1 7.4mv

Post your DC voltage between pad 21 and ground for:
20:1 -9.69v
12:1 -1.09v
8:1 -1.088v
4:1 -1.089v

Post your DC voltage between pad 19 and ground for:
20:1 -.872v
12:1 -.872v
8:1 -.872v
4:1 -.872v

Hello everyone!  I posted the above over a month ago but received no response.  In the meantime my poor 1176 is gathering dust without compression.  Is there anyone that  might be able to point me in a new direction of troubleshooting?  Thanks aplenty for your time!

E

Hey everyone . . . so I really need some help.  I've posted this twice now over the past six weeks and no one has responded.  The unit's been gathering dust and I'm pretty frustrated.  Would anybody have a moment to let me know if my measurements are normal and/or point me in new a troubleshooting direction? 

Thanks!!!!!!!!

 

[Echo North]

I also noticed that the ratios seem odd. I get the most compression when 4:1 is engaged.

I was also wondering why the ratio selector switch was dual in the schematic, now as far as I know the switch bank on the left changes the ratio and the one on the right the Threshold.
Right?

One changes the negative DC bias at the diodes on the sidechain output. The other attenuates the AC (Audio) at the output pot as it enters the side chain.  The larger the AC and DC the higher the ratio.

Keith killed it here:
http://prorecordingworkshop.lefora.com/topic/3841871/All-Buttons-In-1176#.U-16dtz7PbV

Mike

 

[Echo North]

Audible tones can happen when the output is loud enough.

No Compression, but passing signal:

Something is wrong with your side chain.  Things that can cause this:

- Improper QBias adjustment.
- Component error on the Ratio PCB
- Component error on the Attack/Release Pot
- Component error on the side chain section of the PCB
- Wiring between all of those parts.

After checking all of that troubleshoot.

Troubleshooting:
Feed a 1K 0dB signal into the compressor.  In/Out/Att/Rel all set half way. Confirm that you see 0.775 VAC between input pin 2 and 3.

Post your AC voltage between pad 22 and ground for:
20:1 -
12:1 -
8:1 -
4:1 -

Post your DC voltage between pad 21 and ground for:
20:1 -
12:1 -
8:1 -
4:1 -

Post your DC voltage between pad 19 and ground for:
20:1 -
12:1 -
8:1 -
4:1 -

Mike

Hello!  This is my first post here.  I have built a Rev D and it is passing signal.  I do not appear to have any compression through and although the Q bias and Discrete Meter Circuit/Null Adjust seem to calibrate fine, I get no compression when following the "Gain Reduction Meter Tracking Adjustment" steps.  Turing on/off the attack does nothing.

If done my best to check everything.  Connections look fine.  I double checked all resistor codes and cap value stencils.  I haven't found a short.  I also checked the voltage values of all transistors to the MNATS troubleshooting schematic.  Although not perfectly the same, all were close and were proportional between pins.

I did check the HFE on a pile of 708s when stuffing the board and they are closely matched.  Although I purchased a complete kit, I failed to check the HFEs when first stuffing the board, so I purchased a bunch of 708s after the fact and made a matched pair.  If I recall, they measured around 320.

As suggested in Mike's post several months ago, I took the following measurements.

Thanks to anyone who is willing to help!

Eric


Post your AC voltage between pad 22 and ground for:
20:1 13.9mv
12:1 12.5mv
8:1 11.5mv
4:1 7.4mv

Post your DC voltage between pad 21 and ground for:
20:1 -9.69v
12:1 -1.09v
8:1 -1.088v
4:1 -1.089v

Post your DC voltage between pad 19 and ground for:
20:1 -.872v
12:1 -.872v
8:1 -.872v
4:1 -.872v

Hello everyone!  I posted the above over a month ago but received no response.  In the meantime my poor 1176 is gathering dust without compression.  Is there anyone that  might be able to point me in a new direction of troubleshooting?  Thanks aplenty for your time!

E

Hey everyone . . . so I really need some help.  I've posted this twice now over the past six weeks and no one has responded.  The unit's been gathering dust and I'm pretty frustrated.  Would anybody have a moment to let me know if my measurements are normal and/or point me in new a troubleshooting direction? 

Thanks!!!!!!!!

Those are way off.  I would start by completely rewiring that ratio switch.

If you want I'll send you a new switch and PCB to rule out something wacky.

 

[Echo North]

Before I send out a new switch try this.

Open the schematic:
http://mnats.net/files/1176REVD_VOLTS.pdf

For these Q's power the unit, no need to put signal in.  Knobs all mid way, GR ON, ratio 12:1.

1.  What is your DC V on either side of R64 (1.5K) with reference to ground (CT).
2.  What is your DC V on either side of R63 (1.5K ratio PCB)) with reference to ground (CT).
3.  What is your DC V at pad 21.

Now feed in a 1K 0dB signal.  Confirm 0.775 V AC across pin 2 and 3 of the input XLR.  Knobs all mid way, GR ON, ratio 12:1.

1.  What is your AC V on either side of R78 (56K on ratio) with reference to ground (CT).
2.  What is your AC V at pad 21.

Post those and that should help a lot.

Mike

 

[Alexwfm]

Hi, i had the same problem at the beginning. Sound going thru but no compression. I got wrong pads 15 16 17 on the main board.. but apparently you have wrong voltages in many parts of the circuit.. So that may not be the solution..

 

[Alexwfm]

Also, another thing I never understood about the rotary version: why the rotary version has a 6 position ratio switch? It's 4 ratio settings plus slam mode and this unknown one where pad 7 is shorted with the threshold side of the circuit. Does anyone knows what is it about?

Thanks for the help,
Alex

 

[miko]

hi im building my first 1176 rev D clone D) but i have 2 questions: I cant figure out in what position i have to put the meter switch on the pcb (rotary version) probably something logical but i cant find it. and 2nd: the big resistor in the power supply is getting REALLY hot. is that bad? the voltage is good 29,9 at the resistor and -9,8 at the diode. thx in advance, miko

 

[Alexwfm]

hi im building my first 1176 rev D clone D) but i have 2 questions: I cant figure out in what position i have to put the meter switch on the pcb (rotary version) probably something logical but i cant find it.

That shouldn't be too hard. If you follow the schematic and locate the signal path X both on the rotary and on the pcb, knowing that the X path has to be connected to the meter when the rotary is turned fully CW, then it's just about to get the central pins right.

This page helped a lot.

http://mnats.net/1176-wiring-rotary.html

Cheers!
Alex

 

[ericfergus]

Before I send out a new switch try this.

Open the schematic:
http://mnats.net/files/1176REVD_VOLTS.pdf

For these Q's power the unit, no need to put signal in.  Knobs all mid way, GR ON, ratio 12:1.

1.  What is your DC V on either side of R64 (1.5K) with reference to ground (CT).
2.  What is your DC V on either side of R63 (1.5K ratio PCB)) with reference to ground (CT).
3.  What is your DC V at pad 21.

Now feed in a 1K 0dB signal.  Confirm 0.775 V AC across pin 2 and 3 of the input XLR.  Knobs all mid way, GR ON, ratio 12:1.

1.  What is your AC V on either side of R78 (56K on ratio) with reference to ground (CT).
2.  What is your AC V at pad 21.

Post those and that should help a lot.

Mike

Thanks Mike for your reply and help!!  You pointed me in the right direction. 

I discovered a cold solder joints on R78 and R63.  The unit now compressors, calibrates as expected, and sounds great.

Thanks again and keep up the good work.

Eric