1176 ae 2:1 ratio. Need some help calculating resistor values

YLab · Jan 3, 2012

Hi, i want to modify my pair of diy mnat 1176 rev D to have the same ratios as the 1176ae. 2:1 4:1 8:1 20:1 So no more 12:1 ratio but a new 2:1 ratio. Here's a drawing with what i think are the right resistor values. To resume how i have done it : R19 is now the sum of R19+R20 to get the 8:1 on the button where the 12:1 was. R20 get the previous R21 value to get the 4:1 in place of where the 8:1 was. The new values of R21 and R22 are taken from Igor 's 2:1 ratio on his 1176 51x. Same logic for the second side of the switch.
I would be pleased if someone could double check my changes. Or maybe if someone have the 1176ae schematic!
Hubert

G-Sun · Apr 26, 2012

Has it been a success for you?
I'm interested in this mod as well.

pucho812 · Apr 26, 2012

if you have the parts lying around why don't you just put them in and see what happens.

You've given me the idea to mod my mc77's to have a 3:1 ratio

Oh and schematic for the 1176 ae is here in the manual.

http://www.google.com/url?sa=t&rct=j&q=1176%20ae%20schematic&source=web&cd=3&ved=0CD4QFjAC&url=http%3A%2F%2Fwww.soundpure.com%2Fresources%2Forg.apache.wicket.Application%2FassociatedFiles%3Fid%3D2766-Universal_Audio_1176_AE_Limiting_Amplifier-12a248971c9-18.pdf&ei=uZiZT6zFOqafiAKhrqTsDw&usg=AFQjCNHbQmqh5RP_aYWeHJmF9o4wxjcbsQ&cad=rja

G-Sun · Apr 26, 2012

pucho812 said:
if you have the parts lying around why don't you just put them in and see what happens.

You've given me the idea to mod my mc77's to have a 3:1 ratio

Oh and schematic for the 1176 ae is here in the manual.

http://www.google.com/url?sa=t&rct=j&q=1176%20ae%20schematic&source=web&cd=3&ved=0CD4QFjAC&url=http%3A%2F%2Fwww.soundpure.com%2Fresources%2Forg.apache.wicket.Application%2FassociatedFiles%3Fid%3D2766-Universal_Audio_1176_AE_Limiting_Amplifier-12a248971c9-18.pdf&ei=uZiZT6zFOqafiAKhrqTsDw&usg=AFQjCNHbQmqh5RP_aYWeHJmF9o4wxjcbsQ&cad=rja

Thanks! Well, I have to build one first

But, think I'll include this mod on a 2-1176D

YLab · Apr 26, 2012

Hi, yes the mod work perfectly. I have a pair of 1176 that have the mod just like the schematic that i have post and they are great as buss compressor. Really different than the 4:1 ratio. Slower and smoother attack i would say. The side chain hi-pass filter on igor's 51x 1176 is great too.

pucho812 said:
if you have the parts lying around why don't you just put them in and see what happens.

You've given me the idea to mod my mc77's to have a 3:1 ratio

Oh and schematic for the 1176 ae is here in the manual.

http://www.google.com/url?sa=t&rct=j&q=1176%20ae%20schematic&source=web&cd=3&ved=0CD4QFjAC&url=http%3A%2F%2Fwww.soundpure.com%2Fresources%2Forg.apache.wicket.Application%2FassociatedFiles%3Fid%3D2766-Universal_Audio_1176_AE_Limiting_Amplifier-12a248971c9-18.pdf&ei=uZiZT6zFOqafiAKhrqTsDw&usg=AFQjCNHbQmqh5RP_aYWeHJmF9o4wxjcbsQ&cad=rja

If you look closely, the schematic in the 1176ae manual is not the 1176ae schematic. Normal ratios there. If someone have it it would be great!

Hubert

G-Sun · Apr 27, 2012

YLab said:
Hi, yes the mod work perfectly. I have a pair of 1176 that have the mod just like the schematic that i have post and they are great as buss compressor. Really different than the 4:1 ratio. Slower and smoother attack i would say.

Good

Thank you!

Kingston · Sep 18, 2012

Just thought I'd chime in. The values in the above schematic seemed logical for a 2:1 so I did this quick mod as well. Wondering now how this mod isn't more common place. It tremendously increases the usefulness of this limiter into glue-compressor territory. It's easily the most transparent of all the ratios and much reminiscent of some of the best mastering compressors I've heard. It's also much easier to dial in just the right amount of compression due to the transparency.

I see how back in the day the original design was more of a fast peak limiter so 2:1 wasn't a priority. Today when 1176 is first and foremost a sound shaping device I would recommend always doing this mod. I always had trouble justifying the minute difference between 12:1 and 20:1 ratios. No hard feelings losing one or the other.

sr1200 · Dec 30, 2012

Can't believe i missed this thread! Dumb question, if the unit is in "bypass" or off on the hairball kit, would that be the same as 1:1 or does that take things out of circuit?
I've been thinking of building a "new" ratio board to do 1:1, 2:1, 3:1, 4:1, 8:1, 10:1, 20:1 and "all buttons".

gswan · Dec 30, 2012

Have you actually measuerd the compression ratio at 2:1 or just assumed that it is 2:1?

Kingston · Dec 30, 2012

gswan said:
Have you actually measuerd the compression ratio at 2:1 or just assumed that it is 2:1?

Not assumed, but estimated from the resistance values available from the schematic. As you know the right side switch bank can be "ignored" from the estimation since it only changes the make up gain of the control amp. The result is in the ball park but R58 should be more like 100ohm for more accurate scaling of the "auto" make up gain. Otherwise the 2:1 setting will be a bit louder than the rest.

Chrys · Jan 30, 2018

Noticed just today this awesome post.... are you sure guys it can works?
I would to do the same for my third unit ( just like ea 1176)
Do I have to follow the mod attached in the first post?
Thanks

pucho812 · Jan 30, 2018

yes.... your swaping out resistors. as mentioned above.

Chrys · Jan 31, 2018

pucho812 said:
yes.... your swaping out resistors. as mentioned above.

Thank you so much

Ilya · Mar 17, 2018

Has anbody actually measured the 2:1 ratio with this mod? I'm getting closer to 4:1 ratio, and the threshold point seems to be shifted way up (that is, I have to feed a louder signal for the unit to start compressing).

frejo89 · Jan 18, 2024

YLab said:
Hi, i want to modify my pair of diy mnat 1176 rev D to have the same ratios as the 1176ae. 2:1 4:1 8:1 20:1 So no more 12:1 ratio but a new 2:1 ratio. Here's a drawing with what i think are the right resistor values. To resume how i have done it : R19 is now the sum of R19+R20 to get the 8:1 on the button where the 12:1 was. R20 get the previous R21 value to get the 4:1 in place of where the 8:1 was. The new values of R21 and R22 are taken from Igor 's 2:1 ratio on his 1176 51x. Same logic for the second side of the switch.
I would be pleased if someone could double check my changes. Or maybe if someone have the 1176ae schematic!
Hubert

So Iam very interested in this mod too

Are the resistor values confirmed ?

I think this table should help me to transfer it to the hairball unit i guess?
I own A 1176 MNATS REV A unit

gswan · Jan 18, 2024

Ilya said:
Has anbody actually measured the 2:1 ratio with this mod? I'm getting closer to 4:1 ratio, and the threshold point seems to be shifted way up (that is, I have to feed a louder signal for the unit to start compressing).

The compressor has a soft knee so it's most likely that 2:1 isn't really 2:1. It's probably why the original started at 4:1. Ratios below this tend to get messed up by the knee which gets softer for lower ratios.
I measured the ratios of all the settings when playing around with this in a 2-channel build and found them to be inconsistent, as expected. There are too may tolerance and temperature variables to get accurate ratios in a single channel, let alone two identical channels. It's not a compressor that I'd use in a stereo configuration.

frejo89 · Jan 18, 2024

gswan said:
The compressor has a soft knee so it's most likely that 2:1 isn't really 2:1. It's probably why the original started at 4:1. Ratios below this tend to get messed up by the knee which gets softer for lower ratios.
I measured the ratios of all the settings when playing around with this in a 2-channel build and found them to be inconsistent, as expected. There are too may tolerance and temperature variables to get accurate ratios in a single channel, let alone two identical channels. It's not a compressor that I'd use in a stereo configuration.

thanks for your input - so you wouldn't recommend using this mod on a single channel Rev A either ?

gswan · Jan 18, 2024

You can experiment with it and see. Do the measurements and find out

frejo89 · Jan 18, 2024

1176 ae 2:1 ratio. Need some help calculating resistor values

Help Support GroupDIY Audio Forum:

Well-known member

Attachments

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Similar threads

Join the conversation!

Join today and get all the highlights of this community direct to your inbox. It's FREE!