Modding my 1178 to 2x1176LN

[nacho459]

I know the UREI 1178 is not two 1176 comps in one box (like some people claim) even some 1176's are different than the popular blackface 1178LN and have different components.

What is the main different between the 1178 circuit and the 1176LN?

How hard would it be to mod my 1178 to sound like two blackface 1176LN's?

 

[soundguy]

which "blackface" 1176 do you want it to sound like, there are three different versions that sound distinctly different. One has a class a output amp, another has an AB output amp and a third has differential input/outputs.

dave

 

[Kev]

[quote author="soundguy"]... which "blackface" 1176 do you want it to sound like,... [/quote]

thanks Dave,
I'm glad someone else is saying this when the situation comes up. I think it is one of the oldest and most common misconceptions ... to describe an 1176 as a Black Face suggesting that says it all.

As far as the 1178 goes ... it has a Dual Fet in an 8DIP package and it is all op-amp so it might be difficult to get the sound you are looking for.
As Dave suggested ... the sound may be all about the Class-A and Trafos ... or both.
Adding trafos to your 1178 may not be enough to get there.

These types of questions can be the most difficult to answer as it is impossible for us to know exactly what part of the 1176 sound you are looking for.

 

[bovox]

Hey guy´s, in mine 1178 there´s the 5532 input balance buffer and
the output tx. Actually the same output circuit as in the LA-4.
Sticking my nose out.. as I have buildt my 1176 as well( the K version)
Its a class A/B uot amp type. But I have used the class A version as well.
I would say that the usefullness and the uniqe construction with this
fet vca ,makes more sounddifference´s than the use of class A or
class A/B output amp.
If you try to use a concentric double pot instead, at the attack
and release places You get a perfect two channel model of 2 x 1178/2.
Cheers Bo

 

[Kev]

cool

I know people that do love their 1178's
The two chanel mode for the 1178 sounds interesting.

back to the original post
Keep your 1178 an 1178
and look to making a dual 1176 with the sound you are looking for.

best of both worlds. :green:

 

[nacho459]

I am more talking about the actual compression than the tonal sound, although they kinda go hand in hand. I mainly use my 1178 on kick, snare and bass, but I can never get it to punch like the 1176. On the 1176 you can get that sweet spot with the attack and release where on a bass drum you can hear more thump and it really adds puntch. I can't really get my 1178 to do that.

I like the way the new UA 1176s sound, so whatever thay did diferently, I don't know.

I remember runing across a web page where it broke the 1176 down by serial number and stated all the cosmetic and internal changes, but I forgot where it was.

 

[soundguy]

I may be wrong, but I think the control circuit remained fairly unchanged throughout the evolution of the box. the difference in depth that you are hearing is more likely the amplifier than the control circuit IMO.

which "new" 1176 are you talking about, they already made some changes to those, while not telling anyone about it. The early reissues were pretty much the straight up class a circuit with an ouncer and a t attenuator, the newer ones ditched that and went with a cinemag and a slightly different front end to accomodate it. IF you want to get close to that sound, you want to build the class a version which is about as worlds away from an 1178 as you can get.

dave

 

[Rob Flinn]

I remember runing across a web page where it broke the 1176 down by serial number and stated all the cosmetic and internal changes, but I forgot where it was.

I think this might actually be on the Universal Audio webpage, though I don`t have time to check it just at the moment.

 

[gyraf]

You may think of John Klett's document:

http://www.technicalaudio.com/pdf/1176/UREI%201176%20VERSIONS.pdf

Frank "NG" has some history:

http://www.nrgrecording.de/html/history.html

and:

http://www.soundonsound.com/sos/jun01/articles/universal1176.htm

http://www.uaudio.com/company/history/compressors.html

Jakob E.

 

[bovox]

I want disagree on that there is a difference between an 1176 and the
1178.But in my "universe" you can certainly get punch, without working
in class A. I would of coarse want that output Tx if I can afford it,but..
I could have more fun with 8 homebuild 1176 a´la Gyraf PC-card,than
buying one original Universal product.
Nacho; Is there by anychance a difference in sound if you load the source,
from wich you feed the 1178, with 600 ohms.
You can put a 1kohm resistor across the input bridges of the 1178.
Cheers Bo

 

[Kev]

[quote author="bovox"]I want disagree on that there is a difference between an 1176 and the 1178.[/quote]
:?
??
err which 1176 ?
1176's can be different from each other so if there is an 1176 just like an 1178 then ... there must be 1176's that's not like ... an 1178 ??
now I'm confused.

 

[pucho812]

This is a reprint from universal audio web site about the 1178.

1176 in Stereo (Old)
So who remembers the 1178? The UREI 1178 was a product that essentially took two 1176s and made them into a stereo unit. What a great idea! Why was it a great idea? Well, in case you?ve never run a pair of 1176s in stereo, 1176s are famously funky when it comes to stereo operation. An external stereo adapter (the 1176-SA) is needed if you want your 1176?s attack and release to track together. The pair of 1176s have to be connected and unconnected on the rear of the units with the dedicated 1176-SA RCA connections, which means that switching your units between mono and stereo is done behind your rack. The 1176-SA runs on 9v battery, and therefore causes your meter calibration to drift as the battery loses energy.


1176-SA Yesterday 1176-SA Today
While a stereo capable 1176 is a fantastic idea, the 1178 had some shortcomings. The 1178 came out about the same time as the ?Revision H? era of the 1176. This is the generation when the 1176 went back to a silver faceplate. Unfortunately this era did not see the Class A circuitry of its ancestors, and the input transformer had been replaced with a differential amplifier. These design changes apply to the 1178 as well.

Also, the 1178 has only one set of attack and release controls and only one ratio select. The unit has a STEREO / MONO switch, and therefore can operate in dual mono, but without independent controls for attack, release and ratio, you?re really only de-coupling the attack and release. The 1178 is really only practical as a stereo unit...

--Will Shanks

 

[bovox]

Kev,sorry I have to be more specific. To my knowledge the later 1176,s
the K version and soforth comes close to 1178.Which of course have
another Fet-type ; 5566 (DIL) but two more 5532,s than the discrete
variants in the 1176. I´m aiming that the "E" version and the 1178
sound different, but not with a worldwide difference.
When I got my 1178 I thought it was a bit thin. I measure it up but
it was almost flat down to the bottom (10Hz). When I builded my
K-version I got another more full bottom, perhaps because of
another output Tx or... but it was still a class A/B version like in the
1178. Cheers Bo

 

[Kev]

[quote author="bovox"] To my knowledge the later 1176,s
the K version and soforth comes close to 1178.Which of course have
another Fet-type ; 5566 (DIL) but two more 5532,s than the discrete
variants in the 1176. .... [/quote]

yep

it's all good

I think there is enough background here now for people reading this thread to have a good understanding of what might be inside these units and if they wish to look a little deeper they have a starting point to base their google searches on.

mods, retrofitting and scratch building ... all of it
we love our DIY.
:thumb:


... oh and thanks to pucho for the cut and paste from UA.

 

[nacho459]

[quote author="bovox"]Nacho; Is there by anychance a difference in sound if you load the source,
from wich you feed the 1178, with 600 ohms.
You can put a 1kohm resistor across the input bridges of the 1178.
Cheers Bo[/quote]

hmm, that's a good idea, I'll try that.