1176 in 51x/500 format: FEELER. Goto page 5 for pre-orders.

[Igor]

Just to share some pictures...

Seems like my 51x rack will be filed with another pair of compressors...

In case of whatever, NOT FOR COMMERCIAL PURPOSE!!! FOR EDUCATION USE ONLY!!!!

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/51X_F76_prevw_front.jpg

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/MAIN_SCH.png

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/PCB_TOP_PREV.png

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/PCB_BTM_PREV.png

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/GR_SCHEM.png

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/IN_AMP.png

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/OUT_AMP.png


Features:
2:1 ratio added
Sidechain HPF (100Hz)
Many types of amplifiers can be used here as well as original 1176
No need for DC/DC converter
Input balanced line receiver and pot/ or transformer and 600Ohm att option
Should work on +/-16 and +/-24 or +/-16V only (for owners of Lunchbox who still not get into 51X
Etc etc....

 

[Brolik]

damn man. you're outta control

 

[AudioGimmer]

Wow way to go Igor!!.... And I haven't had time to start my Mixbuzz yet.......


AG

 

[briomusic]

great, I just needed a little push into 1176 land...  8)

few initial questions:
-which revision is this based on, and what changes (if any) to the original sound/functionality, except the very welcome addition of SC HPF?
(I am delighted to see that the analog meter disappeared, rather than the transformers  ;D )

-any plans for stereo link via the 500 series stereo link connection?

 

[dandeurloo]

i'd love to know these as well.  I to like the LEDs with transformers instead of VU.

 

[Igor]

great, I just needed a little push into 1176 land...  Cool

Welcome!

I make my UN76 commercially, stereo in 2RU, same gain reduction circuit,
but with Neve class A output stage, my output trunny's (HI-B C-core),
and some other tweaks, about 5 years. First version of UN76 was done for my friend,
http://tantanstudios.com/gear
/just for impression

few initial questions:
-which revision is this based on, and what changes (if any) to the original sound/functionality, except the very welcome addition of SC HPF?

About revisions,
http://www.uaudio.com/webzine/2003/august/index4.html

For now, I made DOA adapters PCB's for input and output amplifiers as in 1176 REV. F.

Most of discrete op-amps as well as adapter board for NE5534/etc will work here.
51X-F76 done to work in both 51 and 500 cases, it is matter of amplification stages used.

A chance to try 1176 with Forssell FET or JLM op-amps!!!

Maybe, I will do single ended output amp PCB like in rev. A-E.
The problem is there's no A-E rev. (5002) output transformer substitute which fits into 500 format.

I added current source at the output stage of input amplifier (lower output impedance,
possibility to use 10k log pot for output control),
and changed some resistors values to let it work right at 24V.
For those who cares about sound signature of amplifiers,
it is same at analyzer and sound-wise; I run input amplifier at +24V
in my UN76 for years with this mode.

Most of sound comes from transformers and distorted FET; it depends how "distortion" trimmer
(R16 according to orig.1176 rev F) is (mis)adjusted.

Another tweak-up/down's..... Ratio 1:2 is useful with vocals, guitars, soft
coloring compression, etc.

I want to try 2520 at output stage with API output trafo.

SLAM mode: when ratio switch is at 4 or 20 position, it is exactly same way
as it happens when all 4 RATIO buttons IN.

Another "mod", for 51x-F76, circuit before diode rectifier with 4 transistors and
pervert values resistors thrown from there and replaced with 2 op-amps. It does not affects
neither sound nor compression, but saves some space on PCB and makes build easY-er.

I prefer stepped attack and release controls, release control /11-pos switch/ done as 5meg log pot.
Attack control is 11-pos switch, acts like 100k extended log pot.
Other values can be used for attack/release.

I can use potentiometers instead of switches, BUT 5meg log pot is impossible to find in size
which fits in 500 format. Recall-ability is matter as well.

(I am delighted to see that the analog meter disappeared, rather than the transformers  Grin )

I prefer line level 10k:2k4 input transformer and 2k5 log pot on its secondary for input,
but it is impossible to fit big trunny in 500 format.
Input options are: OEP 2:1 or Altran 0-12 copy with 600 Ohm attenuator;
balanced line receiver like THAT1246/OPA137/SSM2143 with 10k log pot.
/edit: ssm2143, all these line receivers are -6db gain

To run it as cheap drum compressor, I can fit balanced line driver and balanced line receivers instead of trafos and make 8 of 51X-F76....instead of distr/essor's; bad taste but money-saving
Seriously, this can be version to learn how things work.

Yes, all we like analog meters, but no space here.
I will do my test version with Altran O-12 and API output clones from Hairball Audio.

-any plans for stereo link via the 500 series stereo link connection?

Already there. FET matching is pain, but IMHO it works better than summing the signal
into mono before detectors.

 

[helterbelter]

Wicked.... unfortunately I'm not able to afford myself a pair. But this is something unique. Damn....

 

[dmp]

EA-5002 from Hairball audio fits in 1U. Transformer is 1.5" wide.

 

[Igor]

Have a pair of them, great runny's....
They measure 1.4x1.9x2.3', vert. mounting bracket, but don't fit into 500, mind, we need some space too....
I have a good feel wit API output transformer clone........

 

[deuc224]

damn these just came out of no where. I think this might push me into 500 series land :'(

P.S. Those are tears of joy lol.

 

[jsteiger]

Boy Igor. You are a machine.  ;D

A tip of the hat to you. Looking very good as usual.   

 

[RedNoise]

wow e-gore !!!! what's in your pipe man???Can't wait to get a pair!!Hat off!

EDIT :
Bakelite front pannel ?
LM3914 for GR metering ?

 

[stereokillah]

hehehe, mine is almost finish , just need board, bom and parts  
there is some place nearly my mixbuzz500 and my future 51 DAOC.

after a good eq multiband will be fine

 

[ultra-alex]

awesome, igor

 

[Ryake]

I want one!

 

[Igor]

P.S. Those are tears of joy lol

LMAO

Boy Igor. You are a machine.

Nooooo....

wow e-gore !!!! what's in your pipe man???

Once to clarify. I don't smoke anything except tobacco.
Preferred types:
long cut Virginia Flakes and Erinmore Mixture. Sometimes, when
I am not at home and nobody in radius 20 meters, I smoke specially
dedicated pipe filled with strong Balkan Latakia, this is very stenchy for others but
people who smoke it enjoy from very reach, cool taste. My girlfriend btw hate Latakia

Bakelite front pannel ?
LM3914 for GR metering ?

99% I will use for my unit black 3.16mm thickness PCB like in Mixbuzz500.
Copper writings never comes down like silkscreening.
LM3916 is for metering. 14/15/16 are same pin-out,
except: 3914 is lin scale, 3915 is log 3db per LED, and 3916 "mimics" analog meters.

hehehe, mine is almost finish , just need board, bom and parts  Tongue
there is some place nearly my mixbuzz500 and my future 51 DAOC.

after a good eq multiband will be fine

You superfast , French DIY team guys!!!!

I want one!

Let's slow down and see what happens. I have to test it thoroughly first.

 

[Igor]

A....Little spoiler
Or, sneak preview. I don't like those ALPS switches, they causing me
cognitive dissonance. Have to change them to toggles.
Except this. Measures are right. Nuff better than stare into new PCB's!

Well, have to do something with these ALPS switches.
Move some resistors-to get some space between the comp's!!!!
LL1524/1517 fits by dimensions, as well as API out clones bought from Hairball.
First class service.
Enough for today, testing-tomorrow!!!!

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/prew_contr_2.jpg

http://i251.photobucket.com/albums/gg291/diy33609/51F_X76/prew_contr.jpg

 

[Ryake]

8) Looking good!

 

[Igor]

In case of whatever. DOA sockets can be filled with 1176 amps or
almost every other DOA or even IC op-amp...
At all, people should have a choice, when building a project like this.

 

[gemini86]

brilliant!