Marti CLA-40A/H... info?

[theblotted]

i recently scored a Marti CLA-40A/H Compressor/Limiter... for $80US!! i tried to do some Google info search on the unit, but came up short. not even a schem.

does anybody have any info on this guy? my understanding is that it's an Opto comp, but there are some other interesting circuitry going on...

i've made a photo album. would appreciate it if some of you knowledgeable guys could give it a gander and share some nuggets of wisdom... 'cuz i'm quite a noob when it comes to identifying circuitry!!

http://theblotted.myphotoalbum.com/view_album.php?set_albumName=album01

much thanks!

 

[theblotted]

it has 3 Module cards on the back... and within each card, there's stuff like little "RCA" or "VACTEC VACTROL" cans...

some of the pots inside dates it 1977.

there's also internal controls when you take the cover off.

unfortunately, as of now the amplifier section works (input/output controls), but the compressor/limiter section seems like it's not doing anything (no Gain Reduction).

i want to take it to my tech for look-over, but there's no schem.... :sad:

 

[stinky]

I've had my hands on this unit at the shop. We weren't having any problems with the functionality but it was definitely in need of a recap. We never found any service information on it either. I will tell you that if you haven't got a lot of money into it it'd be worth getting it up and running. It's no LA3A but it's got some squish and some of that noise that is so pleasant. Just thought of something. The threshold, as I remember, is very high. It wants a big input signal. That's something I would tweak.

 

[theblotted]

[quote author="stinky"]I've had my hands on this unit at the shop. We weren't having any problems with the functionality but it was definitely in need of a recap. We never found any service information on it either. I will tell you that if you haven't got a lot of money into it it'd be worth getting it up and running. It's no LA3A but it's got some squish and some of that noise that is so pleasant. Just thought of something. The threshold, as I remember, is very high. It wants a big input signal. That's something I would tweak.[/quote]

stinky,

cool thanks for the info. i'm dying to get it fixed, but lack of funds at the moment and Tech being swamped...

question, what kind of Opto element is it using, same as the Urei boxes (LA2A, LA3A, BL40)? is it also a FET design for the Compression? (sorry if i come across like a *******, i'm still having a hard time telling apart diff circuit parts...)

 

[SSLtech]

Opto = Vactrol.

Urei optos are all Cadmium-sulphide long-time constant type... very different.

Keith

 

[theblotted]

[quote author="SSLtech"]Opto = Vactrol.

Urei optos are all Cadmium-sulphide long-time constant type... very different.

Keith[/quote]

so what would you say the sonic difference is between the two Opto's?

 

[theblotted]

:?: what's the general consensus on Vactrol Opto's? yay or nay?

 

[theblotted]

got it back fro my Tech, all calibrated and recapped, just tried it out...

input level needs to be cranked in order to see some GR. but listening carefully there's a bit of GR happening even before the meter starts working.

the limiter's headroom is pretty low, distorts almost immediately. i had to have Limiter Level cranked as high as i can. i suppose this works well for Snare.

i prefer the comp only mode. only using FET. much smoother, no fuzz distortion. since the release time is pretty slow (1 is fairly slow, 2 is 5 sec, 3 is almost 30 sec!), works better for vox or bass.

got a nice smoothness to it, can bring the vox really upfront and pin it down.

oh yeah, i also have it set at AM (no high roll off like FM) and Asymmetrical (more ear pleasing distortion). i prob have it set wrong, but sounds good to my ears.


thought i provide an update for whoever else that needs some info. i managed to find schem/operator's manual from a fellow Marti user; that was incredibly helpful.

 

[stinky]

Any chance you can scan the schematic in? I'd love to have a copy of it.

 

[the groke]

If anyone still cares, I have posted a copy of the schematics and manual here:

http://rcarchives.com/swirlies/manuals/index.html

They are also available on the Marti website.

From reading other posts for related gear, it would appear that it is very important to terminate the outputs with a 620-649Ohm resistor (put resistor between the two terminals for hot and cold). I'm curious if anyone ever worked out a good way to make the threshold more sensitive.

 

[emrr]

Thanks!  We have a technical documents section here, you may want to post that and others there as well. 

 

[okgb]

I maybe wrong but I thought that they actually decreased bass freq's to provide more headroom , [ limiting ]
meant for short hop wireless broadcasting  , there's probably allot of marti product though .

 

[the groke]

OK, I'll try to post the docs.

Also, my Marti's have Vactec Vactrols marked 21L53A. There is no info on this part online. Does anyone have any idea what a suitable replacement would be?