Any info on CCA electronics LA1D vari mu compressor

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gary o

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Any info on CCA Electronics vari mu compressor. I have a schematic from Sowter site

http://www.sowter.co.uk/

have found only this...

http://www.oldradio.com/archives/hardware/cca.htm

I remember reading about it a while back and getting the schematic , done some searches but cant find anymore.

Ive just bread boarded the control voltage part of the circuit to replace the control voltage part of a home made BA6A ...it works a treat I have 12 different recovory times and a kinda ratio control gonna put a switch in to choose between original BA6A release times or the 12 different LA1D release times.

Any info might be interesting ...thamks ......Gary O.
 
im not sure what youre asking, exactly. i didnt see any schematic on the sowter site.

i did find this on jakobs site:
http://www.gyraf.dk/schematics/CCA_LA1D_Limiter.gif

circuit looks pretty conventional.
 
Ah thanks thats the same as on the Sowter site under pro vintage, just any info could be interesting I like the adjustable release times

Thanks ....................Gary O.
 
That's awesome!!! I'm building one of these puppies!!! It's now top priority, right after finishing that 1176 clone, my second GSSL, those Pultecs, Calrecs, 1081s and getting my Flickingers racked up! :grin:
 
Joe you sound like me everything at once ...cool :grin: there are some very long release times in this unit, well compared to my BA6A anyway, im currently tryin to decide which selection of times im gonna use, I put a 4m7 pot in there to save 4 switch positions. Those 6386 tube are rare sadly, I was gonna try 2 6BA6 tubes I think thats the right number ...meant to be half the 6386 es daul triode so will use two and balance poy or somethin.



Cheers..................Gary O.
 
[quote author="solder_city"]um, you did notice that it uses a 6386 tube right?[/quote]

Got eight of 'em hidden away :grin: $10 a piece at a TV repair shop in Venice, Fla. back around '95 or '96. RCA 5 star. :grin:
 
[quote author="gary o"]Joe you sound like me everything at once ...cool :grin: there are some very long release times in this unit, well compared to my BA6A anyway, im currently tryin to decide which selection of times im gonna use, I put a 4m7 pot in there to save 4 switch positions. Those 6386 tube are rare sadly, I was gonna try 2 6BA6 tubes I think thats the right number ...meant to be half the 6386 es daul triode so will use two and balance poy or somethin.



Cheers..................Gary O.[/quote]

Manley apparently came up with a circuit to replace the 6386 that uses two remote cut-off pentodes in place of a 6386. Maybe somebody on this forum has the details on that. There was some guy selling the details on evilbay for $95 or so last year but I didn't want to know it that badly. :grin:
 
Lots of discussion has taken place here about 6386 replacements and various varimu designs. Check the META.

You gotta read PRR's posts.... one begins with "6386 is NOT magic!" :grin:
 
two matched 6ba6 wired in triode can sub for 6386.

but matching them... thats the part thats not so easy if you dont have the right equipmt.

like skipwave says this has been discussed thoroughly and you should find the threads in the meta
 
[quote author="solder_city"]two matched 6ba6 wired in triode can sub for 6386.

but matching them... thats the part thats not so easy if you dont have the right equipmt.

like skipwave says this has been discussed thoroughly and you should find the threads in the meta[/quote]

Thanks, that'll make good reading over dinner :grin:
 
You could always use a 6ES8 like the Pendulum unit uses. Also, Manley had a version of their limiter where they used a 2C51/5670 in place of the 6386, and just changed the value of the cathode resistor. There are still a number of tubes that will work well for this kind of service with a slight mod of the sidechain to provide the right voltage curve.
Fortunately, I still have a stash of 6386's left from back when I had a 670 limiter as part of the complete Fairchild cutting system I used to own. Of course back then, replacing the the 4CX250's in the two drive amps was the expensive part, as 6386 tubes only went for about 6 bucks a pop.
 
I just scored one of those tubes new for $1.50... and I just wrote the number down after reading another post to see if they had any.

I guess I didn't know what I was looking for or what they had.
 

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