500 series FSC opto kit... second run.... any interest?

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

peter purpose

Well-known member
Joined
Jun 3, 2004
Messages
2,082
Location
London
Lads... anyone up for more FSC goodness?
Kindly express any interest here.

rack9.jpg
 
I have built a stereo (rather dual mono) unit from leftover pcbs on the black market.
I think the unit sounds phenomenal, and I haven't even started on DOA's yet, just plain vanilla 5534s.
My only problem is that the units are very different to each other, and I am struggling to get a similar threshold and ratio.
This makes it near impossible to use them as a stereo unit, which I would LOVE to do (drum subgroup).
I also have problems getting the meter to track properly.

I would like to know if these issues have been addressed in your version, and if you are possibly planning a stereo link for the new edition? I'd be interested in buying a unit, just to learn more about the circuit. The 500-ness is a bonus obviously.

canidoit: there are two massive threads about the forssell optical compressor on here, and a lot is being said about the sound and behaviour of optical compressors in general, and this circuit specifically
 
Brio,


    you could try 'em an stereo as mid and side 'til you match them up. Great fun on a drum bus I think, ms . .


    Are you the Brio who used to work at Hit and Run in London by any chance?


    Kindest regards,


      ANdyP
 
briomusic said:
My only problem is that the units are very different to each other, and I am struggling to get a similar threshold and ratio.
This makes it near impossible to use them as a stereo unit, which I would LOVE to do (drum subgroup).
I also have problems getting the meter to track properly.

I would like to know if these issues have been addressed in your version, and if you are possibly planning a stereo link for the new edition? I'd be interested in buying a unit, just to learn more about the circuit. The 500-ness is a bonus obviously.

Brio,
I've got a trimmer to set max slope, so as long as your ratio pots are pretty much the same, no reason why two units shouldn't track well. You could of course use rotary switches for ratio.
Threshold should be a LIN and not Log pot, as was originaly spec-ed.
As for the meter... I just set the last led to be what you want with regard to max gain reduction. 20dB or so.

peter
 
thanks for the advice everyone!

@ peter purpose: the trimmer replaces the 100R max slope resistor, right? it just seems that even attack and release times are different, with pots set to the same min/max positions on both channels....for the time being i have resorted to just using them as dual mono, and tweaking until I like the sound (which usually doesn't take too long...) I managed to get hold of a 3rd f.o.c. pcb now, which I will use for R&D. I think I will rather get a 525 from you, Peter, as I will be all forsselled up with 3 optical channels.

@ strangeandbouncy: like the m/s idea, but I need to build a converter first, or find a way to do it with plug ins and analog inserts. I was going to build a m/s adjuster anyway, in order to try to do something like the wide button on the neve summing box. and, yes, I did indeed work at hit&run...what is your connection to them? cheers brio
 
Brio,


  I have no connection with Hit n' Run other than Jo and Gil Cang! I have worked loads with them over the years. We have definitely met a few times back in the day.

M+S easily achieved if you have any kind of analog mixer - L+R and L-R to encode, and the same to decode. LOgic even has a plugin for it. _ guess you are in Tools, tho'. Someone posted a very simple circuit using opamps, and you can easily do it with transformers, but I guess the jury is still out as to which transformers will give the best results. Good luck, and let us know what works for you. I was actually planning to do the same over the mixbus and was contemplating which way to derive my MS, so you've spurred me into action!


      Kindest regards,


        ANdyP
 
@ andy, I think I remember....found you on myspace  :D

also....bump:
this is a great compressor, IMO better sounding and more flexible than the LA-4,
definitely worth checkin out if you fancy goin optical without goin tubey but WITH Attack+Release control!
vocals sound smooth and alive, even with silly settings.
 
briomusic said:
@ peter purpose: the trimmer replaces the 100R max slope resistor, right?

Brio.... In addition...  Don't want to be sending a non current limited V to the leds by mistake.... pop goes the vactrol.
 
peter purpose said:
briomusic said:
@ peter purpose: the trimmer replaces the 100R max slope resistor, right?

Brio.... In addition...  Don't want to be sending a non current limited V to the leds by mistake.... pop goes the vactrol.

thanks for this moneysaving warning. so trimmer+resistor it is.
 
Back
Top