Vintage Synth Explorer Forums

Based on some dialog here, I bought a used Bellari RP583 opto/tube hybrid compressor some months back, and had it modified to replace some of the components with better ones by Matrix Audio Systems, who did a wonderful job and also replaced the meters for me, which the previous owner neglected to mention were broken in the auction sale.

It appears I acted in haste, as I did not look into the practical uses of opto-compressors first.

First thing I find out when it finally gets here is that the tubes do not color the sound in this unit at all. I guess if one wanted something like a Universal Audio LA-2A, but with a gentler response, this would be fine. I wanted tube sound and this ain't it. This is opto-compressor sound. Dunce hat firmly placed on my head.
Second thing I find out was that optical compressors have a slow attack response by nature. Found this out very quickly when putting my Oberheim SEM, at the synth's fastest envelope attack speed, through it. All I ended up with was bad compression that actually distorted both the compressor and the mixer channel's pre-amp in a very ugly, crackly way.



So the question is: What are these types of compressors good for? I've so far run an OP-X pad through it, and it sounded nice:
but I'm not certain the compressor makes much of an improved difference. May have given me an extra 2db of headroom at best. This compressor has a very sensitive threshold control though, so I may just not know how to use it properly yet.

I hear they are good for acoustic guitars and vocals, neither of which suit my uses. I'm thinking since this purchase was such a drastically uninformed decision, it should just go on the auction block, but if there are other uses, I'd like to know. I haven't tried drums yet, but the compressor's slow attack response might prevent the intended effect.

Anyone use these regularly in electronic music production? Cheaper examples are the EHx White Finger, Aphex Punch Factory and BBE Opto Stomp for guitar.

I've got a White Finger, and have found it to be better at adding stab to attack with synths, compared with my Boss CS-3, which can push up a pad with some roughness if asked properly. On the other hand, I've dabbled with bass (guitar) through the WF and it did a good job of evening out some very shoddy playing while sounding transparent. I use the WF as an effect rather than a general-purpose unit, for things like you mention with the pad - a touch of colouration, etc.

Drums are my absolute favorite use with compression. Second would be bass, with the right settings makes it very punchy and defined. Seems like most opto's are made to be transparent and natural sounding. I also like to add reverbs and delays sparingly with comp. I used to be jones-ing for a Joe Meek but ever since I got a plug in version of the Neve 33609 I've been on cloud 9. With the 33609 - a compressor is combined with a limiter. The limiter can be driven with a really hot signal coming from the compressor make-up gain which sounds really nice.

Well, after another 3 weeks of playing with this thing, I can't seem to get it to do anything but lower the overall volume of sound. With makeup gain to match previous loudness, then A/B'd with the bypass switch, and comparing the waveforms in Sound Forge shows little, if any change in dynamics at all. This could be because the minimum release time is 1 freakin' second!! There is also no knee control. No apparent added warmth from the tubes. When it distorts, it sounds like a*s.

This thing is a placebo. Lame. $600 down the tubes. It sucks. Anybody want it for cheap?

You honestly think that's lame, I spent (ok not as much) about 300 quid on a JoeMeek SC-2.2 optical compressor and man oh man it sucked balls...I like compression to be used more as an affect but I wouldn't even call the Joe transparent cos I honestly don't think it was doing jack..you say you are having gain reduction..great! Cos I was barely getting that! Honestly it was the placebo affect to the max...this might be optical compressors in general then.
The only other comps I have used are the API-2500, Alesis 3630 and one of those cheap DBX units...all kick the JoeMeeks week a*s (The API wasn't my unit, used to belong to a friend who sold it...I don't have that kind of cash!!)

At the moment I just whack things on cheapo cassette then compress the living s**t out of them in Logic just using the normal single band compressor it comes with hahah all in good fun of course
example:

Solderman wrote:the minimum release time is 1 freakin' second!!

Are you sure it's not 0.1s?

What are you doing with it? I've just seen a couple of reviews that don't suggest it's as useless as you make out.

vinyl_junkie wrote:Honestly it was the placebo affect to the max...this might be optical compressors in general then.

Hardly. I suspect it's just a case of knowing how to use a particular tool to best effect. Two of the four compressors I've had have been optical, and both are useful, and not placebos at all.

nathanscribe wrote:

vinyl_junkie wrote:Honestly it was the placebo affect to the max...this might be optical compressors in general then.

Hardly. I suspect it's just a case of knowing how to use a particular tool to best effect. Two of the four compressors I've had have been optical, and both are useful, and not placebos at all.

Agree but it really didn't work the the material I was putting into it, the joe meek also doesn't compress the low end..which I don't get why, the lower frequencies have less gain reduction..I confirmed this with a test oscillator.
On acoustic piano it sounded alright, kinda gave a certain sound without any noticeable pumping which is good if you are after that kind of thing..every one goes on about how good it is on drums but I didn't think much of it

nathanscribe wrote:

Solderman wrote:the minimum release time is 1 freakin' second!!

Are you sure it's not 0.1s?

What are you doing with it? I've just seen a couple of reviews that don't suggest it's as useless as you make out.

Oh for f**k's sake, the screen print was wearing off, and the manual says it's .1. Regardless, I know what I'm hearing and seeing in the audio-editor, so maybe it's useful for vocals and acoustic guitars and such things with less than percussive dynamics, but I really wanted compression for hardware and software synths. I have an RNC1773, but have been using it mostly as a limiter. Call me amateur, because that's precisely what I am.

Dumb question, but do you have the ACTIVE button pushed?

As mentioned earlier, I A/B'ed the bypassed and compressed(plus gain compensated) signals. In most cases they sounded alike and looked alike, as far as amplitude peaks, in Sound Forge. I did get the minimum release time wrong(it really is .1 seconds) earlier, but it doesn't matter, if this thing isn't making any difference, no matter how I set the threshold and attack. It's useless to me.

Solderman wrote:Oh for f**k's sake, the screen print was wearing off.

We've all been there...

As for it being any use to you, if you can't get it to work for you, fair enough. If it's more a case of not knowing how to get it to do what it should be doing well, you know what to do. I find I know I won't gel with a piece of kit fairly quickly; I've had a few bits that were potentially great for somebody else, but left me nonplussed. You never know till you try I suppose.

Opto compressors are generally used because they're pretty gentle on stuff and don't have a quick attack and decay time, so are more transparent. That's what they do, so if you expect them to do something else then you're going to be disappointed.

Like Nathan I think this is a case of not knowing what your tools are best for or how to use them. The suggestion that people only use opto compressors because of some placebo effect is slightly hilarious.

When you're comparing comped and non-comped signals, where have you got the threshold set? If the threshold is so low that it's compressing the whole time and then you make up the difference with the make-up gain then of course you won't hear anything. The trick to compression is around where it goes from uncompressed to compressed, setting your threshold and attack and decay times is the real trick.

Points taken, all. By placebo, I meant just this device for my current applications, which I can't seem to find any use for. True, a very low threshold is just going to keep the volume down, and also true that the Bellari RP583 has an overly sensitive threshold control, so maybe I just don't have the patience for this bit of kit.

I assumed the best practice is to flick threshold fully clockwise and start turning it back until the meters just start to register activity, then carefully adjust threshold, attack and release accordingly.

In any case, I don't think it is meant to be used with software or hardware synths.