Two-in-one compressor?

[H4T]

A while ago I saw a neat and, if I remember correctly, not totally impossible pedal that combined the MXR Dynacomp with some other one..I think it may have been the Ross compressor. You can switch between the two different compressors with an SPDT switch. Anyway, I can't find that schematic again! I would like to build this pedal, unless someone here thinks that I really should build one of those pedals, but not the other.

Oh, and I'm kind of confused on something. Which is better, a compressor or a noise gate? From what I've heard, a compressor brings the loud (high?) notes down to level with the low notes, and a noise gate brings the low notes up to meet the loud (high?) notes. So...do I have that right? If so, its kind of hard to decide which I'd rather have.

[jbm222]

You've got compressors, limiters and noise gates all a little mixed up.

First, a limiter softly squashes the high volume signal to a lower level.

A compressor also does this to volume peaks, but also increases the volume of the low level signals.  Compression can increase your sustain, while limiting will not.  Limiting is useful for smoothing out your sound a little, and in some cases preventing clipping where you don't want it to occur (like when recording a clean electric guitar).  Compression can be seen as a bit more of an effect since it can be used to sustain notes much longer than normal (especially when followed by distortion).

A noise gate cuts out all signal when the average volume is below a certain point.  It's used mainly to cut out noise below the signal level when you're not playing.  If you extend the time it takes for it switch on, making it fade in, you can get effects like a Slow Gear, which masks you pick attack when playing single note sort of runs.

Ross Compressor and the Dynacomp are very similar and can both be built using almost identical PCB layouts. www.generalguitargadgets.com has a pdf file that explains a little bit about how they work and shows schematics for both.  However, I think there's enough difference between the two that it's not very practical to build them on the same board and try to switch between the two.

[H4T]

Wow! That was an excellant response, makes perfect sense now. Thanks a ton for that, I've been confused about all those for quite some time, lol.

I would love to have more clean sustain and keep those soft notes, so I'm going to stay with a compressor. I think I'll go with the Dynacomp...just because it...uh...has a cooler name, lol.

Thanks again for the great help! ^_^

[H4T]

Here's what I was thinking of, I found it. Apparantly its a combination circuit for BOTH pedals, not two seperate pedals you can switch between.

Here's a link
http://www.geofex.com/PCB_layouts/Layouts/d&rpub.pdf

I think I'll stick with the Dynacomp, though that does seem interesting.

[Mark Hammer]

Yep, jbm did a nice one on that.

Just to provide a little context, it's important to consider the reason why limiters have been around.  Once you get a sense of their purpose, it's easy to understand their design.

Traditionally, recording and broadcast involved:

a) mixers and mic preamps that had a limited dynamic range before they distorted

b) tape that was able to handle only a limited range of input levels before it saturated

c) vinyl discs that were limited in terms of the dynamic range THEY could handle/reproduce with any reasonable amount of content on a side

d) broadcast transmitters that were limited in terms of their ability to handle dynamics

It wasn't that dynamics of ANY kind were uninvited.  Rather, it was just those pesky peaks that stepped the meter "into the red" and made problems.  The answer became the limiter, as a device that left MOST of the dynamics in but kept a lid on peaks that exceeded a certain threshold.  I haven't been in one recently, but there was a time when it was inconceivable to have an AM or FM broadcast studio *without* a limiter that stayed on 100% of the time (along with that Studer/Revox open-reel deck that ran at ultra-slow speed 24/7 to provide tape backups of broadcast for the federal regulatory agencies).

Limiters also found considerable use as "system protectors" in sound reinforcement, as a way of making sure that speakers were never fed signals by enthusiastic musicians or sound mixers that might result in a popped voice coil or fried output transistor.  Of course, all of that came from an era when the sorts of fast-shutdown technologies we have now, as well as the sorts of speaker protections afforded by the materials filling voice coil gaps (for cooling), the tight tolerances that higher quality speakers can now achieve in voice coil alignment (it's the friction-derived heat from voice coils that wiggle a bit to the side and rub up against the magnet that precipitates many speaker failures), and the widespread use of bi-amping and tri-amping as a means of assuring that more fragile tweeters never receive the sorts of signals that would blow them.

I'm obviously not suggesting we are "past" using limiters, rather that they are a technology that came from a time when there were MANY reasons to  insist - through technology - that a signal could be *this* loud, but not *that* loud.

What I find interesting is that limiting was built into so many aspects of the history of rock and popular music, from how it was recorded, to the broadcast medium, to how it was produced in concert settings, that the almost compression-like sound introduced by multiple stages of re-limiting during recording and broadcast became an intrinsic part of what we think rock is supposed to sound like.

[H4T]

Very interesting post, I think I got the gist of it at least, lol.

Through some further research I've discovered a TON of mods for the MXR/Ross pedals, like your recovery time mod. I've also found that a lot of people prefer the sound of the Orange Squeezer. I may go with that one, if its easier. The schematic I found of it was pretty crowded compared to my Dynacomp schematic, but I think it does have less parts.

I will be using this schematic, with Mark Hammer's mods for variable gain. Is there anything else I should change or take into account other than whats in this schematic?

http://generalguitargadgets.com/diagrams/orangesqueezer_marks_variable.gif

[octafish]

Check out tonepad for the wiring of a switch to choose between dynacomp warble, and ross smooth. Also two nice pcb layouts for the DynaRoss and the plain vanilla OS. I built mine using audiophile parts because compressors are (generally) noisy beasts, so try to avoid ceramics and lash out on some low noise metalfilms, maybe.
I like the OS for slide and county style pickin' but the Ross for rock sustain and things like hammering with my weak stubby fingers.

[H4T]

I should start a new thread, but that would just be annoying.

No, I said I've decided to go with either the Dynacomp or the Orange Squeezer. I don't know which I want, but I know what I won't be doing the two-in-one anymore.

I will be playing more distorted stuff and chords and such, no country pickin', lol. I leave that for kinda stuff for my acoustic.

I'm leaning towards that schematic I linked to in my last post, but if someone thinks the Orange Squeezer is better, then....   I haven't had much luck finding sound samples of these pedals, so I can't compare them.

[transient]

You can find sound samples of both OS and ROSS at the Analogman compressor page:
http://analogman.com/rossmod.htm

Just keep in mind that juicer=OS comprossor=ROSS.

.
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[H4T]

Thanks! I think I like the Orange Squeezer sound more than the ROSS compressor, lol.

Now I think I found the compressor that I will build. I may have to buy a PCB layout board for this though, looks difficult.

[octafish]

I built my first Squeezer on vero, but I didn't draw up the layout, and that one has gone now. The second, I made with perf using the layout from tonepad glued to the perf as a guide. Except for having to go out and buy a trimpot it took me about twenty minutes to populate the board. An easy way to build one if you want to try it in its standard(ish) form. I believe the original used a trimpot to set the volume to unity. The OS doubles as as nice little booster.

[H4T]

I would really, really love to build Mark Hammer's version of the OS, but I can't find a layout for it anywhere..ahh...looks so much better, but can't do it.

Mark, if you read this, do you know of any PCB layouts anywhere for your version of the OS? All those controls really make me want to make this pedal!