The Maxon/Ibanez Tubescreamer circuit has been around since the late seventies. No new electronic concepts were present in the design except in combination of plainly accessible op amp "cookbook" elements. Any patents dealing with the original circuit have become public domain, as 20 years is the typical limit for solely profiting from a patent. The U.S. had a 17 year patent term until 1995, when new patents were granted a 20 year term. The point is, after a patent expires, the content is public domain and usable without penalty. Modifying the original circuit to create a derivative, therefore, no longer requires permission from the originator. So, what ethical considerations are there in using these circuits to create one's own devices for personal use? Many of the variations which have emerged in the boutique overdrive pedal market are trivial modifications to the original circuit. How much consideration do we give to the vendor of a pedal who has modified a public domain circuit in a simple way, regardless of whether this produces a revolutionary audible result? Circuit in question:

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CS-2 for leads? 

I looked up Wampler and a couple of others and their names aren't to be found. How can you possibly keep up with who's inventing what?

Yea, but the CS-2's just sound bad. Build a Ross clone.

As for building amps, I'm wanting a 6G6 as in blond bassman. Marsh as a kit for ~$900.

I had heard the same thing. I played around with a CS-3 for a while and promptly sold it. It was unpleasant to listen to.

I've always found using a compressor at low volumes makes the guitar behave much more like you're playing loud, though I've not found one yet that does it well as a pedal.

That idea of adding a compressor after a light transparent overdrive circuit should be a winner for small church musicians, but probably wouldn't sell to those that crank an amp within an inch of its life. The Golden Cello addresses a slightly different market, and provided the gain is kept under control, will likely sound acceptable over a very wide volume range. I've replicated something tonally similar with my Dano cool cat fuzz and MXR Carbon Copy, and it sounds pretty good for all sorts of soloing. The GC seems to have a more transparent overdrive than a typical fuzz, even though it is quite fuzzy, and a big bucket of gain available.

My recollection is that there are only a few basic compressor designs - Ross type (VCA), Dbx Compander (Maxon), Squeeze (Armstrong) and Optical. Well, that's a mite more than there are overdrives I suppose. Know of any more? I suspect there are variations of these in studios, but still the same basics.

Hey - just for fun - look at The guy is more of a compressor freak that I am!

Oh yea, VCA into overdrive or vice versa depending on what you have - sounds great. Right now, I'm doing Gretsch into Diamond optical compressor into Timmy into Allen 6G2 amp. Heavenly.

It's a specialized op-amp I think you could say. It's an op-amp because it's truly a black box, but it has special circuitry beyond just amplification. To me, it's a very cool idea. 

My Keeley is a VCA design based on Ross and sounds fabulous. I started noticing some crazy noise and called Robert Keeley. He sent me three new VCAs to plug and play. They're NOS if that makes any difference. So now I have two spares.

Also, in response to Toni, Diamond claims the optical compressor which I currently own, is "studio quality in a pedal." I can't tell you what studio quality is, but it's very smooth and never pumps.  I use it to make a smaller amp sound bigger...

For a very cool compressor (more than one model) that has some of the controls you see in the studio, look at:

One of their pedals has sidechain capability which seems to be the ability to choose which frequency band you want compressed.

Stevo - it's not the noise etc that's an issue for me (and that's usually what marks a studio quality compressor) but the quality of compression. But I'd think that a compressor should pump if you want it to and can set it that way.

Diamond compressors are a bit too boutiquey for my level of finance right now, and I play so little these days it's not really justifiable. I'm even debating over whether to spend $40 on a Joyo chorus pedal that will fit on my (small, cheap) board.

I'm just relating that Diamond makes this claim and seems to live up to it with a smooth, low noise unit. It doesn't seem to lose and highs or lows either. I can't personally compare it to anything lika a UA 1176, so I have no idea if it's truly "studio quality", but it's very good.

I know I don't like a compressor that can't do anything but pump - like the Barber I once owned. The Diamond has yet to display any of that.

I do want to hear about the Joyo Chorus - do relate if/once you buy one.

OK, I'll do that. I'd been thinking about a Dano Cool Cat, but really didn't like the mechanical chorus tone and excessivly square-wave warble. The JoYo demos suggest it can produce the shimmer and sparkle that I like from choruses (which my Rocktrom Deep Blue does well, but won't fit the board).

Stevo - I nearly ordered a Joyo, but instead was given a discount code for a site carrying those tiny Mooer pedals. I've ordered a chorus ensemble and a shimverb at 1/2 price. If you're interested the site is marcmart ( and the code mooer132.

They do a bunch of stuff including various overdrives and fuzzes, but in all the youtube demos the fuzzes sounded too abrasive and the overdrives lacked the singing quality and defined crunch that comes from the best units.

Toni - I'm interested in what you think of the Mooer. I was drooling at those cute little things about a month ago. Love their description of the Chorus:

"Very small and exquisite"


Woah - love the Shimverb. Just may buy one! Thanks!


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