Recommend a good CMOS inverter distortion pedal?

[cb]

Anyone know of any pedals from a major manufacturer (e.g. Boss, DOD, etc) based on CMOS inverters for distortion? I'd like to pick one up cheap and hear what is sounds like, and possibly tinker with it. Thanks.

[Nasse]

I believe companies that big do not have such pedals but I may be wrong

And I dont see not much benefits in modding ready made unit instead doing one yourself, honestly

[Dutchie]

yeah, the 3 legged dog of runofgroove is guite simple...although i have lots of hiss and oscilation, i think i can get it to work.

[Mark Hammer]

There have been a couple of commercial pedals over the years which used a 4049, but the only ones still in production that I know of (and that is certainly going to exclude all those Japanese pedals we never seem to hear about on these shores) are made by Snarling Dogs. They make a number of pedals that are based on a 4049 hex invertor, one of which is pretty much a note-for-note clone of the original E-H Hot Tubes.  I forget which one, but it is one of the trio of Black Dog, Blue Doo, or Tweed E. Dog.  You can check out their site for sound clips.

[cb]

Actually, in production or not is ok, since I'll probably look for a used one on ebay.

So the original EH Hot Tubes was based on inverters, eh? Might have to check that out.

Thanks for the info.

[Mark Hammer]

Several schematics for the E-H Hot Tubes are posted around, including the factory schem  One of them, erroneously labelled an MXR Hot Tubes (and if the site is simply a mirror of Jamie Heilman's old Leper's Archive, that's whatit will be called), is the same pedal.  Somewhere in the mists of time, I sent a hand-drawn tracing to RG Keen, and he redrew it properly, but it ended up being posted under that name and was never changed.  Honestly, these things are like nudie pictures you posed for while drunk and broke in college; they just never seem to go away.

The original Hot Tubes had an on-board transformer PS and plugged into the wall.  The Snarling Dogs pedals all operate off battery supply WITH leds to power up too.  I've run clones of the HT for years now with battery supply and never had a problem, but then I've never used one in a gigging situation where the pedal was plugged in for several hours straight.  I don't think these pedals are out and out current hogs like the early digital delay pedals, but my gut sense is that some opportunity to supplement what the battery can deliver is probably a good idea if gigging is your intention.

Personally, I like the modded Anderton TSF better than the Hot Tubes, but obviously that's a matter of taste.  The Snarling Dogs line is generally pretty competitively priced, though.

[Ben N]

Honestly, these things are like nudie pictures you posed for while drunk and broke in college; they just never seem to go away.

Damn, Mark, that was you!?!?
:twisted:

[Mark Hammer]

Could be.  How long did it look to you? :wink:

[cb]

The reason I'm interested in hearing an inverter-based distortion unit is something I read in the Stompbox Cookbook in the section on distortion. The author describes the squashing effect this kind of circuit can have on a signal - that made me think it should sound 'tubish'. I have number of distortion pedals and my favorites are the ones with an actual tube in them (Tonebone, Ibanez Tube King) - but we all know tubes have their downsides (they break, they go bad, etc).
Incidentally, there is a distortion project based on inverters in the "Cookbook" - I might have to give that one a try.

[Athin]

cb -check runoffgroove.com for eighteen, matchbox, thunderchief, tweed - listen to the samples - the closest to tubes I've heard + easy to make.

[Mark Hammer]

CMOS invertors are, at their heart, simply MOSFET transistor arrays.  Part of what they contribute that is different is the distribution of harmonic content, although I suppose there is some dynamic squashing in there, but then every clipping circuit squashes.

My own bias towards CMOS invertors is that I like how they sound when something else does most of the amplifying.  In the E-H Hot Tubes, the invertor itself does a good deal more of the amplification, as it does in the EPFM-II version of Anderton's Tube Sound Fuzz.  Stellan Lehrberg thought I had something interesting to tinker with and came up with the Slowfinger (http://www.fortunecity.com/tinpan/humperdinck/223/effect.htm), which you can hear at his site.  It doesn't sound exactly like mine, but it's in the ballpark.

You can also look at the EM Fuzz over at GGG.  This was Charles Fischer's last contribution to Electronic Musician before his untimely passing.  Some very interesting ideas there, including separate current regulation of the invertor chip itself for different tones.  Somebody here still has to build thatone, or at least publically comment on it based on a tryout.

Do all these things sound like tubes?  Damned if I know.  I have some great old tweed amps and I know they sound *better* when pushed with a 4049-based device, but what part of that is the invertor's capacity to mimic tubes?  Moreover, when 4049's do generate distortion, exactly what part of a tube amp are they mimicking: the preamp tubes, the power section, the effect of a tube rectifier, the output transformer, the whole shebang?  I simply don't know.  I've also never been in a position to listen to them through something that wasn't a tube amp being asked to break up.  On the other hand, if I want to sound like Waddy Wachtel or Mike Campbell, playing some P90-equipped temptress through an AC30 or blackface Fender, I use a 4049-based TSF, so maybe that says something.

What I do know is this.  If you have any intentions of cascading several invertor sections, whether using a cookbook circuit, a project from somewhere, or something innovative on your part, the smart thing to do is to restrict high end in the early stages and gently spool it out in later stages.  The reason is that each invertor stage generates additional harmonic content.  Subsequent stages generate harmonic of whatever they receive.  If you restrict early stages to just lower order harmonics, you don't end up with tons of fizzy harmonics-of-harmonics.  It just sounds sweeter in the end.  Besides, given the cumulative effect of several stages, even if you chop the high end at 6khz or so in the last stage, you'd be pleasantly surprised at just how much bite and crispness is still there.

[Ansil]

what about the la metal pedal  i thinki  twas dod i could be wrong  but anyway it had aninteresting sound to it and also had that misbiased gating sound that some of the inverter based distortion has

anyway also check out a replacement for a dual opamp  i bleive it was tonegod that turned me onto this chip

cd40107be  dual nandgate tie the inputs together and u have two inverters. hmm interesting if you flip it around 180 degrees  the inputs and outptus are just like a dual opamp  but the v+ and ground are different.. i foudn a way to wire it up on perf or with an ic socket specially soldered and put in backwards

shameless plug my rose pedal is invertr based.

lol i had to say it..

[bobbletrox]

I've tried the CA TSF and didn't like it, so then I tried the Red Llama and didn't like it...

...Their fuzziness is a bit too grating for my taste.  IMO, try building the Bounce channel of runoffgroove's Double D if you want a great high gain tube sound fuzz.

[puretube]

Several schematics for the E-H Hot Tubes are posted around, including the factory schem  One of them, erroneously labelled an MXR Hot Tubes (and if the site is simply a mirror of Jamie Heilman's old Leper's Archive, that's whatit will be called), is the same pedal.  Somewhere in the mists of time, I sent a hand-drawn tracing to RG Keen, and he redrew it properly, but it ended up being posted under that name and was never changed.

Mark: do you happen to remember if that "MXR" circuit is exactly the same as the E-H factory circuit? (I don`t have that orig. E-H schem...).

Thanks, Ton/puretube.

[Mark Hammer]

No, it is not the same as the E-H factory schem.  I got my HT originally around 1979 or so from a biomed tech at the teaching hospital I was working at.  He, in turn, had photocopied the layout of one he borrowed from a buddy and reproduced the unit from that (still have that board).  What I got from him omitted the tone control (and of course the tone-bypass).  I reverse engineered what I had received from him and sent the schem to RG, probably around 1991 or so, who then redrew it using software.  And THAT is what is erroneously posted around as the "MXR Hot Tubes".

I can send you the real factory schem if you want, although I'm pretty sure it is posted around.

[puretube]

merci, Mark.
I`ll look around some more (its not at all urgent - only the collector in me -) .
should the (inner) need ever really occur, I`ll molest you about it again...  


btw: I`m a little afraid we`re going to face the obsolescence of a whole lot of "old" solid state devices in the not so far future...