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DIY Stompboxes => Building your own stompbox => Topic started by: Bluesgeetar on May 26, 2004, 10:06:13 PM

Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bluesgeetar on May 26, 2004, 10:06:13 PM
Ok I have the full package of values of this thing.  I noticed that R.G. changed a couple of things on the original that Moeller did like adding some mods to the Bass/treble circuit and some substitutions here and there for harder to find parts.  SO what gives man!!!!!!!!!!!  You've changed the circuit so why can't you post a new AC30 sim pedal with your mods and let everyone else share in trying to build this thing.  It would be nice to have some input and experimentation of others here.  I thought since the circuit is not exactly like Moellers now with the few improvements made by RG that everyone can see it now provided RG doesn't mind showing off his ideas on the AC30 sim.  I mean aren't the two circuits different now with RGs improvs?!!!  :x
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Peter Snowberg on May 26, 2004, 10:14:38 PM
Copyright law in the US says that you must change the invention 30% as a minimum. In any case, the folks who received that circuit had to sign a non-disclosure agreement. It's very objectionable to me to see people go back on agreements.

-Peter
Title: hmm
Post by: Bluesgeetar on May 26, 2004, 10:37:02 PM
30%?  How would you measure that?  Don't put words in my mouth!  I didn't say break the agreement.  I mentioned putting the modified version up.  

Seriously, how would you measure a 30% change?  I would think in dealing with audio circuits that one is very subjective.  I mean one change in a part or value changes the sound 100%.  

I didn't sign no agreement but I did give someone my word.  Which is something pretty important to us Southern Country boys.

Also where can I reference that Copyright law 30% thing you mention.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Peter Snowberg on May 26, 2004, 10:57:14 PM
I'm not putting words in your mouth brother. Just statin' my opinion. :)

I was told the 30% figure by Stanley Mouse (http://www.mousestudios.com/) who is one of those big 60's poster artists that did many of the famous rock posters. He and the other poster gurus "appropriated" a fair amount of artwork from other sources so he's "in the know".

http://www.mousestudios.com/gallery/skellroses_poster.htm

I think this one was originally from a book of Robert Frost poems. He colored it up. :)

As far as measuring 30%.... that comes down to how much you pay your lawyer.

Take care,
-Peter
Title: AC 30...
Post by: petemoore on May 26, 2004, 11:08:25 PM
Now that would be cool....
 Neat to see if it could be made to respond similarly to the way a tube AC30 does to a Rangemaster !!!
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: R.G. on May 26, 2004, 11:22:55 PM
QuoteSO what gives man!!!!!!!!!!! You've changed the circuit so why can't you post a new AC30 sim pedal with your mods and let everyone else share in trying to build this thing.
It's a matter of principle. I realize that this will seem like splitting hairs but
(a) I have great respect for the technical prowess that went into the AC30 sim and the work that went into it. It's a far greater set of work than designing a MOSFET booster, for instance. Stephan set the terms for the use of his set of values, and did not ever post them publicly. Even though I did not sign a NDA with him and did not receive the secret values from him, I would respect his wishes. He earned it.
(b) I changed, enhanced, or offered alternatives only for things that were part of the publicly disclosed information. As such, I have no trepidation about telling people about the stuff I modified - and I did. For instance, Stephan made public statements about the circuits that let me compare the tone controls to those of a Vox AC30 TB and discover that he scaled the tone controls down in impedance as befits the lower voltages, and from that a way to more flexibly emulate the full range of adjustments of the AC30 sim, instead of having a fixed setting. The alternate parts were obvious to one skilled in the art; knowing a ZXY47 (for a made-up example) zener is a 4.7V 100mW pare, one can easily suggest a 1N4237 type as a replacement if the 1N4237 is also a 4.7V zener. My changes do not, in my mind, qualify as substantial enough changes to post the whole mess even if I had signed Stephan's NDA.
(c) I regard the publicly available material as a usable starting point for much more than an AC30 simulator. I think it's a clever way to simulate triodes, and it is an avenue of exploration that I will not cut off for myself by signing an NDA. By taking this position, I have satisfied my internal requirements for ethical dealings with the situation. I believe that I remain free to use the circuit concepts Stephan displayed publicly without restriction. In a manner of speaking, I believe the concepts are too valuable to piss away on just building an AC30 sim.
(d) Stephan's circuit as separate from the schematic drawings, etc. that he made is not copyrighted nor copyrightable. (Note - both Stephan's schematic , viewed as a work of art, and my PCB layout *are* copyrightable, and copyrighted. It's the circuit concepts that may not be protected by copyright.) If I encountered a version of that circuit that I did not have a hand in putting together, I would be ethically free to reverse engineer it, and do whatever I wanted with the information. Copyright includes the right to control derivative works. I believe the "30% changed" feature that was referred to is not correct. I believe all literary and artistic derivative works are controlled by copyright if there is even a small part of the original work. Even better, if you are about to do something that involves sailing that close to the wind, better get a lawyer's advice.

So: (a) I choose to respect his preference for an NDA (b) I changed only public parts, or parts I reverse engineered (c) I will not limit my future freedom of action and (d) Copyright law is not what is active here - it's trade secret law. I choose where I stand on trade secret law.

As an aside, the secret values are not that huge a deal. Someone skilled in the art could take Stephan's public work tinker and think a bit, and come up with the mystery values, close enough. But the concept is far more valuable than the specifics; I have the concepts, as freely given. There may be more there someday when I have time to mess with it.
Title: hmmm
Post by: Bluesgeetar on May 26, 2004, 11:51:23 PM
I dig those posters man!  I love that kind of stuff.

Funny!  That 30% lawyer statement. :lol:

Well I was just wanting everyone with the skill to have a crack at this pedal and possibly make some other creations or maybe even make the pedal better.  I would dig a Fender Tweed Twin sim.  Which I thought could be hacked out of  this circuit.  But the guru clik once again rules here on the forum, I guess and another great circuit will never be updated or recreated into something greater or better.   :cry:

It just kills me to wonder what some of the great minds here could cook up from that circuit.  
:cry:
[/quote]
Title: Re: hmmm
Post by: Peter Snowberg on May 27, 2004, 12:34:49 AM
Quote from: Bluesgeetar...But the guru clik once again rules here on the forum, I guess and another great circuit will never be updated or recreated into something greater or better.   :cry:

Guru clik??? Not here man.... everyone is equal here. This is about respecting the work of the author who doesn't want the info made public.

There's nothing stopping you from doing a detailed circuit analysis of an AC30 and building your own pedal from it. It's a tall task to do it to the depth he did, but it's pretty basic task over all.

If you want a tweed sim the AC30 sim won't help you much. Check out the Fetzer Valve from Runoffgroove to see how to get started on that adventure. Next check out the "eighteen", the Matchbox, and the Supreaux for more complete emulations including some speaker emulation. Next on the list would be to check out Doug Hammond's Meteor and compare that to a real 'Wreck.

You can see that it's not too hard to make a simulator. Make a better one, or better yet, make the one that you want! :D you could always release it like the 'Groove folks did and hope that others will improve it somewhere along the way or use it as inspiration to make yet another circuit.

I scanned the US copyright law (http://www4.law.cornell.edu/uscode/17/index.html) and didn't see 30% mentioned by number, but I can tell you for sure that after almost 40 years of making event posters, Stanley Mouse and the other big poster artists have the details of how copyright works in the real world. ;)

Take care,
-Peter
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Ge_Whiz on May 27, 2004, 03:49:33 AM
So, a 30% change would mean it would come out as an AC20 or AC40, right?  :lol:

Sorry, couldn't resist.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Peter Snowberg on May 27, 2004, 04:11:11 AM
I think it depends on the channel, a 30% change to the top boost channel would be the AC40 and the regular channel would be the 20.  :P
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: B Tremblay on May 27, 2004, 07:28:49 AM
Meanwhile, at the runoffgroove.com proving grounds...

http://runoffgroove.com/voxAC30TB.mp3
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Doug H on May 27, 2004, 08:34:41 AM
Quote from: B TremblayMeanwhile, at the runoffgroove.com proving grounds...

http://runoffgroove.com/voxAC30TB.mp3

Haha! When I first saw this I missed the ".mp3" file extension and assumed it was another emulator. I thought, "Oh no, those Runoff boys are at it again!":-)

Doug
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Doug H on May 27, 2004, 08:41:52 AM
Quote from: R.G.But the concept is far more valuable than the specifics;

And I would say that applies across the board, on this board. A good example is what the  Runoff Groove guys are doing with their emulators.

But the idea that "it is better to teach a man to fish..." will be buried under the next wave of requests for the xyz schematic that is being cloned.

Doug
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Marcos - Munky on May 27, 2004, 08:53:29 AM
What about this schematic? This is the preamp of the AC30, I think it will be easy to change it in a amp emulator.
http://www.blueguitar.org/new/schem/vox/ac30_pre.gif
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 09:15:25 AM
8) Don't look here.....wonder what  this is....hmmm...... (http://www.freewebs.com/elroy2/ac30%20sim1s.jpg) (alt+p)

sorry, no one likes an ass but I couldn't resist :oops:
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 09:24:45 AM
Oh well, can't make the picture work, nevermind. :shock:
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: moosapotamus on May 27, 2004, 09:31:55 AM
IIRC, Stephan sold his design to a commercial manufacturer, yes/no?

So, does anyone know anything about who he sold it to and when "THE" commercial version might become available?

~ Charlie
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: JonC on May 27, 2004, 09:47:10 AM
Could be the box discussed in this thread

http://www.diystompboxes.com/sboxforum/viewtopic.php?t=21877

Timing seems right. etc.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Gary on May 27, 2004, 10:19:35 AM
Quote from: B TremblayMeanwhile, at the runoffgroove.com proving grounds...

http://runoffgroove.com/voxAC30TB.mp3

Patience, Grasshopper.  The time is near.

This has been in the works for a couple of weeks now.
Along with a few other circuits (cue the mysterious-sounding music)...
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Peter Snowberg on May 27, 2004, 10:26:08 AM
Quote from: Bill Bergman8) Don't look here.....wonder what  this is....hmmm......

http://www.freewebs.com/elroy2/ac30%20sim1s.jpg

sorry, no one likes an ass but I couldn't resist :oops:

Very nice Bill! 8) ;) (or should I say Elroy)

If you cut-n-paste the address just like a geocities link it works. For off-site image hosting photobucket.com looks like a good way to go.

Take care,
-Peter
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 10:30:37 AM
thanks Peter
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Fret Wire on May 27, 2004, 10:33:35 AM
Quote from: Gary
Patience, Grasshopper.  The time is near.

Patience?......At the rate you guys keep pumping them out,.... we could all use a little patience! Let the planet's perfboard supply replenish back to safe levels :lol:
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 10:43:56 AM
Someone needs to build all of Brian's and Gary's simulators in one box with a rotray switch.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Doug H on May 27, 2004, 10:53:45 AM
Ohmigod, so you guys *are* at it again...

Doug
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: B Tremblay on May 27, 2004, 11:02:03 AM
Quote from: Bill BergmanSomeone needs to build all of Brian's and Gary's simulators in one box with a rotary switch.

Are you volunteering?  It certainly would be an impressive way to come out of your semi-retirement!
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Peter Snowberg on May 27, 2004, 11:04:22 AM
Quote from: Bill BergmanSomeone needs to build all of Brian's and Gary's simulators in one box with a rotray switch.
Just imagine a box with 47 trimpots. :o I don't think Boss will put it out any time soon.

Take care,
-Peter
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 11:37:03 AM
Brian, I'm fighting the urge.
Peter, Boss would, but it would only have 3 knobs and be DIGITAL.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Gary on May 27, 2004, 11:59:14 AM
And sound like crap!

Bill, your craftsmanship  is amazing.  I've seen factory work look unprofessional compared to your excellent work!
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 12:10:53 PM
Thanks Gary, but putting something together is no match to the ability to design.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Gary on May 27, 2004, 02:25:35 PM
It's much easier to design when Dick Denney, Jim Marshall, Leo Fender and Randall Smith have done all the hard stuff for you!
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Bill Bergman on May 27, 2004, 03:08:31 PM
I suppose that helps a little :wink:
Title: hmm
Post by: Bluesgeetar on May 27, 2004, 05:02:24 PM
That is some serious Pedal Porn Mr. Bergman.   XXXX rated   :shock:

I could actually see myself getting a poster printed of that and putting on my wall over the tiny spot where I tinker.  :D
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: puretube on May 27, 2004, 05:20:57 PM
Quote from: GaryIt's much easier to design when Dick Denney, Jim Marshall, Leo Fender.... have done all the hard stuff for you!


sorry: hard stuff?

(some may notice, that 1 name has been left out in the quote...)

and: L.F. was the genius for solidbodies - no doubt, incl. mech. vibrato...
Title: Take some planning...
Post by: petemoore on May 27, 2004, 06:14:52 PM
Modular design, with multi pin jacks.
 have the box with 1m, 500k, 100k pots that are in your favorite circuits, connect them to the multi pin jack, the on the multi pin plug, have your circtuit use only the pins that relate to the size pot it needs...use the same pots and power supply, switching, led indicator, [etc?] and jacks for different circuits...pot a 100k on a treadle, and use it for wah or Fuzz volume, gain if you like.
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: WGTP on May 27, 2004, 07:28:29 PM
Has anyone checked out Jake Nagy's Earthshine in the schematics II section.  It isn't an emulation, but looks like one with the Mosfet and Jfets.  Interesting how his design ended up looking like a tube amp, sort of.   8)
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Ben N on May 28, 2004, 12:58:02 PM
Quote from: GaryIt's much easier to design when Dick Denney, Jim Marshall, Leo Fender and Randall Smith have done all the hard stuff for you!

R. Smith did it all--who the heck are those other guys?  :P
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: puretube on May 28, 2004, 01:08:37 PM
Quote from: Ben N
Quote from: GaryIt's much easier to design when Dick Denney, Jim Marshall, Leo Fender and Randall Smith have done all the hard stuff for you!

R. Smith did it all--who the heck are those other guys?  :P

here I disagree with you, Ben: he didn`t do all, but he added,
to go beyond the others...
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Gary on May 28, 2004, 02:33:17 PM
It appears, after analyzing the MkI schem a million times, that amp is pure Fender.  Sure, there are extra gain stages, but they are copies of the original gain stages of the Fender design.

Still, It's an interesting amp.  I don't like the newer amps, but the MkI is kinda cool, especially in an historic aspect.  Wasn't this the first of the cascaded preamps?
:wink:
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Peter Snowberg on May 28, 2004, 02:52:38 PM
I think the Mk I was the first commercial cascaded preamp at least. I can't help but think that somebody must have done the same thing in the 50s, but he was probably looked upon as strange by his "peers" at the time.

The odd thing about R. Smith is that he's a sax player. I friend's son used to be in a band with him.

The negative thing is that he has patented several very "obvious" design methodologies and paid his lawyers well. :(

Take care,
-Peter
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Gary on May 28, 2004, 02:57:28 PM
Quote from: Peter SnowbergI can't help but think that somebody must have done the same thing in the 50s, but he was probably looked upon as strange by his "peers" at the time.

Yeah, I could imagine that was something!
"What is that HORRIBLE sound?!?"
:lol:
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Ben N on May 28, 2004, 03:34:48 PM
Quote from: Peter Snowberg... and paid his lawyers well.
Well, that part I have no beef with.

Ben (Esq.)  :D
Title: Aron R.G.! Why no AC30 Sim alternative circuit from U guys?
Post by: Eric H on May 28, 2004, 07:27:16 PM
Quote from: puretube
Quote from: Ben N
Quote from: GaryIt's much easier to design when Dick Denney, Jim Marshall, Leo Fender and Randall Smith have done all the hard stuff for you!

R. Smith did it all--who the heck are those other guys?  :P

here I disagree with you, Ben: he didn`t do all, but he added,
to go beyond the others...

I believe that was meant as sarcasm. ;)

According to people who know about this stuff, Dumble got there first --but Randall Smith actually wanted to sell his. ;)