This isn't new, but I find that people tend to miss or forget the things at GEO, and *I* was reminded of it by some email.
There's a vacuum tube based wah circuit at GEO,
Quotehttp://geofex.com/Article_Folders/tube-wah/tube-wah.htm
It's a straightforward tube implementation of the Vox inductor wah, and I'm now had over a dozen reports that it works...great...
Some of the versions used the MOSFET, some used another 12AX7 for the cathode follower, and they both seem to be good. Reports are that it's quite sensitive to the initial setting of the wah pot on the rack, and that it gives a very vocal Vox wah sound.
If you want to mess with some tube stuff, this might be a good place to start. The power supply is set up to work with a 12Vac wall wart and an onboard 120:12Vac transformer for high voltage. All the normal cautions about tubes apply: high voltage is dangerouse, so **don't** try this unless you can do it safely.
TUBE-WAH(R)
is a registered trademark of Anthonie Th. Barmentloo...
(http://www.pure-tube-technology.de/TW24.jpg)
Looks like elegance with HV tubes for the Wah Coniaseur.
Plenty of tested mods for the inductor wah...
A Very tempting build, but with substantial tasks.
Shaping and working the metal also can be hazardous ...
I dont' know of any treadle/shells that would house a tube'n related circuit...
Mount the 'side plate', which will be the 'floor' for the 'new room addition' [perhaps an L shape sheet, adding wood struts for strength and feet, so the tube circuit is mounted and resides next to the wah shell, top right, or in front of the toe], using the VOX shell's bottom plate screws, and mount the Tube 'n circuit to the shielded box...run the wires to jacks, BP switch and inductor...
you can find a schem. on my site of a svetlana tube wah by e. barbour....
http://photobucket.com/albums/v324/caseyseffectpage/Wahs/?action=view¤t=svetlanafuzzwah.jpg
cool stuff.
QuoteTUBE-WAH(R) is a registered trademark of Anthonie Th. Barmentloo...
Yes, I know that. That's why I was careful to refer to "vacuum tube wah" and "vacuum tube based wah". I would not dare to infringe on the rights of someone who has had the foresight to stake a claim to a set of words.
As I understand it, the circuit of the "TUBE-WAH(R)" is a vacuum tube implementation of the multiple feedback bandpass filter with tubes instead of opamps. That's one reason I pointed out the further difference that this one is an implementation of the Vox inductor based circuit, which I and some people prefer the tone of. Matter of taste, really.
Of course, owning the rights to the use of the words "TUBE-WAH(R)" lets the owner put anything they like in there, since the words don't imply anything in particular about the circuit, so that could have been, or in the future may be changed to the Vox style circuit. I really don't know.
Quoteyou can find a schem. on my site of a svetlana tube wah by e. barbour....
And Eric's version of a vacuum tube wah uses a multi-henry iron cored inductor and a - big - AM radio style moving plate variable cap to sweep the wah resonance. Sourcing that variable cap is a modest-to-major pain, depending on how many old tube style AM radios you have lying about.
Hmm... I wonder if it's possible to fit that vacuum tube wah circuit in a CryBaby shell? You could lay the tube down flat in there. I'm just not sure about the internal transformer...
EDIT: You only need 100mA for that internal transformer?! Is that because the wall wart is 500mA?
EDIT #2: Nevermind, I looked closer at the text. :oops:
the full story of the TUBE-WAH(R) will be written down one fine day in its historical contest -
- including how it evolved into the invention of the TUBE-TRON(R) in 1971 - and who really played the first envelope-followah the first time...
(the full story is known by the persons concerned :D )
8)
Hey, I actually built the e. barbour tube-type wah a few years ago. It hums like a Mother! I think I actually built a nasty ground loop into it. I've been meaning to revisit that someday. For now it's living in the closet of freaks and mutants.
http://www.angelfire.com/indie/gladmarr/index.html
The pic's not all that good. But it's there alright.....
Quote from: Paul MarossyHmm... I wonder if it's possible to fit that vacuum tube wah circuit in a CryBaby shell? You could lay the tube down flat in there. I'm just not sure about the internal transformer...
sure:
(http://www.pure-tube-technology.de/TW530.jpg)
http://www.pure-tube-technology.de/TW527.jpg
http://www.pure-tube-technology.de/TW528.jpg
http://www.pure-tube-technology.de/TW533.jpg
http://www.pure-tube-technology.de/TW534.jpg
(well, it`s not a CB-shell, but an exact clone by Schaller-shell...)
:P
Thanks for the pics! Interesting. I bet it could be done PTP with some careful thought.
The only thing that I don't see in those pictures is an interanally mounted transformer... 8)
there`s a tiny empty spot in the lower right end of the pedal in this pic:
http://www.pure-tube-technology.de/TW528.jpg...
that`s where the 80kHz 12V to 250V HF-transformer used to sit before it went into the pedal on top of this thread...
(incidentally the same type and size core, as the classic wah inductors);
(it was the DC-powered version from 1996, with built in HF DC/DC converter, before new radiation requirements were introduced in europe).
That`s why you see 2 power-semiconductors on the bottom plate:
a voltage regulator, and a HF power transistor...
BTW: note the yellow rubbers shock-proof mounted tube-socket!
(http://www.pure-tube-technology.de/TW534.jpg)
PS: the mentioned TUBE-TRON(R)`s workalike is currently better known as Electro-Harmonix`s "Tube Zipper".
I was wondering what those semi's were on the bottom plate for. :wink:
Anyone know who to credit for this tube wah circuit?
http://www.muzickicentar.co.yu/sheme/effects/wahsweel/WahWahTube12AX7.jpg
Hmm...Thanks puretube. You've given me a good idea! I can now get power transformers without the filament winding, and just use voltage regs....They'd be cleaner!
Cheers,
Nish
that`s probably already been said or mentioned in all of those "toroidal" threads :?:
Sorry I don't pay too much attention :D
I remember a time when that GEO article had a variable capacitor rather than a Wah pot, so I never had a second look. I do agree though...some new peeps here should have a nice long gander at GEO, I've read a lot of stuff on there, and there is very very very little "useless information". (Good job RG, on a site well done....I have a question for you though....can a purchase on of 'em PCB layout books from you?)
Cheers,
Nish
So, pure, those look really cool. How about showing us the schematic for that, as I did for mine?
:)
QuoteThanks for the pics! Interesting. I bet it could be done PTP with some careful thought.
Easier with a PCB and an aluminum L-bracket for the tube socket.
QuoteAnyone know who to credit for this tube wah circuit?
That ... was... a trademark infringement, right pure?
I believe that's the one I pointed out as a multiple bandpass filter unit. Might as well use opamps - the tube-iness won't come through that much. Feedback hides it, and you have to have the feedback to make the filter work. I don't know who to credit, though.
QuoteHmm...Thanks puretube. You've given me a good idea! I can now get power transformers without the filament winding, and just use voltage regs....They'd be cleaner!
And hotter. If you run the tubes from 100Vdc ore more (highly recommended), then you linearly regulate, you have to provide 150ma to the filaments if they're in series, and that's (100V-12V)*150ma = 13.2watts of power to get rid of, and you'll need to do something to get the raw 100V down to the 40V that a three terminal reg can live with.
QuoteI remember a time when that GEO article had a variable capacitor rather than a Wah pot, so I never had a second look.
To the best of my recollection, I never posted a variable cap version. Am I getting senile?
Quotecan a purchase on of 'em PCB layout books from you?)
soon... I'm waiting on some commercially bound copies.
Whoops...sorry, I thought that was Geofex...I remember it was a big PDF article, and I kinda linked it in my mind to Geofex.....
good good! I'm looking forward to buying a copy of your book!
Cheers,
Nish
I think it must have been eric barbour's article on the svetlana one.
Just a dumb question: what is the difference in the sound between a inductor wah and a tube wah? I don't know the advantages of a tube wah, maybe it's because I played only in inductor wahs until now :P.
QuoteEasier with a PCB and an aluminum L-bracket for the tube socket.
Yeah, that's true. I was thinking about the pictures that puretube posted when I said it could be done PTP...
I 'Think' I'd want the tube and inductor isolated from each other, to keep noises from hitting the SP?. Seems logical...[?].
Better question is...what are the components that lend themselves to producing unwanted noise, and allow for isolation shielding to be used?
Transformer, tube, inductor, SP wires, HV supply wires...I'd think selective isolation design would take up some of the room for improvement as far as noise.
Any suggestions as to the best places to start reducing noise?
The two main sources of noise would be from the 12VAC heater supply and more so from any transformers within the wah enclosure. I had a wall wart close to my vintage CryBaby wah pedal, and it picked up hum even though the circuit is in that metal enclosure. It wasn't too self-evident until you used something like a Boss Metal Zone with it, and then, massive hum and noise! I moved the wall wart to the opposite end of the pedalboard, problem solved. I'm not convinced that any internal shielding would help against this sort of EMI that transformers radiate, unless maybe it's a toroidal type?
Quote from: R.G.So, pure, those look really cool. How about showing us the schematic for that, as I did for mine?
:)
Thanks for the flattery - I`m lucky to have withstood the urge of "letting everybody know", for 25 years;
- it`s currently a so called `trade secret` between E-H and me -
QuoteThanks for the pics! Interesting. I bet it could be done PTP with some careful thought.
Quote from: R.G.Easier with a PCB and an aluminum L-bracket for the tube socket.
another solution (pic) coming up, soon. (opto-version).
edit: here it is... :
(http://img.photobucket.com/albums/v437/latronax/twah456.jpg)
(http://www.puretube.de/Tube-Wah_2-0.jpg)
(Paul and someothers know those pix...)
QuoteAnyone know who to credit for this tube wah circuit?
Quote from: R.G.That ... was... a trademark infringement, right pure?
Yes, I was very angry when the schem appeared a couple of years ago,
and I couldn`t find the originator...
QuoteHmm...Thanks puretube. You've given me a good idea! I can now get power transformers without the filament winding, and just use voltage regs....They'd be cleaner!
Quote from: R.G.And hotter.... = 13.2watts of power to get rid of,...
that`d be a nice foot-warmer, yes!
QuoteI remember a time when that GEO article had a variable capacitor rather than a Wah pot, so I never had a second look.
That`s the Eric Barbour circuit, IIRC...
Quotecan a purchase on of 'em PCB layout books from you?)
R.G.: that reminds me of another recent thread, where somebody wanted to purchase a PCB from your site, where it says: send an email - but it shows no address...
Quote from: Marcos - MunkyJust a dumb question: what is the difference in the sound between a inductor wah and a tube wah?..
an inductor wah can be transistor-, IC-, or tube-powered;
a Tube-Wah can use an inductor- or other kind of filtering;
Quote from: Paul MarossyI'm not convinced that any internal shielding would help against this sort of EMI that transformers radiate ...
so-called MuMetal will shield that "Dynamohum";
toroidals will emit much less than conventional ones.
Quote from: petemoore...Any suggestions as to the best places to start reducing noise?
quite like you already suggested...like in every tube project, and with
the proper layout of any inductor-based design...
R.G.,
Csj and i were also interested in purchasing one of your books, Clay said he e-mailed you but got no response. I'm sure you get alot of e-mails though =D
Anyhow, i know alot of people around here would be really excited if you made another batch of books.
Puretube, im sure keeping a secret that long about something that you are so passionate about has to just about drive you to the edge of insanity...
I can't even seem to keep christmas presents from my Girlfriend...
:oops:
Quote from: Sic
Puretube, im sure keeping a secret that long about something that you are so passionate about has to just about drive you to the edge of insanity...
:oops:
It almost for sure will ruin you financially, when the passion even doesn`t give you the time to work a "regular" job... :wink:
beware!!
ISTR another Eric Barbour design that was a Twin T, using a pentode.
that`s the one with EF86, and the triple varicap, mentioned before.
I just found it. It's actually supposed to be a simple tube VCF.
http://www.cgs.synth.net/tube/vcf.html
oops - yes Tim - sorry, I mixed up yet another schem -
the before mentioned Barbour I referred to was in fact the big core plus the triple varicap...
[/quote]And Eric's version of a vacuum tube wah uses a multi-henry iron cored inductor and a - big - AM radio style moving plate variable cap to sweep the wah resonance. Sourcing that variable cap is a modest-to-major pain, depending on how many old tube style AM radios you have lying about.[/quote]
i collect AM tube radios from the 30's 40's and 50's....so not a problem... :D
Quotei collect AM tube radios from the 30's 40's and 50's....so not a problem...
Then you're one of the few people who would not be back here moaning about Mouser not having them.
'course, if I collected tube AM radios, gutting one for the tuning cap for a wah is the last thing I'd want to do with one of my babies...
Quote from: R.G.Quotei collect AM tube radios from the 30's 40's and 50's....so not a problem...
Then you're one of the few people who would not be back here moaning about Mouser not having them.
'course, if I collected tube AM radios, gutting one for the tuning cap for a wah is the last thing I'd want to do with one of my babies...
yeah, i didnt say that i was going to do it... :) i just said that i could! :roll:
i do have a radio though that is really messed up, but the vari-cap dooga-ma-hicky (technical term) is good in it though. :D
Quotetoroidals will emit much less than conventional ones.
Yes, and that gives me a thought - I could try RG's tube wah project using a small toroidial transformer inside the enclosure and the 500mA wall wart, if I can find one... Hmmm. 8)
Hello??? Blink Blink Blink. Doesn't anyone else want to hear it before asking the guy how you build it? I've made alot of stuff over the years that no sound came out of. Does it work? How does it sound? Did I miss the sound clips or has a KGB virus preventing me from seeing the link?
Oh, I'd buy your book too RG. -ph
Quote from: TryingToDo613 on March 16, 2006, 04:08:23 PM
Hello??? Blink Blink Blink. Doesn't anyone else want to hear it before asking the guy how you build it? I've made alot of stuff over the years that no sound came out of. Does it work? How does it sound? Did I miss the sound clips or has a KGB virus preventing me from seeing the link?
No. It has a tube in it, so it *must* be [insert superlative here].
Kidding aside, some might be interested in the challenge alone, regardless of how it sounds (assuming it's no worse than a Crybaby). DIY's whole appeal to me is the challenge.