"Tube-o-Vibe" tube driven vibe pedal

[Acerockola]

Has anyone built this project from Vacuum Tube Valley issue17? I read an old post on this forum from Scott Swartz who designed it. He said he has an update to the design. Any insight?

[ddr]

There is updated info here:

http://msswartz.tripod.com/tb_o_vb1.htm

[Rectangular]

Ive always wanted the schematics for this thing, but as far as I know they've never been leaked onto the net. considering the article is 10 years old, and that most people will never see or order a copy of that magazine, I wish scott would just update his page with the schematic. throw a little paypal on there, I'd gladly pay a few bucks for it.

the design doesn't seem too different from solid state phasors. an array of 12AU7s are used for allpass filters (I'm guess 4 AP filters, then another 12au7 for the input/output stages). the AP filters are controlled by the vactrols...which are being driven by a non-tube LFO (the 8038, I guess). the real kicker would be if the LFO was also tube, but I guess thats more for bragging rights than practicality.

I thought about reverse engineering the thing, from the gut shots and parts list, but really, I don't care enough. I have enough phasors as it is.

[frequencycentral]

There's this too: http://www.diystompboxes.com/smfforum/index.php?topic=74262.0 

[R.G.]

I never bothered with that particular article, but I did reproduce the vibrato from the old Magnatone amps with enough stages to be a real phaser. It was heavily pollinated with the Univibe.

Overall, it's a lot more trouble than you get extra goodness over and above the stock univibe.

Simply making something out of tubes, or germanium or whatever does NOT automatically result in better sound. And you can spend a lot of time and money that way.

I remember corresponding with Scott about the time he was writing up the article.

[Rectangular]

ever since I joined this forum, or even back when I was a lurker, I've noticed a steady increase in people working with tubes with each passing year. has anyone ever considered making a proper, separated Tube section, to compliment the Digital/DSP  section ?

to be honest, a lot of the reason I work with tubes is because I kind of maxed out most of what I could do with solid state... I built all of my dream devices, and tube has been the new challenge, and new sounds...which has been weird because aside from the more involved power supply, tube circuits are actually easier to construct in most instances, at least where part counts are concerned.

[R.G.]

to be honest, a lot of the reason I work with tubes is because I kind of maxed out most of what I could do with solid state... 

How the heck did you max out what you can do with solid state?!?

Working with tubes is, as you note, simpler in many ways. And more limited than working with solid state: there are fewer different types of tubes. Tubes are simpler in most respects, bigger, more expensive, fragile, and power-consuming. There is one justification for tubes, and that is that they can (not 'do', but 'can') produce certain tonal colorations more simply than with solid state. "Tube sound" has achieved a holy grail status, though to be frank, many of the things done with tubes could be done more simply with a hammer and an old kitchen pot.

Neither tubes, nor germanium, are a magic tone elixir, except in the minds of advertisers. And all things which can be sold are magic elixirs to advertisers. 

I'm not trying to dissuade you, just noting this for clarity and perspective.

[R.G.]

Hit "send" too soon.

Also, I suspect that more tube work goes on here all the time because
(a) the pool of people who have developed some electronics skills is getting larger. I can remember a time when there were countably few of us, around the mid 90s. Today there are over 17,000 registered members and probably more lurkers in this forum alone.
(b) there is a subsection of people for whom building is the end result, not playing. I'm one of these, but I recognize it as a perversion.

[Ben N]

Hit "send" too soon.

Also, I suspect that more tube work goes on here all the time because
(a) the pool of people who have developed some electronics skills is getting larger. I can remember a time when there were countably few of us, around the mid 90s. Today there are over 17,000 registered members and probably more lurkers in this forum alone.
(b) there is a subsection of people for whom building is the end result, not playing. I'm one of these, but I recognize it as a perversion.

One more reason: the "sudden" availability/awareness of submini and low-voltage tubes that make doing cool, mojorific tube projects far less daunting than when they necessarily involved substantial power transformers, big chassis and scarey risks.

[Rectangular]

Neither tubes, nor germanium, are a magic tone elixir, except in the minds of advertisers. And all things which can be sold are magic elixirs to advertisers. 

I'm not trying to dissuade you, just noting this for clarity and perspective.
[/quote]

I would never suggest that tubes (or germanium) devices are better, or instantly produce better sounding results. In fact, I've found that they're often noisier and more unpredictable in a lot of applications, compared to all of the linear, low noise solid state devices you can get on the market these days (for a few cents, in some cases).

but , there is definitely something rewarding about digging an old thyratron out of a dead oscilloscope or television, and giving it a new lease on life as a buzzy, asymmetrical, non-linear, VCO. Everytime I complete a new tube device I find some additional behaviour that I haven't quite encountered working with my solid state equipment (both homemade and commercially produced). because I didn't grow up in the in the 30s, 40s or 50s, tubes are still open to a lot of discovery. Its especially interesting to discover many of our modern devices are directly replacing some specific tube device. eg: the thyristor was a solid state replacement for the thyratron. how LDRs are used all of the time (with hobbyists,  they're almost as popular as LEDs),  but when was the last time you saw a Phototube ?

I accept that tubes can be cumbersome and expensive, especially if you stick with only the "pop" tubes that are in demand (ie: the 12a_7 and 6_6 families). but on the whole, I dont find $1-2 bucks per tube to be any worse than paying 5-10 bucks for a CA3280, or 15 bucks for a MN3205.