freestompboxes.org

Just in case you had a few minutes to kill... here's some pics I found on my harddrive:
http://www.indyguitarist.com/twintube/

bw

Well, they certainly get the award for the most stupid way to mount a pair of tubes...

How I'd like to reverse engineer this.....

Is that a pair of those tubes that do not go in a socket but have solderable leads? I can't recall right now what they were called. If so, they are probably designed for battery use, thus low voltage/low current/low heat. That means that the tubes are probably mounted properly. It also means that the tubes are NOS, probably inexpensive, and there is probably a finite supply of them available, so if you've got one of these pedals you might want to stock up on replacements as they might become hard to find. They are also a bear to replace.

Ummm the fact that it says high voltage in about 8 places would indicate to me we're talking about high AC plate voltages.

The tubes are probably 6021(?) types. The same that are found in ZVEXs Nanohead. HV tubes but miniaturized, as far as I recall originally designed for use in air/spacecraft vehicles. That should mean they are pretty reliable.
Timo

Yeah, but still, non-socketed tubes, close to the PCB = bad design for a stompbox. Tubes fail, no matter how reliable they are, it's just a matter of time.

We could argue that tubes shouldn't be in a stompbox format anyway, since the stress from the box being constantly stepped on and kicked isn't good for any tube.

soulsonic wrote:We could argue that tubes shouldn't be in a stompbox format anyway, since the stress from the box being constantly stepped on and kicked isn't good for any tube.

+1 ... however ...

Those tubes were designed specifically for aerospace use. They were designed to resist vibration, shock, and rapid temperature changes. Im my humble opinion they are as resilient in a stompbox as a transistor, and probably less prone to problems than the pathetic sockets some builders use for passive components. I just wish I could buy some locally in the UK

Not in the UK, but in Europe
http://www.military-tubes.com/xtcommerc ... urers.html

Wow Thanks - ordering some (lots) now, I'm constantly amazed at the amount of websites I don't find

I have one that sounds farty and is somehow not working correctly.

I would happily donate it to whoever would be interested in reversing it.

Me like it. I can pay shipment cost thru paypal if its ok with you. besides, i have some 6021 tubes lying around here in my bin.

Got a taker. The pedal will soon be flying its way across the ocean for a right proper demystification.

Thanks for all the PMs!

Well, they certainly get the award for the most stupid way to mount a pair of tubes...

WTF is up with that! Aren't the people who design these things Engineers???

Here is a schematic I found on a German website today. Thought it might help with the twin tube.

and here is the link- http://www.musikpartner.dk/gemfile.asp? ... lassic.pdf
I stripped the schematic from the PDF for obvious reasons. If you compare with Indyguitarist Pics it looks to be correct.

I can't see the link above! Is it correct?

It is great... Maybe I am a little greedy but... Is there the second page of this schematics?

Yes but I could not retrieve it. It is posted in the same area but it fails to download. It is the power supply section. Sorry man!