Tube in DS-1?

[wui223]

How to wire a 12ax7 as a pair of diodes in a DS-1 or similar dist/OD unit? the power need to be raised to B+ or not?

[brett]

Hi
tube diodes have low Vf.  Is that the effect you want?
there are 12V diode tubes available (and 12V triodes kinda like the 12ax7).
Or maybe explain the effect you want?  Or do you just want to jam a tube in a DS-1?
cheers

[petemoore]

  Diodes 'n tubes...don't see much of that !
  I'd just work up a tube with the DS-1 sitting on the bench, get that going and then try to figure a way with /tube diode..but reads on tubes I've done doesn't show 'input' types as clipping elements, if there is reading available on that subject that'd be a good place to start, getting a tube operative, reading about tube operations.
  12v...I would try starting with a low voltage car radio type tube 'low voltage tube'. or try starved voltage tube first to see what mileage can be wrought there.
  Apart from that you're talking power supply, tube etc. all in a DS1.. I had trouble fitting exactly 1 opamp in the space available.

[wui223]

i saw someone mod a DS-1 wit a tube inside somewhere in Indonesia. So i was just wondering how he/she did it

[alextheian-alex]

Just use it as a shunt diode, use the VR reference to bias the clipping level of and run the heater in 12v mode (pins 4-5) and strap it right across the 9v battery.  You'll drop battery life down to 5 hours.

[alextheian-alex]

Check out the schematics i posted in this other thread for ideas:  http://www.diystompboxes.com/smfforum/index.php?topic=55642.0

[O]

Someone had posted here a schem of a Dist+ with a tube in it. Since the circuit is relatively simple, you might could see how the tube was implemented (don't remember if they used it as diodes, though)

[alextheian-alex]

You could also use it to replace the input/output buffers if you wanted.  They will definately not *function* as well as the BJTs that are in there, and you'll have to do a bit of rewiring on the board, but the transfer curve will be so bent at those low voltages that you'll definately add some 'tubiness'.  i would recommend a 12au7 instead of a 12ax7.  Otherwise you'll have virtually no negative excersion.

[wui223]

just wonder how it will sound with a 12AU7 inside. size and power supply not an issue. will try it out,thanks for the input

[theblueark]

I did the mod with a 12AX7 before. You'll find it here:
http://www.diystompboxes.com/smfforum/index.php?topic=42438.0

and all you'll need to know about heating and powering the tubes here:
http://www.diystompboxes.com/smfforum/index.php?topic=41416.0

[fikri]

may i know where do you saw it ? (i'm from Indonesia)

[wui223]

I am not sure where i found it. Many years ago i came across it then friend told me that the pedal modder is from Indonesia. I live at Malaysia.\

[brett]

Hi
Why not use diode tubes like the 12AL5 (12V heater) or 6AL5 (6V heater)?
Otherwise it's a bit like wanting a bicycle and deciding to cut a car apart to get one.
The sound will be very similar to a tubescreamer with germanium diodes. 
ie softer distortion
Not like an overdriven tube at all.  (unless to your ears a tubescreamer sounds like tubes)
To get a 12AX7 to sound tubish, just run it as a pair of high-gain triodes.
cheers

[alextheian-alex]

Hi
Why not use diode tubes like the 12AL5 (12V heater) or 6AL5 (6V heater)?
Otherwise it's a bit like wanting a bicycle and deciding to cut a car apart to get one.
The sound will be very similar to a tubescreamer with germanium diodes. 
ie softer distortion
Not like an overdriven tube at all.  (unless to your ears a tubescreamer sounds like tubes)
To get a 12AX7 to sound tubish, just run it as a pair of high-gain triodes.
cheers

yeah, if you are just going to use tube diode clippers, 6al5/12al5 is the way to go... and they are about half the size of a 12ax7... it would be better if they drew less heater current, but oh well.  I guess you could triode strap a submini that has a lower heater draw.

[fikri]

Otherwise, you could try some starved plate tube buffer like shaka-tube. You could change the opamp section with DS1 circuit and see if you like it. I made it once here: http://fikri_ilyas.blogs.friendster.com/photos/new_project/index.html

[puretube]

http://www.diystompboxes.com/smfforum/index.php?topic=41316

here`s the "Indonesian":

http://www.diystompboxes.com/smfforum/index.php?topic=24757.0

[Aharon]

I have been doing a little research into this too,like a real tube screamer if you will.........I found a tube that has a hi mu triode plus a diode in each,it's called 6Av6.
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6AV6.pdf
Maybe this tube will work.
Aharon

[ryechua]

i think you were referring to this mod..

http://www.diokay.com/ds1toob.htm

http://www.diokay.com/dsmasta.htm