“Vintage Vibe” Low Voltage 6111 Submini Tube Vibrato

[littlewing]

beautiful, your layout is so elegant...

[crochambeau]

could i use 9 pin 12AX7 tubes with this?  and if so, what do i do with the extra pin?

12AX7 has a center tapped filament, so if you were to wire it up for 12 volts you'd feed heater voltage to pins 4 and 5 and leave 9 alone. It looks to me that the pinout of the 6111 is different in other ways, so you'd want to be mindful of that as well.

Regarding functionality, it'd be hard to say without comparing datasheets (or building one). I'm going to guess that filament current is higher in the 12AX7. I like feeding tubes higher plate voltages personally, but that makes it somewhat prohibitive to build stompboxes with them...

I've never worked with subminiature tubes, it seems logical that they would be more forgiving of lower voltages since the internal distances have to be smaller.

[frequencycentral]

could i use 9 pin 12AX7 tubes with this?  and if so, what do i do with the extra pin?

12AX7 are high mu, whereas the tubes I used (6111 on the breadboard, 7327 in the build) are medium mu tubes, closer to 12AU7. I'm experimenting with some 6112 subminis at the moment, which are high mu, so pretty similar to 12AX7. With these high mu tubes I'm finding that it really  a case of taming the gain, which means lower value plate resistors and lower value grid leak resistors.

This shouldn't really matter with stages 2 and 3 of the Vintage Vibe, as those two stages are cathodyne phase inverters, so I think the volume at the plate should be the same as the volume at the cathode. You will need to reduce those resistor values I mentioned for stages 1 and 4 though, or the circuit will distort. Try 100K grid leak resistors instead of 1M.

12**7 tubes have an extra pin which is a centre tap for the heater/filament. If you use 12**7 tubes for this circuit, connect pin 5 to 12 volts and pin 4 to ground. Leave pin 9 (the centre tap) unconnected. Each 12**7 tube will draw 150ma across pins 4 and 5.

Be sure to compare the data sheets of your 12AX7 to the 6111 data sheets, as the pinouts do differ.

[flood]

looks nice, canm't wait to proto this one using 12AU7s. out of sheer coincidence - my other brower window is open to your new post on ampgarage.net!

love the crushed glass too btw. keep them coming! <img src="http://experimentalistsanonymous.com/phpbb3board/images/smilies//grin.gif" alt="" title="biggrin" />

Thanks flood!

Did you actually build the Crushed Glass?

sorry, i haven't checked back here in a while. i did build it, on channel only and loved it for all its weirdness!!! i'm going to be building a "proper" crushed glass soemtime replete with photoresistors for some hand waving tomfoolery. was also thinking of upping the voltage to about 100V on the plates...

right now, i'm swamped with amps, "proper" stompers etc. so i don't have any time for the more unusual stuff... would like to do a metasonix TM-7 workalike sometime though.

[Pantheon]

Hi there,

I really love this effect, but unfortunately all the links are dead and I cant see the schematic

I would love to make this with some space charge tubes, 1SH24B's or DAF92's.

Does anyone have a copy of the schematic they can post?
Or even a link to a similar schematic?

Thanks,
Pantheon

[EDIT]

I did a little digging and found out that if I hit the print icon, the links show up but with a preceding "http://" that is screwing them up. I have manually followed them, so I actually have a copy of the schematic now.

What a lovely little circuit, I cant wait to get started on this.

Sorry for bumping this then, typical forum nooby screw up, sry

Link to the schematic is here, to save other people to trouble:
http://i210.photobucket.com/albums/bb292/frequencycentral/VintageVibe.jpg

[/EDIT]

[expanoncolin]

Actually, that's a bizarre forum problem where images from an old version of the board get preceded by two http://'s.  I didn't realize hitting "print" fixed that.  Weird!  I will fix the images in the thread.

-Colin

[Pantheon]

On close inspection of the Schematic, I see that the LDR is connected between the cathode and the anode (post capacitor). This is giving me some trouble choosing a suitable tube to work with. Perhaps someone here could help?

I would like to use either a 1J24B or a DAF92, but both have a directly heated cathode. This would suit me, but since the cathode is held at a constant voltage, I expect that the LDR in this circuit would not server its original purpose.

Am I able to tie the LDR instead to ground (threw a resistor i presume), similar to the following setup? Any idea what the effect this would have?

My guess is that this would lessen the effect of the phase shift.



Or, is it a case that I really need an indirectly heated tube so that the cathode is free to swing one side of the LDR? In that case, then I will either try some 12AX7's or some 12BL6's (space charge).

Thanks for your help