boobtube twin revisited

[juansolo]

Well I tried to sell it to make the high voltage version and no one wanted it. So it got gutted and rebuilt in it's original enclosure. The outside is the same as it ever was, the insides however, quite a bit different; 190V & 12AX7. Another we're really pleased with. It can go from one of the nicest sounding clean boosts ever to a massive OD. It's also damn near silent.

The optotron was re-used, I really should have cleaned it up...

[lincolnic]

You guys are artists.

[SmoothAction]

Agreed, but Juansolo has my heart <3

[juansolo]

More details:


EDIT: Can't fix these as my schematics folder has gone private. Though again, there are details in the 'making tube pedals' section on the site and Grind do a kit to make all these now.

[blackedition]

This looks sweet!  So this pedal runs the tube at requisite high voltage?  That's awesome, if so...  I have always thought tube pedals were false advertising because of the much lower than optimal operating voltage

[juansolo]

Yep, we've tried 12AX7s at lower (even 80v) voltages and they just don't work. 190 seems to do the job nicely.

I'll also add, refresh the schematic as I've been editing it a bit. It's right now though.

Got some ideas for re-vamping the Baby Boobtube also...

[Scruffie]

I recall Merlin (tube dude) saying tubes like the AX7 don't really get in to their stride until they hit 100V.

A nice mod could be to turn the cathode follower in that in to a MOSFET based one and have an extra triodes worth of gain...

[juansolo]

We've done that in the past and it's too much in all honesty. It's got more than you'll ever need with three stages.

[Scruffie]

You underestimate how much I need

[GrindCustoms]

Great job mate! Digging that you did it on tagboard.

Been trying to source those damn inductors from Mouser... 26week lead time.... found some on ebay tho, just hoping that they are true to spec.

I feel the need to replace all the 6.66Multipliers in my other tube builts.. 120V sounds lame now...

[juansolo]

Could always send you some over. They're not a problem to get here.

Baby Boobtube is going to be a two tube affair next at 190V also Haven't got around to sticking it into DIYLC yet, but I have Cleggy's hand drawn schematic in front of me Hold on, I'll get a camera...

UPDATE: Obv this is subject to change as we haven't built it yet:

[marauder]

I was looking for that schematic.

I've changed it, the cathode followers are now biased for the 190v supply rather than something like 280v.

The tagboard is 2 columns wider than the boobtube twin, so should still fit with the same internal layout.

[GrindCustoms]

Thanks John, i'll see how it goes with those from the Bay... grab them from a Canuck seller.. should be more reliable than a random asian seller...

For the new BabyBoob tube, i see that you're putting the 6BR7 as the second gain stage.

From my experience and testing with both circuits, the 6BR7 has lots more gain on tap, got the best results in gain cascading when having it in front of the Boobtube circuit... maybe a flipper switch to switch the order of both gain stage could be handy?

[juansolo]

It's the only gain stage. the 12AU7 is being used as a pair of cathode followers.

[juansolo]

I was looking for that schematic.

I've changed it, the cathode followers are now biased for the 190v supply rather than something like 280v.

The tagboard is 2 columns wider than the boobtube twin, so should still fit with the same internal layout.

I'll bring it over Weds. Your Kraken has arrived also and the other bits and bobs.