modding a tube cricket

[maiko]

Ive built and am still using my tube cricket.

Planning to build another one but wondering why the power to the 386 was jumpered , perhaps so easier to
experiment with higher voltages.

would running the tube at higher voltage give me a much more head room or is it the other way around make
it a durty amp. hehehehehe

if  i run say 24v thru the tubes upgrade all electros to 35v and run power for the 386 thru its own regulator.

any thoughts on this idea would be greatly appreciated

[GibsonGM]

Hi Maiko,

What you're thinking is correct...a tube run in "starved plate mode" as these low-voltage circuits are will distort sooner than one run "normally" (which for the 12AX* tubes, is over 100 volts anyway - more like 300).   24V would make a BIT of difference, but not that much, IMO...not enough return on the labor to do the work.

Seeing as you've probably 'wrung out' all the mojo from the cricket, it might be time for you to build something more advanced.  You COULD use a regulator to provide 12V to your tube heater(s), and the 386 too.   But my instinct is that someone who has this kind of interest might do well to learn a little more about tube preamps, and start to build THEM.   

Look up the "GTFO" on here (good one to start with),   or visit AX84, Valve Wizard (who has a nice book on the subject you can get)...you're not THAT far from being able to make a really nice tube pre that would do a lot of  things, from fat/blues/OD to massive tube distortion.  I think if you pick up some fundamentals on how they operate, you might enjoy working on a little bigger tube circuit!

[maiko]

Thanks for the reply

i though so to it would be frivolous to attempt this if 24v would not affect it.

but say how about i charge pump this thing and run it up to 120V    and use a 12 ax7

[GibsonGM]

If you're going to do that, why not add like 5 more parts and a triode, and do a "GTFO"?  The thing screams!   I run mine on about 250V, and it is insane.

Read thru a bunch of this thread.  The most recent version is the 'best sounding' one...Joker's posts about mods is the one I built.
http://www.diystompboxes.com/smfforum/index.php?topic=93936.msg1061651#msg1061651

I built the Nixie Supply, use a 12V regulator for heaters, 13.5V wall wart, but ANY way you can get 120V+ on the thing (other than direct mains, don't do that!!!!! Need a 1:1 transformer at minimum) will power it.  12V to heaters, and the plates will accept a wide variety of voltages.

You could get a small power transformer for a tube preamp, build a rectifier and all that jazz....personally, I'd follow what was done in that thread.

Read how others are powering this. There are 2 things here...the PS, and the circuit itself.  Once you get the PS giving good voltage without overheating and so on, you have it made.

Read up some Valve Wizard info on his site.


>>If you WERE to up your cap ratings and run that on 120V, you would basically have a clean booster with some harsh grit from the 2nd stage that I don't think you'd like.  It would output way too high a signal, so you'd need to cut it down (voltage divider) to feed it to your amp (a waste, there is so much more you could use it for!).  You can do the same thing on 9 or 18V with a Mosfet boost x2 (or one with diodes).   

The tube "thang", for me and many, is to provide smooth tube OD or distortion, but that takes a few stages to 'do right' (not harsh and abrupt).   That's why I'm pushing the GTFO, which can get you there without TOO much high voltage danger (altho there is some where it outputs over 300V). 
A well-done tube preamp will get you Van Halen creaminess from 2 tubes and not that many other parts, actually.    Depends what you want to do.

[maiko]

Thank you sir for your reply i really appreciate it.   

I was looking at the GTFO and i think its a cool project to start on.    annd will look into that
may be you have a link to much cleaner more detailed pcb layout for that project i'd really appreciate
that.

Once again thanks

maiko