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hybrid mini 12au7 practice amp?

Started by dan6896, January 23, 2011, 02:55:23 AM

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dan6896

One day i was looking around the internet for little practice amps with tube preamps. I saw the ruby tubey (but that has too many parts) and i also saw the tube cricket but i could not find a schematic. then i remembered seeing something about a tube boost that runs on 9v called the valve caster.(in case you dont know you can find that here: http://www.diystompboxes.com/smfforum/index.php?topic=63479.0

anyway that gave me an idea for a little practice amp like a ruby or noisy cricket. replace the fet input thing (not sure of the propper name) with a valve caster circuit running into the input of an lm386 power amp. Ill post a schem later

my question to you is do you thing this will work.

in advance thanks for the help.

J M Fahey

QuoteIll post a schem later

my question to you is do you thing this will work.

Who knows?  :)
Post the schematic !!  ;)

joecool85

Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

dan6896


rowdy_riemer

I don't know if there is anything to it or not, but I've heard that 12AU7's don't sound too well with anything less than a 48V supply. I haven't tried to find out, though. I've got a 12au7, but I might save that for a firefly amp. The real magic with the ruby type amps is the way the LM386's sound when overdriven. Probably might as well stick with fets or op-amps. Of course, there is one way to find out for sure.  :)

dan6896

im ordering the parts tommorow ill post again when its done. :tu: but i only have a 12ax7 and the 12au7 has to come from england so that might take a while.

J M Fahey

Quotethe 12au7 has to come from england
Well, that doesn't mean too much because we don't know where *you* live.
You might be as close as Jersey and Guernsey or as far as Marambio Base in Antarctica or the middle of Gobi Desert !!! :lmao:

rowdy_riemer


J M Fahey

It's a small crazy world indeed !!!  :o :D ;D ;) :loco

Zipslack

Looks like you're re-creating the Tube Cricket.  Here's a link to a discussion forum with the schematic.  I have a Valvecaster running at 12.6V that I really like...I have not tried bridging it to a 386 yet.

http://www.diystompboxes.com/smfforum/index.php?topic=66623.0

dan6896

thanks for the info, Ive almost finished my prototype just gotta build a power supply and then it should be done. i didn't use an 386 because none of the ones i can find work properly, so i used some car amplifier chip amp kit its about 11.5 watts amp sounds pretty good with just the guitar plugged straight in to it.


darwindeathcat

Hey, did you ever get this wired up and working? I've had it in my head to do the same sort of thing for a while now... I've got all the parts sitting around, but wanted to see if someone else had made this work (and what it sounds like!) before i give it a go...
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dan6896

when i tried it with a 12ax7 it didn't really sound very good, so i built a fetzer valve instead and it sounds much better. You could try it with a 12au7 and see what it sounds like. 

darwindeathcat

Thanks for the response. Yeah, the fetzer valve is a neat circuit. Easy to slap together and sounds so good! Interesting that it sounds better than a space-charged 12ax7... I do have some 12au7's sitting around, so I might give that a try one day, but I'd have to order some tube sockets, and I'm lazy!
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joecool85

Quote from: darwindeathcat on October 13, 2011, 05:18:03 PM...but I'd have to order some tube sockets, and I'm lazy!

Heck, at least you're honest!
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com