Boost For Thrust

[gtudoran]

So hello dear fellows i had a dream... submini pentode for stompboxes preamps . I've bought some 1P24B from russia (with love) and there we go... not much about this tube only the russian data sheet. Spoke with Rick (Freq. Central) and asked for help ...after a little talk late at night, the next morning i've tryed the next schematic.
This is the link:

http://i479.photobucket.com/albums/rr153/gtudoran/boostfortrust1.png

Any questions are more then welcome and also comments.

Best regards,
Gabriel Tudoran
Analog Sound

[frequencycentral]

Well of course we want soundclips Gabriel!

BTW, how are you achieving the 2.4 volts for the heater?

[gtudoran]

1.2v or 2.4v you could obtain them from a LM317 (in fact is Rick schematic only that I've add a trimmer to dial the right amount of voltage). I do recommend a separate voltage for the heater... maybe a battery... or a very good stab. voltage (still don't know if LM317 got the lower voltage as low as 1.24v)

I will try to put some clips tomorrow.. the sound right now is very glassy and bassy in the same time and it's very hard to overdrive it (you'll need approx 1.2v PtP at the input to overdrive the tube... maybe tow in cascade? )

Best regards,
Gabriel Tudoran
Analog Sound

[gtudoran]

http://www.analog-sound.com/sounds/mini/01-100117_1349.mp3 a little clip with my boost

Recorded using a computer microfon and my onboard laptop sound card (the hiss is from the mike).
Guitar -> Kustom 30w Soulid state guitar amp (EQ on flat) -> mic -> laptop (no other effects added)

Best regards,
Gabriel Tudoran
Analog Sound

[frequencycentral]

Nice clip, sweet sounding and transparent.

(still don't know if LM317 got the lower voltage as low as 1.24v)

LM317 really comes into it's own when you're looking for exactly 1.25v. If you connect the adjustment pin to ground you'll get 1.25v from the output (once under load) no matter what you put into the input. No other parts required.

[gtudoran]

I was just speaking with a friend of mine... and he got a brilliant  idea... A tube headphone amp like vox-amplug or Rockman but only made with tubes . One fetmos stage for a little push and one tube stage (1P24B) for a tube sound running on 2x9v batteries, one for the heaters and one for anode voltage. It could be made in a box that could be hanged on your guitar strap... what do you think about that

Best regards,
Gabriel Tudoran
Analog Sound

[frequencycentral]

I like it........I'll be thinking about that all night now!

[tranceracer]

sounds nice, makes the Les sound kind of jazzy.  It'd be interesting to hear how it sounds overdriven w/ a booster in front.  Good job!

[gtudoran]

Thank you for you replay, i will take some clips with a booster in front and a 80v anode voltage (from Rick 555 schematic ), but for now i will try to make a little more experiments with this tube, i don't believe that is in the optimum performance point. I will keep you up to date.

Best regards,
Gabriel Tudoran
Analog Sound

[gtudoran]

I run into a little problem... if i put the 2 pentodes in cascade ... i get a much lower volume comapring to only one pentode. I think is all about impedance missmatch.... could you guys take a look on the schematic... and propose a wrokaround?

Thx in advance,
Gabriel Tudoran
Analog Sound