I get a few CK5702 submini pentodes... any schematic/project with them? I cannot find anything. ???
Data sheet: http://frank.pocnet.net/sheets/127/5/5702WA.pdf
is it equivalent with 5840?
Quote from: frequencycentral on January 25, 2010, 06:31:05 PM
Data sheet: http://frank.pocnet.net/sheets/127/5/5702WA.pdf
thanks
The 5702 has very similar grid curves to the 5840 and has a higher plate dissipation (like 1.5 to 1.7W or somewhere thereabouts). I think you can actually use this as an output tube with a primary impedance in the 11k to 14k range.
Quote from: frequencycentral on January 25, 2010, 06:45:38 PM
The 5702 has very similar grid curves to the 5840 and has a higher plate dissipation (like 1.5 to 1.7W or somewhere thereabouts). I think you can actually use this as an output tube with a primary impedance in the 11k to 14k range.
Is it possible to use your design with this tube? Any mods?
(http://i210.photobucket.com/albums/bb292/frequencycentral/5840Boost.jpg)
Worth a shot (on breadboard) providing you observe the correct pinouts! 5840 and 5702 pinouts differ.
I built it... it works, but it is so silent... any tips to increase gain or the output volume?
Try making the grid 2 resistor and the plate resistor into pots and see what you can dial in. Or you could try more volts: http://www.diystompboxes.com/smfforum/index.php?topic=74088.0
http://www.ultrarapide.net/moregeometrico/SIMPLEPREAMPS.pdf
tomorrow's free-time activity... :-\
At 12V?? It's gonna distort! :D
Set the ratio of plate and screen resistors like the ratio of typical plate and screen currents. Fiddle the cathode resistor to set the plate roughly halfway up the power supply voltage.
Squinting too deep in the dark corner, I estimate 5702 at 12V perhaps like this:
(http://i45.tinypic.com/2cf8p3n.jpg)
If that aint happy, disconnect that stuff from G2, tie G2 to plate. It's maybe a better triode than pentode. You'll still get more distortion from a well-whacked guitar than you'll know what to do with.