DIY Guitar Pedals

[CJ]

put some foam under the tube, as they can be microphonic,

i do not know whats worse, microphony, or a phony at the mic, 

I/O installed, no batteries required, gonna hard wire the wall wart to the board to eliminate a major source of grief which is the pwr jack, just plug and play,

data:

http://www.mif.pg.gda.pl/homepages/frank/sheets/137/5/5636.pdf

 

[CJ]

input circuit done, going with the 0.1 tropical,

buss bar installed, your either on the bus or off the bus,

 

[CJ]

kathode screen and plate resistors installed, plate cap also,

keeping the flux loop down for less noise, just like they do on discrete opamps,

left some room for a toshiba at the front end just in case we want more mojo,

non polarized lytic for the funk,

screen resistor upped in value to cut down voltage = less noise and microphony,

just the heater and screen bypass and we are ready to party!

 

[CJ]

ok we wired up the heater to get the exact current at 6.3 volts so we can figure out a series resistor to drop the plate supply down,

then we can work out how much plate voltage to use in order not to waste a lot of heat,

one problem i see with the posted schematic up a few posts is the 10 uf screen bypass cap,

since we are running a 3.3 meg at say 24 volts, we will only have 0.72 micro-amps of screen current, well, if a lytic sits around for a while, it will possibly leak that much current reforming the electrolyte, this would screw up the screen voltage by dragging it down, so i used a 0.01 @ 1kv ceramic for zero leakage,

you can see that sucker glowing away  so now we look for a wall wart to haedwire into the box,

 

[CJ]

we have the tube wired in triode mode because the 3.3 meg was way to high to get the tube going,

with pentodes, the screen voltage controls the plate current, not so much the plate voltage, with the 3.3 meg we only had 4 volts screen with 20 volts B+, doh, 

used to values for 250 volts B+, but for 48 volts B+, we need to bring that 3.3 meg way down, which can be done by putting a smaller resistor across the 3.3 meg,

the large size resistors are more for mechanical than anything else, the stiff leads hold the circuit wires from flappin in the wind,

so we will plot plate current, Ip,  against B+voltage  so we can get a rough idea of where we  want to run this thing, then we can plot the curve in pentode mode, then we can hook up some 1/4 jacks and plug a guitar in to tune it by ear, picking the best mode, triode, pentode, or somewhere in between, we can also play with the cathode bypass cap, if any need be used,

where we want to run it in this case is somewhere on a non linear portion of the curve for maximum boogie woogie, 

dual supply is nice as we can use the left side for the heater and maybe tweak that for starved plate distortion,

right here we have 4.22 ma at 50 vdc,>

 

[CJ]

we are dialed in now for a 20 volt supply, gonna sound check it next.

got rid of a resistor and a cap so now 3 resistors and 2 caps, 1 tube and a couple of phone jacks, easy DIY,

no gain knob, full shred all the way,

more gain in triode mode which is weird, must be the voltage we are using,

darn, 1 more resistor to add to drop 20 to 6 volts heater, 

should be about 80 ohms at 2 watts or better,

now this is Not a normal tube plot, we are using a cathode resistor, so bias drops with plate voltage, just wanted to see where it cuts off,

the usual graph fixes the bias point while moving plate voltage,

gonna use a Dunlop 18 volt wall wart at 150 ma, seems pretty clean, no AC measured on the pwr leads,

 

[CJ]

ok this thing is done, too late to crank it up, but from what i can hear at low volume it is gonna sound pretty good! kind of made the Fender sound like a vox, no distortion, just volume boost, which leads to more crunch from the amp itself, which is fine by me,

had a lot of hum, supply rated at 150 ma, we are running it at 144 ma, so maybe their idea of a duty cycle is different from ours, 

so i put a big cap in there and the ac went from 1 volt to 30 millivolts, still a bit high so we will add a resistor and another cap to straighten that out,

that big 100 ohm  is the heater dropper thngy,

will do a sound bite tomorrow,

 

[Kingston]

had a lot of hum, supply rated at 150 ma, we are running it at 144 ma, so maybe their idea of a duty cycle is different from ours, 

so i put a big cap in there and the ac went from 1 volt to 30 millivolts, still a bit high so we will add a resistor and another cap to straighten that out,

I also found these random DC supplies are terrible, 1VAC at the rated "DC" output sounds familiar. And if it says 9VDC at the label, you can expect anything between 8-12V.

I've used a 78XX regulators for the kill, no need to worry about heat sinking at these currents.

 

[kato]

should take about....maybe.....20 minutes,  ;D

I was thinking 20 minutes to twist-tie seven parts onto a tube - without considering an enclosure, power supply...  ...random power tools...

The fuck is this??? some kind of rotating blade? 
I'm both impressed and horrified.
My left hand involuntarily formed a metal sign while my face twisted into a grimace.

You been raiding this guy's tool chest?

I was considering a Buy CJ Some Garolite fund, but I suspect this is not an issue of dinero, but rather a case of willful insanity. 

 

[CJ]

dude, i still smell like fiberglass, and now potting compound from the UTC, jus sayin...

i'm a walking Superfund site, call the hazmat freaks, 

hey, give me a mig welder and a 4 inch grinder and turn me loose, i could build the titanic, which some rich freak is doing right now,

 

[PRR]

> i still smell like fiberglass

If you just wanted all that silly-state stuff off the board, you cudda just used the torch. Soften the solder, smack it on the table. (Be sure the dog wears safety-glasses.)

 

[CJ]

i bet the Wagner heat gun would would work too, high range is pretty hot,

ok the tube screamer is screamin now, when i put in a 3000uf - 33 ohm - 3000uf pi filter to de hum the pwr supply (which made it dead quiet) it dropped the heater voltage down to 4.7 volts which dropped the bias down to 60 mv  which then gave it the funk.

before it was too clean, all it did was boost the volume without the funk,

now we have about 300 micro-amps plate instead of 800.

looks like seymour duncan is using the mini tubes also, only 6211 in his stomp box,

so we are ready to tear it up with the second harmonic non "rocks in a blender" sound that you get with the NPN stuff,,  jus sayin,,,,

 

[tchgtr]

ok the tube screamer is screamin now, when i put in a 3000uf - 33 ohm - 3000uf pi filter to de hum the pwr supply (which made it dead quiet) it dropped the heater voltage down to 4.7 volts which dropped the bias down to 60 mv  which then gave it the funk.

before it was too clean, all it did was boost the volume without the funk,

"Funk is it's own reward."
G. Clinton

 

[CJ]

ok got tired of the wimpy second order stuff already, so we clamped the output with a 1N69 diode for more sizzle my bizzle,

the 69 is a rare Ge contraption, but it has been sitin in the junk box for so long that we were glad to find a use for it,

added a bypass cap on the cathode, it takes a little harshness off the high end and boosts the bass a bit since these stomp boxes usually suffer from too much treble,

sounds pretty crunchy, so this box is done, just run it from output to gnd and you are ready to grind out some Buckcherry, Your Crazy B, but i like the way,

you know the song,

two filter caps and 33 ohm are stashed under the board,

 

[CJ]

sloppy soundbyte:



final schematic>

 

[shabtek]

have mercy! we love you.

give it up fellas

 

[kato]

have mercy! we love you.

give it up fellas

I will join you in the slow clap. CJ, that's badass. You made that tube sing.

Gotta stock up on DOD death metals while they're cheap so I can cash in later.

  Drooling musician #1: How's the guy from Vacuum Brain get such wicked tone mang?
  Drooling musician #2: He uses a DOD Death Metal pedal.

  $240 Buy It Now, 10 available. Ka-ching!

Seriously though, nice going. Your know-how alone made it sound great. I concur with Kingston, the stock sound samples are uninspiring. Yours is an altogether different beast.

 

[CJ]

thanks!

i was wearing boxing gloves when i played that, 

will post a soundbyte of the Crunchmeister 50 pretty soon,  without the gloves on,

i should have used an A/B box to give a contrast between the amp and the 1N69 thing,

 

[kato]

Whut? Buckcherry has a new album??
I haven't been to a titty bar in so long I had no idea.

 

[AMZ-FX]

1) Jack Orman's Mosfet Boost - nothing but clean boost - no grit or drive, honestly just gives clean increase in headroom (well within reason, not perfectly). Very few commercial boosts can even do this. Almost all other's start overdriving or distorting, whether by virtue of their own circuit or because they force the front end of a tube amp into overdrive. 

Many thanks for your kind remarks!

Best regards, Jack