Onboard Preamp , stratoblater ?

Started by petey twofinger, November 08, 2012, 03:01:34 AM

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petey twofinger

i want to spice up my kids mini strat , i was tinking a startoblaster would do the trick . i see that there is a pot involved , i would rather avvoid this . my question  is this , if i eliminate the pot and sub in a jumper , would that be too much gain for anice clean tone , or produce hiss ?

am i barking up the wrong tree ?

is there a better , quieter circuit , say a tillman perhaps ?

i do realize this is a cop out, asking this type of question ... i am so busy atm , my back injury prevents me from working as long as i used to be able to ... trying to cut the tinker time down a bit

thanks !
im learning , we'll thats what i keep telling myself

brett

Hi
the stratoblaster is a cool buffer+booster. Without the pot, there's be too much boost.
There are a few different versions, but in each case you can replace the pot with a resistor about half or one third of the source resistor. e.g. one version has a 22k drain resistor and 12k source resistor. In this case, I'd replace the pot with a 4.7k resistor.
The gain will be approx (drain resistor/source resistor). In the case above, that's 22/4.7 or about 6. That's in the middle of the "good" range of 2 to 10. At 2, the gain would be almost undetectable, and at 10 it'll be very solid. Beware wishing for too much gain (unless you like distortion all of the time).
have fun
Brett Robinson
Let a hundred flowers bloom, let a hundred schools of thought contend. (Mao Zedong)

Ronan

What Brett said, or another approach is fit a trimpot in place of the pot and adjust it to taste.

Mark Hammer

I'd agree with Ronan's suggestion.  Use a trimpot to set the amount of gain.  Ideally, you want a maximum output that optimizes S/N ratio, and makes it a little bit easier to overdrive an amp, without wreaking havoc with pedals.  Keep in mind that there are plenty of pedals designed around assumptions about maximum possible input level.

petey twofinger

#4
she is using a boss gt6 atm , but during the summer we go to the woods for remote jams , she uses peals . i tried the ministrat / gt6 combo with a gus smalley npn boost and it seemed to add more hiss/background noise than what actually was worth the boost improvement , when i was using the gt6 for dirt that is . .... i am thinking i will try a few options before cutting anything in , a tillman , for instance . i know the trim pot is better than a fixed resistor , but i am thinking an actual gain pot , mounted on the pickgaurd could be the best solution ... as long as i have the circuit by passable with a switch ... that way it would be the most flexible . i have a really tiny pot that looks like its 35 k but the bom calls for a 50k ... hmmm . also  i dont have a knob for the tiny shaft yet , but i am thinking wrap saran over the shaft then add some jb wled maybe . either that or go for a full size rev log 50k and get a strat stykle knob , i think there is room .

i am just hoping there is room for a 9 volter inside the strat cavity , i have a battery compartment i could " route it out " with a drill bit , but ... . i have a new rechargable 9volt , i could double sided tape that  that in maybe between the pu's or somewhere . then add an inline style 2.1 mm dc jack somewhere by the strap post to recharge it . seems like it could be a nice feature , if i like it , eventually gonna do the same to my american standard , but that pick gaurd is signed by adrian belew ...

i am curious , whats the deal with active pick ups , are the the same as a normal pick up and is it just some sort of boost circuit / buffer , or am i completely knackered when i try to think .
im learning , we'll thats what i keep telling myself

WaveshapeIllusions

The stratoblaster is a good circuit. You could also use a spdt switch to flip the source cap in and out if the circuit. Perhaps with a resistor in series so the gain isn't too high.

Regarding the battery options,  I've gotten 3 CR2032 coin cells to fit in a small cavity easily. They have less available power than a 9 volt but current draw is low, so they'll last a while.

Active pickups just have the preamp enclosed in the shell. EMGs, for example have a really small preamp in there. Sometimes they're underwound for better frequency response, since the preamp provides enough make up gain.

petey twofinger

i was thinking about that cr3032 idea as well , i would say use 3 to get 9 volts ... arent those things " rechargable " in a sense , hmmm .

thanks for the info !
im learning , we'll thats what i keep telling myself