Stratoblaster.

[QSQCaito]

Hello guys! I was about to build a Stratoblaster to put in my guitar. I saw that on GGG there's a stompbox version, and a "fit on cavity of guitar" version. As i have an extra knob in my guitar, i don't need to put trimpot, i would rather prefer regular pot to control its gain. The question is the following: appart from size, which are the differences from this two versions of the stratoblaster, i see they have different (more/less)components, and difference in values. Could i just build the one that goes in the guitar, with a regular pot?? Could i just build the stompbox one, smaller. And do the wiring for the guitar?'


Thanks a lot!

See you soon.


DAC

[Hanglow]

There are a few layouts in the gallery for the stratoblaster on stripboard and perfboard

maybe try one of them instead of getting a pcb from GGG?

using a normal pot instead of a trimpot is fine

[markm]

I beleive both circuits are in fact the same.

[QSQCaito]

Thanks to both

MarkM, If they're in fact the same, why are they different :p. Can i build the on for the cavity guitar and change the 47k trim for a 50kB pot, right??

And, one last advice. Where would you put this, any pic or something?

Thanks a lot once again!

DAC

[modsquad]

I built mine on perfboard even though I prefer PCB.  It fit in the cavity where the Jack on my strat is.  I put a toggle on it and it works great. 

[QSQCaito]

Looking for parts I found a 10uf cap, polarized. And one ceramic cap labeled 104. Thats 1uf right?? Because it says 1.5uf, or 1 if you cant find. It's ok if it's ceramica right? Thanks you all. see you soon.


Thanks

DAC

[QSQCaito]

I built mine on perfboard even though I prefer PCB.  It fit in the cavity where the Jack on my strat is.  I put a toggle on it and it works great. 

I'll make that then

What about the battery, where did you put it?


Thanks a lot, bye bye!

DAC

[modsquad]

I guess I cheated because I have EMGs and already had a battery in there to tap off of.  Its located where the 5 way switch is.  And 104 is .1uf not 1uf if my memory is correct.

[Mark Hammer]

Looking for parts I found a 10uf cap, polarized. And one ceramic cap labeled 104. Thats 1uf right?? Because it says 1.5uf, or 1 if you cant find. It's ok if it's ceramica right? Thanks you all. see you soon.


Thanks

DAC

Yep, 104 is 1, 0, and 4 zeroes after that = 100,000pf = 0.1uf.

The 1.5uf cap can really be anything from 2.2uf to .22uf (and probably even lower) without affecting the signal in any audible way.

Keep in mind that once upon a time, 1.5uf appeared to be a "standard" value!! along with 2.7uf.  Just TRY finding those anywhere these days.

BTW, when it comes to pots and trimpots, 47k = 50k, just in case there was any concern about that.

In some respects, it may be more appropriate to make R4 ( http://www.generalguitargadgets.com/diagrams/asb_sc_i.gif ) a trimpot to set maximum output, and replace R5 with a 100k log pot to adjust output level.  That can actually serve as your master volume control.

[QSQCaito]

I was wondering which was the difference, because the schematic of the other stratoblaster had less parts. Now that I see this one says "improved" i'm going to build this one

Mark, may the caps be electrolytic?? I live in Argentina, and i have to go downtown to get all those stuff, and i was planning to do it with I had home  Is it ok 1uF instead of 1.5uF? And i'll do what you told me, R4 = 100k trimpot(as variable resistor right? Lug 1 and 2 only, lug 3 unused.) And R5 = 100k A pot.
BTW, are this changes worth if i'm going to put a switch to turn it off/on?

To end, the battery (-) should be connected at the output. And when FX is off, FX input should be grounded, right?


Thanks a lot. Now i'll make the PCB as small as I can.

Thanks, bye bye!


DAC

[QSQCaito]

News: I got the PCB done yesterday maybe 2.30 am .. i was really bored and couldnt sleep. It's really small 3cm x 1.5cm. I've got all the components, but the caps aren't tant. They're electrolitic, there won't be much difference with that, right?

And, one last question.

What are the advantages of doing this:

In some respects, it may be more appropriate to make R4 ( http://www.generalguitargadgets.com/diagrams/asb_sc_i.gif ) a trimpot to set maximum output, and replace R5 with a 100k log pot to adjust output level.  That can actually serve as your master volume control.

I'm asking because i don't have the trimpot, neither the 100klog. But if there will be a significant difference, i can wait.

See you all

Thanks, bye bye.

DAC

PD I'll keep you informed of the progress :p

[petemoore]

  IIRC when I made this for my brother, I made R4 a 47k, and that put the gain a little above unity, he put it in his guitar, I put a 100k/DPDT pull/push switch for volume control/bypass.
  Basically you can turn R5 into a pot on the schematic by drawing an arrow pointing at the reisistor[see schematics with volume controls, making it look like a volume pot symbol], and take the output from the wiper, and the output side of the switch, as shown on the diagram would then come from the wiper.

[Mark Hammer]

Electrolytic caps are fine, and using a 1uf instead of 1.5uf probably makes no difference at all unless you install it in a bass.

The value of using a trimpot for R4 is that right now you don't know what gain you actually need.  The range of gain provided by the value of R4 shown might be a lot more than you actually need, such that maybe only 1/4 of the total range of the trimpot is useful.  That's why it is handy to set the max gain of the circuit, and have a volume pot to trim back from there.  It will function like a "normal" guitar volume, except with something that sounds like hotter, brighter pickups.

[QSQCaito]

I understand. It maye sound too loud with R4 actual value. Using a trimpot this could be solved, but, may it sound even louder?
What should be the value of R4 trimpot, 100k is ok?

So finally, what will sound better: to put the stratoblaster directly coming from the pickups, and the Master volume, and master tone(because i'll be having just one) later. Or put the stratoblaster directly before the output jack, after the master tone and volume.. It's the same for me since my guitar is disassembled(is ok that word ?)

If i had to guess, I'd put it before the master tone and volume, because i could have lot of gain, it wil sound hotter as you said, but still having low volume, which otherwise would be impossible. I could lower the master volume, but that would send maybe a too low signal to the stratoblaster.


Thanks to all of you

Bye bye!

DAC

[petemoore]

  at 100k, the bypass cap will have max resistance, hence lowest volume gain setting/output, in the case of the SB that equates to about above unity...IIRC.
  long legged 100k w/100k parallel
  using testclips or 'longlegged' 100k on the board, piggybacking a 100k...
  two 100k's parallel = 50k,  1/2 of 100k, see what that does...play with that value, O.k on the source bypass cap resistor of course allows the bypass cap to increase gain to 'full' as in you can't go lower than 0k, the cap allows AC to flow through it less ~unimpeded, increasing gain, the pot reduces this effect by introducing resistance between Gnd., and the cap to source.
  with a 100k resistor on the output being the same as a 100k volume pot on full, set the gain and voicing of the Jfet amp with the source bypass cap, reduce gain and current through the cap with 'a' resistor, chosen between O.k max gain, and open/min. gain, You'll probably start hearing the Jfet/source bypass cap more, and increasing gain with a limiting R of <47k there.
  Perhaps tweek resistor values on a switch, selecting values, or paralleling or seriesing 'built' values.
  The 100k you have can be made any value <100k, using any value resistor, 0.k would be a wire across it. Use DMM to test built values, start with circuits consisting of 2 100k's:
  100k = 100k [or slightly less because of tolerance]
  100k series with 100k = 200k
  100k parallel with 100k = 50k
  Swap equational values as avalailability and preferences require.

[QSQCaito]

  I got a bit messed up, pete. Let's go step by step.

  at 100k, the bypass cap will have max resistance, hence lowest volume gain setting/output, in the case of the SB that equates to about above unity...IIRC.

Ok

using testclips or 'longlegged' 100k on the board, piggybacking a 100k...
  two 100k's parallel = 50k,  1/2 of 100k, see what that does...play with that value
There will be a trimpot in r4, so this shouldn't be necesary, right? I just turn the pot.( to connecto as variable resistor, lug 1 to as one end of resistor, and 2+3 as the other end, right?)

O.k on the source bypass cap resistor of course allows the bypass cap to increase gain to 'full' as in you can't go lower than 0k, the cap allows AC to flow through it less ~unimpeded, increasing gain, the pot reduces this effect by introducing resistance between Gnd., and the cap to source.

Ok

with a 100k resistor on the output being the same as a 100k volume pot on full, set the gain and voicing of the Jfet amp with the source bypass cap, reduce gain and current through the cap with 'a' resistor, chosen between O.k max gain, and open/min. gain,

Got my doubts. You're saying to put R5 (http://www.generalguitargadgets.com/diagrams/asb_sc_i.gif) Pot at max ressistance, and play with the trimpot to set it how i like it, to set the minimum gain?

You'll probably start hearing the Jfet/source bypass cap more, and increasing gain with a limiting R of <47k there.
Got lost at this part 

Perhaps tweek resistor values on a switch, selecting values, or paralleling or seriesing 'built' values.
  The 100k you have can be made any value <100k, using any value resistor, 0.k would be a wire across it. Use DMM to test built values, start with circuits consisting of 2 100k's:
  100k = 100k [or slightly less because of tolerance]
  100k series with 100k = 200k
  100k parallel with 100k = 50k
  Swap equational values as avalailability and preferences require.

If I'm not wrong, this shouldn't be necessary because i'll have a trmipot in R4, and a regular pot in R5, right?



Thank you all a lot lot, I hope I don't bother


See you, bye bye

DAC