Alembic Blaster / Gain on Potentiometer / What Value?

[Football]

One of my Strat guitars has a Blaster, but there is not a trim pot on the board.

Instead the board is wired to a potentiometer to control gain.

If I’m using my tester properly, I think the pot controlling the gain of the blaster is 50k.  Master tone is 250k.  Master volume I’m not really sure what the reading is.  Shows 5.6 when meter is set to 200k Ohms.  I attached a couple pics of the reading I’m getting for master volume.

Will you please let me know if that’s a good value for that pot?

Also, the Fender pickups go to the five-way switch, then to a master volume, then the master volume goes to the Blaster.

Curious if there is a typical value used for the master volume.

Noticing I lose highs when rolling down the guitar’s master volume (not the Blaster gain).

Thought I had read that treble bleed may not be needed when using a Blaster, but maybe how this is wired is not ideal.

[JimmyJ]

I'm not a guitar guy but let me take a stab at this anyway.  The little hole next to the Blaster's switch originally was there to allow screwdriver access to the trimpot mounted on the board.  So your Blaster has been modified making the "trimpot" an always accessible knob.  That must mean your 1/4" output jack is somewhere else?

You can't really get a reliable reading of a pot's value when it's in a circuit because what it's connected to will affect your meter.  You'd need to isolate 2 of the 3 leads or lugs to get an accurate number.  That said, most pots have the value printed or stamped on the housing so take a close look if you're trying to figure it out.  And why are you trying to figure out?

I think a traditional Strat had Volume, Tone & Tone controls (??) and believe they were all 250k pots.  That thing you describe where lowering the master volume rolls off treble is how the passive hi-z guitar circuit always worked.  Some guys use that to get a mellow tone.  The Blaster is a high-quality on board buffer amp which should help transmit the full spectrum of sound down the cable and to the amp.  It sounds like your guitar is set up with an interesting mix of passive & active.

Now I'll get outa here and let some actual guitar guys give you better answers.    I mostly wanted to say that bit about using the meter...

Jimmy J

[Football]

Hi, Jimmy.  Yes, the 2nd "tone pot" position in a typical Fender layout, that is the Blaster gain.

Would like to not have the treble go away while rolling down the master volume, but maybe that's going to require a treble bleed with the way this is wired. Not sure if there is an alternative way to wire this modded Blaster so that wouldn't happen.

1/4" jack is in the usual location.  Uploaded another pic.

The master volume and master tone pots are mini sized.  Can't read anything on those pots. 

The pot, which is full size/typical size, that is a CTS that says 50ka.

[JimmyJ]

Remember, not only am I an old dude but I only know a few things and only about Alembic Series models.  Even worse, I'm just a bass player! 

OK duh...  The 1st pic you posted had me confused.  I thought I was looking at a pot mounted in the hole for the 1/4" jack but now I see that IS the 1/4" jack with a cable plugged in.  Sheesh.  So somebody made the trimpot into a panel mounted "boost" pot.  Of course the circuit wasn't designed to be run that way but I do believe the original trim pot was 50k so that CTS pot is probably the correct value.  The thing is, that trimpot is only meant to adjust the Blaster's GAIN from +3 to +14db, not work as a master volume control.  It's how much boost you want to happen when you switch in the circuit.

Now I'll let somebody else who actually knows something steam in.  Really this time.   

Jimmy J