Replies to This Discussion

Permalink Reply by Elmar Zeilhofer on May 19, 2013 at 12:12am

John, could the mounting screws have a negative effect? This is a suspect which I haven't verified yet. Maybe I'll ground them and listen what happens..

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Permalink Reply by John Davidson on May 19, 2013 at 1:01am

I don't have a Flatpup to experiment with although I've been meaning to order one.
I don't think grounding the mounting screws will do much but ya never know until you try.

Are the Flatpups' windings shielded?

John

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Permalink Reply by Elmar Zeilhofer on May 19, 2013 at 1:36am

If you like, I send you one to experiment with.

Both coils are in series; if you touch the tape protection of the first coil, there's a hizz. Touching the other side doesn't have an effect, because the windings at the outside are connected to ground and appearantely protect the underlying turns.

The Flatpups in a metal housing are totally silent.

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Permalink Reply by John Davidson on May 19, 2013 at 1:51am

Sounds like the tape protection of the second coil is grounded but the tape of the first coil is is not.

A grounded metal housing shields both coils.

John

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Permalink Reply by ron carlson on May 19, 2013 at 2:15am

Hi John,  

Not sure I'm following you here. Are you saying to place a circuit high pass between pickup and jack eliminating volume control all together or before both volume and tone??? I assume a cap on the tone, right?

My apologies for sounding like a maroon. I'm more of a audio guy than a guitar guy. I can sort out and build a speaker x-over and make it do what I want it to do, but I'm still having a difficult time wrapping my head around a preamp circuit for guitar. 

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Permalink Reply by John Davidson on May 19, 2013 at 3:06am

My apologies for being about as clear as mud Ron.

A simple high-pass filters shunts low frequencies to ground and allows higher frequencies to pass on to the amplifier.
For our purposes, the filter is wired between the 'hot side' of the volume pot and ground.

The simplest form would run a capacitor from the volume pot's hot side to the tone control pot or output jack if no tone control is used.
A resistor runs from the capacitor's output to the volume control's ground lug.

You can find some pictures and pretty ugly math at http://www.electronics-tutorials.ws/filter/filter_3.html

 

John
 

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Permalink Reply by ron carlson on May 19, 2013 at 5:35pm

Hey, no problem John. I appreciate you taking the time.

Not sure what approach i'm going to take here yet. I didn't add a tone control to my last one but my give it a go. It will probably be a few more days at least  before I get back to work on it anyway so I have some time to mull it over.

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Permalink Reply by Slowpaw Steve T on May 19, 2013 at 11:15pm

most amps have volume and tone controls if i have to fit volume and tone controls i use 500k pots usually, they sound great, but wiring flatpup direct to jack reduces interference/earthing issues imho (-:

 

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Permalink Reply by SlowHound on May 20, 2013 at 5:37am

IMO have to agree with Steve.  Wire it straight and forget the headaches. 

 

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Permalink Reply by Elmar Zeilhofer on May 20, 2013 at 6:05am

I also agree to Steve. And I'd like to share my recent test results:

1) A 500k cuts off the volume too fast, a 250k is way better to adjust the volume

2) The mock up test with alligator clips, a pot and a Flatpup was noisy. Replacing the Flatpup by a common humbucker gave the same noise. Therefore the source of noise must be the unshielded environment, not the pickups.

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Permalink Reply by The Phrygian Kid on May 20, 2013 at 8:19am

(1) this is probably more about the taper on the resistance than the resistance itself. Do you have both a and b types?

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Permalink Reply by Slowpaw Steve T on May 20, 2013 at 7:23pm

i always twist wire pairs from the flatpup to the jack.... Elmar have you tested this for benefits? the idea for me is inherited from the hi-fi boffins - i never agreed with all their theories but the twisted wire sure keeps things tidy! (-;

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