Odd wiring idea....sensible or stupid?

[Soundfarmer Pete]

Please excuse me if this is a bit long and rambling but I would welcome comments.....and I want to explain my reasoning.
Although I make emandos, my gigging instrument is bass guitar and recently, I`ve taken to playing the odd solo. I found that turning the volume to max for the solos and backing off the rest of the time was unreliable so I made a simple volume cut pedal by mounting a footswitch and volume pot into a DI box. The pot is adjustable with a screwdriver through a hole in the base of the box so once the desired level has been set, then it`s foolproof with no knobs to accidentally turn.....Full blast or a bit quieter...works a treat!

So I`m working on a couple of new electrics that I propose to fit with a piezo and magnetic....how to keep the face of the instrument simple rather than loads of knobs?

My idea would be to have 2 banks of controls (piezo vol, magnetic volume and maybe individual tone controls for each...or just master tone).

The 2 banks could be accessed from the rear to set the balance and tone then switched using a push/pull master volume on the front.

OK, it would take a little time to set up and there would only be 2 presets available but how many different tones are needed? ......and at least, once set up, it would be foolproof.

[mandroid]

in another topic there was a mention of a stomp box that could be preset to A/B in 2 different levels .

never owned one , but It seems that is functionally its purpose ..

http://www.mandolincafe.com/forum/sh...-Amp-as-preamp


My 4 string got individual pieces for each string.
http://www.emando.com/images/builders/Biller.jpg
Piezo preamp is in the black box RMC Polydrive 2 that connects thru the
8 pin cable to the DIN connector [bayonet lockring to never come loose]
pin #7 got the magnetic PU signal , installer added a 1/4" lack to the Box.
so 2 cables split the 2 sources ..
[+ the 13 pin to send on to guitar synths ]

RMC, Berkeley Cal, supplies Godin , so they have a wholesale price to builders .

[Tom Wright]

Calls to mind my first good electric axe, a 60s Jazzmaster with the "rhythm" circuit, a separate volume/tone group for the neck pickup, with slide switch to engage.

Seems to me that the pre-set approach is too specific to a given playing situation, so an outboard box is preferable. But you could optimize for that by having two outputs--a regular blended out through 1/4" or a multi-pin cable to the box (useful for keeping outputs separate for recording).

My preference is good ergonomics on the instrument. Having pots and switches handy but not in the way is not always easy to arrange but worth it to me. Good layouts include Stratocaster, bad include Tele with that awful selector switch; and Les Paul, again the switch, in a different place than the pots and too far away to be handy.

How about this idea? Like a Scruggs tuner, a pot with an adjustable stop so that you could roll it back to precisely where you want. And that could even be hand adjustable by having the stop carried in a plate with a circular track under the pot. Thumbwheel on captured nut intercepts pointer sticking out from the knob. Moving it all the way around disables it. Easy to change for a different song. That device could be added to any pot, plate held by mounting nut, pointer carried on a plate under the knob that is splined to fit on the shaft.

[Verne Andru]

There are a few things to be aware of if you plan on mixing and matching standard mag pickups with piezos like K&K.

First, the two types of pickups have different impedance that may cause issues. In theory you should run the piezo through a preamp, then the 2 pups through an active mixer to please purists. In practice I don't notice any difference in this type of application - the preamp can be viewed as optional IMO.

So you can dispense with the impedance issue and wire them together as if they were 2 standard mag pickups. Some problems come into play because on certain settings the piezo will act as a capacitor in the same way a tone circuit does. Because of this forget about adding tone controls as they won't work as expected. And you will have to play with the volume settings so you get a mix that works for the tone you're going for, but no biggie.

After much trial and error I've gone to foregoing the active circuitry and tone controls inside the instrument. I wire both pickups to their own volume and a 3-way switch, as you would find on a Les Paul, but no tone controls. In most circumstances I plug the instrument into an amp, as you normally would, and fiddle until I get a mix I can work with and adjust tone at the amp.

The exception/trick I came up with is, when the switch is set to the humbucker [could be the other way around if you want] the clean piezo signal goes to the ring on the stereo output jack and the humbucker goes out the tip [stereo jacks are called TRS for Tip, Ring and Sleeve]. With this configuration I get pure signals coming out different sides of the stereo jack. With a normal mono instrument cable the wiring still works, you just don't get the piezo tone when the instrument is switched to the humbucker, which is the normal case anyway.

I built a special cable with a male stereo jack on one end and 2 mono jacks at the other. I also built a couple preamps into a stompbox with an active mixer circuit so I plug one end of the cable into the stereo out on the instrument and the mono jacks at the other end into separate preamps in the stomp box. The preamps have EQ, gain and volume, so I can tweak each to taste. The stompbox has a bunch of outputs including a mix out with both signals going to a mono 1/4" jack and an XLR plus a separate output from each preamp. Similar off-the-shelf stompboxes include the Radial Pzpre.

Hope this helps and best of luck.

[Marty Jacobson]

I've been thinking about something similar. Verne's TRS / external breakout is a good solution, and the box could be designed to match the instrument in some way to make it feel like part of the instrument.

If you want to keep it all onboard, which is always a plus, then something like the Fishman SmartJack preamp to solve the impedence issues is a good first step. To solve the ergonomics problems, you could have two stacked concentric volume/tone knobs. Outer ring for piezo and inner ring for humbucker. Or something along those lines.

[Soundfarmer Pete]

Hmmm....all interesting input but I want to focus on avoiding potential operator error....I will explain......
As I mentioned earlier, I`m a bass player who only basically uses 2 tones so everything is turned to full on my bass and I have the sound I want dialled into my amp - if I play something with a hint of reggae about it, I`ll back off the treble. Set up time is minimal...find a mains socket, plug in my amp, bass and line out DI.....couple of minutes tops.
Our guitarist on the other hand (who fortunately is not a Café subscriber so will not be reading this) seems to take quite a while setting up but the main issue is a damn great array of buttons on the floor. Now, and I`ve seen it with other musicians as well, suppose he wants to go from a rhythm setting to solo and accidentally catches another pedal with the edge of his foot? ...all of a sudden, what`s supposed to be a great solo is ruined as his brain comes to terms with the fact his tone is not the one he wanted.....oh no.....then the brain makes the fingers go all wonky and bum notes ensue

That doesn`t happen to me....I like to keep things simple so I was wondering how gigging simplicity would appeal to mando players....

But another thought struck me......how about something like a 6 position rotary switch (and master volume) ?..... I like the idea of a positive click!
Should be an easy matter to rig an experimental setup, work a nice blend of tones, measure the pot values and make a setup with appropriate value resistors and capacitors ?

[mandroid]

I know you are asking about onboard I still think there are simpler tries and proven K.I.S.S options already out.

.. Another piece of outboard gear that does the Task described

Morley volume pedals like this have a Non zero settable minimum+ Max http://www.morleypedals.com/pvo+man.pdf


FWIW I found a Gang pot that had 2 knobs on the same shaft .

I used that on my Fender FM61 redo to double up the T&V further away
so I didn't hit the V knob accidentally..

That may reduce the number of Knobs by Half..

there is also the orienting the pot at 90 degrees to the top
and then just having the edge of the thumbwheel
sticking thru a slot in the scratch plate . (wasn't Fender Jaguars using that )

the A/B level button maybe above the bridge ..

Older electric mandolins had 1 knob on either side of the bridge .
that would reduce the function confusion by having them set a ways apart.


Hmm this does look rather Busy https://www.google.com/url?sa=i&rct=...12625991521959