What is the fifth pot on Rickenbacker guitars for?

[line6man]

I came across this schematic today, and I am a little confused.
http://www.rickenbacker.com/pdfs/19511.pdf

The "mixer" pot is basically a second volume pot for the neck pickup. The only reason I can think of for having such a control would be to run both pickups at full volume, and place a resistance in series with the neck pickup, so that the pickups will not run directly parallel. This would increase the output impedance of the neck pickup, and thus decrease the load on the bridge pickup, causing it to get a bit louder. 500k is quite resistive for the given signal impedance, however, so the range of control would be limited. (Especially so, for audio taper pots.) And the effect can be achieved by rolling the regular volume pot down, anyway. I guess the other explanation would be that it allows the regular volume pot for the neck pickup to act as a sort of "output limiter," so the volume can be adjusted with the "mixer" pot, and never get louder than what the volume pot is set to. But that's pointless knob twiddling for no benefit.

Does anyone know what this pot is supposed to do? :dontknow:

 

[Cagey]

Mystery to me, too. But, guitar manufacturers have been known to do silly things with controls. Witness the Jaguar/Jazzmaster pair.

 

[drewfx]

From http://www.rickenbacker.com/pdfs/manual.pdf:

Many Rickenbacker guitars come
with a fifth control knob providing
extra tone adjustment capabilities.
Using this control to adjust the
volume of the bass pickup in relation
to a pre-selected treble pickup
lead volume setting, you can set it
at the tone you will use more often.
Or it can function as a bass/treble
equalization control.
To use the fifth knob as a bass
pickup volume equalizer, first place
both volume and both tone controls
on the instrument at their maximum
clockwise positions. Then, move
the pickup selector to the treble
position and set the amplifier to the
desired lead sound. Now, switch
the pickup selector to the bass pick
up. The fifth tone knob can now be
adjusted in order to bring the
rhythm sound to a volume compatible
with the already selected lead
sound volume.
To use the fifth knob in a set position,
first place both volume controls
and both tone controls on the
instrument at their maximum clockwise
positions, and move the
pickup selector to the center position.
Now adjust the amplifier, by
setting the gain controls at the
desired volume and the bass and
the treble controls at their maximum
positions. Finally, adjust the
fine tone selection knob on the
instrument until the tone which will
be used most frequently is reached,
and leave it in that position. After
the small knob has been set, the
pickup selector may be moved
down for maximum treble or up for
maximum bass. The variable volume
and tone controls on either the
amplifier or the instrument can now
be moved to the desired volume
and tone settings.
To use the fifth knob as an equalization
control, first place both
volume controls and the treble tone
control on the instrument at their
maximum clockwise positions, and
move the pickup selector to the
center position. Move the bass tone
control on the instrument to its
maximum counter-clockwise positions,
and set the volume and tone
controls on the amplifier to their
desired positions. Now, with the
instrument's treble up full and the
bass at its minimum, the fine tone
selection knob can be used as a
tone equalizer, moving the instrument
through the entire tonal range
without adjusting the amplifier.     

:dontknow:    :icon_scratch:  :help:

 

[mayfly]

I played Ricks for years. The fifth knob is indeed a volume equilizer between the pickups. I used it to get a good blend between the two. Sometimes I experimented with removing it, but always put it back in. It worked by lowering the volume of the neck pickup, and it worked pretty well. YMMV if course.

If you're concerned about the added resistance, you can always use a super switch or something to take it out of the circuit when using the neck pickup only.

Never needed it in my telecasters. There you can accomplish the same thing by changing pickup heights.

 

[Jumble Jumble]

Mystery to me, too. But, guitar manufacturers have been known to do silly things with controls. Witness the Jaguar/Jazzmaster pair.

I really like the idea of a lead/rhythm switch, but the implementation of it on those two guitars is very odd. However, when I build my Jazzmaster I'm going to start by doing it "properly" (for my own education) and work from there towards my personal ideal setup.

 

[line6man]

I played Ricks for years. The fifth knob is indeed a volume equilizer between the pickups. I used it to get a good blend between the two. Sometimes I experimented with removing it, but always put it back in. It worked by lowering the volume of the neck pickup, and it worked pretty well. YMMV if course.

If you're concerned about the added resistance, you can always use a super switch or something to take it out of the circuit when using the neck pickup only.

Never needed it in my telecasters. There you can accomplish the same thing by changing pickup heights.

So what did it bring to the table, that the volume pots didn't?

 

[Cagey]

I really like the idea of a lead/rhythm switch, but the implementation of it on those two guitars is very odd. However, when I build my Jazzmaster I'm going to start by doing it "properly" (for my own education) and work from there towards my personal ideal setup.

I'm not sure what the education is worth. It's not something you're ever likely to do again. Of course, you would learn to never do it again, but's sort of an unnecessary lesson. Anybody who's done it will tell you not to.

Having done it more than once myself (I'm not really a slow learner, but sometimes I'm a whore), I can tell you it's no fun at all. Also, that you'll almost certainly be sorry you spent the time because you'll want to re-do it.

Treat it like a Tele circuit. Use a 3-way blade or toggle, and put the switch wherever you'd like. Then, 1 volume, 1 tone, and call it a love story. You'll be glad you did. It'll work better and more intuitively, it'll look cleaner, and be easier to implement/maintain. Leave the over-wrought trick bag of pots and switches scattered all over hell's creation to the inexperienced kids who are impressed by such things.

 

[Jumble Jumble]

Ah, but, see, what you're doing there is, giving someone instructions on how to build their custom guitar

It's well documented that you like as few controls as possible. I do too - but I think we have different ideas of the "possible" in there. I will have as few as possible to achieve the sounds I have decided on, but no fewer.

 

[Cagey]

Good point.

 

[line6man]

Leave the over-wrought trick bag of pots and switches scattered all over hell's creation to the inexperienced kids who are impressed by such things.

Words to live by.  :icon_biggrin:

 

[Dan025]

i wouldn't imagine it does much with the neck pickup only. reisistor networks are weird sometimes and of coarse the input impedence of the amp has a little to do with it. not a big deal with amplifiers but some stomp boxes make a quantifiable difference. it may drop the volume enough to notice but not completely. it would just be easier than messing with the volumes because the overall volume wouldn't vary as much as a gibson. so you can dime the controls and still mix without dropping volume. on a gibson you should get the best mixing close to 7 on the knobs.

it's certainly not a needed feature. but don't knock it till you try it....