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Control
panel for Slingshot remote |
 The
real fun with the Cabbone comes when introducing the Slingshot to
your system. The Radial Slingshot is a remote switching circuit
that lets you assign the Cabbone as a slave to receive a toggle
change command from a footswitch or maybe a MIDI controller. To
use the Cabbone as a slave, you must begin by positioning the internal
/ external remote switch selector in external mode. This disengages
the Cabbone’s footswitch and allows an outside footswitch
to control the Cabbone’s electronics and relays.
Cabbone’s Slingshot can also send out a program change command,
for example telling your amp to change channels, at the same time
as a Cabbone speaker cabinet change. To make Slingshot as universal
as possible, the Slingshot Output connection features a choice of
latching or momentary pulse switching type and positive or negative
(tip or ring) switch polarity for ¼” TRS setups. These
settings will allow you to adapt to most popular amplifier channel
switching systems. Simply connect a standard ¼” guitar
cable from the Cabbone’s Slingshot output to your amp’s
¼” footswitch input jack. If you don't know your amp's
switching parameters, you can just go through each of the four possible
switch settings while depressing the footswitch and note when the
amp channels change.
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The Radial Slingshot was developed as a means to remotely
control devices from pedal boards without having to resort
to using complex MIDI routers. The Slingshot combines the
basic functionality of a footswitch while introducing the
concept of daisy-chaining several devices so that multiple
events can occur at one time. Because of the universal nature
of the Slingshot, the system can also be made to work with
various MIDI controllers and custom pedal board systems.
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For maximum versatility, connecting the Cabbone with a controller
from a pedal board like the Loopbone, tremendous options begin to
open up. To get a sense of the possibilities, visit the Slingshot
Universe page.
Note: Some amps employ TRS or tip-ring-sleeve type connectors or
other proprietary switching systems to change channels and/or perform
a secondary function like turning the reverb on or off – Please
consult a qualified technician for assistance should you have to
make an adaptor to access the channel change function.
This page is designed to provide the user with an overview
on how amplifiers work with various speaker loads and options that
can be considered when using the Radial Cabbone with your equipment.
As every piece of equipment is different, we suggest that you consult
your specific manufacturer’s operating instructions before
using the Cabbone. This will ensure your equipment will work properly
and without undue stress.
Before we look at how each amp would be set up, we need to understand
the options and trade-offs that you will be faced with when setting
up your system.
For an amplifier to work correctly, it must have a proper load.
This means that the power being developed inside the amplifier must
be dissipated in the form of sound or, failing this, heat. Too much
heat can cause the power transformer to fail. By always having a
load on the amplifier, one can avoid this problem.
Tube amps and transistor amps react differently to speaker loads.
Both tube and transistor amplifier manufacturers will design their
amps for ‘optimum’ performance based on typical impedances
such 4, 8, or 16 Ohms. With transistor amps, lowering the speaker
impedance or reducing the load will generally produce a louder output.
For safety, transistor amp manufacturers will usually post a warning
stating the minimum impedance on the back of the amp or in the operator’s
manual. Make sure that you do not go below this impedance to avoid
causing damage to your amp. Increasing the load will reduce the
amp’s output level. Tube amps are generally set for optimum
performance at a ‘specified impedance’. Lowering the
impedance or reducing the load will make the tubes work harder which,
according to some guitarists, makes the amp sound better. The downside
will be a shorter tube life-span. Increasing the load will reduce
the stress on the tubes, but also will generally make the amp sound
thinner.
| (*) Note: As we have no control over your
setup with respect to the amps, cables, speakers or switches
that you are using, it is your responsibility to consult the
amplifier manufacturer’s technical specifications to ensure
that you do not expose the amp to speaker loads that are incompatible.
Please consult your Tonebone dealer or a qualified technician
before using the Cabbone. |
Depending on the desired impedance, speaker cabinets with more than
one speaker may be wired many ways. These include parallel, series
or a combination of the two.
 Ohms
Law for parallel circuits is: (X = speaker impedance)
1 + 1 + 1 etc… = 1/Total impedance X X X
When wiring a cabinet in parallel, the (+) terminal from the amp
is connected to the (+) on the speakers in the box and (-) terminal
on the amp connects to (-) terminals on the speakers. In parallel
systems, each speaker is connected directly to the amplifier. Ohms
Law of resistance in parallel networks is simple and works like
this:
Let’s say we have
a speaker cabinet with two 8-Ohm speakers. 1/8 + 1/8 = 2/8 or 1/4
and the reciprocal value is 4 Ohms when wired in parallel for a
4-Ohm load.
Ohms law for series circuits is: (x = speaker impedance)
X + X + X etc… = Total impedance
When wiring a cabinet in series, the (+) terminal from the amplifier
is connected to the 1st speaker, then the (-) from the 1st speaker
is connected to the (+) terminal on the 2nd speaker. The (-) terminal
on the second speaker is then connected back to the amp’s
(-) terminal. In series wiring, the signal works like a train whereby
it must go through each speaker, one after the other before the
signal path returns to the amplifier. In ‘series wired’
circuits the impedance of each speaker is simply added up for the
total impedance.
Using the same speaker cabinet
with two 12” speakers. The speakers have an impedance of 8
Ohms. 8+8=16 resulting in a 16-Ohm load.
If we were to apply similar math to a 4x12 cabinet, with each speaker
rated at 8-Ohms, we could configure the cabinet to have many different
values depending on how we wire the speakers:
Parallel: 1/(1/8+1/8+1/8+1/8) = 1/(4/8) or 2-Ohms
Series: 8+8+8+8 = 32-Ohms
Series parallel 1/(1/8+1/8) + 1/(1/8+1/8) = 16Ohms
A typical 4x12 system employs four 8-Ohm speakers in a series-parallel
combination:
Obviously, using a matched load will give you the best overall
system performance. To make this easy, some amplifiers are equipped
with multiple taps on the output transformers to allow you to select
the load for proper matching. Cabbone has two speaker inputs for
these types of amplifiers to allow you to match the correct load
for each cabinet.
Sometimes achieving a perfect matched load is however impossible
due to the amplifier and speakers at hand. If you only have one
amp output on your amp, and only one impedance selector, you will
have to make a compromise. These means making decisions based on
best sound versus more wear and tear. Here’s how it works:
If the output of your amp is rated for 8 ohms and you put a 16 Ohm
load on it, the output will not be as loud and this will reduce
the amps drive. This means that with a tube amplifier, the tubes
will not be driven as hard and will last longer. The trade off is
that your amp may sound a bit thinner.
If on the other hand your amp is set for 8 ohms and you use a 4-Ohm
speaker, your amp will work harder and be punchier. Of course, this
reduces the life of the tube, which is a trade-off. Solid-state
amps follow pretty much the same rules except that they play louder
when the load is reduced. You do have to be cautious that you do
not expose the head to a lower than recommended load as this could
damage the heads performance and void your amplifier’s manufacturer
warranty. For best results, consult your dealer and he can help
you wire your cabinets so that you get the best sound. To ‘play
it safe’ – we suggest setting your amplifier’s
impedance to match the lowest speaker cabinet impedance in your
system. |
