 Time
for a new amp?
I am often asked for advice about purchase of a bass
amp. Although there are many resources on the net
and elsewhere, I will throw in my thoughts on the
subject. I hope you will gain useful insight.
First you must consider your budget. This issue can
impact considerably on your purchase.
Do you need a better amp very soon, or can it wait
a while until you can afford what you want?
Portability – transport and
maneuverability are important factors to consider.
I prefer to carry smaller, lighter items as opposed
to large, heavy items – been there, done that.
(If you always have roadies, portability is not an
issue for you.)
Sound – This is a major factor
and depends a lot on the genres, styles and techniques
you play. If you have already identified your (current)
favorite sounds, then check out what equipment those
bass players are using. Remember, however, as Jaco
said “The sound is in my hands.”
Solid state, tube (valve) or a combination
of these and other technologies?
The pre amp shapes your tone and can be a stand-alone
unit. It can also be integrated with a power amp and/or
a speaker cabinet. The latter is commonly called a
“combo”.
Watts – There is a common
misconception that the speakers should have much higher
RMS wattage than the power amp. Often inexperienced
bass players and salespeople believe that a 150W amp
combined with a 300W speaker is a good, safe and powerful
combination. It ain’t necessarily so.
Ohms – A 150W 8 Ohm amp running
a 300W 8 Ohm speaker will result in ca. 80W output
– not much for bass. Bass requires headroom.
When you push the volume and have no headroom you
can get distortion and speaker and amp damage.
My advice: Get as many watts as you can in
the amp head. 500W – 800W is not unreasonable.
This will even work with a 300W speaker cab. Why?
Without getting technical, here’s an analogy:
A large car with a V8 engine will be purring comfortably
at 80MPH, whereas a small car with half the engine
size has to work much harder at the same speed. The
speaker is being driven very hard with the small amp
but is not being pushed at all using the amp with
more headroom because that amp is not straining.
If you are not convinced, go to your local music
store, plug a 500W speaker into a 50W amp and check
out the bass sound. Then plug a 100W speaker into
a 1000W amp and compare. (Now we are back to sound.)
Also check out the sound of 8 Ohm cabs versus 4 Ohm
cabs as well as manufacturer-approved combinations.
As always, let your ears be the judge. I prefer the
more saturated sound of 8 Ohm cabs.
EQ – Equalization can be graphic,
parametric, semi-parametric, or a variety of combinations.
What suits you? Usually shop staff are knowledgeable
and will assist.
Compression – Most high-end
bass amps have good in-built compressors. A touch
of compression is not to be overlooked in your sound.
All recordings have a degree of bass compression and
it is an excellent asset for live playing too. (All
of my lessons are recorded with bass compression.
Have you noticed? If not, that’s good.)
If you purchase separate pre-amp, power amp and speakers,
you can always mix and match. This is a great
way of achieving your ultimate sound. You
can try tube/solid state amp combinations with speakers
and speaker cabs of various sizes and quality.
Many amp heads now have the option of blending tube
and solid state pre-amps. Some do amp simulation (of
well-known and successful combinations) too. This
will enable you to find out what is most suitable.
My current setup (for the past 12
years) is an amp head containing two 250W power amps
plus all the other shbang such as DI with output control,
a good compressor, semi-parametric EQ, shelving (graphic)
EQ, headphone jacks, tuner and effects in/out plus
more. And very importantly, a tube pre-amp. This makes
the amp sound better as it warms up. I run both power
amps into bridged mono, giving me 600W RMS into a
350W RMS 2x10 speaker cab with an attenuateable horn.
The cab can handle peaks of up to 800W.
A note on speaker cabs – 2x10
has approx. the same surface as a 1x15 speaker. Therefore
the 2x10 has a similar amount of bass depth as the
1x15, yet a better, faster, clearer response, making
it fine for 5-string basses.
Although the info provided above might seem in-depth,
it is not really. Many issues have not been mentioned.
If you are interested, investigate further.
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