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. So, just investigate further!

Bass Player and Music Educator George Urbaszek

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