The greatest and most embarrassing mistakes I have made as a bassist all revolve around bass amps and cabinets. Some of these mistakes were due to good old fashioned stupidity, but most were the results of a painful ignorance concerning how bass amps actually work. Learn from my mistakes, it’ll save you a lot of money and heartache down the road.

Terminology to Know

It’s super important to understand the vocabulary around bass amplifiers because being able to read a manual is the difference between a functioning amp and a broken amp.

So let’s clear up what exactly an amp is. Basically (no pun intended) an amp amplifies your signal which is then sent into a cabinet which houses the speakers that project that signal into the grateful ears of a listener. Most low wattage, beginner/intermediate bass amps combine these two aspects together: amplifier and cabinet, into one piece of gear: The Combo Amp.

Combo amps are great for rehearsal spaces, small shows, and people tired of hauling around speaker cabinets. They’re reliable, easy to use, and sturdy, and have earned their reputation as the beloved pieces of equipment that they are. The other option for bass amplifiers, as you might have guessed, is a separate cabinet and amplifier, more commonly known as: The Head and Cab

The separate head and cabinet option is super versatile, allowing knowledgeable bassists to customize their rig for many different performance scenarios. HOWEVER, you must have a solid knowledge of how amps and cabinets work if you want to avoid breaking your gear. Here are three factors that I ignored when first venturing into the head and cab setup that wound up giving me broken, useless, equipment. Let me be the cautionary tale.

Ohmage

This symbol Ω is the law of the land when it comes to bass amplifiers. It measures resistance in terms of the current flowing from your amp into your cabinet. Most bass amps are rated at either 4 Ω, 8 Ω, or 16 Ω. The higher the ohmage, the higher resistance your amp will safely operate at. 

Cabinets are also rated in ohms, which tells you how much resistance the cabinets put up to your Amps signal. If your amp head is rated at 8 Ω and you send that signal into your cabinet rated at 8 Ω, everything’s going to be okay. If your amp head is rated at 8 Ω and you send it into a cabinet rated at 4 Ω, you’re playing with the wrath of God. \

Nowadays modern amps can usually handle 8 Ω or 4 Ω, which means you can pair that amp head with a 4 Ω cabinet OR two 8 Ω cabinets. When you pair two cabinets together, their total ohmage is halved in proportion to their individual ohmage. I know this is starting to sound like a math problem, because it is! So basically, two 8 Ω cabinets = 4 Ω total resistance. 

If this sounds confusing, that’s because it is. So unless you’re an expert in audio technology, just match the ohmage of your amp with your cabinet. Remember, before you buy gear or experiment with gear, READ THE MANUALS. Unless you’re using some rare vintage equipment, gear manuals are easily found on their manufacturer’s website.

Wattage

The W is not as unforgiving as the Ω but it must still be feared and respected. Wattage is quite a bit easier to understand than ohmage. Your amp’s wattage rating is a lot like horsepower in your car, and typically it denotes the maximum amount of power your amp can produce. Some manufacturers, I won’t name names, lie about their wattage the same way car manufacturers lie about how much horsepower their newest sport model makes.

Cabinets also have wattage ratings which refer to how much power they can handle coursing through their veins. Just like with ohmage you want to match your cab and head. For example, send a 250 watt head into a 250 watt cab. Now, you do have a bit of leeway here. Technically, you can send a higher wattage head into a lower wattage cabinet and not damage it if played at low volumes, but if the difference in wattage is substantial I wouldn’t risk it.

Likewise you can send a lower wattage head into a higher wattage cabinet, but you do run the risk of underpowering the speakers which can definitely damage them, especially if the difference in wattage is substantial i.e. more than 50 watts.

As with ohmage, if you’re unsure, READ THE MANUAL.

If you’re in the market for a new amp and you’re wondering how powerful of an amp you need, think about your circumstances. If you’re playing with a half-deaf drummer and you want to be heard, I’d recommend at least 100 watts. But it’s more about being heard, it’s about sounding good.

If you have to crank your volume to 10 (never a good idea, jokes aside), you’re going to get an ugly, distorted sound. If that’s what you want, great! But generally I would advise that you buy an amplifier which, in any given situation from band rehearsal to live shows, you never have to push past 60% to 70%.

Speaker Cables

Now we come to the most shameful of all mistakes I have made with bass gear. I have made this mistake not once, but two times! On the back of your amp head, there’s a jack for a cable that will send your amp’s signal into the cabinet. DO NOT use some ¼ inch instrument cable to connect these two pieces of equipment. ¼ inch instrument cables are shielded, they have more resistance because they carry your bass’ small pickup signal to the amp which then makes it MUCH larger. 

If you use another shielded instrument cable to carry that amplified signal to your cabinet, it will be like creating an LA traffic jam in your amplifier. Does that sound like a good thing? No. So use an unshielded speaker cable, they’re just as cheap as shielded ¼ inch cables and found in any respectable music store.

If this is all too much to deal with, buy a combo amp. Fact of the matter is, if you want to play electric music, you have to become an electrician. My final piece of advice is this: don’t take chances with your gear. It costs nothing to look up your equipment’s specs in the manual, it costs hundreds of dollars to replace or repair broken amplifiers and speakers. You learn best from failure, so learn from mine. READ THE MANUAL! 

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