|Wiring your guitar or bass
cabinet incorrectly, or, using a mis-matched combination of cabinet and
tube amplifier; will at best cause excessive wear on your power
tubes, or at worst could result in damage/failure of your tubes, speakers or
Below are parallel, series, parallel/series &
series/parallel configurations for 2-speaker and 4-speaker cabinets. But
1. 4-ohm, 8-ohm or 16-ohm cabinet(s): which is best?
Resistance is measured in Ohms. A 4-ohm cabinet offers less
resistance than a 16-ohm cabinet (allowing more wattage to the
speakers) and is therefore a GREATER load on your amp than the 16-ohm
Up to an amplifier's limit, using a lower ohm cabinet will deliver more
power to your speakers (although not necessarily more volume),
but the trade-off in working your amp harder and
hotter may not be worth it:
When amplifiers suffer shorts in their output power transistors, they
often deliver raw voltage into the speakers, immediately cooking the
voice coils. In my early days of tinkering with electronics, i
destroyed two mint JBL speakers (Earth solid-state power amp) -
the smoke and smell and feeling of horror is something i will probably
That being said: you might be able to get more desirable speaker
distortion by going 4-ohm if you use speakers that facilitate this
(Celestion), and/or you might be able to get a noticeable boost in
volume if you're using speakers that facilitate that (EV). The
bottom line is that you won't really know unless you try (or find
somebody with your amp who has tried it).
Just bear in mind that the difference can sometimes be imperceptibly
subtle. The most dramatic change i've personally experienced
was with a 50-watt Marshall half-stack that i rewired (the cabinet) from
16 to 4 ohms. I did this again a few years later with a different
50-watt Marshall half-stack and none of us could hear any difference at
2. If you purchased your speakers new, or otherwise have access to
the manufacturer's wiring instruction, use it. This seems
like a no-brainer, but it is the case that some manufacturers suggest
different wiring configurations for the same speaker combinations
(number, ohm, watt).
Obviously it wouldn't hurt to wire your 8-ohm
150-watt EV's with the Carvin instruction for their 8-ohm 150-watt
drivers, but it certainly will not help you with your warranty!
3. Don't assume that the operational characteristics of one
amplifier will be the same as (or even similar to) another.
Example 1: You can plug two 16-ohm cabinets into your 1971
Marshall Super Lead by simply setting its Ohm selector to 8 ohms.
But if you want to hook those cabinets up to your 1971 Fender Twin
Reverb you have to rewire them because that amp is hard-wired
for a 4 ohm load.
Example 2: Just about every manufacturer in the world warns you
not to fire up your (tube) amplifier without a cabinet plugged in or you
risk damaging the amp. But you can do just that with an early 90's
VHT UL-100 head because jack #1 shuts down the output when not in use.
4. If at all possible, use the exact same speakers
(brand/ohm/watt) for each cabinet. If you have to mix and match
brands, fine - but both (or all four) of the drivers should have the
same ohm/watt specs!
5. If you want to go louder but fear the risk of blowing your speakers, or, if you just can't
go any louder: you have to add speakers (assuming your amplifier's
power isn't the problem).
A Carvin four-speaker cabinet will facilitate higher volume levels than
a Carvin two-speaker cabinet. Four 25-watt Celestions will
be harder to ruin than two 25-watt Celestions. Etc.