Acoustic Control Corporation B4 Collaboration Series Head

average head lots of unuasable features unless you have accessories like tuner an footswitches ,pedals etc

very good punchy tone

caught on fire power stage of amp blew up an shot a foot high flame out the top of amp cost 500us dollars to repair.

loved the amp let me down on stage after turning it on for 30 seconds.

originally i was told it was worth 2000 dollars when new i paid 900 sh an spent 500 getting it repaired.thats 1400 all up ended up selling it for 600 dollars with a built in themal switch an fan modified to it so as that firey problem never happened again.i guess they let the consumer do the research an development.jaco would be rolling in his grave.

The Acoustic model B-4 bass amp was made in 1994. It features a two stage amp for biamping. It has 320 watts for lows and 120 watts for highs, 440 watts total. High and low level inputs, volume, tone, high/low balance, limiter, and a 7 band eq. The back panel has all kinds of hook ups and patches. This is a pro quality amp. Also they made a matching special design biamp cabinet which has an 800 watt 18" speaker for lows and two 8" closed back speakers for highs.

With the eq you can dial in just about any sound that you like, go from a nice warm tube sound to a dirty gritty punk sound "sweet"
The amp has plenty of power but I did find one minor downfall,
you can't bridge the amp so if you want to use all 440 watts you must use a speaker that can be bi-amped or two seperate speakers like an 18" and a 210. I'm using Peavey's 1820 (one 18 and two 10's) and it's plenty loud sounds good too.
I gave it a 9 because the amp can't be bridged.

I've had the amp about a year and no problems as of yet.

Don't hold your breath, they are no longer in business.

Been playing 4 years
Also have an acoustic 126 combo, 100 watts and a fifteen inch folded horn speaker.
The B4 is a nice amp and if you ever find one give it a try you'll like it.

If the amp was stolen I'd look for another or maybe an acoustic 370 which ever came first.
Overall I like this amp and plan on keeping it around for a while.

I'm guessing this amp was made in the mid to late eighty's. It is a bi ampable solid state head with every feature you can think of from built in crossovers to a built in limiter. It even has a built in power strip for powering up a tuner, compressor or effects processor.
One unique feature to this head which I thought was really cool is that the front panel lights up like an automobile dashboard revealing hidden signals such as clipping etc........

The sound this head produces is amazing. It can go from a growling ampeg tone to swr to basically any tone your looking for, there is no limit like most other heads. It is rated 440 watts but seems to be under rated ( it's earth shaking). I've recorded with this head and it amazed me how clean of a signal it puts out ( absolutely no unwanted noises or distortions at any decent level)

This head is can't be killed, it has the best wiring I have ever seen in a bass amp. I've used this head in all conditions for 10 years and never had a single problem.

I DON'T THINK THE COMPANY EXISTS ANYMORE SO I CAN'T RATE THIS CATEGORY. BUT THE HEAD IS SO DEPENDABLE IT DOESN'T EVEN MATTER.

When this head was first produced it retailed for a thousand dollars, which back in the 80's was extremely expensive for a bass head. Now they average about $300-$450. Let me tell you these heads are very rare but if you do find one BUY IT IMMEDIATELY!!!!!!!!!!! It out performs almost every head currently in production.