The mighty Acoustic 360


This is a customer's Acoustic 360/361 system as dropped off for a major overhaul. It is quite an interesting bass amp. The top section is essentially a preamp and the bottom contains a 'W' style folded horn with a Vega 18" driver, and a power amplifier section on the bottom shelf of the open cabinet.

When I received the amplifier, nothing worked. There was no output from the preamp and the amplifier/driver cabinet produced no sound. The preamp had a failed solder connection, but was otherwise worked. Replacing the tantalum capacitors greatly reduced background noise. The power amplifier needed to be rebuilt. What is interesting was that someone had installed a bank of capacitors, viewed through the grillecloth at the top. There were 8 capacitors in parallel, but their combined capacitance was only 4000 uF, and really not doing much for the amplifier. I replaced them with a single 8700 uF can in the original mounting bracket in the bottom mounted amplifier. The cabinet lost about 10 pounds in doing so, which was welcome.

The speaker was torn around it's surround and completely separated from the frame. It was removed and send to Orange County Speaker (speakerrepair.com), where they rebuilt it with an exact match voice coil, cone, and spider.

When it was all complete, this was quite an amazing and loud amplifier, especially considering it only delivers about 200 watts into 4 ohms before clipping begins, though clipping through this amplifier doesn't actually sound too bad. The folded horn cabinet is so efficient it still manages to create very high sound pressure levels. The preamp is labeled to connect to up to four 361 bottom enclosures to create an incredible wall of sound.

Also note the SVT upper chassis on the bench!