On 7/12/2020 5:51 am, Peter W. wrote:
My brother has a very vintage pair of Acoustat speakers driven from what he describes to me as an Acoustech IV pre-amp, distinguished by having phono-jack outputs directly to the speakers. Which have large, heavy, powered boxes attached. After many years of sitting unused, they went silent on him. I suspect the pre-amp, but at-a-distance, I cannot be sure. No, I do not have the model number of the speakers, but they are self-powered, very nearly 2 meters tall, just over 6 feet, There are three fuses on the back, a removable power-cord, an on-off switch, the 1/4" phono jack input and a 5-position treble boost/cut knob. Which should narrow it down.

Question: is that specialized pre-amp required, or would any normal audio pre-amp do?

Thanks in advance!

**I have some familiarity with a few Acoustat models. I am unaware of
any that came with inbuilt power amps, though I guess it is possible
that one or two were. I can tell you that the load presented by most
Acoustats is brutal. Only amplifiers capable of substantial current
ability and unconditional stability should be used. Here is an impedance
graph I ran on an old Acoustat amny years ago:

https://www.rageaudio.com.au/index.php?p=1_12

Check out the dip at 15kHz.


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Trevor Wilson
www.rageaudio.com.au

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