Vintage Maestro Echoplex model info?

[Simon <simon@dynamite.com.au>]

I'm am going to buy a vintage Maestro Echoplex soon, I am wondering if
there is a web page with information on what models were released, what the
advantages/disadvantages of particular models are, and what models are most
desirable?

Also, a guide to what each model should cost, and any problems to look out,
for would also be helpful.

I was going to find a tube model, I've heard that these have a 'fatter' 
sound.

It would be most appreciated if someone could point me in the direction of
this info, or take a little time to share what you know of these older
Echoplex boxes.


Thanks
Simon
Canberra
AUSTRALIA