[sdiy] OT: Dynair Mini-Pre ???

[Tony Clark]

   Hi Glen,

> Is anyone familiar with these units? 

   Unfortunately no...

> The back panel has two inputs, one is labeled "lo" and uses a male XLR
> jack. The other is labeled "hi" and uses a female RCA phono jack. The
> output appears to be a balanced output, and makes use of a barrier-style
> terminal strip. That's right, you connect the output cable to screw
> terminals, instead of a jack.

   The terminal strips were actually quite popular on many hi-end studio 
equipment.  Go take a look at any of the vintage Urei or Altec stuff (or 
practically any tube gear from that era.
   As for the inputs, good equipment makers provided two depending on 
what you wanted to connect to it.  One is a Low-Impedance input for 
accepting mics and other studio gear.  The second is a High-Impedance 
input for connecting instruments (such as guitars).
   To check this out, you should be able to take an ohm-meter across the 
inputs.  The balanced input (Lo) should have an impedance of 
approximately 600-1000 ohms.  On some gear the transformer is split so 
that you can either hook it up in balanced or unbalanced modes.
   The Hi input should have something around 40K or higher impedance and 
is an unbalanced input.
   The output should be a split transformer similar to the balanced input 
(allowing you to use it balanced or unbalanced).  The impedance of the 
output should be really low (like less than 10 ohms!).

> The front panel has a toggle switch labeled "power", a neon power indicator
> lamp, a small analog meter, and a rotary-style "level" control.
> 
> I'm not sure if these are old mic preamps, or if they are meant for some
> sort of scientific instrumentation application. I tried searching the
> internet, but didn't come up with very much. The Dynair company seems to
> have either been bought by another company, or perhaps has simply ceased
> operations.

   Sounds like you have a rare gem of a piece of gear there!

   Cheers,

   Tony

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