[Scott Dorsey]

Dave Plowman (News) wrote:
Mike Rivers wrote:
On 1/22/2015 9:54 AM, Dave Plowman (News) wrote:
Don't all classic ribbons have a built in transformer? If so you'd
expect that to be designed to work best with the normal input
impedance of the day.

"Impedance Of The day" sometimes was directly into the grid of a tube.

Never seen that with a low impedance mic. I'm surprised you could get
enough gain.

Although a step-up transformer was pretty much always used, it was seldom
more than 1:10 and often just a 1:5. You could get 1:20 transformers for
communications applications where trading bandwidth for noise was worthwhile.

As far as I know, the only commercial preamp using a tube front end without
a step-up transformer is one made by Fred Forssell. It uses a long-tailed
pair in a trick circuit and sounds amazingly clean. Noise floor with a low-Z
condenser mike is higher than a Millennium but way better than a Mackie.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."