On 6/18/2014 11:22 AM, Jamie Howarth wrote:
> Yes that tubes are fast, but transformers are not.

Depends on the transformer. Some of the recent devices from Jensen have 
extended bandwidth, out to 100kHz plus.

> David didn't think a 5534 was a good part for the current to voltage
conversion and that the square steps in the feedback loop at 176.4 kHz
(necessary to do the Nyquist filter) were sufficient to drive the
Signetics chip nuts when used in current mode. The 318 was a lot faster,
more like 50v/usec versus 18v, and more stable. It had lousy RF
rejection and power supply noise rejection (we tuned that with small
inductors and rminimized it by egulating right at the chip).

Yes, the 5534 is good for a lot of things, but not for D/A conversion. I 
should have added that disclaimer -- the LM318 was the best thing until 
the 5534 came along, for a lot of applications. For D/A, no.