[time-nuts] Extron ADA 6 as 1/5/10 MHz DA
Charles P. Steinmetz
charles_steinmetz at lavabit.com
Wed May 22 18:30:14 EDT 2013
What I have been referring to as the "plain ADA 6" is properly known
as the ADA 6 Component:
<www.extron.com/download/files/userman/ADA6ComponentB.pdf>
Judging from the dates on some of Extron's documents, it appears to
be a newer model than the ADA 6 300 series -- which is consistent
with Bruce's comment that his ADA 6 300MX had through-hole
resistors. Accordingly, it is possible that the ADA 6 300 models do
not share the circuit I attached to my last e-mail. As always, use
due diligence!
Best regards,
Charles
>Following the recent discussion of using the Extron ADA 6 as a
>distribution amplifier for 1/5/10 MHz reference signals, I dug out
>the schematic of the amplifiers and typed up my notes re:
>modifications (see attached).
>
>Note that the ones I have are "plain" ADA 6's, not "MX" or
>"MX-HV." I do not know if the MX or MX-HV units use this circuit
>or, if they do, if the component numbers are the same. However, the
>gain-switching circuitry is present on the "plain" ADA 6 PC cards
>(but the switch itself is not), which leads me to believe that at
>least the MX version was built with this same card.
>
>There may be other Extron video DAs that use this circuit -- in
>particular, models that have a PC card parallel to the rear panel
>and mounted to it by the BNC connectors may do so.
>
>There is another, discrete design that Extron apparently produced at
>the same time, one example of which is the ADA 3 180. This design
>cannot drive 50 ohm loads to +13dBm (1 Vrms) without severe
>distortion (negative peak clipping), so you need to attenuate the
>typical 1 Vrms input signal 6 dB to stay out of
>clipping. Unfortunately, there is no easy way to modify this design
>to drive +13dBm into 50 ohms (and, IMO, there is a lot not to like
>about it for any use, including RGB video). I have a schematic of
>that circuit, too, if anyone needs it.
>
>Best regards,
>
>Charles
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