by Ian Bell <ruffrecords@[EMAIL PROTECTED]
>
Oct 12, 2008 at 07:36 PM
John Byrns wrote:
> In article <gco10t$5pn$1@[EMAIL PROTECTED]
>,
> Ian Bell <ruffrecords@[EMAIL PROTECTED]
> wrote:
>
>> John Byrns wrote:
>>> You also mentioned consoles where "Mixing took place using 200 ohm
bridged
>>> T stepped rotary channel faders connected to these transformers and
the
>>> resultant mix fed into another transformer and amplifier." Could you
post
>>> the "pdf" of an RCA mixer that used this approach for comparison?
>> I have put one here:
>>
>> http://www.ianbell.ukfsn.org/data/RCA-76-B2-B4-Console.pdf
>
> Thanks for posting that. One question, you mentioned "200 ohm bridged T
stepped
> rotary channel faders", was that merely an example for illustration, or
does
> this RCA mixer use 200 Ohm faders? I was unable to find the
specifications for
> the faders in the manual you posted, perhaps I didn't look hard enough?
The
> resistor values used in the mixing network suggest to me that the faders
would
> be something like 500 Ohms or thereabouts.
>
I did not see them in that manual either. I supposed they were 200 ohm
from the labelled secondary impedance of the output transformers of the
mic pres. They may not be bridged T in topology but I would expect them
to be constant impedance.
One other thing. In the later console design (with no transformers in
the mix circuit) I could find no HT return connection to the power
supply. They appear to connect it to 'ground' (shown by the earth sign)
at the mic pre input but I cannot find a connection to the HT -ve supply.
Cheers
Ian
