[Jukebox-list] AMI R145 Amp Modification

[Steve Wahl]

On Thu, Jun 07, 2007 at 10:59:01AM -0500, WHITE, JAMES P wrote:
> Steve,
> The fellow who is helping me could not locate the RIAA EQ.  He
> recommended we start at the grid (pin 2) of the 12AU7 (V2).
> 
> Anyone care to comment on where the RIAA Equalization Circuit is on the
> R-145 amp?

Thanks for the schematic pointer.

There are an awful lot of R/C networks before the point where you plan
to inject the signal.  I'm not a good schematic reader, but I suspect
the stuff around the High Freq Range switch may be the RIAA EQ, or
perhaps the stuff around the fidelity equalizer; maybe both work
together.  So it looks like you may be bypassing the RIAA EQ already.

OOH, Just had a thought:  My F120 manual has a paragraph or two on how
to connect a second amplifier to driver more external speakers.  There
were two options; they differed in what controls still worked on the
second amplifier because the signal was tapped / injected in a
different place.  One of the options also allowed a larger distance
between the two amps, I think.  Those instructions might give you some
insight into what would be a good place to tap into the amp.

Let me know if you can't find this; my manual is at home right now
(and I'm not).

--> Steve
-- 
Steve Wahl    steve at pro-ns.net

There are only 10 kinds of people in this world... those who
understand binary and those who don't.  -- Unknown