[Bret L]

On Jun 14, 8:16*am, John Stone wrote:
On 6/13/10 4:13 PM, in article
, "Bret L"

wrote:
*A properly updated Marantz 7C is at least the equal of any
commercially available pre today, with the exception of its phono
stage being good really only with a few carts.

What does "properly updated" mean? The stock 7C is decidedly sub par by
today's standards in almost any measurement of specs. *It's basically the
same thing as a pair of Marantz 1's, dating back to the early 50's. It used
a crude half wave unregulated HV power supply, and was loaded with "bumble
bee" caps that are, by now, all leaky as hell. It couldn't drive even
moderately low impedance amps without considerable bass droop. The volume
control didn't track very well and had a tendency to get noisy or fail
altogether. Residual noise in the line stage was high enough to be annoying
with high sensitivity speakers. While it was reasonably well built for the
day, *was nice looking, and had decent tone controls, it also had 50's style
RCA jacks which were horrible.


I would build a modern and better power supply, for starters. In
fact in a commercial product I'd build a chassis like the many
communications equipment mainframes where the PS would be unitized and
either physically bolt to the back of the chassis or could be run
remotely via an umbilical. This beats the CE regulations because the
set is one piece in those markets.

All components would be modern and of good quality.

A stereo stepped attenuator would replace the volume control pots .

Residual line noise would be lower with a better power supply and with
fewer noisy components of course.

An article on this was put forth in Audio Amateur magazine in the
mid-1980s. That was actually the start of American, versus mainly
Oriental, interest in the Marantz 7 (and its impossibly close copy the
McIntosh C22) : people realized how well the old beast worked when
updated.

As far as high output impedance, it's fine with most all tube
amplifiers. If lower output impedance is needed, one refinement would
be to provide for transformers to be added via sockets as was done in
so much commercial gear. This would provide for true balanced 600 ohm
output so it could fit in tho the Real World of pro audio if needed
whilst not inflicting the considerable cost of the transformers on
users not needing them.