"Sander deWaal" wrote in message
news
"Robert Morein" said:

Don't let the Yamaha haters give you any crap. The C- series is well
designed and very reliable.

I use a couple. It's a great preamp if you know how to solder, but there
are
two considerations:
1. The circuit boards are single sided epoxy paper. The solder connections
holding the relays on the board develop cracks from the vibration of the
relay action. The units can always be repaired by resolding them, but this
is a definite design weakness. On the plus side, these preamps actually
have
a balanced output, supplying both normal and inverted phase. The output
impedance is the lowest I've ever seen, around 15 ohms.


I've serviced many Yamaha (pre)amps, and other brands as well, but the
relay problems you describe here don't sound familiar to me.

Maybe it has something to do with my silly habit of resoldering PCBs
entirely, regardless of the problem they came in with :-)

Well sure. That is an unusual habit. But single sided boards, without plated
through eyelets, tend to develop problems. With Sony stuff, it's the RCA
jacks. With Yamaha, it is the relays. Sander, surely you've noticed the
tactile "clunk" when a Yamaha relay latches? Tin lead fatigues very easily
from vibration.


2. The analog power supply is cooled via vents on the top of the cabinet.
This area of the preamp runs extremely hot. These vents must not be
obscured
by stacking, or very expensive repairs will be required. Even so, the
board
tends to brown in this area.


Resoldering of the drivers, resistors, and power supply regulator
transistors is a prerequisite, not just with Yamaha.

In general, I found it to be nice and reliable gear.

That has been my experience also. I have found the full, though 2-band,
parametric equalizer very useful. The inverted outputs can be used to bridge
amplifiers that do not contain internal bridging circuits. The sound is
second to none, in my solid state world .