wrote in message
oups.com...

First off, there's little question in my mind that tube RIAA stages
can and frequently do deliver superior subjective sound over many solid
state ones. This fits with Hamm et al.

**Prior to ca. 1975, that may have been true. It is no longer the case and
has not been so, for many years. Moreover, ALL tubes have major problems
dealing with such low signal levels, due to the microphonic nature of all
tubes. Transistors make MUCH more sense, in this application.


Secondly, as I indicated before, I think the question of line level
stages is best solved by minimizing the circuit path and the number of
interconnects, i.e. no preamp at all. Tuners, tape machines, and DACs
(whether separate or built in) should be capable of directly driving
most power amps with which they may reasonably be expected to used
(i.e. 1Vpp into any bridging load single ended or +4dBm into 600 ohm
balanced or not) or the stereo amp should have a volume control and
switchable inputs (i.e. a line stage integrated). The preamp should
ideally be an obsolete critter. Especially in an era where so many
"audiophiles" have no analog sources.

**An opinion you get to have. I prefer to keep 2kVA+ power transformers well
away from low level stages, wherever possible.


(A corollary is the "passive preamp", another way of saying a
switchbox and volume control. I am sometimes inclined to think we'd be
better off doing it "telco style"-no, not doggystyling Lily Tomlin, but
putting WECO double jacks on the front and patching them as desired as
is still done in pro audio and even video with 75 ohm BNC cables in
patchbays.)

**Been there, done that. All passive controllers possess their own set of
problems. An active preamp can easily be made to provide essentially zero
distortion, yet provide a 0 Ohm output impedance. A device with a varying
output impedance (ie: a passive controller) is not a real smart idea, when
using long interconnects.


Thirdly and most significantly, I really have come to the conclusion
that whether the phono stage is solid state or tube is less important
than whether-or I should say _how far_-it is located from the
cartridge. Phono stages should be as close as possible as long as they
aren't too close to the table's motor. Putting a good solid state phono
stage in the table itself or immediately outboard, is the way to go. My
next project is going to be a phono stage in a little box using two
stage passive, as opposed to Baxandall, RIAA. If I use a variable lab
supply I can build it so I can use triode tubes or N-channel FETs and
experiment easily (and indeed if I use a 90-volt B+ as recommended with
6DJ8's I could probably just find a suitable FET that will live at that
source voltage.)

And as an aside, what magic mojo does c-j do that a hobbyist couldn't?

**Nothing, I can see. It uses a relay matrix volume control, with Vishay
resistors, capable of 1dB steps. Excellent, low noise power supplies, DC
filaments, etc, etc. Programming a micro to control the volume an input
selection (Also with relays) would be difficult for a hobbyist to organise.
Ditto, the high grade PCBs, isolated from the main chassis. Difficult, but
certainly not impossible.


--
Trevor Wilson
www.rageaudio.com.au