Q: You have a bit of a reputation as being someone who listens to, by typical audiophile notions, a very diverse selection of recordings. Why is that?
A:
Part of the answer lies in something we spoke about earlier. One of the
saddest aspects of the high end audio community is the fact that so many listen
to such a small, select group of recordings. Cello products like the Audio Suite
allow for whatever source recordings might be preserved upon. The modular inputs
guarantee that whether you listen to CDs, LPs, reel-to-reel tapes, radio, video
tapes, audio cassettes, whatever, you can listen to them in the best possible
manner. Similarly, the Audio Palette allows listeners to correct for tonal imbalance
in the majority of commercially available recordings. Mono, stereo, and now with
the introduction of the Cello Rhapsody amplifier, multi-channel recordings can
be enjoyed fully as well.So, philosophically, Cello products have always allowed for the inclusion of the widest range of formats and recordings.
My
intention is to demonstrate that wherever your musical interests lie, choosing
Cello products will allow you to achieve greater satisfaction than would otherwise
be possible. The main point is that the things I listen to, are the things I imagine
most people would be interested in listening to. If I can encourage those listening
to this kind of music, the popular music of our time, to hear how well it can
be reproduced with great equipment, then there will be a much larger pool potential
Cello owners than there would be otherwise. If high-end consumer electronics companies
in the 21st century only reach out to those who listen to approved audiophile-type
recordings, then they're limiting there potential. With the ever increasing venues
for people to be entertained at home, there are more and more people listening
and watching to all types of software. The great majority of people believe, as
I said earlier, that what they listen to would not benefit from being reproduced
by better equipment...and even if it did, they believe they couldn't hear the
difference...or it wouldn't matter to them. To bring the joy of listening to music,
or watching movies, or sports, or Music Television, or playing video games, in
the best sound possible within the limits of what technology and human imagination
allow, to this greater pool of people who would consider owning Cello equipment,
is the big challenge for Matthew James.Q: Let's talk a bit about your first new product from Matthew James, the Cello Rhapsody amplifier. What are the things that you have tried to achieve with it?
A: I think it is a little bit dull to talk about the purely technical aspects. I don't know how many people will be interested in knowing that the Rhapsody amplifier utilizes a dual-monolithic J-FET input stage, or that it has a low negative feedback factor. I'm sure there are any number of amplifiers that contain these same design aspects, which sound very little like the Rhapsody.
The
primary design criteria for the Rhapsody has been to produce an amplifier capable
of delivering sound that is as neutral as possible while remaining stable under
all conditions likely to be encountered in the home listening environment. Again,
I can imagine any number of brands developing products with this goal in mind.What is probably interesting about our approach to the development of new products is how we approached the design of new products at Matthew James. It probably will also help explain why it has taken Matthew James so long to bring our first product to market.
In the summer of 2000, we set out to build all of the electronic products that were ever designed and manufactured by Cello, Ltd. and to determine what exactly it was about those products' sound that we liked or disliked. After gathering together all of the documentation that was available, we had every one of the products built in as many iterations as there was documentation that would support the building of a complete unit. For example, we built as many as 4 completely different versions of the Encore preamplifier, 3 unique Audio Palettes, 4 different Master Supplies, and on and on throughout the line, studying closely what it was that gave each it's own sonic signature.
And
so, getting back to the Rhapsody, whatever the path chosen, the input stage of
the Rhapsody amplifier remains under control under any overload condition. The
design tactics were chosen because they provide wide dynamic range and provide
a greater measure of resistance to overload, before loss of control, than other
possible choices.Many amplifiers utilize some form of soft-clip circuitry to deal with overload. The problem is that many of these approaches introduce additional forms of distortion before the actual overload threshold is reached. Furthermore, most designs to control overload are not comprehensive in dealing with all of the situations that negatively affect an amplifier's ability to remain stable under demanding situations. They might only control voltage overload, while current and frequency overloads also have a significant impact upon the reproduced sound. The Rhapsody has been designed to control all three forms of overload under all conditions.
Furthermore, the Rhapsody is designed to have the lowest possible levels of distortion while under actual use, as opposed to measuring well simply on a test bench. The circuitry is designed to perform well under the complex resistive, reactive and regenerative loading which loudspeakers present to an amplifier. And again, it does so without adding additional forms of distortion before the overload threshold is reached. The design approach has been to place importance on the requirements of actual music and film sound reproduction.
Considerable
effort has been made to reduce low frequency errors, because most of the energy
in music and film sound reproduction is present in this part of the frequency
spectrum. It is crucial, in order to maintain and improve upon the type of musical
performance Cello has come to be famous for, to maintain low intermodulation distortion
of low level, high frequency information in the presence of large low- and mid-frequency
signals under complex loading. In the Rhapsody, the driver and output stages are
set to have the lowest distortion at small signal levels and to gradually increase
with signal level. While this results in slightly higher total harmonic distortion
(THD) measurements at full power levels, it conversely allows for the lowest possible
distortion under actual listening conditions. Again, the requirements for accurate
music and film sound reproduction have taken precedence in all design decisions.
The
output stage of the Rhapsody employs six pairs of 250 watt, metal case, bipolar
output devices per channel. The number and type of devices were chosen because
they remain stable with a less complex circuit, requiring less negative feedback,
and are easier to match to each other than other possible choices for this stage.
The choice of devices, the location of devices on the heat sinks, and the heat
sinks themselves, were carefully considered to minimize the temperature variations
among the output devices. The power devices are mounted with all metal hardware,
compression washers and special graphite and metal composite gaskets to insure
maximum thermal conductivity and full utilization of the output devices. Once
again, consistent performance, stability and reliability under normal conditions
of actual use were the driving factors in the design.The location of the transformer was carefully considered relative to the other circuitry in the amplifier that can be affected by the magnetic fields that it generates. Heavy nickel plated copper buss bars have been utilized to improve grounding and power distribution within the amplifier. The signal from the amplifier's audio channels is delivered to the speaker buss bars via flat silver cables (AWG 10) insulated with Kapton. Special high temperature filter capacitors, with high current terminals are used to insure the utmost in performance.
Another
first for a Cello product is the inclusion of high quality XLR connectors for
balanced operation. An on-board microprocessor controls both protection from overheating,
shorted speaker cables, DC offset and over-voltage as well as certain "house-keeping"
functions like diagnostics, soft-start and muting. Also, for the first time in
a Cello product, there is the inclusion of a remote turn-on trigger, simplifying
placement considerations in all types of installations.The chassis is manufactured with machined, heavy aluminum plates on all sides. Three specially designed feet eliminate the possibility of surface-borne disruptions from affecting the performance of the circuitry.
The feet, developed by Matthew James, are made from hardened stainless steel that has been treated with a low-temperature multi-state process of electrocoating based upon chrome plating technology. The process involves cleaning and removing the matrix on the metals surface by chemical and mechanical means. The proprietary process causes the metallic elements to permeate the pores of the metal, actually becoming a part of the metal itself, and insuring a positive lasting bond with the basis metal. The feet reduce the broadband intermodulation distortion generated when the amplifier is moved however slightly, and is effective down to a frequency of Less than .5Hz. They are located at specific points under the amplifier to maximize their effectiveness at isolating the Rhapsody from its environment and allowing performance to be unhampered by whatever is going on around and below it.
The
Cello Rhapsody amplifier is available either as a two-channel or as a three-channel
amplifier (delivering 200 w/ch into an 8-ohm load in either version). The two
channel version can be bridged into a mono amplifier (delivering 800 w/ch into
an 8-ohm load).While I'd much rather be listening to the Rhapsody, I hope that you can come to understand, from this exhaustive explanation of what we have incorporated into it's design, just how completely it has been conceived and engineered by a wide range of individuals and affiliated companies, far beyond anything that could have been considered by any individual, or even a team employed by a single company.
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Matthew James
84 Long Hill Road Middlefield, Connecticut 06455 USA 860 349-5999 Fax 860 349-0579 Email - jimm@matthew-james.net |