|This is how we describe our approach to the components
in a no-compromise audio system. No unnecessary frills or emblishments,
but each component in the series does the job that it was designed to do
far far better-since part of its value wasn't frittered away on useless
gimmicks. We don't believe in selling a consumer tone controls which won't
allow him to make an effective correction on frequency unbalanced source
material - because adding them to a preamplifier would mean that we would
have to subtract something from the specification of the preamplifier.
Everything must be paid for, either in money or performance. If frequency
correction must be made, there may also be a need for scratch and or rumble
filtering - and all these functions are provided on our Graphic Equalizer
- and not at the 6 6db/ octave rate found on most preamplifiers but at
a really usefull 18 db and 24 dB octave respectively.
Our SPS preamplifier is the best basic preamplifier we know how to make and where only a single tape recorder is used will handle virtually all of the requirements of an audiophile working with carefully chosen records and tapes -the former played on a normal output level phono cartridge.
Where a low output level moving coil cartridge is used, our DW 535 pre-preamplifier is ideal, preserving the very low distortion characteristics of the moving coil cartridges. While expensive, it does the job without compromise in circuitry which could lower the price but which would be easily audible as lowered definition or a muddy mid range.
As an alternate, and where two tape machines are used, our SPL preamplifier uses a circuit derived from the basic circuit of the SPS, but which requires considerably more circuit board room to ensure proper stability margains at ultrasonic frequencies. It has the DW 535 pre-preamplifier built in, and has a separate low power stereo power amplifier which permits it to drive even electrostatic earphones.
For frequency response corrections on material of musical merit but less than ideal recorded characteristics, our SG Graphic Equalizer is the Black Box of choice, permitting exacting frequency compensation with the ability to filter out scratch or rumble.
|As the user might very well be preserving valuable material
on tape recordings we felt that this was the proper place to bring-out
internal system circuits onto the front panel - as well as their usual
position on the case.
Two items are still missing from our line up, one is a stereo metering unit which we have designated SMP unit - in design at present it will have true VU meters meeting proper balistic specifications combined with a pair of strip-line bar displays which will indicate true peak levels - over a range (unswitched) of 50 dB. The unit will interface with both the SPL and the SG units with front panel source switching.
The second missing item is the Power Amplifier. In the past we have built power amplifiers to order, but have felt that it must be possible to build a unit having total reliability with exceptional performance. We have never made any secret of the fact that as yet we have not found such a unit on the market. We do think, after several false starts that we at least have the circuit and the mechanical packaging system - but the most we will say is that it's in the works.
This brings us to our speakers - which started us in business. It is not generally realized that the very first full range electrostatic speakers manufactured in North America in 1958 were designed by personnel now with this company. However our designs diverged from the mainstream in 1965 so that our full range units are unique in that they have no crossover networks from below 30 Hz to above 15+ kHz - about nine octaves. Thus, with all cells carrying the entire range there is Total Coherence of sound without phase distortion to modify wavefronts, and to introduce coloration.
In spite of this, Patented operating principles allow
our 3rd Generation Speakers to operate at concert-hall levels at reasonable
efficiencies. This is expensive, but we have tried to keep the designs
as simple as possible, paying a premium to obtain components which behave
as close to the ideal as possible. In this respect we feel that we have
solved problems both psycoacoustic and electroacoustic that our competitors
don't even realize that they are going to have to solve.
|Our speakers are now available in two finishes; the internal
design is essentially identical.
One is a distinctive black-cloth belted design, capped top and bottom with rosewood and having a sunken black band bisecting the cabinet around the sides and across the top. Internally, the driver cells are hermetically sealed into a welded steel frame with mylar front and rear diaphragms.
The other is derived from the enclosure used for our Mark
2 and 2A units. This uses a 1/8" thick aluminium extrusion as the case.
It is inert gas welded into an exceptionally rigid frame, and lined with
mastic bonded dampening material. The frame is pebble finished in black
anodizing having a muted sheen which does not fingermark. This style of
cabinet permits units to be stacked in multiple for sound reinforcement
or other professional use. It is admittedly too modern for some environments,
but totally functional.
|Either type of speaker operates from a revised ST-300
A matching unit. We are unique in using a separate matching unit with special
cables and connectors. However in our market, many of the speakers are
used in physical ways, (such as being hung from ceilings) in which an additional
50 lbs of electronics would preclude. The ST-300 A is heavy (over 95 lbs.)
out of necessity, for we use matching transformers which are of a size
that shock our competitors, by keeping core flux densities low we avoid
We don't attempt to design our equipment for everyone.
If you have a feeling that part of the prestige of owning a stereo system
comes from the complexity of the control panel, then you probably wouldn't
be happy with our equipment. But if you're choosing components for what
they don't do to excellent sound source material, then our equipment is
|THE SPS Mk 3 PROFFESSIONAL PREAMPLIFIER
Noted for exceptionally low distortion and ultra high
definition, a state-of-the art device employing discreet semiconductor
augmented integrated circuitry.
|Inputs: Phono 1, Phono 2, Tuner, Aux. 1, Aux. 2, Tape.
Input Sensitivity: Approx. 400 uV for 1.5 v out. (phono) Approx. 600 mV
for 1.5 v out. (high level).
Phono Overload: 105 mV at 1 kHz.
Distortion: Harmonic well under.002% 20 to 10 kHz, @1.5v out. Intermodulation under.002% @ 1.5 v out.
Signal to Noise Ratio: Better than 80 dB referenced to 10 mV on Phono Input.
Frequency Response: High Level ± 1.5 dB from 4 Hz to.7 mHz. RIAA Phono ± .2 db 40 Hz to 20 kHz.
Square Wave Performance: Rise Time: Typically under 950 nanoseconds.
Settling Time: Typically under 1400 nanoseconds 1/2 % error. Overshoot: Well under 1/2 of 1% at 20 kHz.
Controls: Balance, Volume, Input selector push button group, Stereo/stereo reverse, Stereo/Mono, Tape Monitor, Power Switch.
Earphone Provision: Output Jack for medium impedance earphones.
Power Outlets: Three switched, one unswitched.
Dimensions: Faceplate 6" x 6 l/2", case 5" x 5 ½" x 10, Weight 9 lbs.
|THE DW 535 INFRANOISE PREAMPLIFIER
||This is a very low noise low input impedance stereo pre-preamplifier
designed to be used as a pre-preamplifier for moving coil phono cartridges.
It has unexcelled performance with audible superiority in this application.
It is line powered.
Inputs: Low level magnetic, Load Impedance approx. 8.2
ohms; 47 ohms or 100 ohms.
|THE SPL PROFESSIONAL PREAMPLIFIER
A refined and developed SPS type circuit with the addition of an infranoise pre-preamplifier for use with moving coil cartridges, and a low power stereo power amplifier for use with earphones. Also provides more flexibility on tape recorder use.
Inputs: Low Level Magnetic 1,2; Normal Magnetic 1,2; Tuner,
Aux. 1, Aux. 2, Tape 1, Tape 2.
Controls: Balance, Volume, Separate left and right channel controls only for earphone input; Input Selector Pushbutton Tape: Monitor 1, Monitor 2, Tape Dub 1 to 2, 2 to 1;
Stereo/Mono, Stereo/Stereo, Reverse, Left Channel Input only, Right Channel input only; Mute, Earphone on/off, Power on/off.
Earphone Provision: Stereo Power amplifier approx. 2 watts/ channel max for low impedance/medium impedance ear- phones, jacks on front panel dual phono-type connectors on top of case. Power Outlets: 2 switched on main case, 3 switched on transformer case, 1 unswitched on transformer case.
Dimensions: Panel 13"x6 1/2", Case 11" x 5 1/2" x 10",
Trans- former case 4" x 6" x 6". Total weight under 18 lbs.
|THE SG Mk 2 GRAPHIC EQUALIZER
A versatile equalizer/filter unit designed primarily for the correction of frequency response errors in source material.
Connections: Preamplifier input and output; Tape 1 in,
Tape 2 in, Aux 1 in, Aux 2 in, Tape and Aux. inputs brought out on top
of unit using RCA-type Jacks, and on front panel using earphone type jacks.
Tape 1 out, Tape 2 out, Aux. 1 out, Aux. 2 out. Tape and Aux outputs brought
out on top of unit using RCA-type jacks, and on front of unit
H.F. filter at 8 kHz or 11 kHz, 18 db/octave cut off rate (Bessel type filter).
L.F. (Rumble) filter at 25 Hz or 50 Hz, 24 db/octave Tape Monitor 1, 2; Tape Dub 1 to 2, 2 to 1.
Equalizer connection: Normal (cut into preamplifier circuit), Tape 1 to 2, Aux. 1, Aux. 2.
Dimensions: Panel 13" x 6 l/2", Case 11" x 5 1/2"
x 10". Wt.12lbs.
|THE XG-8 Mk 3 SERIES SPEAKER SYSTEM
Now available in two finishes and styles, these units are the third generation series of a design type first manufactured in 1970.They have increased efficiency and reduced distortion as well as low frequency response surpassing most conventional speaker systems. They are sealed against dust and moisture, and are designed for demanding service conditions.
It is difficult to express the performance of these speakers
in specifications, much of the psycoacoustic art used in their design is
apparent only upon listening, and no definitive parameters as yet exist
in this area of perception. As an example, the large radiating area used
results in a very low sound gradient in the listening field of the speaker,
that is there is only a very small level change from the area right in
front of the speaker, to the area at the rear of the average an actual
listening room. This approximates the gradient field in an actual concert
land this absence of "acoustic glare" results in an apparent ability of
the listener's hearing to increase the apparent ability of the listener's
hearing to increase its discrimination between subtle tonal differences,
and do this without listening fatigue. The resultant sound has an effortlessness
which is lost where the sound is projected from 10" diameter holes as in
most speakers. (or 14", or 8" as you will have it). The combination of
a crossover free 9 octave region, the very wide frequency response, and
the excellent high frequency dispersion result in a sound that is closer
to the source in fidelity than ever before achieved.
Input Imperence: The input impedance (contraryto general belief) is quite smooth from 600 Hz through 14kHz being 2.7 ohms ± 0.2 ohms.This median level will rise to approx. 3.8 ohms after 4 months of operation. The anomalies in the impedence response is a 70% rise at 16 kHz (the upper crossover point to the ultrasonic units), a rising characteristic above 25 kHz (approx. 17 ohms at 100 kHz) and a smooth rise below 600 Hz which peaks at about 22 to 40 ohms depending upon room loading at 110 Hz. At low frequencies the impedence does not drop below 8 ohms (even at DC).
Frequency Response: With the necessary qualification that frequency response below 100 Hz will be dependent on its smoothness on room characteristics and speaker placement, it is generally possible to obtain a response lying within ± 4 dB from 30 Hz to 18 kHz. The high frequency response smoothness will be somewhat dependent upon the number and level of room reflections.
Distortion: Generally under .1%, there is a rise above 10 kHz to .3% at 16 kHz, and a rise below 55 Hz to about 2% at 37 Hz, at a level of 85 dB 1 meter on axis. We have found that the most prominent distortion characteristic noticed will be the transient intermodulation distortion characteristics of the power amplifier used. Having tested a number of commercially available power amplifiers we have found that there is far less ringing at square wave inputs (from 5 kHz to 20 kHz) than would be inferred from the trade literature and power amplifier reviews.
Size: Aluminum 1 meter x 1 meter x 24cm.
ST-300 A 10 1/2” H x 19” W x 11” D same
The ST-300 A unit comes complete with 25 foot cables for
each speaker and weights 105 lbs.
DAYTON WRIGHT ASSOCIATES
P.O. BOX 419, THORNHILL, ONTARIO, CANADA L3T 4A2 Phone (416) 884-3244
Please note: The above address and telephone number are no longer valid - they are included as they were on the original!
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