Cary Audio Design CAD 808 User Manual
Page 2
Dear Audiophile Friend:
I would like to take this opportunity to personally thank you for purchasing a Cary Audio
Design Rocket 88 R stereo power amplifier. I have spent many, many hours designing and voicing
this latest iteration of our very popular Rocket 88. In fact, I have had tremendous fun listening to
the new Rocket 88 R during and after the design phase. There are several design projects that
stand out to me in the recent past. The three design projects that immediately come to my
mind are the new CAD-805 10
th
Anniversary Edition single ended triode mono bloc power
amps, the new V12 R stereo power amp and now the new Rocket 88 R. Designing and releasing
the new Rocket 88 R has been a real treat to me and I hope it is for you as well. It combines
our superb Cary Audio Design sound and build quality at a surprisingly modest price. We
believe it is a truly a ‘Best Buy’ stereo vacuum tube power amplifier!
The basic premise I started with on the Rocket 88 R was to develop a truly linear, wide
bandwidth, stereo vacuum tube power amplifier. Also, in direct response to Rocket 88 owner’s
comments about input sensitivity we wanted to ‘harmonize’ the input sensitivity level of the
amplifier to match other components used in an audio system. I was seeking an amplifier design
that would precisely mimic the input signals up stream from the source signals while being more
sensitive. In the design, the front end stage EL-84 tubes are used as current sources for the high
gain 12BZ7 driver stage and phase inverter tubes, with one used for each channel. (12AX7 or
12AY7 tubes may be substituted for the 12BZ7.) The EL-84’s do not do any of the amplification.
They allow the 12BZ7 phase inverters to operate in an equal balanced fashion.
From the first incarnations of this project to the final result it was an intriguing concept, to say
the least. We found that changing the input circuit to accept the ‘12 series’ vacuum tubes caused
a dramatic drop in total harmonic distortion. Overall circuit dynamics and frequency bandwidth
improved with the new driver tubes as well. We have come to the conclusion that the limiting
factor in the previous Rocket 88 design was the 6922 tube we used in the front end stage. The
‘12 series’ tubes certainly fixed that!
I realize you may think I am rambling but I am just so excited about the Rocket 88 R amplifier.
Imagine listening to a compact stereo tube amplifier driving a pair of B &W 801 Nautilus 15”
woofer loudspeakers to thunderous levels in both 30-watt Class A triode and 60-watt Class A/B
ultra-linear pentode mode. Full speaker control with complete coverage of the frequency
extremes is the result of the changes. I just can’t imagine it any better.
Please read the complete operating manual before turning on your amplifier and get ready for
the musical time of your life.
Thank you once again for your interest and continued support for Cary Audio Design.
Dennis J. Had
President
Cary Audio Design