This amplifier has been in storage for at least five years. I’m assuming the top was removed to repair the broken fuse holder but it was never repaired. I have the top but not the mounting screws. I know nothing about this amplifier except what I found while trying to research it. I will copy and paste what I found below. It’s a lot to read but informative. Thanks for looking and check my other listings for more vintage audio and collectibles. I will include an eight foot custom built power cable that is the same vintage as the amp. If you check the pictures I put up you will see the power cable itself cost way more than I’m asking for this listing. It was just pointed out to me that I had no pictures of the front side of the unit so I added it to the pictures. I have since found the front panel with the handles mounted. See the last pictures. It looks like sonogy is making a comeback. There is a new site at sonogyresearch.com to announce upcoming products and there is a history from the original company.
This amplifier was originally made by Allego Audio Designs here in NJ before the name changed to Sonogy. This is thought to be a modified version of the very unusual Rappaport AMP-1. Perhaps the Cantata was an attempt to make the AMP-1 a more stable and robust design
from . . . .
New Jersey Audio Society 1992
THE SONOGY CANTATA
by Russ Novak
A spiritual heir to the Rappaport AMP-1 and an affordable one-step up amp which successfully competes with higher priced amps for quality of sound. That is what you get with the Cantata amplifier from Sonogy Ltd. (formerly Allegro audio designs, inc.).
Audiophiles sitting with basic amps, say, 10 years old, who are looking to step up their systems are faced with questions of how much to spend on an amp to get significantly better sound. On one hand the progress achieved over 10 years should have brought better sound, but to what extent has inflation diminished the value of today's dollar? Would yesterday's $500 amp now cost $1000 (probably) for no better sound?
The only way to approach this problem is pragmatically, by auditioning the amps out there against your old unit. I suggest that a good starting price point would be the $2000 range, and I suggest that you seriously consider a Cantata.
The amp is an 85 watt per channel, zero negative feedback design. Sonogy feels that negative feedback has been used by designers as an easy and cheap way to stabilize circuits and lower rated distortion levels. A piece of the output is fed back to the input, and the differences "compared" and "corrected". Large negative feedback was identified early in the history of high-end audio as being a contributor to poor sound. This is because an output fed back to an input inherently produces time and phase errors.
The Rappaport AMP-1 was a first attempt to make a modern amp with zero feedback. It failed in the marketplace because poor execution led to an unstable component. Octave Research then took up the Crudgel and produced an amp that was well reviewed for its sound, but the company did not make it financially.
Grant Lenahan, who worked for Octave, kept the faith, and along with Izzy Marrone, and Octave Owner and New jersey Audio Society member, began Sonogy Ltd.. Their first product is a direct descendant of the purist philosophy of zero negative feedback.
It's a plain old black amp of average size and weight, with an on/off LED switch on the front and enough room on the back between input and output jacks to work comfortably with stiff cables. Sonogy uses polypropolene caps, metal film resistors, Tiffany RCA jacks, and other quality parts. It uses 8 bipolar output transistors per side and runs in high bias class AB mode. The zero negative feedback features is achieved by using a DC servo in the output stage which operates below 1 Hz, which means it is virtually always out of the circuit.
Izzy claims that the amp was designed by ear, i.e. that each component part and design option was listened to before committing it to the circuit board. For example, when queried on the lack of power supply regulation, Izzy claimed that you could hear regulation and that the music sounded more natural with a hefty, but unregulated supply. The slogan for the Cantata is "the delicacy of tubes", which gives you an idea of how choices were made.
The Cantata can be used for mono operation and balanced operation, with a commensurate power increase to 340 watts/channel simply by using a balanced interconnect from the preamp output or by using two pairs of unbalanced cables from inverted and non-inverted preamp outputs. Strapping circuitry is avoided in this design along with the inherent increase in distortion. How many times have you heard that an amp sounds better in stereo than in mono? That's the reason.
The input stage amplifies voltage only (for 26 dB of gain) while the output stage dumps current only. Sonogy feels that this is one of the major design features which affects the sound and when I asked why they couldn't give us a few more watts for the buck, Izzy replied that they'd have to muck up this scheme and compromise the sound. He correctly pointed out that 100 watts (into 8 ohms, 200 w/ch into 4 ohms) is virtually the same as 125 or 150 anyway - not worth changing the sound for.
The system I auditioned it on was (front to back) a Sumiko Blue Point cartridge on a well tempered arm on a VPI turntable, an Audio Research SP-9 preamp, MIT 330 and 750 interconnects and speaker cables, and Mirage M1 speakers. Also used was a Musical Concepts modified Philips CD player with the latest "Crown" chips. Also on hand was my modified Amber and another amp selling for $4.5 K.
Later I used a "passive pre-amp" which presents no POT or stepped attenuator to the signal, only a 10k metal film resistor per channel. This was used with the above system and also at Bill Donnally's house with his Sound Lab A1 electrostatic speakers.
Since the unit I auditioned was not fresh off the assembly line, and had been well broken in, I gave it only a day of burn-in before beginning my listening. The unit sounds rich without the mirkiness in the midbass I have gotten with tube amps driving the Mirages. In this system therefore, it had some of the advantages of tubes, without the main disadvantage.
The sound is very creamy. Notes appear to emerge from a darker background than with the Amber. Transients are better unraveled and are never jarring. The amp has less in the presence range (around 3-5 khz) than the Amber. This could be easily heard in the difference of emphasis on the surface noise of records as amps were changed.
All of these units are acceptable in this regard, but it means that the Sonogy will make an especially synergistic match with speakers that are fast, slightly bright, slightly forward in presentation. But that is what matching the component to the system is all about. You must listen for yourself.
The bass is warm but transparent, although there is somewhat less extension in the bottom octave than with the other two amps. The midrange is rich and very musical. This amp has the ability to separate instruments well. On Bridge: The Sea (EMI ASD 3190) solo instruments were separated better from the massed strings instead of seeming part of the glut. Stridency was tamed and the strings were presented smoothly. The record was a very enjoyable experience through this amp.
Dynamics are slightly restrained. Not in the sense that the amp can't go low with strength (it can), but in the inter- instrumental sense: the rise and fall of the sections against each other. This is not a problem with classical music which is generally genteel in presentation, but can be heard with the forwardness and gut-bucket dynamics needed for rock music. Pink Floyd's The Wall (Columbia cd C2K 36183) was better served by the Amber.
To be fair, I believe that the somewhat power hungry M1s perform best with high power, high current designs. Two Cantatas set up in the balanced configuration performed very well at a meeting of the Gotham City Audio Society in my home. They presented a seamless, lush, sound
which was generally appreciated by the group. The bass remained warm, which emphasizes the need for every audiophile to do careful system matching.
Soundstage. Its good. I am now using my mirages about 6' from the front wall, 2' from the side walls, and I sit about 7' away from the speakers. With the Cantata, the soundstage fills up the rear of the room almost to the corners. The sounds furthest away seem to come from the fire escape (this is Brooklyn, after all), about 8' in back of the speaker.
The Amber, by contrast, presents a trapezoid shaped stage: only as wide as the speakers in the front and narrowing to about 4' of centerfill in the rear. With the Amber, instruments are presented right at the face of the speaker, whereas with the Cantata even forward sounds appear to come from a space about 1' in back of the speaker.
Specificity of instrument placement is good, though the $4.5k amp is a clear winner here. Centerfill is good.
So what have we got? An amp which is a bargain at the $2,000. asking price. The Cantata gives a rich sound, throws a good soundstage, and is more transparent than your basic amp. System match to neutral to bright speaker/room combinations. You may also be interested in sending for their white paper on Negative Feedback in Audio Components.
-Russ Novak
The preceding review was printed in its entirety with only underlining added to highlight comments. Opinions are those of the author; typos and errors are likely added by us.
Our thanks to Russ Novak for taking the time and effort to review the Cantata and write this review, and to the New Jersey Audio Society for publishing the review in the December, 1991 issue of the NJAS Journal.
Membership and subscription information are available from NJAS at RD2, Box 69D, Miller Drive, Boonton, NJ 07005.
SonogyTM "The delicacy of tubes.
The authority of transistors."
- Sonogy, Ltd. • 53 Briarwood Road • Florham Park, New Jersey • 07932 • tel: (973) 301-0685 • fax (973) 377-3661