ADA PTM-6150 * Six Channel * Power AmplifierVery Good condition with minimal wear. Some smudges, light scratches on the top from rack mounting or stacking components. This amp sounds absolutely stunning. Excellent dynamics, soundstaging, etc....The PTM-6150's output stage reportedly runs in class A operation up to 50 Wpc before switching to class A_B. What this means to you is that you get pure, audiophile quality sound not found in your typical home theater gear....especially for my asking price! Designed by Albert G. Langella, ADA's award winning senior engineer, the PTM-6150 provides over 1500 Watts total power and will efficiently power all six home theater speakers. Rated the best multi-channel amplifier by Home Theater Technology Magazine, the PTM-6150 is the complete solution for any size home theater and is perhaps one of the finest values in home theater. The PTM-6150 is a six channel home theater amplifier, engineered for the stringent demands of a Lucasfilm Home THX® System. Power, derived from a 1500 Watt toroidal transformer, is distributed evenly to all six home theater speakers. Over 1_4 Farad of capacitance provides the power reservoir for the most dramatic cinematic effects. As with all other ADA A_V equipment, the PTM-6150 is constructed from professional components, specially selected for long-life durability. Utilizing a low-noise fan and custom heat-sink design, the PTM-6150 is force-air cooled to maintain even thermal loads on the FET amplification modules. The chassis is constructed from 1_8 inch thick aluminum. Banana pin speaker connectors, included with the amplifier, make for a solid and secure connection of all types of speaker wire. Sonically, the PTM-6150 provides warm, wonderfully smooth sound with high-current, FET-type power output. The amplifier operates as an A-A_B class amplifier delivering over 300W class A. All of this in a single chassis design. Inputs_Outputs 6 Matched Inputs (RCA) & Outputs (Banana Pin)
THD @ 1KHz, 1W, 8 Ohm 0.006%
S_N Ratio @ 1KHz, A Wtd. -99.05 dBr =_- .15
Input Sensitivity 0.23 dBr +_- .02
Input Impedance 10K Ohm
Output Impedance 2-8 Ohm
Continuous Voltage @ 1KHz 30.9 V, =_- 0.1
Crosstalk @ 1KHz -87.5 dBr
Class of Operation A-A_B
Frequency Response 20 Hz - 20,000 Hz, =_- 0.3 dB
Continuous Avg. Watts_Ch 150 Watts @ 8 Ohm, 250 Watts @ 4 Ohm (Individual)
Size & Weight 5.25"H x 19"W x 16"D, 65 lbs (Shipping Weight)
AC Power 120V, 60Hz, 1500W - 220V, 50Hz, 1500W
Excerpts From the Summer 96 Issue of Stereophile's Guide To Home Theater By Robert Hartley Although the name Audio Design Associates (ADA) may be unfamiliar to many audiophiles, the company has been designing and manufacturing audio products for more than 20 years. ADA has largely focused on multiroom systems, custom installation, and (since 1990) the burgeoning home-theater market. The company makes more than 200 products, ranging from sophisticated multiroom audio distribution control systems to the $29,000, gold-plated (I kid you not), Olympus III tube-based surround processor to the PTM-6150 6 channel THX-certified power amplifier reviewed here. The amplifier looks like it means business. The industrial look is heightened by front panel handles and rackmounting holes. ADA makes another line of home-theater products, called the "Select series," that features nicer cosmetics. The PTM-6150 Select is identical in internal construction to the PTM-6150, but has a rounded faceplate rather than rack-mount handles. A large output-power display consumes nearly the entire front panel. Six rows of wide LEDs flash to indicate the PTM-6150's output power, although no scale is included on the meters. When multiple channels are playing, the amplifier provides quite a light show. Fortunately, the display can be turned off so it doesn't distract from watching movies. The rear panel holds six RCA input jacks and six pairs of banana jacks for loudspeaker cable connection. If your loudspeaker cables have spade lugs, you'll need adapters to use them with the PTM-6150 (I used Monster Cable X-Terminators). Binding posts would have been a better choice for loudspeaker output terminals, in my view. The PTM-6150 is designed and handbuilt in-house at ADA's New York factory. The unit features a massive (1.5 kVA) power transformer and a whopping 250,000 micro-Farad of filter capacitance. This huge power supply suggests the PTM-615O should have no trouble driving low-impedance loudspeakers. ADA claims the PTM-6150 is stable into a 2 Ohm load. The all-discrete input and driver stages are made from matched transistor pairs. Six power MOSFET output devices per channel drive the loudspeakers. These are bolted to a massive, custom-made heatsink that consumes a big chunk of the chassis's interior. The V-Shaped heatsink is flanked by a large round vent on one side of the chassis and a cooling fan on the other. With a total of 36 output transistors, getting excess heat out of the amplifier is an important design element. The PTM-6150's six output transistors per channel and huge heatsink suggest the PTM-6150 can deliver lots of current to the loudspeakers. For contrast, the Marantz MA500 and Denon POA-8200 and POA-8300 THX amplifiers reviewed elsewhere in this issue use four output devices per channel. The PTM-6150's output stage reportedly runs in class A operation up to 50 Wpc before switching to class A_B. Class A amplifiers tend to sound better than class A_B, but they generate more heat. Some clarification of the PTM-6150's output power and class A operation is in order. The 150 Wpc continuous rating is with one channel driven at a time, not with multiple channels driven simultaneously. Moreover, no distortion figure is provided at full output power, and the bandwidth isn't specified. judging by how cool the PTM-6150 runs at idle, it's hard to believe that it's biased so that six channels are running in class A at 5OW each. A class A amplifier generates as much heat at idle as it does at full power. Given 300 watts of class A power, an amp should produce lots more heat than I felt from the PTM-6150. System and setup The PTM-6150 saw action in my home-theater room driving the Infinity Compositions system. The Compositions front speakers feature an integral powered woofer and extremely high (96 dB) sensitivity; the PTM-6150 drove them without even breathing hard. [A complete review of the Compositions system can be found in our Fall 1995 issue, VoL 1, No. 2-Ed.] For a tougher challenge, I connected the PTM-6150 to the current-hungry Avalon Radian HC loudspeakers in my separate music-listening room. Source components included the reference-quality Mark Levinson No. 30 CD transport, Spectral SDR-2000 Pro digital processor, and MIT cables and interconnects. Back in the hometheater room, I used a Sony MDP-600 LD player (with an Audio Alchemy DTI V2 jitter filter and DDE V3 digital processor), a Yamaha CDV-W901 AC-3 LD player, and Marantz AV600 and Denon AVP-8000 A_V preamplifier_tuners. A Sony KPR-46XBR 46inch rear-projection TV provided video monitoring. Cables were Monster MC3F FIT across the front loudspeakers and Monster SuperFlat on the surrounds. In the music room powering the Avalon loudspeakers, the ADA amp showed high output-current ability. The PTM-6150 drove the Radians to loud listening levels without strain. At levels a little louder than what's comfortable, the PTM-6150's meters pegged on the highest peaks, but this wasn't accompanied by audible clipping. The PTM-6150 depth and space were excellent. The PTM-6150's slightly warm midbass was an asset when playing film soundtracks, adding some weight, power, and warmth to the presentation. The slightly forward character produced a more vivid, immediate, and incisive rendering, which I found more exciting and involving on movie soundtracks than the subtler Marantz and Denon amplifiers. The PTM-6150's sound was big, dynamic, and effortless. I got the feeling that its output muscle could drive six low-impedance loudspeakers to any sane listening level without running out of power. When driving the highsensitivity Compositions, the PTM-6150 didn't even get warm. Conclusion The ADA PTM-6150 is a rugged, well made 6 channel amplifier that should work well in a wide range of hometheater systems. The amplifier was at home reproducing the impact and vividness of video soundtracks. Powering a hometheater system, the PTM-6150 had tremendous dynamics, a big and open soundstage, and a heightened sense of presence and power. Comments: The frequency response, signal_noise ratio, distortion, and crosstalk results were all excellent.
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