Hybrid Amplifiers

[Ron Resnick]

KeithR's amplifier search has reinvigorated interest in the Bascom King-designed PS Audio BHK Signature 300 hybrid tube/MOSFET monaural amplifier.

Using a 6SN7 input tube (rather than the 6922 in the BHK) the Aesthetix Atlas appears to utilize a similar design and achieve a very similar power output level.

Who has compared directly the BHK to the Atlas in a familiar system?

Has anyone compared directly the BHK or the Atlas to the Lamm M2.2?

 

[tima]

The Atlas Signature mono certainly looks impressive on paper.
I wonder if Jim White will do an Eclipse version in mono.

Atlas Mono
Power Output: 300wpc channel into 8, 600wpc into 4
Input Sensitivity: 60mV (1 watt), 3.1V (full power)

Input Impedance: 470K
Output Impedance: .25 at 1kHz
Signal to noise: 120dB
Bandwidth at full power: 4 - 150kHz
Rated THD at full power: <1%
Power consumption: 100 watts at idle
Dimensions: 18"w x 8"h x 19"d
Weight: 70 lbs
Finish: black or silver
Warranty: 3 years, non-transferable

PS Audio BHK Signature 300
@Ready75 Watts
@Idle175 Watts
@Rated power 8?850 Watts
@Rated power 4?1600 Watts Signal
Gain30.5dB +/-0.5dB
Sensitivity for rated output power of 250 watts into 8?1.3V
Noise100-20KHz <-85dBV
Signature 300 mono
Unbalanced 50K?
Balanced 100K?
Output Impedance50Hz, 2.8VRMS <0.1?
Frequency Response@2.8VRMS
10Hz – 20KHz +/- 0.1dB
10Hz – 200KHz +0.1/-3.0dB
21”x 13” x 19”
92 lbs [41.7 kg]


Lamm M2.2
1 6DJ8 /6922/7308 tube
HIGH IMPEDANCE SETTING
minimum continuous sine-wave power, from 20Hz-20KHz with no more than:
0.3% THD (FTC) @ rated line voltage > 220 Watts into 8 Ohms (41 Watts Class A operation).
0.3% THD (FTC) @ rated line voltage > 440 Watts into 4 Ohms (20.5 Watts Class A operation).
0.5% THD (FTC) @ rated line voltage > 700 Watts into 2 Ohms (10.25 Watts Class A operation).
1% THD (FTC) @ rated line voltage > 900 Watts into 1 Ohm (5.125 Watts Class A operation).
LOW IMPEDANCE SETTING
minimum continuous sine-wave power, from 20Hz-20KHz with no more than:
0.3% THD (FTC) @ rated line voltage: 220 Watts into 4 Ohms (41 Watts Class A operation).
0.5% THD (FTC) @ rated line voltage: 440 Watts into 2 Ohms (20.5 Watts Class A operation).
1% THD (FTC) @ rated line voltage: 600 Watts into 1 Ohm (10.25 Watts Class A operation).

Rated Output Power
HIGH IMPEDANCE SETTING
With continuous sine waves from 20Hz-20KHz @ rated line voltage:
59.33 Volts peak into 8 Ohms, corresponding to 440 Watts peak.
59.33 Volts peak into 8 Ohms, corresponding to 440 Watts peak.
52.92 Volts peak into 2 Ohms, corresponding to 1,400 Watts peak.
42.43 Volts peak into 1 Ohm, corresponding to 1,800 Watts peak.
LOW IMPEDANCE SETTING
with continuous sine waves from 20Hz-20KHz @ rated line voltage:
41.96 Volts peak into 4 Ohms, corresponding to 440 Watts peak.
41.96 Volts peak into 2 Ohms, corresponding to 880 Watts peak.
40 Volts peak into 1 Ohm, corresponding to 1,600 Watts peak.

 

[JackD201]

I own M2.2s and an Atlas stereo.

I am biased towards peanut tubes over 6sn7s. There are so many good NOS variants of the 6dj8/6922 family around.

While I have a few pairs of 6SN7s that are supposed to respectable such as some Brimars, GTBs and some Russians gifted by Knut of Valvet, somehow the Atlas always sounded best with the provided stock tubes by a wide margin. With the Lamms it was more a case of different but mostly all good starting with the stock 6H23ns. My faves being Valvo Hollands and Mullard CV2492s.

Yes I wonder if they will have an Eclipse. I had my pre upgraded to Eclipse and boy, better in EVERY WAY. I'll probably have mine done if they come out with an upgrade path.

 

[Gregadd]

I would be remiss if I did not mention Moscode line of hybrid amps. My favorite.
Companies. Like VTL and ATMA -SPHERE show you can have it all with a pure tube design. The same goes with solid state. It all comes at a price. If you want to avoid the massive tube complement and output transformers, hybrids represent an elegant solution at a price you can afford.