Multiply by two for monoblocks. 195 wpc McAllister OTL amplifier from Canada. 16 sweep tubes/channel.
An innovative new design offering superb efficiency and reliability with a continuous output of 195 watts per channel using 16 sweep tubes per mono block in the output stage.
OTL’s ( no output transformer ) have the potential to produce lots of power with clean effortless sound and most important, very musical but also have a number of problems that have to be over come;
Inability to drive low impedance loads.
Numerous adjustments to keep internal signal balance.
Shortened output tube life
D.C. offset voltage; in fact some manufactures use large capacitance in series with the output tubes and speaker load to eliminate D.C. Any time large electrolytic capacitance is used in the signal path performance suffers.
Reliability
With this in mind I designed an OTL that overcomes all these issues- the original prototype designed 10 years ago is used in my personal home as the main amplification and still has the original output tubes.
Completely balanced from input to output with only three user adjustments required and internal balance that is not dependent on tube emissions. The ability to properly drive 4 ohm load impedances. No electrolytics in the signal path and horizontal sweep tubes in the output stage that have lower second and 4 th harmonics, pass lots of current and are extremely reliable compared to the standard array of audio tubes. A very unique circuit that tracks the signal level in the driver stage and modulates the control grids of the output tubes. This gives superb efficiency as a super cathode follower and at low to moderate signal levels the output tubes are only operating at 1/3 of their plate dissipation. In addition the idle switch on the front panel reduces the operating current in the output stage to a fraction of the sum- a great standby feature. The OTL-195 using no output transformers with superb reliability, low output impedance, directly coupled is the best amplifier that I have designed and is distinguished from all other amplifier designs with a magical musical sound.
Build Features:
Only film capacitors in the signal path
Hardwired point to point
Proprietary input and driver stage design directly connected to the output
195 watts per channel
Balanced outputs
Balanced and unbalanced inputs
Simple bias check / adjustment
Frequency response 0.2dB 10Hz to 80kHz
THD 0.08% @ 5 Watt
0.3% @50 Watt
0.31% @150 Watt
0.36% @ 195 Watt
Output impedance 0.5 ohm
Unbalanced input 1.7 Vrms for full output
Balanced input 2x 0.85 Vrms for full output
Thermal delay to prevent cathode stripping
Simple bias check / adjustment
Separate Dual Mono power supply14”W x 12”D
Mono blocks finished in hand rubbed curly Maple
Dimensions:16”W x26”D 35LBS each
Build Options:
240 volt configuration available on request
LED colour choices for power on and operation status
Maple, Cherry, Oak or Paduke ( similar to mahogany) wood choices
Pricing: OTL 195 $8895.00
Oh brings up memories of the old Futtermans. Great when they worked which was often enough!
