The 25WPT monoblock pushpull triode amplifier is 25 watts of pure triode goodness. The 25WPT tube amplifiers incorporate two total stages with separate power supplies for each stage for more beautiful, natural music. The 25WPT has a tonal balance switch, 4, 8 ohm speaker switching, and a unique 60hz hum balance control to eliminate hum problems. The hum balance control is not your typical filament balance control but a proprietary designed control to minimize, if not eliminate, hum problems caused by internal and outside 60hz loops.
One other huge plus is that the total harmonic distortion (HD) entering the output tubes is less than .05% with an amplifiers output at 25 watts. At that first critical watt out, the distortion is virtually zero. This means the first stage/driver stage produces almost no harmonic distortion (HD) to combine with the output tube's (and output transformer, opt) harmonic distortions.
This is important as the combination of input/driver tube HD and output tubes HD combine to produce higher order distortions. For example, let us say one has a low harmonic drive tube and output tube, each producing only 2nd and 3rd harmonic distortion. Both tube's HD will combine to produce 4th, 6th, and 9th order harmonics. Suddenly we have higher order harmonics.
The lower the 2nd and 3rd HD from the input tube/stage, the lower the amplitude of the 4th, 6th, and 9th harmonics. Another concern is the higher the drive signal required (low Mu, high negative bias on the output tube), the higher the HD from the driver tube.
The EL-156 tube requires little negative bias, is rated 50 watt plate dissapation, and in tests was capable of 65 watts of plate dissapation (75 watts by another individual) without the plate glowing cherry. In the 25ppt amp, we only run each output tube at 65% of maximum.
Frequency Response: 5-80khz (8 ohm) -1db/-3db respectively Power Output per Channel: 25 watts RMS triode, 28 Watts typical clipping Sensitivity: 2.5 vrms (EL156) Bias Output Tubes: Self biasing Input Impedance: 100k ohms Global Feedback: 0 (No frequency dependent musical feedback through a decoupling cap) Total Weight ea.: 27 lbs. (Shipping Wt. 30 lbs) No. of Stages per Channel: 2 Driver Tube: JJ E88cc triode (approx 1/8 the distortion of NOS 6sn7) Output Tubes: KT88 (Triode Operation) Driver Stage Distortion: 0.05% THD (at 25 watts output) Total Harmonic Distortion Amp: typical 0.05% at 1 watt Total Harmonic Distortion Amp: typical 0.7% at 25 watts Power Requirements: 120vac 60hz Dimensions per Chassis: Width: 17" (approx 429mm) (Tubes sent separately) Depth: 14" (approx 354mm) Height: 9" (approx 228mm) Monoblocks only: Wholesale Price ea. 25WPT: Continental USA shipping included. Outside USA, check on shipping charges.
Tubes must be installed upon delivery. Plug output tubes in either socket. E88cc into its own socket.
30 day money back guarantee, excluding shipping. Warranty, 5 years labor and parts from date of purchase, and 1 year on small signal tubes. 90 days on output tubes.Guarantee, Return Policy on Tube amplifiers:
Simply use a Paypal account or Credit card thru Paypal. Use email@example.com as the email address. Or send a Personal Check, Cashiers Check or Postal Money Order (US dollars) payable to SAS Audio Labs. Please allow sufficient time for such to clear. No refund will be issued if the bottom plate seals are disturbed, scratches or alterations. The audio amplifiers must be returned in new double boxes/materials and must be fully insured for the purchase value when shipped. Prices subject to change without notice.
Danger! Vacuum tubes get very hot during operation and thus precautions should be taken so that children do not come in contact with the tube amplifiers.Design and parts subject to change without notice.