Input Transformer

The Casablanca’s are aptly named for their classic good looks and commanding performance. They came about in response to repeated requests by our customers for a single-ended amplifier with the power to drive non-compliant or inefficient speakers. Typically high power single-ended amplifiers are either run in pentode or using exotic power tubes; we opted for a push-pull based amplifier; the larger version of the Stereo 15.

The Casablanca’s provide 60 watts with KT88/6550 power tubes and 45 watts with EL-34s. Based on the Eico circuit and using a 12AX7/6SN7 front end allows access to a vast array of NOS/NIB tubes. The Casablanca’s come with 8ohm and 4ohm taps and can be ordered with 16ohm taps if desired. To provide reliable power and a sweet sound, we turned to our design partners and carefully evaluated two new takes based on similar designs; the Eico HF97 and the Dynaco MKIII. We built both and did a shootout with the reigning king of push-pull amps, the McIntosh MC275.

The results were startling. The Eico based circuit was a definite improvement over our take on the MKIII and was on par with the MC275. The Casablanca’s provided extremely articulate bass, with remarkable mid and high-frequency extension. The bottom line – this amplifier offers the warmth and detail we all expect from a reference level push-pull amplifier and nearly limitless personalization with different tube combinations. The tubes included with purchase are new Tungsol 12AX7, Tungsol 6SN7, and Tungsol 6550s.

What differentiates ampsandsound Casablanca’s from any of the other well-made gear in it's price range? The answer is that there may be few differences, but the differences that do exist are pivotal to our approach to the reproduction of music. First off, many tube amplifiers in the Casablanca’s price range have lower power. Other similar-price amplifiers are stereo amps, not providing the performance and channel separation for which mono-blocks are known.

We chose the Casablanca design to allow for our massive power supply. Also, mono-blocks require 40% more parts, and like all ampsandsound components, the Casablanca’s utilize modern materials to bring a higher level of performance. Including using 1-2% resistors instead of the less costly and more common 10% variety, and coupling capacitors with 5% tolerance instead of 20%. Point-to-point wiring would allow for streamlined building, but our PCB’s provide superior grounding and noise isolation, with the result that we have realized and improved upon the sonic characteristics of the great amplifiers of the 50’s and 60’s.

Input impedance is 475Kohm, 1.6v for full power.
With the inputs shorted, the output noise is 680micro volts RMS.
Maximum Power @ 1kHz = 60 Watts RMS.
One watt Bandwidth is 10 Hz to 35 kHz.
Bandwidth at full power 60watts is 26hz to 18khz.