Ultravalve Vacuum Tube Amplifier

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  • Regular price $1,599.00


The Ultravalve is our lovely looking and playing pure tube amplifier with a polished stainless steel chassis and a silver anodized faceplate.

The great grandmother of the Ultravalve amplifier is the original Dynaco ST-70, no big surprise. We started taking a close engineering look at the ST-70 in the 1970s and were able to identify several design weaknesses that could be fixed at a rational cost. These included getting the bandwidths of the power supply, audio circuits, and input acceptance into the right set of ratios so that no input signal short of output clipping could drive the unit into gross distortion at any frequency. This made the feedback loop's job much easier and the whole amp cleaned up a lot. We also added a solid reference to the screen grid resistor and achieved even better stability.

Later, we came up with some unique, successful power supply design ideas which we first implemented in other products. Learning more, we incorporated these concepts into a brand new design, the Ultravalve.

To offer you a unique high quality, rationally priced pure vacuum tube amplifier, we designed a lovely polished stainless steel chassis and added a double anodized faceplate.

The Ultravalve has premium input jacks, 5-way binding post output jacks on 3/4" centers for 4 ohm, 8 ohm, and 16 Ohm taps, a line fuse, and an standard IEC power jack and AC power cord. The chassis top has small pin jacks for bias adjusting and the bias adjust controls.

Dimensions: 13" wide, 10" deep, 7" high. Shipping weight is 31 pounds.