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04-08-2023, 02:34 PM
Hi Guys
SV1 and SV2 are now much smaller than they used to be by about one-third. This allows them to be placed in smaller chassis or into tighter spaces. We used cord-wood construction to achieve this, with all the power resistors standing on end with one lead folded back to the board.
The revision also changes how the Power Scale control is wired, improving low-level resolution of the control. This rewiring is actually the original way I wired the PS pot in my amps, but then changed it for the kits to allow easy ground-referenced selection of multiple PS pots. Although that was a useful feature, only two builders ever took advantage of it.
That multi-PS selection optimisation did a quirky thing to the PS sweep which was nonoptimal yet still allowed dialing power to zero. The new/old wiring is nearly ideal in its pot sweep and the power range is from 100% down to 0% as it always has been.
In the Japanese naming style adopted for the Power Scaling kits, the Super Budget SB-series used a very simple circuit that required a very expensive pot. The pot price got to be prohibitive and it was eventually replaced with good-quality 16mm types that are far less expensive, but required a more complex regulator circuit. In my amps, I called this the Super Design SD-series, and with the modified PS connection, the kits became Super Versatile or Super Value SV-series. The kits now conform to the SD form.
The kit evolution also allowed an increase in the voltage range for SV1 and SV2, eliminating the need for SV-TT and SV3. SV84 was originally designed for use in the ValveJr, which uses a single-ended EL-84 PA with a single supply node for the output stage. SV84 has been redesigned as above and its voltage range has been extended to 750V from 450V. The product description will be updated when the new PCBs arrive.
SV1 and SV2 are now much smaller than they used to be by about one-third. This allows them to be placed in smaller chassis or into tighter spaces. We used cord-wood construction to achieve this, with all the power resistors standing on end with one lead folded back to the board.
The revision also changes how the Power Scale control is wired, improving low-level resolution of the control. This rewiring is actually the original way I wired the PS pot in my amps, but then changed it for the kits to allow easy ground-referenced selection of multiple PS pots. Although that was a useful feature, only two builders ever took advantage of it.
That multi-PS selection optimisation did a quirky thing to the PS sweep which was nonoptimal yet still allowed dialing power to zero. The new/old wiring is nearly ideal in its pot sweep and the power range is from 100% down to 0% as it always has been.
In the Japanese naming style adopted for the Power Scaling kits, the Super Budget SB-series used a very simple circuit that required a very expensive pot. The pot price got to be prohibitive and it was eventually replaced with good-quality 16mm types that are far less expensive, but required a more complex regulator circuit. In my amps, I called this the Super Design SD-series, and with the modified PS connection, the kits became Super Versatile or Super Value SV-series. The kits now conform to the SD form.
The kit evolution also allowed an increase in the voltage range for SV1 and SV2, eliminating the need for SV-TT and SV3. SV84 was originally designed for use in the ValveJr, which uses a single-ended EL-84 PA with a single supply node for the output stage. SV84 has been redesigned as above and its voltage range has been extended to 750V from 450V. The product description will be updated when the new PCBs arrive.
