Tubes4hifi has a new product - the VTA-TDB which is a "time delay board" KIT for Dynaco amps. This board may also be used on any amp or preamp where you want to delay the application of high voltage. The time delay allows the tube filament heaters to come up before any high voltage is applied. The time delay is nominally about 17 seconds but may be adjusted for more or less delay at the discretion of the user. There are complete instructions for the assembly of the board and time delay alteration should the user decide to do so. In a stock ST-70 the board replaces lugs 5, 6 and 7 of the 7 lug terminal strip. In a VTA ST-70/ST-120 tube amp kit, the VTA-TDB replaces the 3 lug terminal strip. The VTA-TDB may also be easily retrofitted to any VTA ST-70/ST-120 tube amp kit.
The board is 1 7/8 inches wide by 2 1/2 inches long. It takes about 1/2 hour to assemble and is powered by a 6.3 volt AC line taken off V2. When the board is powered up a RED LED lights up to show that the board has power. About 17 seconds after power is applied, a GREEN LED comes on and a quality Potter & Brumfield relay kicks in to apply high voltage to your amp. Another nice thing is that if you are in an area that has quick ON/OFF/ON power interruptions the board will automatically reset itself. In other words, if your power goes OFF and then ON again a split second later the board will automatically reset itself and no high voltage will be applied for another 17 seconds. Roy and I have been running this board in our own amps for some time now with no issues ...
The board will soon be an option on all VTA ST-70 and ST-120 amp kits. The VTA-TDB KIT will sell for $35 + $5 shipping. Contact either Roy or myself for more information or to purchase a VTA-TDB kit.
Last edited by Bob Latino on Tue Jul 12, 2011 3:09 pm; edited 1 time in total