I have read the details regarding using KT150s in a Audio Research VSI55. I'm think of adding an external filament PS using a Lundahl LL1669A.
Thoughts? Any schematics or kits that would provide the 6.3VDC 2A required for each KT150?
Thoughts? Any schematics or kits that would provide the 6.3VDC 2A required for each KT150?
Are you going to run it at the plate voltages applied for the 6550 tubes ?
The KT150 uses more plate current at its normal plate voltage (running ) than a 6550 or will you be under-running it ?
Thats not a problem according to those installed just a lower output but if you need to use its full potential can your mains transformer take the extra current needed without dropping the plate voltage ?
The AR-VS155 isn't your standard designed tube amplifier .
The KT150 uses more plate current at its normal plate voltage (running ) than a 6550 or will you be under-running it ?
Thats not a problem according to those installed just a lower output but if you need to use its full potential can your mains transformer take the extra current needed without dropping the plate voltage ?
The AR-VS155 isn't your standard designed tube amplifier .
No: the plan was to run the KT150s with the same plate voltage, and just offload the filament supply.
I can design you a board that will turn 8VAC into 6.3VDC using a pair of LD1085/LT1083 LDO regulator if you want. I got a use for this kind of board myself.
You will then need to source a toroidal transformer that will deliver around 8VAC 6A for two tubes. Getting 6.3 from a 6V toroid is damm near impossible considering the rectification losses.
PM for details.
You will then need to source a toroidal transformer that will deliver around 8VAC 6A for two tubes. Getting 6.3 from a 6V toroid is damm near impossible considering the rectification losses.
PM for details.
Remember to connect one side of the heater AC to power supply zero volts.
I wouldn't bother looking at DC heaters I have never found that they made a difference.