Mike in California Emailed me with some photos of the new Tung-Sol KT150 output tubes in his VTA M-125 amps. He said that the tubes biased up fine and sounded "great". I have not tried these myself as yet because of the expense involved. The KT150's are about $100 apiece and eight output tubes for two amps would be $800. The power transformers on the all the VTA amps are "overbuilt" and can handle more current draw than the normally specified output tubes for the amp. So - I guess if you want to try the Tung-Sol KT150's in your VTA ST-120 or M-125's and have a fat wallet, give them a try. Do NOT, by the way, use these tubes in any ST-70 type amp.
Note also > Below the table one of Roy's VTA SP preamps and phono preamps being used to drive the M-125's ..
Bob
NOTE - (12/16/17) I have had other customers tell me that the Tung-Sol KT150 output tubes will not bias properly in the VTA M-125 (or VTA ST-120) amps. I am recommending that you NOT use these tubes in either amp.
Note also > Below the table one of Roy's VTA SP preamps and phono preamps being used to drive the M-125's ..
Bob
NOTE - (12/16/17) I have had other customers tell me that the Tung-Sol KT150 output tubes will not bias properly in the VTA M-125 (or VTA ST-120) amps. I am recommending that you NOT use these tubes in either amp.
Last edited by Bob Latino on Sat Dec 16, 2017 6:28 pm; edited 3 times in total