Does the UL-connection stress tubes?

[Suzuki]

Hello, folks.

I'm going to get a pair of 15-watt/8kohm opt's for USSR made 6F3P(6bm8)'s
on my Sansui receiver.

The OPT has SG taps for UL connection.
I'm wondering if UL is likey to stress tubes.

The circuit design for the gear seems to have good margin to the maximum
plate dispassion, though.

Your opinion will be greatly appreciated.

Taihei Suzuki

 

[Trio]

The tube should be okay in UL mode if everything else is "Design Center Value" or reasonably close to it.

 

[jaymanaa]

I think the tube will be fine, but the sound quality will depend on what % of the winding the UL taps are at. Personally I prefer pentode mode with SS regulated screens. That said, I'd love to hear what you think of that tube in UL. The 6BM8 is one of my favorites. It has a very unique sound, which I like very much.

 

[Suzuki]

I think the tube will be fine, but the sound quality will depend on what % of the winding the UL taps are at. Personally I prefer pentode mode with SS regulated screens. That said, I'd love to hear what you think of that tube in UL. The 6BM8 is one of my favorites. It has a very unique sound, which I like very much.

IMO, the 6bm8 has a clear and open-end sound in the highest audible portion of frequency. Moreover, the 6F3P made by svetlana in the CCCP era has a commanding presence of bass compared to other 6bm8's, in addition, their pinouts are plated, which matters a lot.:yes:

I'll get the opts before long and report the outcome of 6F3P's sound in UL with an increased NFB (by 40%).

Taihei Suzuki