Tube Lab

[@cobar5342]

Looks very exciting!

[@NosEL34]

That new "Rocket" setup sounds fantastic. Great topic today on the cathode follower. I have a preamp that had a Chinese or Russian Psvane CV-181 as a follower & I actually decided to try something else in it's V3 spot. I have a lot of 6sn7's but only a couple balanced singles. Tried a Sylvania GTA & noticed a little improvement. Tried a RCA 5692 & was like whoa! Noise floor dropped, center image got taller, but the bass was completely different than before. I'm still mind blown by the change. The bass is fantastic now. Simple tube change in the CF spot made a HUGE difference...who would have known 😂 Great job guys 👍

[@drdyna]

oo I really wanna try a couple of those 6cg7s and adaptors in my Freya. I might have to go shopping soon.

[@mfr58]

Have you considered using a current source in the cathode follower, or checked out the Allen Wright super linear cathode follower? It all adds complexity, but gives improved drive capability for cables amp input loads.

[@tubelab194]

@@mfr58 No. All our Lab bench work is based on first principles. Which means I never look to see what other amp designers are doing. What we want to achieve is the best sound possible at an affordable price. Years ago, before I developed my own design philosophy, I would prototype these more complex circuits and every single time, I found them to be finicky, unstable and not very good sounding. In my experience the shorter the signal path and simpler the circuit the better it sounds. The funny thing is often a simpler circuits takes a lot of development work to perfect, but the first listen always makes it worthwhile. Our cathode follower circuits drive monoblocks located beside our custom speakers using 16' unbalanced RCA cables (that I designed and fabricated), and we have no problems with impedance or signal loss.

[@febobartoli]

RIP Allen, his genius is still missed

[@mfr58]

@@tubelab194 I appreciate your approach and the passion and craftsmanship that you have. Sometimes less is more when you find the sweet spot.

[@ludmilascoles1195]

Wow someone actually using a cathode follower correctly as an impedance matcher, 😮😮 with a few changes you can get a 'negative inpedance' circirt, look up telephone repeater circuits for some examples from the 40s 😂😂 They actually made industrial tubes just for this, but alas, these are getting quite hard to source. Oops one thing you forgot to mention one other bonus the output is non-inverting.