Same here. Where does one find NOS 6C33C tubes from a reliable source? Whenever I've purchased from across the way it was a nightmare. I've had to pay a premium to buy tested tubes from US Vendors.
6C33C-B tubes
I have 35w p/p Class A monoblocks which use two 6C33C-B tubes per unit. The manufacturer recommends a bias setting of 150mv. Before biasing (once a month), the tubes' measurements rarely deviate more than 10mv over/under the 150mv. Over the last year, I’m guessing that they’ve been in use for about 1000 hours. I have no idea what their expected lifespan might be. So far, biasing is still relatively easy. The manufacturer is no longer around to answer any questions. So, here’s a few for the Audiogon community.
1) For those of you using 6C33C-B tubes, are you able to guesstimate their lifespan in your amp – in Class A operation?
2) Generally speaking, how necessary is it to bias exactly to the manufacturer’s recommendation – in this case 150mv? Is there an acceptable tolerance +/- %?
Thanks! P.S. I’ve been replacing the sockets once a year.
1) For those of you using 6C33C-B tubes, are you able to guesstimate their lifespan in your amp – in Class A operation?
2) Generally speaking, how necessary is it to bias exactly to the manufacturer’s recommendation – in this case 150mv? Is there an acceptable tolerance +/- %?
Thanks! P.S. I’ve been replacing the sockets once a year.