Tubelab SE driver gain

[Klimon]

Hi,

Is it me or is the tubelab SE's driver stage not capable of driving the 300B to clipping? Quick look yields ~85V pk-pk voltage swing, 300B needing about 140. Or is the powerdrive a gain stage after all?

Thanks!

Simon

[rknize]

Mine can push them into clipping...at least as far as I can tell (blue glow flickering off in the 300B).

[DougL]

Is it me or is the tubelab SE's driver stage not capable of driving the 300B to clipping? Quick look yields ~85V pk-pk voltage swing, 300B needing about 140

A redbook CD player puts out about 2V RMS, or about 6V Peak to Peak. The Simple SE has a CSS load, which should allow Av about Mu, about 40. 6 * 40 = 240. The other limit would be B+. Rule of thumb is that a triode can swing up to about 2/3 of B+.
For a B+ of 300V, that should give about a 200V PP max.
Since both are over the 140V, it should not be an issue.

Doug

[Klimon]

A redbook CD player puts out about 2V RMS, or about 6V Peak to Peak.

You just shook my world I've always foolishly taken the typical cdp output for 2V peak-peak (and worked my loadlines around that 2v window).

Cheers,

Simon

[ErikdeBest]

A very interesting post regarding 'line level'.

[tubelab.com]

Is it me or is the tubelab SE's driver stage not capable of driving the 300B to clipping?

The amps that I have measured hit clipping with 1.2 to 1.7 volts RMS applied. The wide range is due to the variability of the 5842's and how hot the 300B is biased. I have used mine with several CD players and reaching clipping with most CD's is not a problem. I currently use an old Toshiba DVD player with my 300B Tubelab SE. It will drive the Tubelab SE to clipping with almost all CD's but I have found a few music DVD's that are relatively quiet. They will not drive the amp into clipping, but are still plenty loud even with my 87db speakers.