Cathode Follower Pre-Amp

[dave dove]

i've been using broskie's aikido linestage
i have to say it is very very good

never had a gain problem with it

it is of course being gutted now....

dave dove

[lt_texan]

unity gain line driver, CF with an active load. 12b4a with a ccs, low output impedence to drive long super thin silver cables to mono blocks?

[bikerhifinut]

Just use a 12b4A. Ra of 1k is low enough to drive any Valve power amp.
Gain of 5 ish means sources of 200mv O/P (and theres a few low output sources still in use) have an out put similar to CD players, just attenuate the CD input (danger of degrading the sound?).
Only draw back I can see is that 12B4 has a high anode dissipation which means a high wattage anode resistor and lots of heat. Oh and they are very microphonic so a damping ring is a good idea.
How can you tell I've just built a 12B4 preamp?

[lt_texan]

bit off topic, but wasn't most of the reason for the CF mod to the WAD pre because of too high gain.

Wouldn't this have been a WAD quick fix with a different spec'd output trannie?

[petercom]

Yes, and also because the multiplication factor of the transformer makes it prone to picking up hum fields.

A fix is coming as soon as we have the design finished.