Ill be rebuilding my amplifier getting rid of all of my 12au7's and 12at7's. I have addressed my gain stages for my main 5 audio channels however my LFE channel still remains to be thought out/designed.
Since im using an silicon style amplifier for my LFE channel i do not need large amounts of gain but i do need a way to balance the magnitude of the channel with my others. Im considering a cathode follower arrangement but have not found many documented cases of using a pentode as an cathode follower. Is there a reason why its not frequently done?
I intend to tune my channels such that 100% at my source is just barely touching clipping on main channels, thus with a matched subwoofer preamp i would only need to adjust master volume on my sound card and not have to fiddle with sub volume level like i do now(nonlinear at the moment with current topology)
Expectations for the b+ is 450 not 500 volts, compensated by different anode resistor choice. This circuit was tested as a single channel and shown to be superior to previous solution:
http://ryujiwarui.com/upload/Pentode-Rev4B.png
Since im using an silicon style amplifier for my LFE channel i do not need large amounts of gain but i do need a way to balance the magnitude of the channel with my others. Im considering a cathode follower arrangement but have not found many documented cases of using a pentode as an cathode follower. Is there a reason why its not frequently done?
I intend to tune my channels such that 100% at my source is just barely touching clipping on main channels, thus with a matched subwoofer preamp i would only need to adjust master volume on my sound card and not have to fiddle with sub volume level like i do now(nonlinear at the moment with current topology)
Expectations for the b+ is 450 not 500 volts, compensated by different anode resistor choice. This circuit was tested as a single channel and shown to be superior to previous solution:
http://ryujiwarui.com/upload/Pentode-Rev4B.png
Generally, the pentode offers a gain closer to unity, but do you really care if it's 0.99 instead of 0.97? Other than that, there's no real performance advantage.
There's nothing wrong with a pentode cathode follower. The tricky part is that g2 must be tied by a cap. to the cathode.
Read Kimmel's μ stage dissertation. A μ stage is a μ follower with a pentode CF "upstairs".
Read Kimmel's μ stage dissertation. A μ stage is a μ follower with a pentode CF "upstairs".
I did not plan on using a cathode follower on my other channels, however i do still intend/need the preamp on my LFE channel.
Using the same grounded cathode topology and then attenuating it back down to line voltage is a poor choice, So a cathode follower in theory would accomplish my goals?
From a implentation point of view is it as simple as taking my 28~33k resistor in the anode of my other preamp design and bringing it down to after the cathode bias resistor, and changing the 1 meg to join in after the cathode bias resistor? or is that a poor way to design my cathode follower?
As such i would think any nonlinearities would match up with my other tubes, just need an log taper on the input to adjust the balance to where i want (the power amp will not have any kind of volume controls after the preamp)
i would have to also elevate my heaters about 100v to compensate
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