... fascinated by amps
Join Date: Jan 2016
Location: In the Düsseldorf suburbs
Originally Posted by kbergsson
... I tried yesterday to exchange my Aikido linestage ( ca 10-15 db gain, using 4x 6cg7 tubes) with a Slagle autoformer box ( used as my pre for many years in front of SE 300B amps). ...
You could try re-configuring your Aikido as an Aikido Cathode Follower (ACF), which mainly acts as a buffer.
I did that by pulling out the first tube, the one that provides all the gain. The only thing that I then needed to do then was connecting the two connections in the empty socket where grid and plate of the lower half of the tube would have been going with a capacitor. 220 nF to 1 µF is fine, and voltage rating must be sufficient for the full B+.
in the attached schematic, the left socket would be empty, and the capacitor would go between pins 1 and 2.
Just try it ... it's an interesting alternative. It gives me enough gain in most situations (M2 into 100dB/W efficient Jericho Horns), and has about half the distortion of a regular Aikido.
Just remember that the regular Aikido is inverting, but the ACF is not ...