ECC82. JJ vs vintage, peculiar frequency response tests

[Alexandru marian]

I find it interesting that the output is coupled from the CCS cathode instead of the output tube plate.

Yeah! I found this version in Millett's srpp headphone amplifier too. He comments:

"If you are using this amp to drive something other than the K-1000's (which require a very low drive impedance), you might want to consider an alternate connection of the output - a current-sourced grounded-cathode amplifier. Taking the output from the plate of the lower tube is more like a "pure" triode amplifier, since in this mode the upper triode acts only as a current source, and not as a cathode follower. The output load - as reflected through the transformer - provides a load to the plate of the lower tube (in parallel with the upper tube), so the load line is dominated by the output load. With this connection, the output impedance is set by the Rp of the lower tube. You could even put in a switch to select between the two if you'd like."

I'm too noob to understand a thing but I wonder what would happen if I would try the anode output in my pre...

 

[DF96]

I find it interesting that the output is coupled from the CCS cathode instead of the output tube plate.

It is (almost) an SRPP.

 

[hpeter]

I dunno. like the designer was not thinking to squeeze best parameters out of whole schematic

 

[gyraf]

On a side note: Yes, the designer was aware of the options - the G9 was a result of chasing sound, not specifications, for a lot of revisions/redesigns/evaluations in our studio. Which is also why we ended up with the LL5402 even though Lars Lundahl did protest 🙂

Jakob E.

 

[Alexandru marian]

From a numbers pov 5402 it mismatched, but the leaner bass definitely allows for a more effortless and sweet exposition.

Now I have ruler-flat high-inductance outputs and the bass is big, but the rest has turned to a more polite neutral thing which sometimes makes me miss the original sweetness.