According to web, el34 needs 20H for 15Hz -3dB.
Pse 4p1l has twice gm; half ra.
So, 35H should not be any problem.
Your LL1682 DF with 8r spk, is about ~12, higher than "standard" 300B..(~5)
I don´t know, maybe such DF is common in the PP territory
Well, now your boomy bass has gone bye bye
LL1664 /8 DF ~4,3
Could you show how you calculate the DF being ~12?
I calculate ~7, about the same value as with 300B.
Agreed that the parallelled 4P1L's should have enough LF bandwidth with LL1682.
4P1L PSE load line | Bartola Valves he says ra=690
OPT impedance ratio 1024:1 ;ra on secondary should look like 0,674R
8spk/0,674rout=DF ~12
Now i realize, i did not include dcr primary
so numbers are bit off ~10
the 1664 should be instead 8spk/2,08rout=3,84
OPT impedance ratio 1024:1 ;ra on secondary should look like 0,674R
8spk/0,674rout=DF ~12
Now i realize, i did not include dcr primary
so numbers are bit off ~10the 1664 should be instead 8spk/2,08rout=3,84
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hpeter,
You are making progress by including the primary DCR, but you are not there still by forgetting secondary DCR.
The right math: (690 + 210) / 1100 = 0,82, + 0,4 (secondary DCR) = 1,22. This is output resistance.
Damping factor with 8 ohm load is 8 / 1,22 = ~ 6,5.
We presume loudspeaker cables to be 0 ohm....
You are making progress by including the primary DCR, but you are not there still by forgetting secondary DCR.
The right math: (690 + 210) / 1100 = 0,82, + 0,4 (secondary DCR) = 1,22. This is output resistance.
Damping factor with 8 ohm load is 8 / 1,22 = ~ 6,5.
We presume loudspeaker cables to be 0 ohm....
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