I have a valve amplifier, ''DYNACO ST120''. What is
impedance of speakers ''JENSEN 1071'' for use with valve
amplifier? 4 or 8 ohm, or maybe something between?
I send you one picture:22W/8851T00,18W8531G00 and
D2905/9900, the crossover is the same like yours. Mid cab
is 22 liter/ 37 Hz and bass cab
is transmission-line. I never heard unbelievable
sound like this!
Thank you for everything and best regards from Goran.
Hi Goran. The
Jensen speaker is a 4 ohm speaker with a minimum of 3.5
ohms at 300 Hz.
I really like the idea of a transmissionline for the bass
driver. I have no doubt it sounds great. Based on
simulation the original Jensen crossover should work fine
with your 22W bass driver. To other builders I have to
say that I cannot guarantee the crossover will work
perfectly as intended due to the minor changes to the
front panel dimension, but as the front panel only
appears to be ~2-3 cm smaller than specified, the impact
on sound may be minor.
One more thing:In this cabinet ,bass is free of
coloration from 20Hz,deep,natural and fast. Reason for
triangular transmission line port is that there is a
"attenuation or suck out" of the line's
frequency response near 120Hz.Triangular port adjust the
maximum upper impedance fH more broadly and reduces the
effect of the 120Hz suck out.
cabinet drawings used by Goran by clicking image.
Damping can be seen here.
Just saw your newest speakers corner. I must comment your
Jensen project. I've been invited by Goran who built your
Jensen with TL bass loading. Goran wanted to bring with
me mine SET amp 2x11W no nfb. I was reluctant to try set
on such big loudspeakers thinking that there will be no
chances to drive Jensen. First we listened Jensen with
Denon 1520 solid state 2x120W, then we connected 6C33c
set and after 20 minutes of warmup we pressed play; well,
I was totally surprised, sound was fantastic, everything
was better compared to SS amp, even bass was deeper,
Jensen simply disappeared, nothing was missing, full flat
spectrum, no dips or peaks. That is testimony of
excellent xo design I guess. Goran, owner of Jensen, was
very, very happy. Even spl was high enough on good
recordings, it seems Jensen proved to be good match even
for SE amp, even with no nfb. Goran is working on upgrade
of his Dynaco pp so we have not listened to PP, latter we
have one drink in your name. One more thing Jensen with
se amp played female vocals briliantly while with Denon
ss such vocals were very, very unpleasant. Wishing you
only the best in new year, good health and new projects.