This was the
initial plan for a three-way TJL. The
W12 stuck in between the W18 bass and the JP3
ribbon. However, the HIQUPHON OWI did so well
with W12 that I wanted to explore this option
first.
So, the test front panels needed some further
routing to accommodate the JP3s, having a much
larger frontplate diameter. And what I hadn't
taken into account was the depth of the JP3...
Had to cut a hole in the rear panel of the mid
enclosure. Hmm...Should you want to build the
TJL3W with the ribbon tweeter I suggest you
increase depth of mid enclosure to avoid what I
had to do. Image below.
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Room for ribbon tweeter.
Finally, test front panel with Fountek JP3 ribbon
tweeter.
TJL3W-JP3
crossover
Simulation and FR prediction from JP3 option: Bass
crossover section is the same as for the OWI tweeter.
Mid section has a single change: 12.2 uF is replaced by
6.8 uF.
Tweeter section: This is completely redesigned to
incorporate the JP3 ribbon.
The 4R7 series resistor produces a flat response with my
homemade alu ribbons.
Should you use the original JP3 ribbons you may have to
use 5R6 due the originals
having an approx. 1 dB higher sensitivity. Check out 4R7
to 6R8 to get the best tweeter-mid
integration. My guess is that you should use 6R8 with the
original ribbon.
Tweeter section or the JP3 version. 3R9 was substituted
with 4R7.
Mid-section for JP3 version; new is only the 6.8 uF
capacitor.
Try 3.3 ohm for input series resistor. You can fine-tune
the 900-3000 Hz range here,
but don't go below 2R7 and above 3R9.
Midrange section, JP3 version. I have tried to make a
logical layout, starting from down left towards right
and then up, followed by the notch filter (4.7 mH + 10R +
1.5 uF). I finally decided using 3R3 to mid.
JP3-version
measurements:
 
Left: FR at 1 metre
distance at between-mid-and-tweeter height. Quite a nice
response. This from the left speaker. A very flat and
revealing tuning indeed but no aggressive mid or treble
from this set-up. The W12 and JP3 ribbon tells you right
away what's going on.
Red is with same mid and tweeter polarity. Blue with
reversed ribbon polarity as it has to be.
3R3 to the mid and 4R7 to the (homemade) ribbons. Try 5R6
to the original JP3s.
JP3s available here: GM Sound -
Produkt 2
I'm going to have a pair of the new Fountek NeoCD3 in a
few days and I'll try if these laminated ribbons are as
good as the true alu ribbons.
Right: How about left and
right speaker? This is what we usually do not see. Red =
left speaker. Blue = right speaker. Up to 2 kHz there
really isn't any difference. From 2-15 kHz we're talking
max. 1.5 dB difference. Not bad at all - from ribbon
tweeters. From my experience ribbons are not as
consistent in frequency response as domes, and I need to
make a new alu ribbon for the right speaker. The small
peak at 12 kHz is most likely caused by a little too
tight ribbon. Needs to be loosened a bit.
But +/- 1 dB is excellent. Actually it's amazing we don't
have any documentation for frequency response and
impedance when we buy a pair of speakers. You get more
quality control when you buy a toaster compared to buying
a pair of speakers.
So, that's it. The TJL
3-way. It's taken some time and it's been quite a journey
into classical three-ways with a small upper midrange
driver.
It's playing in my living room and this is going to be
one of the stock speakers in my collection. A small sized
speaker with a very neutral presentation, high level of
transparency, a very flat voiced speaker that tells you
most of what's on your CDs and LPs. A speaker with a
surprisingly deep bass considering its size. It doesn't
go as loud as the Ekta, but again, the Ekta is a bigger
speaker. Generally it's a more neutral speaker compared
to speakers with paper cone drivers.
2 x 50 valve watts do well here.
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