Hi
Mike, THANKS! What a surprise. All items
received in good condition and I've prepared a
website for a coming article. I guess the brown
caps are PIO and the other caps - alu in teflon?
The cable? Looks like and excellent speaker
cable. The 5GDH4 drivers are fun. I can't believe
these are all NOS. These drivers appear to never
have been mounted. I did a very quick test and
they have a reasonable frequency response - no
nasty peaks. Fs is around 100 Hz and the most
(troublesome) thing is the Qt > 3. Never
before had drivers with as low electrical damping
as these. This creates a huge peak at point of
resonance (100 Hz). Calculated sensitivity is
around 84 dB - and measurement suggest something
around 85-86 dB/2.8V. Would you have time to
write a few lines on these drivers. I've searched
the web and didn't find any references at
all on these drivers. It would be nice to
have a little background material for the
article.
Mike, thanks again! Troels
Hi
Troels.
Brown caps are NOS oil & alu.foil + paper. I
use them in tube amps (as shunt) or in crossovers
to make a sound softer. The others caps are alu +
silver & fluorocarbon polymer. They are very
popular in Russia but quite rare. I send you a
photo of their packing in order to show you the
level of their assembling. I use them everywhere
- as shunt, as interstage , as shunt in
crossovers, try to use them , I think you will
love it. I like them more than MultiCap RXT. This
cable is from
. aviation =). It is
high-frequency silver coated copper + teflon
cable. It is possible to use them as speaker
cable or as assembly cable in amp.
5GDH4 drivers are all NOS. I took them from the
new box. They were made in 1985. Usually we use
them in open box or in open baffle. It is better
to use more than one driver in one speaker. Try
to work up them carefully by 40-50 Hz
sweep tone for several hours. It will decrease
Fs. Our experts say that when more than one
driver is used in speaker, their total Fs gets
smaller. Qt > 3 isnt good thing but it
makes very interesting bass in open box
construction. Try to measure Qts after some time
working.
It is possible to use some types of cone
impregnation to make driver more rigid but
this is not my way, one thing is possible to do,
is to use silicon mastic to make drivers basket
more muffled. I think that these drivers are not
very universal (in music), but vocal is very
impressive. In my case when I listen hard
rock a use EXEL + ribbon drivers and transistor
amp. When I listen vinyl I use tube
amp and these drivers =)
Best regards, Mike
Hi
Mike,
Thanks for the info. Very useful. Have added it
to the website. I've just installed the
alu/silver/teflon caps in my Transcendent RIAA
and they're excellent, probably better than the
Jensen copper foil caps I've used so far. The
values are perfect for this application.
I'll try the 5GDH4 drivers on an open baffle some
day, probably in a MMTMM set-up and use some bass
driver up to 150-250 Hz. The sensitivity should
end up around 90 dB from such a set-up. We'll
see. This is likely to be a summer's fun-project.
-
more to come - some day.
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