Tannoy K3809 - hardened cloth surround issue - solved
I'm lazy , so there are excerpts from my correspondence on Tannoy Yahoo group; all quotes - Mighty ZM
I'm putting this here as future reference for some other desperate Tanner ; I must admit ( or I'm just boasting ) - I'm always having serius backup for all things speakers - from Aleksandar RAAL ....... even if I'm always stubborn and I'm bugging him only post hoc ..... to be sure that I didn't blew something
QuoteK3809 - cloth surround impregnation solvent ?
as I wrote - pair of K3809
cloth surround , no back cone ribs
Fs is high - around 70Hz on both drivers
I contacted Tannoy Support , but they can't help - all they can recommend is
reconing , which is out of possibility , counting on fact that drivers are in
excellent condition and just slightly used (well - same as they aren't used at
all )
so - anyone having real life experience , regarding solvent for surround
impregnation ?
whatever , guy at http://www.haslingaudio.com is doing exactly the same for SH
Altec's , so I think same is possible for Tanns
TIA
QuoteTnx for reply ;
There is no particular info on Altec related link , but point was that planned
procedure was implemented ...... I sent e-mail to Danish guy , asking for his
recipe , if nothing else , as starting point .
Whatever - K3808 (3809) are having impregnated cloth surround , not paper ;
that's visible on many pictures on net , and "cloth surround" is having exactly
that name in related info
In any case , if I succeed in "operation" , I'll share my findings
of course - "Danish guy " wasn't prepared to share his recipe ; I don't blame him
that's why I'm sharing mine
Quotebesides Sam R's problem with teared surround ......... and strictly speaking of hardened cloth surround - I'm stubborn and there is no way I'm going to change them .....
I would go to generic soft (probably acquired from Sonido guys in Hungary )
cloth surround , but will ever never invest money in new cones or - God forbid!
- neoprene surrounds
I remember some guys at Diyaudio speaking of
http://en.wikipedia.org/wiki/2-Butoxyethanol , so I plan to start with that
QuoteHardened cloth surround problem solved !!
soaking both sides of surround , using small brush , with plain Ethanol 95-96% ,
brought Fs from 71Hz to 29Hz .
I'm expecting that Fs will rise to spec. 35Hz , when solvent evaporate
That's what we are calling just Pure Alcohol , and you can buy it in every
drugstore.
So much speaking of recone and surround replacement
QuoteI'll keep you informed , of course ;
even in case that Fs start rising again , I'll just repeat procedure , removing
old impregnation as much I can , and brush new tacky layer above it
then it will permanent solution
no damage , certainly ;
I'll post few pics in few days , after having definitive conclusion about
longevity of cure
QuoteUpdate : after 24h rest and solvent evaporated - two steps forward , one step back
steps forward are :
1 - impregnate is not brittle and cracked (inducing noise , especially
detectable at Fs)
2 - everything looks just nice , almost as new
step back - Fs is back on 71Hz )
whatever , I'll proceed with more cleaning of old impregnate , and then try to
seal it with tacky surround goo , which will (hopefully) prevent repeated
hardening
will keep you informed
QuoteOK
K3809 - cloth surround impregnation solvent ; hardened cloth surround - high Fs - issue SOLVED
procedure finished and confirmed
after 24h (and more ) of solvents evaporating , Fs is still good : 33-35Hz
RECIPE
what you need :
1.small brush , semi hard m ~8mm wide , same as kids are using for painting in
school
2.Ethanol 95% (pure alcohol)
3.Acetone with oil ( nothing else than nail polish remover )
4.mouse glue (yes , that organic everlasting sticky goo)
5.Vaseline
6.cotton cloth ( old T shirt or whatever)
brush - buy it anywhere , mouse glue - anywhere , everything else - nearest drugstore
important to say - surround was originally threated from upper side , mostly ;
just slight residue of original rubbery impregnate is visible from bottom side
of surround
procedure for upper side of surround:
using brush - from upper side - soak surround with ethanol ; it's best to soak
it in parcels of 10cm , then rub it with same brush ; whenever you fill brush
with residue , wipe it on cloth
repeat procedure until you make two full circles (so entire surround perimeter
is twice treated)
move to second speaker ,same procedure , again two circles ;
repeat same soak-rub-wipe-soak-rub-wipe procedure on both speakers , until you can see clear fabric of cloth , without any trace of rubber
it's fun , but only if you have some muzak and coffee
after few steps in procedure you'll see what's happening ; if you think that
you'll gain anything with another soak-rub-wipe circle , just do it
leave speakers 12h , to let Ethanol to evaporate
now - put some mouse glue on small (coffee cup) plate , add acetone and dissolve it to something liquid as milk
using brush - put that mixture on upper side of surround ; if you see that your
mixture on plate is going firmer , add acetone and mix ; when you treat entire
surround , take just acetone with brush and treat entire ( already impregnated )
area with it , to make it more uniform
leave it for 12h
now - bottom side of surround :
soak brush in acetone , rub it firmly in Vaseline , then put that mixture on
entire bottom side area ; goal is to have tiny layer of vaseline on bottom side
leave it 12h
measure Fs
easiest way of measuring Fs - use sine signal generator with 50R output
impedance , connect it to bass terminals , put CRO probes on terminals
sweep frequency from 100Hz down ; when you see biggest sine amplitude , there is Fs
another possibility for measuring - instead of sig gene - use Sig Jenny program
( wave gene with counter ) , sound card to small amp , amp to bass terminals ,
AC voltmeter to terminals
put few volts of sine to bass , sweep from 100Hz down , when you see biggest
reading on Vac meter , that is it
mine are at 31 and 33 Hz , I'm not loosing sleep because of using mouse glue and
vaseline on piece of cloth
Quote
then one guy is saying that Mouse Glue is forbidden in some EU countries ; my reply :
Quotein that case - just buy softest surround impregnation goop ; easy to do on line
, if living in Europe
unfortunately - Serbia , where I'm living - somehow isn't in Europe , so I'm
Paypal-less
that means that I'm just lazy to chase soft surround impregnation goop from
Europe , taking in account that there is no domestic one
then guy asked where to search for surround impregnation goop ;
my reply :
Quotesorry - just google ;
search for something like this : http://tinyurl.com/cw3yc8v
but , it's wise to buy only after confirmation from seller that really soft
thing is in question
Zen Mod
then guy asked for difference sound-wise , pre and post procedure ; my reply :
Quotesound-wise - taking in account that my pair is most mint pair I ever had
opportunity to even see (except surround condition - most probably as result of
no-usage for all long years ), I'm eager to say that they're sounding just as
proper pair of K3809
right now being in stage of preparation of making boxes for them , I'm having
fresh experience just listening them in bafle-less iteration ; even like that ,
there is proper difference in bass , comparing to prior (surround treatment )
performance
whatever , fact that plain and common Ethanol is sufficiently good as solvent
for old impregnation , was nice surprise ....
Zen Mod
I hope you enjoyed little story
In case that I remember to get cam to my workshop tomorrow , I'll make few pics and put it here , along with few pics of same drivers prior to fun procedure
edit : did I told ya that each cone got 2 layers of Dammar ?
all pics are after treatment , except last 3 ones - sent to me from seller , so prior to procedure ...... months ago
if you're puzzled - here is a link for SigJenny sig gene proggie : http://www.natch.co.uk/downloads/SigJenny/SigJenny.html
9 Comments
Preporučeni Komentari
Kreiraj nalog ili se prijavi da daš komentar
Potrebno je da budeš član DiyAudio.rs-a da bi ostavio komentar
Kreiraj nalog
Prijavite se za novi nalog na DiyAudio.rs zajednici. Jednostavno je!
Registruj novi nalogPrijavi se
Već imaš nalog? Prijavi se ovde
Prijavi se odmah