Tannoy Cheviots Replacing cone surround

[mick ritchie]

Hi

Im in the middle of replacing a tannoycheviot surround - (HPD315/8 spkr with Rolloff and energy knobs serial 512818). I know they lived unused for 25 years in a dry warm room but after a year of occaisional use this one started farting on specific bass frequencies and on examination the foam surround was flapping.

I bought a pair or surrounds online and know Ive got the speaker out and the foam off. Ive cleaned the metal struts that hold the surround in place and most of the old foam
off theunderside of the cone but the chassis still has a green coloured residue that is hard to remove especially as i risk damaging the cone. Is there any advantage in cleaning this off now ive removed all the loose bits of foam as i will just be gluing the new surround on top of it before replacing the struts?

thanks in advance

mick

[walpurgis]

Have you removerd the cones from the driver chassis? Installing new surrounds is far easier if you do and almost impossible to do properly otherwise. The are no metal struts. On the back of the cone are the Girdacoustic bracing ribs, they are made from similar paper based material as the cones and are fragile. The edge of the surround is sandwiched between these and the cone lip.

[walpurgis]

I replaced the surrounds on my Cheviot Mk.II speakers some years ago. The thread is here: https://theartofsound.net/forum/showthread.php?19555-My-new-(vintage)-Tannoy-Cheviots!&highlight=Vintage+Tannoys

You'll have to wade through a few pages, but it shows what was done. Mine have the later 3128 drive unit, not the HPD, but the principles are the same. There are cautionary remarks about not getting steel parts near the magnets, worth noting.

[Audio Al]

I sent mine to Lockwood audio , came back like new

[mick ritchie]

Thanks for replies and links - I had read thru your great work in the link and suspect i may have mad e my first mistake as the surround kit ive got specifically says it is made to fit over the edge of the cone rather than underneath as the originals did. My question of struts was misworded as i meant the 4 quarter circle pieces that screw on over the edge of the surround and on your photo the surface is virtually clean.

Yes ive avoided taking the cone off as the instructions with my kit was specific about it fitting over the cone not under - it says apply the glue provided to the "outer upper top edge" of the cone and i am currently in two minds as it could mean outer ie the very edge of the cone or all the way to the upper edge where the surround finishes and the cone heads down?

Whatever I may just try it and thanks for the link to Lockwoods as its always good to have a backup plan

best

mick

[mick ritchie]

Thanks all for advice after a few moments of nerves ie cutting and gluing I have got a new surround in and working as well as the old one in the other speaker though I do intend
to match them up after ive done some frequency tests - so nice to listen for pleasure with the warmth of the cheviots

best

mick

[WESTLOWER]

hi mick, this thread would benefit greatly from pictures.

[Audio Al]

hi mick, this thread would benefit greatly from pictures.

Try doing this > :worthless:

[mick ritchie]

Hi and thanks again - I admit I took no photos b4 replacing the surround. I didnt do anything unusual beyond taking the cone out, cleaning off all the gunk and then a few days looking at the bits b4 following basic instructions on the surrounds Id bought - applying glue to the edge of the cone and pressing in the surround repeatedly till it dried - then applying glue to the chassis and pressing down the edge of the surround over and over till it was dry. All the time testing the cone wasnt rubbing and nudging the drying surround till it wasnt. As I said the surround I bought specifically called it for it to be glued on top of the cone as opposed the original foam glued underneath so I had no need to take the cone appart. In fact I was very grateful for the link to Lockwoods as I spoke to them as a back up in case I messed up. I suspect proper reconing would improve them but as id started I thought i might as well complete the job. I cant tell the difference at the moment between the cheviot with the original surround and the one ive redone but I'll do more experiments before long as I have the second surround waiting

Surround I used http://dump.superorg.com/Photo/Surround%20for%20Cheviot.JPG

Completed http://dump.superorg.com/Photo/Completed.JPG


I suspect I was a bit sparse on the cone glue and then liberal with the chassis glue but im sure that will show itself in time. The surround fit perfectly in one position of the clock though whether a generic 12" surround at a quarter of the cost would have been just as good I dont know.


best

mick

http://dump.superorg.com/Photo/Completed.JPG
http://dump.superorg.com/Photo/Surround%20for%20Cheviot.JPG