B&W 801 80 series tweeter fix

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hello.
I'm new here,
I'm working on restoration of my old 801.


1. step was recapping the electrolytics
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.


2. Bypassing the relay in protection curcuit
3. Bypassing the fuse

I have a issue with tweeter. I cleaned it with alcohol but looks like there was some impregnation and measure is to bad.
An externally hosted image should be here but it was not working when we last tested it.


red one is before cleaning and orange is actual bad state :t_ache:


I found Visaton coating liquid for loudspeaker. LTS 50

Should i use it to impregnate the tweeter? What do you think ? :violin:
 
Last edited:
NOOO!!! The Visaton stuff is for coating paper cone drivers only (woofers and mids). If you put it on your dome diaphragm, you can really kiss it goodbye....
If you removed the original coating, that can definitely screw up the response, just as seen on your measurement graph.
You can try to apply one or two THIN layers of PVA (white hobby glue) with a soft brush, diluted to a thin syrup-like consistency. Try one layer first, let it dry, measure, and listen. The original coating is not "reproduceable", usually a secret formula of the manufacturer.
One other way (worked for me in some cases), is to coat the dome with Damar resin lacquer (available at artist's supply stores). Whichever of the two you choose can be better than no coating at all, since in that state the dome material is air-permeable, and does not function as it was designed to.
 
Brighter

I would just replace it, 801matrix tweeters are out of stock but S2 and S3 ones are still available.

B&W Group North America Service & Support - B&W Parts Price & Availability

S2 and S3 tweeter are not the same as the S80, and are generally considered less sought after. I have S2, and while I do like it, well, I have not heard a 80 tweeter.
My dome looks bluish and very metallic compared to this. So it could well be different enough to matter.

Thanks.
Srinath.
 
Replacing the electrolytics with film caps may well change how they sound and not for the better. The original xover would have been designed with the ESR of the electros taken into account. The film caps will have much lower ESR than electros.
 
Well it looks like you've been lucky. Obviously the implementation of the caps isn't affected too much by their ESR. Measurements don't lie. I have heard of others replacing series electrolytics in the HF path of the crossover with film caps only to find that the tweeter now needs attenuation.
 
I get that this thread is ancient, but, I am beginning restoration of my newly acquired 801 Series 80. These predate the use of fiber-crete. I have one tweeter out due to a failure of the pigtail between the coil wire dome entry and the side post. As the securing post for the headshell is bent, I guess that there was a catastrophic event that stressed the wire. I can still see the end of the coil wire in the dome, so it is theoretically possible to repair provided I find an expert at soldering.

The second part of this will be replacing caps in the crossover...with film caps. You talked about doing this but it seems the pictures are before only. The speaker with the damage has suddenly become very muddy.

Any help with before/after, the "ESR" issue, crossover schematics, people good with tweeter repair. More of you materials ad methods would be good. This is USA, so, Belgium, or Sloakia does not seem a good option for in person resources :)
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.