World-Designs-Forum  

Go Back   World-Designs-Forum > DIY Projects > Loudspeakers
Register FAQ Members List Calendar Gallery Today's Posts Mark Forums Read

Loudspeakers Your DIY Speaker designs

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old 14th March 2019, 06:47 PM
Richard Richard is offline
Super Moderator
 
Join Date: Dec 2005
Location: Notts
Posts: 5,357
Default JR149 speakers

Hi all, anyone had these? I chanced upon a pair going locally the other day. Not cheap or in particularly good condition but one owner and looked like they'd spent the last 40 years in the dry which is perhaps more important. Plan is for a vintage system in the spare room.

Back home, they checked out visually and with a meter ok so I hooked them up to the main amp for a quick listen. They were on 20" stands a few feet away from me, so, near-field in the middle of the room well away from the walls. Wow are they bright - a veritable supernova of treble assaulting the ear 'oles

I put it mostly down to me being used to big speakers and to them needing to be near the back wall (which they will be later). A few tracks was enough to hear that the drivers were all working and they're now in pieces for a look-see and gentle cosmetic make over!

Very impressive build quality but crikey Jim Rogers certainly didn't take the established route of speaker construction did he? These must have cost a fortune to make and are a right Aladin's cave of surprises to work on.

Thankfully there are some very good threads on the web with lots of info from guys like Tony L and Robert over on Pink Fish. I've got the xovers out now and testing, and the metal grilles will be off tomorrow to clean out the last of the disintegrating foam (the black outer grills are long gone but there's still the yellow stuff over the tweeter under the metal grill gone hard and powdery). The grills need to be unstapled before I can remove that and check the drivers.

Plan with all old gear is to do as little as possible, not lose the patina(), but get them working properly whilst keeping them as near possible to original. To that end I agonised over keeping the existing Elcaps in the xover. Then thought, well 40 years... better lift a leg and put the meter on one or two at least.

Well, the perceived wisdom is these caps dry out and lose value isn't it? None were low, ALL are over, some twice or 3 times over! The 6 3.3uFs reading 4.1uF to 8.4uF, the 2.2uFs doing best at 2.5uF and 2.8uF, and the 1.5uFs at 3.8uF and 4.4uF. Difficult to know what's happened or what value they were originally. I checked the meter against a new 2.2uF poly which was spot on. Better check the resistors and tie down the inductors with cable ties too I suppose.

So new caps ordered from Falcon and some outer grill foam on the way from Wilmslow. A light sand and a couple of coats of Danish oil should tidy the woodwork... and I'd like some nice stands, speakers are 8 1/2" diam, if anyone's got any?
Attached Images
File Type: jpg jr149.jpg (101.9 KB, 62 views)
File Type: jpg elcap-reading.jpg (69.9 KB, 56 views)
Reply With Quote
 


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 10:17 PM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright World Designs