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

Reply
 
Thread Tools Display Modes
  #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, 63 views)
File Type: jpg elcap-reading.jpg (69.9 KB, 57 views)
Reply With Quote
  #2  
Old 14th March 2019, 09:41 PM
bob orbell bob orbell is offline
Senior Member
 
Join Date: Nov 2009
Location: kettering northants.
Posts: 2,735
Default Re: JR149 speakers

Hi Richard, these were a alternative to the much now sort after BBC LS3 5A and I think that they use the same drivers, I had a pair of the LS3 5A's that I bought in the late seventy's for £20.00 and sold them some 5 years ago for £1640.00 to a guy in Australia, , if and when you resurrect them, please try them in a small room, alternately, try and find another 19 pair and run them altogether in you main room . Bob
Reply With Quote
  #3  
Old 15th March 2019, 12:42 AM
Phil Y's Avatar
Phil Y Phil Y is offline
Senior Member
 
Join Date: Jul 2006
Location: Bristol, UK
Posts: 816
Default Re: JR149 speakers

Hello Richard,

As It happens I recently sold a pair of those. They were my late father's last speakers. After sitting unused in the back of a wardrobe for many years I decided to sell them. I got a good price and they now live in China of all places.

As to the caps in yours, I have read that if the internal resistance goes high, this can make the value appear falsely high on a meter. I imagine yours will improve with new caps fitted!

I must admit to not being a fan of them, my pair at least. I would certainly not call them bright, in fact, I found them to be rather "midi", being rolled off at both frequency extremes. This is I expect party due to being a long time 12" Tannoy user! In particular I found their very limp dynamics to be a failing. Having said that, they were easy to listen to and would make a perfectly good pair of second speakers for a office/bedroom system, sounding pleasantly inoffensive on small scale music.

Personally, I don't get all the enthusiasm for LS3/5As and JR149s. They do have a certain charm but they sound their age to me and LS3/5As are hugely overpriced.

Phil.
__________________
Commission for Dark Skies (CfDS)

Last edited by Phil Y; 15th March 2019 at 03:05 PM.
Reply With Quote
  #4  
Old 17th March 2019, 02:54 PM
Richard Richard is offline
Super Moderator
 
Join Date: Dec 2005
Location: Notts
Posts: 5,357
Default Re: JR149 speakers

Hi Bob and Phil,

Yes they are what they are but it's been a long time since I heard them so it will still be fun.

They're for a vintage system, backs against the wall in a smaller room, so no problem with size. It will be good to see the old FM3 etc glowing orange again rather than it being sat on the shelf!

In the late 70's I walked into a dealer who had a pair on top of a pair of Ardens playing Carnival of the Animals iirc. I naturally assumed it was the Ardens (the dealer will have his fun!) but it was the smaller speakers. The Ardens actually sounded worse when he switched, too heavy in his small room.

Thanks for thoughts about the caps. Google suggests some small value bipolar electros can start to decrease their resistance as they move towards shorting rather than increase esr. Apparently cap and esr meters aren't a reliable guide for small value old caps so best just to replace. 40 years is too long I think even if they still work in some manner.

All in pieces now. Removed the metal grills and cleaned off the crumbly old tweeter foam and checked the drivers. All looks fine. The inside foam damping is all springy and good and there's no sign of damp on the zinc plated parts.
A bit of white belly on the B110s, is this an issue which needs sorting or just leave them whilst they sound ok?

Oiled the wood and it's come up well. Should have them together again this week and will put them in the same room position to see if there's a change.
Reply With Quote
  #5  
Old 17th March 2019, 08:18 PM
Phil Y's Avatar
Phil Y Phil Y is offline
Senior Member
 
Join Date: Jul 2006
Location: Bristol, UK
Posts: 816
Default Re: JR149 speakers

Hello Richard,

I'm sure they will be just the job for your intended use. Don't take my comments too seriously, they are just not my kind of speaker. A friend of mine who had the KEF constructor version of the LS3/5A for many years thinks I'm too harsh in my judgment of them.
I still have a pair of B110s kicking around that were the midrange in a home built speaker of mine years ago. They also have the coating lifting around the dome. I have read that heat can be used to re-stick it but I have not been brave enough to try it. I should really because I could then sell them if it worked, I can't imagine I will use them for anything myself. The ones in my JR149s looked fine for whatever reason.

Phil.
__________________
Commission for Dark Skies (CfDS)
Reply With Quote
  #6  
Old 25th March 2019, 03:20 PM
Richard Richard is offline
Super Moderator
 
Join Date: Dec 2005
Location: Notts
Posts: 5,357
Default Re: JR149 speakers

Well these are back together again and I've had several good listens over the weekend.

I re-capped them with Vishay polyesters which I've used for coupling before and they sound very nice to me.

I left the metal grills off whilst checking them through as the grills are stapled in place and I wanted to be able to remove the drivers again if needed. They sound great despite a very near-field positioning. The tweeters certainly brought back memories, they have an almost electrostatic resolution seated so close.

Swept frequency with a test CD and all is clean with no buzzes. The teble was still strong so I took a look at the preset adjuster. I'd marked it with a couple of dots but had not had a twiddle. Ah, it was set fully anti-clockwise which is full treble. I don't know if the factory or the po set it there but I adjusted to the mid point and it sounds much better and more integrated. It might be different again of course with foam fitted.

This time, due to the mid room location rather than back to a wall, I raised bass 3dB on the preamp and the resulting sound had me listening for 3 evenings of several hours each. During the first evening the speakers changed dramatically to a fuller and more powerful sound so either they loosened up after not being used for a long time, or the caps ran in a little, or the speakers ran my ear holes in! Anyway the effect has stayed and they sound great now on 2 further sessions.

Metal grills back on next and black foam has just arrived
Attached Images
File Type: jpg xover-recapped.jpg (96.5 KB, 76 views)
File Type: jpg listen-before-grills.jpg (63.8 KB, 76 views)
Reply With Quote
  #7  
Old 24th January 2023, 06:14 PM
martinb082 martinb082 is offline
Junior Member
 
Join Date: Dec 2022
Location: 08034 USA
Posts: 1
Default Re: JR149 speakers

Hi Richard,
I know this is an old thread...
I have a pair of 149s with walnut end caps that are in nice shape with regard to scratches, etc. but look dried out and dull.
Based on your having said "Oiled the wood and it's come up well.", I was wondering if you used the Danish Oil, or something else?
I want to freshen up the wood, but don't want to damage it.
Thanks,
Martin
Reply With Quote
  #8  
Old 25th January 2023, 12:02 PM
Richard Richard is offline
Super Moderator
 
Join Date: Dec 2005
Location: Notts
Posts: 5,357
Default Re: JR149 speakers

Hi Martin, yes, Danish oil, I've used both Rustins and Wilko brand, they're both good and easy.

Not sure if you've used it before but it's very good for this sort of thing unless the old wood and varnish are in really bad condition. It brightens things up and any patina left still looks good.

I did the minimum, wiped over with white spirit, then a very light sand with fine paper on a block not really trying to remove any remaining original laquer, just flatting any rough bits.

The wood is thin veneer of course and easy to go through so less is always better. (You can always wipe it off with white spirit and start over again if it needs more prep.)

Then a gentle rub over with a Green Scotchbrite pad (for cleaning pans - from Asda).

The trick with using the oil (which is a type of varnish really and does dry after a day or two) is to wipe an excess on with a clean cloth, leave it 20 minutes, then buff it all off with a dry cloth, before leaving it a full day to dry.

Then a gentle rub with the Green pad and repeat for 3 coats (it's much quicker than it sounds!).

There are a couple of links here which say similar. (What doesn't work is putting lots on and expecting it to dry as it wont!)

https://www.triedandtruewoodfinish.c...ts/danish-oil/

https://danish-oil.com/how-to-apply-danish-oil/

I used the second method in the second link.

Cheers, Rich
Reply With Quote
Reply


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 03:57 PM.


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