Well, to report that I finished the R50 renovation a few months back, and they've settled in. They are driven by Quad 405/2's most of the time. The X-vers were replaced ( Solens all through) , split into 3 sections, bass, MF and HF, and the speakers biwired and the wool teased out where it had compacted over the years. All the units are as original except that I've given the B139's heavy duty gaskets to soak up any resonance. Both Coles were replaced and one of the T27's, otherwise the units are the originals.
The Xover was also modified to give an 18Db MF rolloff and I also played around with the wool damping on the B110 section to reduce the "quack" with subjectively good results. I don't see much to be gained by changing the unit used now.
The sound is very solid yet transparent, superb bass but not overwhelming, the midrange is now very easy on the ear, and the HF section is well balanced.
Having been through the exercise, I tend to agree with leaving the design well alone except for updating the crossover(s) and doing a bit of routine maintenance/adjustment at the same time. The design still works well!
The Xover was also modified to give an 18Db MF rolloff and I also played around with the wool damping on the B110 section to reduce the "quack" with subjectively good results. I don't see much to be gained by changing the unit used now.
The sound is very solid yet transparent, superb bass but not overwhelming, the midrange is now very easy on the ear, and the HF section is well balanced.
Having been through the exercise, I tend to agree with leaving the design well alone except for updating the crossover(s) and doing a bit of routine maintenance/adjustment at the same time. The design still works well!
Glad to hear of your success.
Sense has prevailed on my side, and I am doing a restore. I am restoring my originals, plus have made two more cabinets and will use the units from a pair of Concertos I got from a school fete a couple of years ago (for £80 - they thought I was mad, I knew I had a bargain).
So I will end up with two pairs, one for the bedroom, one for the sitting room. The bedroom ones will need veneering with careful input from wife. It is a large attic room, so no trouble from neighbours.
Built the new boxes over the holiday period.
I am replacing cross overs, and replacing T27's with vifa XT25TG-30-04 as suggested by Wilmslow Audio.
All four B139's and B110's are OK/
New boxes are MDF rather than chipboard, and I've put more bracing in bass section (a 1x1 L to R across the diagonal bracing) which seems to significantly raise resonant frequency of panel.
Seems long haired wool is difficult to obtain now, so will probably use some wadding.
Both pairs will be bi-wired.
Should all be complete in a couple of weekends. I'll report back.
What I would be curious about is a side to side comparison with best of current speakers - but then maybe ignorance is best.
Sense has prevailed on my side, and I am doing a restore. I am restoring my originals, plus have made two more cabinets and will use the units from a pair of Concertos I got from a school fete a couple of years ago (for £80 - they thought I was mad, I knew I had a bargain).
So I will end up with two pairs, one for the bedroom, one for the sitting room. The bedroom ones will need veneering with careful input from wife. It is a large attic room, so no trouble from neighbours.
Built the new boxes over the holiday period.
I am replacing cross overs, and replacing T27's with vifa XT25TG-30-04 as suggested by Wilmslow Audio.
All four B139's and B110's are OK/
New boxes are MDF rather than chipboard, and I've put more bracing in bass section (a 1x1 L to R across the diagonal bracing) which seems to significantly raise resonant frequency of panel.
Seems long haired wool is difficult to obtain now, so will probably use some wadding.
Both pairs will be bi-wired.
Should all be complete in a couple of weekends. I'll report back.
What I would be curious about is a side to side comparison with best of current speakers - but then maybe ignorance is best.
Good luck with it all.
If it's any help, I had the same problem with getting genuine long-haired wool, eventually I found some at IPL Acoustics
http://www.iplacoustics.co.uk/cabinet_accessories.htm
01271 867439
They're very helpful even for small orders.
One word of caution - the original construction notes are right - you have to be careful not to get too enthusiastic about stuffing (more wool) the B139 line otherwise you alter the damping effect. All I did was to carefully replace the really "lumpy" bits having teased out the rest.
If it's any help, I had the same problem with getting genuine long-haired wool, eventually I found some at IPL Acoustics
http://www.iplacoustics.co.uk/cabinet_accessories.htm
01271 867439
They're very helpful even for small orders.
One word of caution - the original construction notes are right - you have to be careful not to get too enthusiastic about stuffing (more wool) the B139 line otherwise you alter the damping effect. All I did was to carefully replace the really "lumpy" bits having teased out the rest.
Thanks for the tip. But it is still not cheap stuff.
Aother option I have is to use the wool in the original pair and split it between the two pairs - but instead of wool, use BAF wadding in section W (rear of bass panel) and mid enclosure (which is roughly half the total according to original specs). Also use bitumen panels in mid enclosure, as well as lining with underbody sealer. These are fairly cheap enhancements worth doing while I have it all open. I will see how it helps the quack!
I can't wait to replace the Concertos, it's amazing how much better the TL sounds, with the same units.
Aother option I have is to use the wool in the original pair and split it between the two pairs - but instead of wool, use BAF wadding in section W (rear of bass panel) and mid enclosure (which is roughly half the total according to original specs). Also use bitumen panels in mid enclosure, as well as lining with underbody sealer. These are fairly cheap enhancements worth doing while I have it all open. I will see how it helps the quack!
I can't wait to replace the Concertos, it's amazing how much better the TL sounds, with the same units.
Progress is being made. New pair of cabinets made, I've spent the weekend veneering. My first time. Paper backed veneer, two 4x8 sheets, one oak one cherry.
New mdf cabinets are square. Old chipboard have lots of rounded corners and edges gained over the years. I never veneered them originally, just covered in cloth.
Bought myself a Bosch router. Back in '75 I did all the rebates with chisel and hammer, I'm not doing that again. Now the question is how to find a bit big enough to do the rebates, or am I missing something? My router has 1/4" bits.
Trimming seems OK with router. But trimming across the grain seems to need some sanding to clean up. Is this normal, or is my bit not sharp enough?
So, I keep reading all these wonderful accounts of success and immaculate pictures. Not I!
I applied PVA, didn't have any kind of press so just lay speakers on top of each other (4 large boxes) and hoped for the best.
Those boxed are heavy. One mistake was to try to move them around with the units and baffle still in place. Try flipping an R50 by yourself with one side veneered, still drying, not trimmed, all units in place, so the other side can be veneered, then throw another one on top.
Sense prevailed the next morning and I removed the baffle and units. That B139 is heavy.
I almost did a big boo boo and used the wrong wood on on side of one speaker. Spotted it fast and removed it ready for the other pair.
Next morning, my new cabinets weren't too bad. My old cabinets, at least one side was full of large wrinkles.
When I originally applied veneer, I just painted PVA on the cabinet, placed veneer on top, and chucked another speaker on top to press it down.
So, I thought I might try this iron on business. Got the household iron out, turned it on, and started ironing.
Another mistake, it was on a steam iron setting (or was that a mistake). Anyway, empty water and start again.
I must say the mountains were turned into hills. But still not satisfactory.
Luckily my new cherry cabinets seem to be fine.
So, maybe I'll do some more ironing next week.
If we didn't make mistakes we would never learn. That's my moto anyway. Much more fun than getting it right first time.
In short, any ideas how best to iron out the hills in my paper backed veneer? Is it just time and patience?
I wish every body else wasn't so perfect....
BTW, my package from Wilsmlow Audio was delivered by Business Post, but I was away on business, BP only keep it for 4 days, so it went back, BP lost it, then found it again, and WA sent it again, I may get it before the end of January, it has my new tweeters and cross overs.
And in case you missed it, how do I do the wide rebates with a 1/4" bit set? I have searched but cannot find any answers.
To be honest, I am doing all this in a rush between family and job pressures. And I'm most interested in when I am going to hear Mahler properly again, the visuals are for pussies
.
New mdf cabinets are square. Old chipboard have lots of rounded corners and edges gained over the years. I never veneered them originally, just covered in cloth.
Bought myself a Bosch router. Back in '75 I did all the rebates with chisel and hammer, I'm not doing that again. Now the question is how to find a bit big enough to do the rebates, or am I missing something? My router has 1/4" bits.
Trimming seems OK with router. But trimming across the grain seems to need some sanding to clean up. Is this normal, or is my bit not sharp enough?
So, I keep reading all these wonderful accounts of success and immaculate pictures. Not I!
I applied PVA, didn't have any kind of press so just lay speakers on top of each other (4 large boxes) and hoped for the best.
Those boxed are heavy. One mistake was to try to move them around with the units and baffle still in place. Try flipping an R50 by yourself with one side veneered, still drying, not trimmed, all units in place, so the other side can be veneered, then throw another one on top.
Sense prevailed the next morning and I removed the baffle and units. That B139 is heavy.
I almost did a big boo boo and used the wrong wood on on side of one speaker. Spotted it fast and removed it ready for the other pair.
Next morning, my new cabinets weren't too bad. My old cabinets, at least one side was full of large wrinkles.
When I originally applied veneer, I just painted PVA on the cabinet, placed veneer on top, and chucked another speaker on top to press it down.
So, I thought I might try this iron on business. Got the household iron out, turned it on, and started ironing.
Another mistake, it was on a steam iron setting (or was that a mistake). Anyway, empty water and start again.
I must say the mountains were turned into hills. But still not satisfactory.
Luckily my new cherry cabinets seem to be fine.
So, maybe I'll do some more ironing next week.
If we didn't make mistakes we would never learn. That's my moto anyway. Much more fun than getting it right first time.
In short, any ideas how best to iron out the hills in my paper backed veneer? Is it just time and patience?
I wish every body else wasn't so perfect....
BTW, my package from Wilsmlow Audio was delivered by Business Post, but I was away on business, BP only keep it for 4 days, so it went back, BP lost it, then found it again, and WA sent it again, I may get it before the end of January, it has my new tweeters and cross overs.
And in case you missed it, how do I do the wide rebates with a 1/4" bit set? I have searched but cannot find any answers.
To be honest, I am doing all this in a rush between family and job pressures. And I'm most interested in when I am going to hear Mahler properly again, the visuals are for pussies
.Work progresses. I have done main work on renovating old pair.
Mid range/treble is wonderful. I've been listening to first movement of mahler 8th.
But bass is very weak on one of the pair, I've played about with wool, but no help.
The B139 unit on this is a replacement, constructors kit. It feels much more stiff than my other 3 B139's It is slightly smaller. Different chasis shape. Is this a duff unit? It really cannot get anything out of the double basses.
I will do some searching.
Mid range/treble is wonderful. I've been listening to first movement of mahler 8th.
But bass is very weak on one of the pair, I've played about with wool, but no help.
The B139 unit on this is a replacement, constructors kit. It feels much more stiff than my other 3 B139's It is slightly smaller. Different chasis shape. Is this a duff unit? It really cannot get anything out of the double basses.
I will do some searching.
I'm going to get a bit technical.
I have three B139 6171's. I have one B139B 1044 Constructor seris.
In my first rebuild pair, I was using one 6171 and one 1044. The bass on the 1044 sucked. I replaced it with a 6171 and got some bass again.
To be even more technical, the 6171 'flapped' as it should when the bass drum was rolling.
So my B139B 1044 constructor series is destined for scrap heap. I could find nothing wrong with it, but it did feel significantly stiffer.
Now here is the question. Did I just get a duff unit (I bought it in the ?late 70's from a shop up Tottenham High Court Rd) , or is there a difference between the 6171 and 1044? I need to know the answer, as I need to purchase another pair, and I don't know which to go for on ebay.
I seem to remember some message about how constructor series units were the rejects.
I have three B139 6171's. I have one B139B 1044 Constructor seris.
In my first rebuild pair, I was using one 6171 and one 1044. The bass on the 1044 sucked. I replaced it with a 6171 and got some bass again.
To be even more technical, the 6171 'flapped' as it should when the bass drum was rolling.
So my B139B 1044 constructor series is destined for scrap heap. I could find nothing wrong with it, but it did feel significantly stiffer.
Now here is the question. Did I just get a duff unit (I bought it in the ?late 70's from a shop up Tottenham High Court Rd) , or is there a difference between the 6171 and 1044? I need to know the answer, as I need to purchase another pair, and I don't know which to go for on ebay.
I seem to remember some message about how constructor series units were the rejects.
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