snorrewiets
New Member
Nice find Montrecott !
What are the specs?
What are the specs?
-
Feeling lucky? Check out the AK 24th Anniversary Giveaway thread and join in the fun!
B&W Owners Thread
- Thread starter wgb113
- Start date
-
- Tags
- 805 b&w bowers wilkins
Thanks, Ben! I cannot resist classic British speakers.
Specs are hereIn the design brief, B&W mentions that the DM23 was modeled after the DM4. There are some similarities but there are some definite differences, too. Efficiency for example. I can't imagine using the 23 with a tube amp, like you can the DM4. But they are both very good speakers.
https://audiokarma.org/forums/index.php?threads/b-w-owners-thread.706916/page-10#post-15663513
As per the above post I have now almost completed my rebuild - just have to finish the grille refurb with aftermarket B&W badges. I have had a quick audition and they certainly seem to be a very good speaker and should be excellent for reproducyion of /male/female vocals and stringed instruments in particular - at least that appears valid on such a short duration listen.Will post photos here when completed.
I did have to purchase a pair of new production (2018 I believe) of the coles 4001G (16 Ohm) super-tweeter at great expense and I had to replace the surrounds on both woofers (they were from different batches and one surround was vey stiff) as well as re-centreing the voice coil on one of them. I had to perform the latter operation because it was very easy to cause the voice coil to scrape down the magnet poole-piece with light downward pressure on one side of the cone. The other woofer was OK in this respect and after re-centreing the voice coil the repaired woofer was also fine.
With regard to the original open circuit supertweeters I decided to investigate just why they went o/c. I removed the terminal block screws on the first tweeter and it just fell away indicating both wires from the voice coil were broken. Upon removing the diaphragm securing ring I extracted the diaphragm and inspected the voice coil with a x10 magnifier. I was able to see that both voice coice wires had broken off at the exact point that they emerged from the glue used to fix the V/C to the mylar diaphragm. I performed a similar operation on the other tweeter and found exactly the same thing. When thinking about why this could have happened it occurred to me that since the diaphragm moves up and down by very small degrees at high frequencies the point where the voice coil wires emerge from the solid adhesive must form a flexure point which over time results in the solid copper wires becoming brittle at the egress point and they eventually break off due to fatigue. The method of bringing the voice coil wires out from the diaphragm and voice coil is imo a very weak point on these tweeters. Unlike other units - such as the KEF T27 et-al - where the wires from the voice coil emrge 180 degress apart where they are fixed horizontally to the diaphragm plate itself. In such tweeters the wires do not have a single flexure point and they will not break due to fatigue.
Has anyone else carried out a similar investigation?
As per the above post I have now almost completed my rebuild - just have to finish the grille refurb with aftermarket B&W badges. I have had a quick audition and they certainly seem to be a very good speaker and should be excellent for reproducyion of /male/female vocals and stringed instruments in particular - at least that appears valid on such a short duration listen.Will post photos here when completed.
I did have to purchase a pair of new production (2018 I believe) of the coles 4001G (16 Ohm) super-tweeter at great expense and I had to replace the surrounds on both woofers (they were from different batches and one surround was vey stiff) as well as re-centreing the voice coil on one of them. I had to perform the latter operation because it was very easy to cause the voice coil to scrape down the magnet poole-piece with light downward pressure on one side of the cone. The other woofer was OK in this respect and after re-centreing the voice coil the repaired woofer was also fine.
With regard to the original open circuit supertweeters I decided to investigate just why they went o/c. I removed the terminal block screws on the first tweeter and it just fell away indicating both wires from the voice coil were broken. Upon removing the diaphragm securing ring I extracted the diaphragm and inspected the voice coil with a x10 magnifier. I was able to see that both voice coice wires had broken off at the exact point that they emerged from the glue used to fix the V/C to the mylar diaphragm. I performed a similar operation on the other tweeter and found exactly the same thing. When thinking about why this could have happened it occurred to me that since the diaphragm moves up and down by very small degrees at high frequencies the point where the voice coil wires emerge from the solid adhesive must form a flexure point which over time results in the solid copper wires becoming brittle at the egress point and they eventually break off due to fatigue. The method of bringing the voice coil wires out from the diaphragm and voice coil is imo a very weak point on these tweeters. Unlike other units - such as the KEF T27 et-al - where the wires from the voice coil emrge 180 degress apart where they are fixed horizontally to the diaphragm plate itself. In such tweeters the wires do not have a single flexure point and they will not break due to fatigue.
Has anyone else carried out a similar investigation?
Last edited:
Pics of my refurbished DM4's
New Coles 4001 supertweeter. Note the small hole at 6 o'c;ock. This is where the voice coil wiresemanate from the diaphragm and go to the back of the magnet where the terminal block is attached. This is the exact point where the wires eventually break due to fatigue.
New Coles 4001 supertweeter. Note the small hole at 6 o'c;ock. This is where the voice coil wiresemanate from the diaphragm and go to the back of the magnet where the terminal block is attached. This is the exact point where the wires eventually break due to fatigue.
snorrewiets
New Member
You did a very nice job here.
I have the same speakers and I am using them every day and enjoy them a lot.
See my post:
https://audiokarma.org/forums/index.php?threads/b-w-owners-thread.706916/page-9
Personally I think that they perform best on stands.
I had bought them secondhand in Holland, the supertweeters were not in them but Taiwanese tweeters.
Because I want them original I had found also in Holland a pair of used Coles supertweeters 16 Ohms
and they are ok,when you measure them with an universalmeter they should be around 23 Ohms.
Since you wrote about the little holes on the 6 o'clock position, I was not aware of that and checked mine
and indeed with the help of a magnifying glass I could see them.
Mine are produced in 1978 , so later models of the series.
DM 4's are very much sold in Holland, so it is not difficult to find them there secondhand.
For the supertweeters I have paid 40 Euro's for the pair..
Still happy with them....
Regards, Ben.
I have the same speakers and I am using them every day and enjoy them a lot.
See my post:
https://audiokarma.org/forums/index.php?threads/b-w-owners-thread.706916/page-9
Personally I think that they perform best on stands.
I had bought them secondhand in Holland, the supertweeters were not in them but Taiwanese tweeters.
Because I want them original I had found also in Holland a pair of used Coles supertweeters 16 Ohms
and they are ok,when you measure them with an universalmeter they should be around 23 Ohms.
Since you wrote about the little holes on the 6 o'clock position, I was not aware of that and checked mine
and indeed with the help of a magnifying glass I could see them.
Mine are produced in 1978 , so later models of the series.
DM 4's are very much sold in Holland, so it is not difficult to find them there secondhand.
For the supertweeters I have paid 40 Euro's for the pair..
Still happy with them....
Regards, Ben.
Picked up this pair of Nautilus 803 in January of this year.
MIC
@montrecott , congrats on your DM23's...they look like my DM10's with an added midrange (?)...running mine with a Pioneer SX-626 receiver and its a nice "mellow" match
You're right, the woofers and tweeters certainly do look the same! It would be interesting to do a shootout.@montrecott , congrats on your DM23's...they look like my DM10's with an added midrange (?)...running mine with a Pioneer SX-626 receiver and its a nice "mellow" match
Hi, i recently bought some dm4, this is some early version unfortunately one coles doesn't work. The other is ok and it is the 8ohm version, measured. Now the question is, if I buy a pair of 16ohms, will I need to change the crossover? Is 1: 1 replacement sufficient,
Regards, Artur
Regards, Artur
WillVT
Super Member
Hey! I'm now part of the club!
A few weeks ago I became the proud owner of a beautiful pair of 802f Special Series 80. I absolutely love them. I got them with one bad tweeter. I replaced the diaphragm, and they are singing.
I'm still trying to find a better amp for them . My Marantz 140 doesn't quite wake them up. They sound great with my Carver pm1200, but it has some issues, and I don't love the fan noise.
I guess I've been in the club for a while actually. I have a pair of DM602's in my bedroom, run with an Onkyo tx4500.
A few weeks ago I became the proud owner of a beautiful pair of 802f Special Series 80. I absolutely love them. I got them with one bad tweeter. I replaced the diaphragm, and they are singing.
I'm still trying to find a better amp for them . My Marantz 140 doesn't quite wake them up. They sound great with my Carver pm1200, but it has some issues, and I don't love the fan noise.
I guess I've been in the club for a while actually. I have a pair of DM602's in my bedroom, run with an Onkyo tx4500.
If the good tweeter is the 8 Ohm version then it must have been changed over at some time. The DM4's were fitted with 16 Ohm tweeters and the crossovers are designed for this value. So swapping in an 8 Ohm version will not work as intended without re-working the crossovers.
IMO the Coles tweeters are badly designed because the voice coil wires are unsupported where they leave the diaphragm and high frequency vibration over a long period of time will eventually cause the wires to fatigue and break. Both Coles in my DM4's had failed in this manner. Unfortunately, the latest production batch made by Coles are exactly the same design.- apart from a plastic frame instead of metal.
Exactly, I saw it on a damaged speaker, I do not know if the crossover complies with the diagram, because I did not measure the elements. I have not found info about any coles replacement. Coming back to the question, if I connect the 4001G to the current crossover, what could be the differences?
The original cross over is designed for 16 Ohm mids and tweeters so it should be ok to use the 4001G without any changes. You need to download the DM4 x-over schematic from hifiengine https://www.hifiengine.com/manual_library/bowers-and-wilkins/dm4.shtml and compare the component values with those on your x-over. Note you will need to log in before you can download.
The ASW608s have been in the system for a few days now. Oh my, they are fantastic. Can’t believe I waited so long to do this. It seems like the last piece of the puzzle has been put in place and now it’s time to sit back and enjoy.
Bowers and Wilkins has done splendid job in creating a powerhouse in such a small package. Nice to have features like basic DSP and EQ in such an affordable offering. The build quality is excellent and they fit superbly into the system and the room.
Cheers,
Scott
Bowers and Wilkins has done splendid job in creating a powerhouse in such a small package. Nice to have features like basic DSP and EQ in such an affordable offering. The build quality is excellent and they fit superbly into the system and the room.
Cheers,
Scott
Finally somewhere that loves B&W speakers. There has been too much criticism of them for some years now.
So good to see you guys. I will scroll through over the next few days and check out your systems.
I have used the DM17's for 35 years and everyone who had heard them have commented on how good they sound. I have recently finally upgraded to some 805S' in good condition and they take it to another level, but they required an amplifier that takes a firm grip to get the most out of them. In my case a 1975 Luxman M2000 did the trick.
So good to see you guys. I will scroll through over the next few days and check out your systems.
I have used the DM17's for 35 years and everyone who had heard them have commented on how good they sound. I have recently finally upgraded to some 805S' in good condition and they take it to another level, but they required an amplifier that takes a firm grip to get the most out of them. In my case a 1975 Luxman M2000 did the trick.
Erik Tracy
Everyone's happy when the wizard walks by
Still using CDM-1NTs (CDM-SE center) in my HT setup!
TimF
Super Member
I always liked the cabinets and looks of this model, not to mention how they sound, nice looking pair you have. Enjoy!
