I've also discovered that the chambers like to be clocked a certain way for the most even fitment. The small notches in the flange dont appear to matter whether they line up with the motor fasteners, but I'm going to try lining them up anyways.
The round shims which go under the wool discs are supposedly there to provide a specific amount of compression and preload, according to Bliesma. I don't really see how this is critical aside from clamping the wool disc to the extent it won't vibrate, but I'm going to do whatever I've been instructed to so the driver specs aren't affected in any way.
I had to fabricate a thin nozzle to apply the RTV adhesive consistently on the flanges. So far the test pieces I used the RTV on adhere very well. I trust the RTV more than the contact adhesive due to its flexibility and long term stability, not to mention it won't shrink over time.
The round shims which go under the wool discs are supposedly there to provide a specific amount of compression and preload, according to Bliesma. I don't really see how this is critical aside from clamping the wool disc to the extent it won't vibrate, but I'm going to do whatever I've been instructed to so the driver specs aren't affected in any way.
I had to fabricate a thin nozzle to apply the RTV adhesive consistently on the flanges. So far the test pieces I used the RTV on adhere very well. I trust the RTV more than the contact adhesive due to its flexibility and long term stability, not to mention it won't shrink over time.
Well, I'm going to point out the fact I'm BEYOND FRUSTRATED with these stupid tweeters. First attempt failed with RTV due to insufficient control over centering the back chamners with weight placed on them to overcome the idiotic preload required to compress the wool material. There is so much radial slop in the way the chambers fit, which allows it to tip sideways during clamping. I'd have to build a fixture ie some sort of sleeve setup to keep these chambers centered. Its an idiotic design on Bliesma's part to engineer this much slop into the fit.
They told me to use 2 liter bottles of soda to weigh down the chambers, but its not enough weight. You need at least twice that amount to put enough force on the glue joint to be confident its being compressed enough.
They stated that some sort of UHU product is used to glue the chambers. I dont have access to that product being over here in the US and any decent adhesive will have to be mail ordered being i live in the armpit of the country. Im going to be paying over 50 bucks round trip to ship these stupid things just to get them put back together and wait a few weeks. This is idiotic.
I'm goinh back to my Seas T35-C002 soft domes which are built to a higher standard than these T34Bs. They may not have the top end extension of a Be driver, but they will do almost the same dynamic range. Sorry guys, these Bliesma drivers aren't put together as well as some of the Seas and Scanspeak stuff. I can at least get replacement diaphragms for the Seas T35-C002.
I shouldn't have to pay shipping to get these things fixed. What a joke.
Go ahead, flame away at me for not being a Bliesma fan. I don't care. These things can go onto the shelf for my son to do what he wants with. I dont have the time or patience to deal with this anymore. I would have thrown them in the trash if it wasn't for the Beryllium they contain. Unless Bliemsa offers to pay the shipping both ways, I'm done with these things.
They told me to use 2 liter bottles of soda to weigh down the chambers, but its not enough weight. You need at least twice that amount to put enough force on the glue joint to be confident its being compressed enough.
They stated that some sort of UHU product is used to glue the chambers. I dont have access to that product being over here in the US and any decent adhesive will have to be mail ordered being i live in the armpit of the country. Im going to be paying over 50 bucks round trip to ship these stupid things just to get them put back together and wait a few weeks. This is idiotic.
I'm goinh back to my Seas T35-C002 soft domes which are built to a higher standard than these T34Bs. They may not have the top end extension of a Be driver, but they will do almost the same dynamic range. Sorry guys, these Bliesma drivers aren't put together as well as some of the Seas and Scanspeak stuff. I can at least get replacement diaphragms for the Seas T35-C002.
I shouldn't have to pay shipping to get these things fixed. What a joke.
Go ahead, flame away at me for not being a Bliesma fan. I don't care. These things can go onto the shelf for my son to do what he wants with. I dont have the time or patience to deal with this anymore. I would have thrown them in the trash if it wasn't for the Beryllium they contain. Unless Bliemsa offers to pay the shipping both ways, I'm done with these things.
First scan speak and now Bliesma are off my list. Crazy how these companies can't seem to do basic customer service right. Anything other than a full replacement at no cost to the user is unacceptable here.
I want to be very clear here, that I'm not trying to rag on Bliesma for the heck of it. I wanted these drivers to work out, but opening a box of brand new drivers with high expectations to find defective units is a massive let down. Leaving the customer to deal with the problem himself unless he wants to spend more money and potentially have to wait several weeks isn't particularly good customer service. Shipping these things back and forth to Germany isn't cheap. What a massive let down.
Sorry to hear about the difficulties with the repair.
Perhaps after some time, a solution will come up. Perhaps after some frustration, anger, annoyance, over some time a solution comes up that you didn't think of initially. Don't despair.
I too have a tale of woe:
I had TWO Purifi midwoofers damaged- one from my own mistake of dropping the loudspeaker cabinet from about 2m above the ground. (Note to self- learn how to strap down something properly before doing vertical polars). Another from shipping damage from USA to AUS after I had a different cabinet on @bikinpunk 's Klippel NFS- I could see that it that the poor thing had been on a bumpy journey, resulting in a ubbing voice coil.
You can imagine the annoyance of having ~USD$450 of transducer turned into paperweight.
Not just once, but twice!
Thinking that I had nothing to lose, I tried everything, including forcing the frame back manually, and whacking it with a mallet! I mean, when it's this bad, it could only get better right? No dice.
The firs time I enquired with Purifi, whose initial response was- can you show us some photos and what was the serial number? And followed up with, sorry it's not repairable.
Hmph! (and something not so polite) I thought!
But who could blame my contact at Purifi?- he's probably not on the assembly line building these things! Even if (s)he is, he's probably not dropping them on the ground from above 2 metres for a drop test. Even if (s)he is, he's probably not trying to repair the thing- he's looking to improve the packaging. But he's definitely not slapping his forehead over USD$900 of lost product.
US$900 could feed a small family in Asia or Africa for a month (or three). That's the lens through which I view waste.
Well guess what?
Months and month later, it occurred to me how to repair it! And after some action, I did it!
I reported my findings to Purifi. Sure, it's not my job to do so, but if anyone gets their drivers damaged in transit- hey don't ditch it out!
Perhaps consider offering replacement basket/cone/voice coil assemblies in the future? Or offer B stock drivers as replacement? Or something (I'm not in the business of driver development, but you get my drift)
I know this doesn't take out the bite of losing a pair of top priced tweeters. But I think you have the knowledge, experience, resolve, and communication skills to sort it out, even though it doesn't feel like that right now.
So, sometimes a mishap provides an opportunity for learning!
Perhaps after some time, a solution will come up. Perhaps after some frustration, anger, annoyance, over some time a solution comes up that you didn't think of initially. Don't despair.
I too have a tale of woe:
I had TWO Purifi midwoofers damaged- one from my own mistake of dropping the loudspeaker cabinet from about 2m above the ground. (Note to self- learn how to strap down something properly before doing vertical polars). Another from shipping damage from USA to AUS after I had a different cabinet on @bikinpunk 's Klippel NFS- I could see that it that the poor thing had been on a bumpy journey, resulting in a ubbing voice coil.
You can imagine the annoyance of having ~USD$450 of transducer turned into paperweight.
Not just once, but twice!
Thinking that I had nothing to lose, I tried everything, including forcing the frame back manually, and whacking it with a mallet! I mean, when it's this bad, it could only get better right? No dice.
The firs time I enquired with Purifi, whose initial response was- can you show us some photos and what was the serial number? And followed up with, sorry it's not repairable.
Hmph! (and something not so polite) I thought!
But who could blame my contact at Purifi?- he's probably not on the assembly line building these things! Even if (s)he is, he's probably not dropping them on the ground from above 2 metres for a drop test. Even if (s)he is, he's probably not trying to repair the thing- he's looking to improve the packaging. But he's definitely not slapping his forehead over USD$900 of lost product.
US$900 could feed a small family in Asia or Africa for a month (or three). That's the lens through which I view waste.
Well guess what?
Months and month later, it occurred to me how to repair it! And after some action, I did it!
I reported my findings to Purifi. Sure, it's not my job to do so, but if anyone gets their drivers damaged in transit- hey don't ditch it out!
Perhaps consider offering replacement basket/cone/voice coil assemblies in the future? Or offer B stock drivers as replacement? Or something (I'm not in the business of driver development, but you get my drift)
I know this doesn't take out the bite of losing a pair of top priced tweeters. But I think you have the knowledge, experience, resolve, and communication skills to sort it out, even though it doesn't feel like that right now.
So, sometimes a mishap provides an opportunity for learning!
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That's some crazy mental gymnastics to try to put a positive spin on someone getting defective products. Are people afraid of calling out bad customer support here?
I'm not trying to bash Bliesma, but this is not an impressive loudspeaker factory, but a single guy working from a home in a residential area in a small German town. Also, Stanislav is not German as far as I know.
So this is not really a product "made in Germany", maybe in part it is assembled in Germany. I'm perfectly sure no one is allowed to manufacture something from Berylium in a residential area, at least not in Germany.
The glue problem is something I found on quite some small batch production items. Mr. Malikov may be a genius in loudspeaker design, but often such personalities don't care that much about "some stupid glue".
I often spent hours to find a certain glue for a specific task, even more time to match a lubricant to some item. There are not many "pro's" that think this is really necessary. Many skip this "waste of time" and take what is aviable or cheapest at the next Home Depot.
We have and produce a lot of high tech glue in Europe, you just have to pick the right stuff. Something from the "SikaFlex" line (made by SIKA Corporation) for example.
So IMO this is not a technical problem, but self made from a one man show running a loudspeaker "factory".
If the pressure is to high to close the pot, take out some of the shims compressing the felt. The tweeter will not sound any worse. You can sure measure it.
Clean the surface with some non petroleum based solvent like alcohol and use a glue compareable to the stuff they use for car windscreens. It is not aggressive or corrosive and will stick like hell. Don't use too much if you plan to open it again. Cures in about 2 hours.
So this is not really a product "made in Germany", maybe in part it is assembled in Germany. I'm perfectly sure no one is allowed to manufacture something from Berylium in a residential area, at least not in Germany.
The glue problem is something I found on quite some small batch production items. Mr. Malikov may be a genius in loudspeaker design, but often such personalities don't care that much about "some stupid glue".
I often spent hours to find a certain glue for a specific task, even more time to match a lubricant to some item. There are not many "pro's" that think this is really necessary. Many skip this "waste of time" and take what is aviable or cheapest at the next Home Depot.
We have and produce a lot of high tech glue in Europe, you just have to pick the right stuff. Something from the "SikaFlex" line (made by SIKA Corporation) for example.
So IMO this is not a technical problem, but self made from a one man show running a loudspeaker "factory".
If the pressure is to high to close the pot, take out some of the shims compressing the felt. The tweeter will not sound any worse. You can sure measure it.
Clean the surface with some non petroleum based solvent like alcohol and use a glue compareable to the stuff they use for car windscreens. It is not aggressive or corrosive and will stick like hell. Don't use too much if you plan to open it again. Cures in about 2 hours.
I tried a second time attaching the back chambers with 3m contact cement and failed once more. The problem is ONLY 1mm CONTACT AREA overlapping the flange surface on the motor. There is also no self centering provision to guarantee a perfect airtight seal once the chamber is glued on, so only having 1mm of contact margin is unreasonable to expect a good solid glue joint and most importantly an air tight seal. Once the tweeter is installed in an enclosure and the seal to the dome is compromised, you can damage the dome from the LF driver's generated air pressure. Thats not a good scenario, especially with a Beryllium dome.
Its very clear the rear chamber design is flawed. Attaching a couple of rear chambers shouldnt be a big deal. The Bliesma design however makes this a near impossible task without a dedicated jig of sorts. My last attempt will be using a different chamber. The original chambers are going into the trash. What a disappointingly engineered design.
I spent over $700 on a set of paperweights. Sad and unacceptable.
Its very clear the rear chamber design is flawed. Attaching a couple of rear chambers shouldnt be a big deal. The Bliesma design however makes this a near impossible task without a dedicated jig of sorts. My last attempt will be using a different chamber. The original chambers are going into the trash. What a disappointingly engineered design.
I spent over $700 on a set of paperweights. Sad and unacceptable.
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The right thing to do would be to send me a new set of drivers in exchange with shipping expenses covered both ways. I'm not interested in wasting my precious time bickering about who's fault is what. I just want some properly assembled and functioning drivers for the money I paid. I dont want to waste my time repairing brand new drivers which were defective right out of the box.
I know my way around adhesives and their proper application, compatability and assembly methods. I can't rely on a 1mm margin of error which isn't visible once its all assembled.
The back chamber design is flawed on these tweeters. Different machining of the chamber flange area would fix the issue. I suspect they were trying to get the most air volume from the given chamber dimensions to lower Fs as much as possible, so the flange area was reduced as far as it could have been. The flanges also sit unevenly by a few thousands on the rear magnet, which worsens the adhesion issue. The slightly uneven flange surface is enough to cause the chamber to become cocked sideways once pressure is applied on the chamber needed to set the glue joint. This is how most contact adhesives are applied, as the final assembly pressure is what sets the glue joint and determines its bond integrity. The lack of flange surface area really compounds the issue.
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If I was better at CAD design I'd just 3d print some new chambers from ABS and carry on with my life. I'm just tired of fixing my Creality printer for the 5th time (cheap junk). Such basic, simple back chambers and I can't even make those myself despite having purchased the tools.
These things aren't that deep. Why not make your own back chamber with a thickness of MDF glued to the back of the cabinet front panel, with a hole in the middle for the entire tweeter including mounting screws, and the whole thing covered with a square of MDF? It'd be like a subcabinet for a midrange, except for the tweeters. Sure it's a kluge, but at least it gets you there.
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