NEWBIE: Seeking 2 or 3 way SEALED DIY project!

[Lojzek]

There may be a chance to repair the original tweeter. Manufacturer states aluminum flat wire (ribbon) and I wonder what the conection to tweeter terminal looks like. May be just a electrical continuity issue. I wonder what the schematic is and what the crossover looks like.

[boswald]

If you really love those speakers your best bet is to get a microphone, learn to measure, and give us (esp. Paul) the data. Luckily you still have one good tweeter, so a pair of new tweeters can be set up to sound the way the originals were set up to sound.

I have been able to repair many tweeters for Allisons(I have Ones), but they too are becoming unobtanium(now they are merely inaffordium). So I am working on a current replacement with modern parts. So you know I "feel your pain".

Stick with it, if you love them. We'll help.

Yours in liking what we like, David

[diyrob]

I have some naim arrivas in a second system - they sound exactly what you want - totally sealed and very punchy. I think drivers are stock vifa models though this needs looking into. if you could get the exact drivers (and the circuit) this could be a good design to copy - sloping front baffle and separate inner enclosures for bass + mid (both 6'' drivers). they are cheap as chips 2nd hand (in uk anyway) maybe a refurbish (re-veneer?) and xover upgrade is an option if you find a 2nd hand pair?

[omsoc]

Troels did a sealed bass design recently using a plate amp for bass letting you use your valve amps on the mid/tweeter....best of both worlds, maybe.

MUN17-3W

[Paul Vancluysen]

Originally Posted by omsoc

Troels did a sealed bass design recently using a plate amp for bass letting you use your valve amps on the mid/tweeter....best of both worlds, maybe.

MUN17-3W

The used Hypex plate amplifier in that project has a latency of 1.12ms for the analogue inputs, because of the digital processing. So the bass is delayed w.r.t. midrange and tweeter. You can compensate for a part in the frequency domain by changing filter slopes, but in the time domain the bass will always come too late. I don't say it isn't good, but I don't like it for a crossover frequency at 200Hz.
A friend of me did a test with a miniDSP in a digital 3-way by delaying the woofer 1ms. He said he could hear the difference as a less focussed, more enlarged sound image. In my opinion the timing will be affected in such concept. I think it is better to make it full analog or full digital, not mixed.

[SONDEKNZ]

Originally Posted by Paul Vancluysen

Concerning the damaged tweeters of the Magnats. It is like Lojzek is telling also, sure there are other tweeters for replacement. The problem is the implementation, especially the X-over adaptation. If you are able to do some acoustical SPL measurements and electrical impedance and transfer measurements I can give you the support to realize this.
Paul

Guys

I think this is a very sensible step forward to us. Failing success in this endeavor, we will attack a new build.
Frankly, I never would have guessed that I could expect such support from strangers on a forum. We are quite overwhelmed by your generosity.
So, sincere thanks again, to Paul, Lojzek, Boswald, LineSource and others. What an A-Team!




Sometime soon, I will post very clear photos of that faulty MAGNAT tweeter and the inner area that appears to have gone 'open' circuit.
(It seems that the wire connecting the tweeter to the internal speaker cabling is thinner than a cat's whisker - not a flat ribbon wire BTW - so I can imagine that a well-intentioned blob of solder is probably not going to help restore the frequency extension that these tweeters excel at...)

So, photos to come.


(One more thought... Should I start a new thread entitled "MAGNAT ALL-RIBBON 6 TWEETER REPAIR OR REPLACE..."?)

[Paul Vancluysen]

Tony

I also think, it is the best to do it in that sequence and maybe with a new entitled thread for the repair or replacement of the tweeter, you are reaching more forum readers.

[Lojzek]

Once I had to to repair 2 open circuit midrange units and both had the same fault, hidden in the circled area. So I disolved the glue and started looking for the point of a broken connection. Before that I scraped the enamel lightly at the spot that arrow shows to make sure which terminal was faulty and if the voice coil still measures normal DC resistance.


If this was the case with magnat tweeter, that would make it even harder to repair but what has got one to lose? Good luck, I am confident that you (we) will have this sorted one way or the other.

[SONDEKNZ]

Confirmed with thanks Paul.

Let's put this thread on the back-burner for the moment and I will start a new thread for the MAGNAT ALL-RIBBON 6 TWEETER REPAIR OR REPLACE, including all of the salient information to date.

(To be continued... Perhaps. )

[Dave Bullet]

Originally Posted by SONDEKNZ

Confirmed with thanks Paul.

Let's put this thread on the back-burner for the moment and I will start a new thread for the MAGNAT ALL-RIBBON 6 TWEETER REPAIR OR REPLACE, including all of the salient information to date.

(To be continued... Perhaps. )

I think you could replace the tweeter, quicker than probably building a new proven design. You might be able to even improve the sound by replacing old capacitors with more accurate values (they wander over time).

It depends on your woodworking skills in being able to modify the existing baffle for the new tweeter.

Here's my setup to measure - what it cost.
PC - $25 (an old lenovo off trademe). You might be able to get away with a USB soundcard (pulse response will vary) but you can get around that. I won't describe that here

Microphone - I use a Behringer ECM8000 - it cost about $100 from memory. You can self calibrate - I can show you how (or do it for you if you send it to wellington)

A balanced XLR cable (to connect mic to preamp) ~ $30?

A microphone preamp - I found one on Trade me for about $100 - with balanced XLR connector

A jig - this connects the mic pre-amp. You can just make this up yourself. Mine comprises a plastic box with a few RCA connectors and speaker binding terminals, so I can swap in and out stuff

Software - I use speaker workshop (free) for xover sim and measurement. I also use Bagby' and Laub's excellent spreadsheet tools

+... new tweeters.

If you just want to fix your existing speakers, nothing more... someone in Auckland must have the above setup.

If however you might get into speaker DIY - then the above will pay off in the long run and you'll be able to tweak / tune / measure and optimise your refurbished speakers until just how you like them.