Martin Logan Aerius i rebuild

[Steever]

A few years ago now, I was introduced to panel speakers through some Apogee Calipers at a hi-fi show in Auckland, NZ.

 

Since then and after listening to various panels (Magneplanar, Audiostatic, Martin Logan, etc) I have always wanted to own panels. Apogees came up a couple of times but I couldn't afford the amplification that was required to drive them properly. My short time with some Maggie SMGa speakers at home left me unimpressed, but I think that was more an amp and speaker synergy issue at the time.

 

I became involved in the industry for a few years and almost purchased some Martin Logan SL3s. Alas, the timing and circumstances weren't quite right and the SL3s were put out of my mind. I had more recently auditioned the new Electromotion speakers from ML. These are much more affordable at nearly half the cost of the Aerius i. But a regular favourite of mine over the years has always been the Aerius. It was well suited to the smaller to average sized rooms I've had, was relatively easy to drive, and it just sounded right and balanced.

 

When a set of the Aerius i came up for sale recently, and for what was effectively straight swap for my lovely Aurum Cantus Leisure II stand mount speakers, I jumped at the chance.

 

Yes, I got them very cheap but there were issues I knew I'd have to deal with once I got them home;

• The serial number indicated that they were made in May 1998. That makes them 15 years old and I know that the Mylar coating is less effective when older. Many owners report a softening of the sound on their panels with age, sometimes one panel is worse than the other.
• My panels had the original Mylar recoated but it wasn't done properly.The coating was applied over the diaphragm portions that were stuck to the spars on the stators. It's supposed to only be applied between the spars. Not a biggie anyway as the original factory coating is applied across the entire film anyway from what I know.
• One diaphragm was damaged at some stage and so the Mylar was cut out of the very top of one panel above the top spar.
• There were wrinkles at the top and bottom of the film.
• There was some MacGyver (dodgy) wiring done to run the signal to both sides of the rear stator panel. It looks like tonearm lead out wire - very thin indeed.
• The stator halves were not stuck back together securely and the front halves were mixed left to right so the spars on each speaker didn't align properly.
• The enclosures were knicked and scratched in places.

They actually sounded very good off the end of my Chinese integrated valve amp (better in my view to the newer Electromotion, if you can believe that - more weight down low and a smoother mid and treble, perhaps at the expense of the EM's outright detail) but I had some work to do in fixing them up. I love doing this though and I'm not afraid to tackle less technical jobs in the quest to repair and/or improve something. I'd previously changed all the audio op-amps in my Sony cdp-XA5ES CD player for Burson fully discreet modules and loved the result.

 

I have big plans for these speakers that include;

 

• New 6 micron German made Hostphan film diaphragms (ML factory film is 12 micron Dupont Mylar) and coating (thank you Rob @ ER Audio in Western Australia for a full refurb kit - copper foil tapes, diaphragm tensioner, glues, etc)
• Full capacitor replacement with Mundorf Polypropelene M-Caps and M-Cap Supreme bypass caps (thanks to Soundlabs Group in Sydney)
• A full rewire with Kimber 4TC internally to replace the cheapie Monster Cable already in there. I'll also be replacing the factory Kimber PBJ interconnect style lead to the stators with heavier Kimber 4TC.
• Internal woofer enclosure treatments with Dynamat and sTp panel deadening.
• Stator support strengthening and rear diffraction treatment
• A respray in hi-fill textured paint in black for the cabinets and maybe something special for the wood trims that run down the front edges of the speakers.

At this stage, I've pulled one speaker fully apart and have studied what needs to be done and what extra consumables I might need. I've also started the enclosure treatments.

 

I've been taking pictures of things and will post these up as I get the chance.

 

More updates of progress soon.

Edited September 11, 2013 by Winno

[Steever]

Some work done so far on the chassis/enclosure.

 

Here's one speaker chassis stripped of all but the LED power indicator and its wiring;

 

 

Internal bracing for the woofer enclosure;

 

 

Dynamat panel treatment;

 

 

 

Some stator support work to more securely fix the MDF runners the stator is pressed against when the front trims are in situ;

 

 

These runners are only glued very lightly to the main stator chassis and one had started to pull away. Now the runners are fixed with screws.

 

Quick question for you guys;

Can you think of any reason why the two blue Kimber wires in this pic were not run as a single wire?

I mean, they meet at the front stator panel in the end anyway.

 

 

One is fed off one part of the cross over - yellow wire

One is fed off the power supply board - blue wire

 

 

I'm thinking that I can just run the yellow wire to the blue wire next to the transformer, and then run a single, heavier gauge cable (Kimber 4TC) up to the stator yeah?

 

Cheers for the help.

Edited September 11, 2013 by Winno

[Gordon Macfarlane]

Thanks for sharing Winno , I have a pair of Sequel 2's in a similar state of undress in the spare room. Have stripped and cleaned the panels but still to finish the  copper foil application and 'painting' the mylar.

[Steever]

My pleasure.

You really should finish the project.

I've heard it said that a few little tweaks and a recoating can actually make our speakers better than new.

 

These are the new caps beside the factory cross over.

 

 

The caps will physically fit onto the board once I get to it with a drill, zip ties and hot melt glue. The factory caps are all Nakamichi electros except for the yellow poly one. A good name but a cheap, shortcut product. 

 

The inductors are decent quality air cores but the middle one of the three here will be oriented differently as the current layout is not ideal for inductors close to each other like this. It'll be moved slightly and sat up on its edge.

 

The new re-diaphram kit from ER Audio

 

 

6m of Kimber 4TC for the internal rewiring

 

 

New heavy duty cone feet and gold plated copper binding posts made for larger cables (I run Kimber 8TC between the amp and the speakers). I may size up to the new Kimber 12TC or give Nordost another go - still undecided.

 

Edited September 11, 2013 by Winno

[Steever]

Here's one of the panels. As you can see, a little worse for wear.

 

 

 

 

 

[craigs2222]

Great little project! I'll be watching this with great interest as my Aerius i's are definitely in need of some attention.

[Steever]

Ok, I'm after a little feedback here this time...

 

These are a couple of images off the 'net of some 'new' ML Aerius speakers.

 

 

 

Mine look the same - matt black finish cabinet and stator frame and satin black finish front edge trims.

 

I'll be refinishing the cabinet and frame in the same colour and finish but want some ideas from you guys for the front trim colour.

Part of me wants to stay satin black but another part of me is saying, 'Why not dark metallic grey or even silver?'

 

What do you guys reckon?

[jazzman53]

Nice work Winno!

I'm sure you found the experience empowering?

 

I think those trim pieces would look great in a contrasting color...let's say replaced with white or red oak wood, lightly stained in yellow tint (like a mixture 1/2 golden oak & 1/2 natural stains).

 

again, great job!

Edited September 14, 2013 by jazzman53

[Dr Good Vibe]

Winno, great work are you using ER power supplies with their film and coating.

The number of times I've helped with ML speakers using different film other than ML you needed a different power supply you are properly on to that anyway.

[Steever]

Hmmm, Rob's not mentioned this when I have spoken to him about the project a few times now. 

[Steever]

A little more work was done tonight.

 

 

I replaced the factory caps with Mundorf M - caps. I used a Supreme bypass cap in each group of caps as well - they're the small black cap in each bundle. The caps were hot glued in place and then zip tied to the board. Obviously, there was no room on the board for the inductor anymore so this was moved to where you see it at top right. I'm hoping that the proximity of the inductor and the transformer to each other isn't an issue and I welcome feed back on this. The transformer to its left was moved a few cm to the left and the resistors in front of it were realigned as well thus freeing up space for the inductor which was also oriented to sit on its edge to reduce interference from the inductor on bottom right. From factory, all three inductors sit on the same plain, same orientation and close to each other. Not ideal at all.

 

Mundorf vs factory Nakamichis

 

Edited October 2, 2013 by Winno

[mkaramazov]

Beautiful work - look forward to hearing how it all sounds. 

[Chill3]

Great work Winno

Good to see these in the right hands !

I could never have done all that

Should end up with som epic speakers

Do I miss them

Mmmm

Only every second day

[Steever]

Great work Winno

Good to see these in the right hands !

I could never have done all that

Should end up with som epic speakers

Do I miss them

Mmmm

Only every second day

Thanks mate.

I enjoyed them immensely when I got them home. In fact, I hadn't enjoyed music so much for years.

I have this habit of tinkering though and like to do simple things to improve my listening experience and increase my knowledge of how things work. Every now and then though, I'll tackle something like this that pushes my boundaries.

I did a similar thing by changing out all my op-amps in my CD player for Burson modules. That worked a real treat.

I'm hoping this work will reap something similar.

[Steever]

One cross over fully wired now with Kimber 4TC and checked and double checked against the factory wiring.

 

 

New gold plated, solid copper binding posts that will take much thicker cables (like my Kimber 8TC) directly without the need for banana plugs (I like bare wire connections). The factory posts are really shite and wont take anything larger than 16ga wire.

 

 

The stator supports strengthened and woofer enclosure Dynamatted on the other frame.

 

 

Next up is the same mods for the other cross over.

Then I'll make the diaphram tensioning frame and do the panels.

The rear of the speaker frame surfaces perpendicular to the rear of the stators will be dynamatted and then covered in thick black carpet to minimise HF reflection and make them 'invisible'.

Will also t-nut the woofer enclosure for more secure mounting of the woofer and might start considering a nice replacement woofer set. Although the factory woofers are actually quite a good driver, their suspension looks like it may be starting to collapse. This will be the last thing I do though, if I encounter issues (a couple of nice alloy cone drivers might be nice but).

Edited October 2, 2013 by Winno

[Steever]

After a few days of car audio stuff filling my evenings, tonight was spent on getting my second cross over ready for wiring.

 

 

And new binding posts

 

 

And a peek at my new CSS SDX7 midbass drivers in the car. This is part of my other music related passion.

 

 

Installed

 

Edited October 10, 2013 by Winno

[Sierra]

Looking good Steve ... the mods are progressing very nicely!

 

And yes the CSS's do look good too 

[Steever]

A little more progress has been made over the past week. The second cross over had its new caps fitted and the whole thing had the Kimber 4TC rewire treatment. I'm just checking all the wiring now to make sure it has been done correctly before I dress it with zip ties and pop both xovers back into their enclosures. I've still got to pop along to my local fasteners shop for some T-nuts for the woofers as self tapping screws into mdf are not the best way of doing things. I did get this done today:

 

It's the tensioning frame for the new film that'll go between the stators. Now I just need a day with no interruptions to tension, fit, coat, wire up the film.

Edited October 24, 2013 by Winno

[Steever]

Not much, just t-nuts and overkill bolts.

[Steever]

Today my stator tape arrived - 3M VHB clear tape.

Now I can finally put the film onto the stators. The old tape was a little worse for wear and I didn't know how well it would hold tension on the diaphragm. This new stuff is incredibly sticky .

And with this stuff, I can replace the black spars (the thin black ribs you can see on the panel in the pic) for clear ones - much more attractive.

[Steever]

Cleaning up the stators.

This is the remains of the factory diaphragms, copper strips and adhesive tape.

There's still a little tape to go on one panel. It's bloody hard to push off. Might have to break out my wife's hair dryer tomorrow after my thumbs have had a chance to recover.

[Steever]

After a thorough soaking of the ends of the stators in metho, the adhesive almost fell off which made life much easier.

Today I cleaned up each perforated panel and put brand new 3M VHB (very high bond) tape on them.

The red is just the backing. I'm going for clear spars this time instead of the factory black for a 'cleaner' look once the speakers are finished.

Clean panels and a start on the new tape.

Taping done

[Chill3]

Hi Winno

Your doing great work !

Just a question, is that tape / spars on both front and back stators ?

I thought there was only spars on the back stator ?

Chill

Ps been on my own journey after these left me, moving from the sonus fabers ( will be for sale soon ) and now going down a different direction - JBL

[robin-hobart]

Hello Winno;

Have been watching your progress with interest as I have some elderly ML Ascents.  Which remain my favourite 'all-rounders' over and above approx 60+ other pairs of speakers auditioned in my lounge over the past 7 years.

But as you have mentioned, I suspect these loose a bit of their top end sparkle as they age so I have also been considering options.

Not sure if my old ears would benefit; and doubt I would be up to the rigors of a total refurb such as you are carrying out.  Looks scary!

Do you have any ball-park projected final costings as yet?

Robin

PS 1:  I replaced my original fried 10" woofers (Vifa M26WO-06-04 badged as ML) with Scan-Speak 26W4534G00 units;  the Scan-Speak specs were more or less identical and luckily were dead-set drop in replacements even down to the screw holes. And about half the cost that ML were asking for 'originals'.  I've been very happy with them.

PS 2: Bi-wiring has made a noticeable improvement to their performance.  Worth trying - I find more focus and richness - and this from a bit of a cabling sceptic!

PS 3: One chap locally sourced some complete drop-in replacement panels for his SL3s but reports they seem a bit too 'toppy'.  I think new panels will need an extended running in.

[Tritty]

Nice work mate! Keen to have a listen to these once they're up & running

Edited December 28, 2013 by Tritty