MA 2002e Stylus replacement

[nailer]

Are you saying that the suspension can be refurbed for $25?

It's what I paid for the cartridge.

 

[KrisM]

It's what I paid for the cartridge.

Oh, OK. I paid $20 for the table mine came on. That table is doing duty in my living room system at the moment, so I figure my MA was basically free.

 

[Pio1980]

Kris have you checked to make sure the stylus is fully and correctly snapped onto the cartridge body, if not it may cause the condition you describe?

Actually the suspension on the 2002e has no tie wire, the end of the cantilever sets in a suspension block called a "resolver" that rests against the two electrets and only the electrets are fixed inside the cartridge body this design results in a unique lossless coupling giving the cartridge its superb transient ability.

Dave

Yes, but it still needs a fulcrum attachment to attach it to the 'knob' and I was/am pretty sure there was an axial tie. I no longer have a stylus on mine, dunno what happened to it. The electrets are set into elastomeric mountings IIRC.

 

[ChairSpud]

Yes, but it still needs a fulcrum attachment to attach it to the 'knob' and I was/am pretty sure there was an axial tie. I no longer have a stylus on mine, dunno what happened to it. The electrets are set into elastomeric mountings IIRC.

Yes it does have a fulcrum, MA calls it an elastometric bearing and there's two of 'em but no tie wire, here's a pic of a 2002e brochure with cutaway view I borrowed from a post on VE.

Dave

 

[Pio1980]

Thnx for the pic.
The nylon tie wire pivot is the thin black line behind the resolver in line with the cantilever. It's just visible in the illustration I attached previously. It is also the attachment of the the stylus unit to the knob, neither of which are labeled in the advert illustration.

 

[ChairSpud]

Looks like we were uploading pics at the same time.

Am looking at an actual MA stylus assembly right now and believe you've mistaken the pivot for a tie wire. The unique pivot on the MA Micro Acoustics serves the very same function as the more common rubber suspension to act as a pivot and universal joint for the cantilever, the remainder of the resolver functions as the dampener.

The tie wire you mention is sometimes used on cartridge designs like Shure, Stanton, Goldring... that can't by themselves zero the position of the cantilever via their pivot suspension (not the case with MA) so on those cartridges a thin tie wire is attached directly to the cantilever with the other end to a nonmagnetic tube surrounding the cantilever to help the cantilever return to zero, on the MA there is no nonmagnetic tube and nothing besides the elastometric resolver attached directly to the cantilever, well except for the diamond of course.

Dave

 

[hifitommy]

i truly miss my 2002e

it was fast, exceedingly flat (as in linear) and imaged like a champ. i can only hope to stumble in another good one. my original was bought new and i bemoan the fact that the company is gone.

too bad someone didnt carry on the legacy. i never got to hear a 3002 but if its better than a 2002, i wnat one.

i consider it to be nearly the equal of my original ADC XLM.

 

[nailer]

it was fast, exceedingly flat (as in linear) and imaged like a champ. i can only hope to stumble in another good one. my original was bought new and i bemoan the fact that the company is gone.

too bad someone didnt carry on the legacy. i never got to hear a 3002 but if its better than a 2002, i wnat one.

i consider it to be nearly the equal of my original ADC XLM.

A 3002 was recently listed on the Barter Town forum.

 

[ChairSpud]

The 3002 vs. 2002?

The 3002 adds a Micro-point II stylus vs. a 0002 x 007 elliptical yielding a bit better separation and flatter frequency response. The 3002 also has a carbon fiber body and three 0.5 gram removable weights stored under a trap door that can be used to vary the mass of the cartridge from 2.5 to 4.0 grams.

Dave

 

[Pio1980]

Looks like we were uploading pics at the same time.

Am looking at an actual MA stylus assembly right now and believe you've mistaken the pivot for a tie wire. The unique pivot on the MA Micro Acoustics serves the very same function as the more common rubber suspension to act as a pivot and universal joint for the cantilever, the remainder of the resolver functions as the dampener.

The tie wire you mention is sometimes used on cartridge designs like Shure, Stanton, Goldring... that can't by themselves zero the position of the cantilever via their pivot suspension (not the case with MA) so on those cartridges a thin tie wire is attached directly to the cantilever with the other end to a nonmagnetic tube surrounding the cantilever to help the cantilever return to zero, on the MA there is no nonmagnetic tube and nothing besides the elastometric resolver attached directly to the cantilever, well except for the diamond of course.

Dave

Hi Dave. I really wish I could find the stylus for mine to micro-photo the back end of the resolver but now even the box it came in has disappeared.
Oh well--.
Nonetheless here's a description from this revue http://www.gramophone.net/Issue/Page/July 1976/117/818003/MicroAcoustics+QDCle+cartridge
for it's predecessor with a similar arrangement, the QDC-1e;

"In the Micro-Acoustics QDC-le cartridge, the 18 x 5cm (0.0007 x 00002 inch) elliptical nude diamond stylus is mounted in the conventional tubular cantilever bar. This is terminated in a four-point resolver system, the points forming an exact square with the effective pivot at the centre. The two lower points are simply elastic bearings attached to the base of the cartridge, while the upper points are coupler pins in contact with the left and right electret transducer elements. Thus lateral motion of the stylus generates equal signals in both channels, while 450 motion produces a force on one channel electret only. Tension is applied by means of a fine nylon wire and I understand that three small screws permit accurate centering of the pivot system during the quality control stage in manufacture."

Breakage of the nylon wire would cause the suspension system to collapse under load, if not come out of the knob altogether. If the lower suspension "bearings" are attached to the resolver and knob, the stylus won't fall out if the tie breaks but the suspension will fail, collapsing under load. I think this the most likely suspension failure mode and nothing to do with the carcass' internals. Any electrical/signal path failure will of course be internal to the carcass.
I thought these carts generally a brilliant product but one needing the loss of the reverse RIAA micro-circuit for an internal active interface like an electret mic capsule and a dedicated interface/pre for a TOTL effort. Having to first comp the output then de-comp it in a mag phono pre seems a redundant compromise to what could have been a more direct & simple signal path.

 

[ChairSpud]

Pio, thanks for posting that info. I took a closer look at the stylus this morning with strong magnification and indeed there is what looks like a thin black roughly same diameter as the cantilever rod or solid wire. No adjustment screws though, maybe only used during construction. One end of the wire seems to penetrate the center of the square resolver directly behind the cantilever, the other end comes out for a short distance then turns down 90 degrees passing through a small plastic tab in the stylus shell, the opening appears to have been sealed closed with some kind of hot plastic or adhesive anchoring the wire firmly.

Interesting, so the plastic wire applies tension to the resolver + cantilever assembly and that seems to be the method MA used to adjust and set the stylus compliance. I can imagine how they may have used a construction jig with adjustment screws to set the stylus compliance during assembly. A benefit of the design is a self centering to zero cantilever with no need for a tie wire.

During MA's heyday I lived only a few minutes from and even visited their factory in Elmsford, NY. I also knew a few of their employees (the source of my now depleted spare stylus) and remember hearing stories about how the cartridges took an unusually long time to assemble. After looking real closeup I have an even better appreciation for what went into these guys, if you ask me, I think the demise of MA after a costly legal suit by Bose over MA's tweeter array is a tragedy. :sigh:

Dave

P.S. Yes I agree failure of the tension wire would cause the suspension to collapse under load. As far as the EQ network, remember the MA has direct physical connection all the way from the LP grooves to the transducer, not possible on other designs where the information must jump an air gap between the coils and magnet, sorta like having sex with a condom, not as much fun

 

[Pio1980]

Mornin' Dave!
I took a couple pix showing the adjustment screws and scales with my new $30 macro/micro camera. https://www.dealextreme.com/p/digimicro-200x-zooming-usb-digital-microscope-11743
They are part of the carcass, not the stylus assy.

 

[Pio1980]

How sad to think that M-A could have sunk because of Bose's defense of a questionable notion and an M-A product's vague resemblance to it.
I read from one person with an inside view that M-A was basically staffed by creative geniuses and managed by gangsters with "creative" bookkeeping procedures. Can't find that series of postings.
Nonetheless;
http://www.patentgenius.com/assignee/MicroAcousticsCorporation.html
http://www.micro-point.com/history.html
http://www.roger-russell.com/sonopg/micropg.htm

The last site mentions that the carts' transducer elements were not electret piezo-electric film, rather lead-zirconium titanate piezo-ceramic.

 

[ChairSpud]

I'll checkout the links later but yes a sad story. Maybe my eyes are crossed from lookin' at tiny things but where are the adjustment screws in your pics?

Dave

 

[nailer]

... If the lower suspension "bearings" are attached to the resolver and knob, the stylus won't fall out if the tie breaks but the suspension will fail, collapsing under load. I think this the most likely suspension failure mode and nothing to do with the carcass' internals...

This perfectly describes my 2002e's problem. What do you think are the chances of someone having the wherewithal to affect a repair?

 

[Pio1980]

Nailer, Hard to say without knowing for sure the tie is broken on your stylus. That is pretty much kiss of death for the stylus assy without someone who will establish a specialty to deal with this.

Dave, the adjuster screws are just visible to the left of the black block pair in the middle of this pic.

The new pic below shows the business end of the adjuster screws visible thru a window cut into the cart's bottom. They are accessable for factory trim thru the two small holes under the terminals on the rear.

 

[ChairSpud]

Thanks Pio I see them clearly now, can you tell if they're used to adjust the position of the rubber bumpers?

Nailer, I agree if the tension wire is broken it would be practically impossible to repair. But if only loosened from it's anchor it should be possible to reattach but getting it re-tensioned for the correct compliance would be a guess.

Dave

 

[bobrown14]

Hey just wanted to let y'all know that there is a MA 3002 II
over on Barter Town... >10hrs on it for a decent price. No repair needed and a step up from the 2002e. I'd be all over it for a backup to mine (middle of a laudnry room rebuid). Hard to beat the sound of that cart.

Cheers,

Bob

 

[Pio1980]

Thanks Pio I see them clearly now, can you tell if they're used to adjust the position of the rubber bumpers?
<----snip---->

Dave

I think they each move the entire channel transducer unit in the blue damper/retainer blocks to ensure proper alignment/orientation of the inserted stylus assembly. The single black bit on the other side of the larger blue blocks is one piece and probably doesn't move. Not sure yet what the 3rd adjustment screw under the other two does, it may set the clamping force for the two transducer beams. The basic cost of the materials and initial assembly must have been very modest to make these one-at-a-time hand-aligned steps yield a profitable end result.

I'm not positive which version I have opened up, it may be the QDC-1e which is very similar to the 2002e but lacks a pair of additional long dampers IIRC.

The patent description refers to a "pivot anchor", I think this is also the tensioning tie.
From the 1976 patent application;
"Note that the resolver 15, pivot anchor 17 and elastomer blocks 18 are all preassembled into the replacement unit, thereby permitting proper tensioning of the pivotanchor 17 when tightly inserted under the influence of the clip 47, which will cause the projection portion 41 to abut against a prealigned edge of the cartridge, proper stressing of all portions of the arrangement will result. Also shown are set screws49 which may be used for adjusting the stressing and position of the pizoelectric members 11 through their associated elastomeric blocks 12 during factory assembly."
Here is a cross-section of what I believe to be the cart I'm showing, from the 1976 patent:

 

[Sk8ter]

it was fast, exceedingly flat (as in linear) and imaged like a champ. i can only hope to stumble in another good one. my original was bought new and i bemoan the fact that the company is gone.

too bad someone didnt carry on the legacy. i never got to hear a 3002 but if its better than a 2002, i wnat one.

i consider it to be nearly the equal of my original ADC XLM.

I have a good one....let me know if your interested in it....but IMMHO other MI/MM carts kill it in sonics....


Lawrence