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Replacement tweeters for vr-m50


regiolanthe

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Hi,

Bought a used pair of vr-m50's fairly cheap to use as rears/surrounds (to replace some Wharfedale Diamond bookshelves I donated to son). One has a dinged/compressed tweeter (tried to attach pics. Did not work). Have not tried vacuuming, other suctioning, super-gluing, taping, etc. yet- although I may. Just wondering if I was looking for a donor speaker on CL, which would have a compatible VR/lynnfield tweeter? Obviously another VR-M50/60, but would any of the later VR tweeters be fine? Would a VR-91x center tweeter be fine, or Micro 90 IIx tweeter be fine? And should I be looking to replace the okay tweeter as well, if the donor has the later "HO" version of the VR tweeter? I wouldn't be listening super-critically.

Also - not being a tweeter or speaker expert by any means, does the tweeter just "plug and play" if I undo the hex nuts on the front and pull out the tweeter and reconnect some wires, or is there soldering going on or something (and no, I've never touched a soldering iron in my life - and not sure I want to start now).

Thanks,

Reg.

 

 

 

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  • 2 years later...

Old post. Not sure if you (or anyone) still looking for a response, but I am in a similar boat, and I'll let you know what I've found so far.

The tweeters are held in by two allen bolts (not nuts). The allen is SAE, not metric, but I can't see what the size is. The bolts unscrew and the tweeter falls out to the front. Nice and accessible. Behind the tweeter, between the plastic molded piece holding the tweeter and the MDF cabinet, is a rubber-ish washer. Behind that is the extruded aluminum heat sink, which slides neatly into a cavity in the MDF, and is supported by "shoulders" on the heat sink. There is a substance which looks like a light oil on the heat sink, where it contacts the back of the tweeter.

The tweeter on the VR-M50 is the "lynnfield" model, 1" aluminum dome. I know it is shared by a lot of Boston VR series speakers (most? all? idk). Some are anodized black, some are not. They have a plastic bit in front of the dome called the AMD (amplitude modulation device I think?) which is supposed to help with dispersion. IMHO this tweeter makes the speaker.

Problems:

The AMD is fragile and has been broken off on lots of used speakers that share this tweeter.

A healthy VR speaker is not without value, so you can't find donor speakers for super cheap. (I'm in the same boat because I just bought a VR-MC center and a pair of VR-M50s on that auction site for super cheap... because two of the three tweeter domes were collapsed.)

Most of the VR series (the vr-m975 and 965, I personally know) use a four-bolt mounting pattern for the tweeter. You can actually find these on that auction site. However, the VR-M50 (and M60) need two bolts on either side, and those are nowhere to be found.

Solution: It looks like the Micro 90x speakers use the same tweeter with the same bolt pattern, so my next step is to find a pair of Micro 90xs, have a little memorial service, and then sacrifice them to my M50s (i.e. pull the tweeters out of the Micro 90xs and attempt to transplant to the M50s).

Alternative: make a four-bolt tweeter fit. Some drywall screws and bondo should do it.

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  • 1 year later...

Hope this helps the next person landing on this page...

Short answer:  If you've dented the dome and broken the AMD - you probably want to find a VR-M parts speaker.  Probably best is a VR-MC, since it goes for less $ on auctions.  Chances are, if the tweeter looks fine, it is fine.  The VR tweeters were extremely difficult to damage from hard use.  Now, if you just have a dented dome and you're willing to do some mild surgery, read on...

Long answer:

I've got several Bostons with various versions of the VR aluminum tweeter.  They differ in a few ways:

  • The plastic frame/housing that includes the AMD arch.
    • There is also a common plastic inner-housing that is basically the tweeter body.  Appears to be the same on all.
  • The dome itself - anodizing color and what looks like coatings/treatments on some of the silver colored domes.
  • The heatsink, and how it is fixed to the housing or tweeter.

If you want an easy swap (or if you have a broken AMD) you need to match the plastic frame and the heatsink.  That's tricky with the VR-M50, 60, 80, and 90.  They all used a dark gray plastic that does not appear to match any other series exactly.  Just aesthetics, but the VR-Ms are very pretty speakers.

In terms of compatibility between the various speaker models using the VR tweeter.  By model/series...

VR, VR9xx, and [strangely] the VR-MX and VR-M/EX:

All used plastic frames with an arc along the edge that matched the speaker basket frame - since they were placed right up against each other to achieve a "point-source" effect.  The CR-8 and CR-9 used the exact same frame with their soft dome tweeter.  I don't have the center channels from these series but VR10/12, VR910/920 appear to use the same frame between all of them - but it's got one flat/squared edge where the stereo speakers have a rounded edge - different from non-center siblings above.  The inner plastic tweeter body is just pressed into the outer plastic frame (from the back), but the two parts are held together with the heatsink on the back - because the heatsink is mounted on 4 plastic posts on the back of the outer plastic frame that are then melted in place once the heatsink is positioned.  So you can harvest the tweeter easily if you cut away the melted plastic posts holding the heatsink on.  But - all of the tweeter domes were all bright/silver finished and will not match VR-M50/60.  The bright colored domes started getting a kind of satin finish look during production of the VR900 series and I've seen different levels of that coating as the years went on.

Micro90 series:

The Micro90x and 90xII used a color-matched plastic frame (white, black, and later a gray).  Two Allen screws rather than the 4 wood screws on the VRs above, (7/64" allen key). There is no heatsink on any Micro90x speaker.  It uses the aluminum front baffle (which is molded to fit the back of the tweeter) as one big heatsink.  So the tweeter just has some thermal grease to transfer heat and the allen screws hold it tight.  The inner plastic tweeter body is fixed to the outer plastic frame by a tiny melted bit of plastic.  Looks easy enough to cut if you want to harvest the tweeter from a Micro90x or 90xII.  The 90x has a bright/silver finished dome. The 90xII is black anodized like the VR-M series.  The gray Micro90xII (there was black and also gray) might be a color match to the plastic frame on the VR-M50/60.  The rare Micro100x also has a black anodized dome, but a completely unique outer plastic frame.

VR-M50/M60/MC (and probably M80 and M90):

I have not cracked open my VR-M60s to check, but looking through the bass port it appears that the plastic outer frame has some heatsink mounting plastic tabs on the back rather than melted plastic posts like other VRs.  The heatsink is smaller and does not have the holes for those plastic posts anyway.  That would make this another unique plastic frame with AMD - not just another color.  Would the Micro90x plastic frame bolt-in?  Maybe.  But you need a way to attach a heatsink.  Maybe a good adhesive thermal pad would be good enough?

VR1/2/3/B/C/X:  This series uses a different plastic frame as well.  It looks similar to Micro90 and VR-M with 2 screws, but the shape around the mounting screws is larger and would not fit in a VR-M50/60.  I am sure the tweeter body is probably unchanged inside the frame and using one of the methods above could be harvested.  Probably cheapest to source a VRC.  The good news is that the tweeter domes in this series were black anodized and should match okay.

That's about all I can speak for.  The VR tweeter was also used in the Micro110/120/130 series, the Bravo series, several in-wall models (maybe also some Voyager outdoors) and finally the P-series and E-series aluminum bodied speakers.  I think it had a very long and successful lifespan because it was mass-produced (very consistently reliable) and ahead of it's time with AMD - able to achieve superior clarity over silk or plastic with an aluminum dome while removing the harsh ringing of other failed implementations.

Best of luck,

Brian

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