VMPS SuperTower/R Question

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baco99

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Re: VMPS SuperTower/R Question
« Reply #20 on: 8 Jun 2016, 06:45 pm »
Thanks.  I will double check, but doesn't look like he has those.

baco99

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Re: VMPS SuperTower/R Question
« Reply #21 on: 27 Jun 2016, 01:50 am »
OK, Some updates.  I double checked and these speakers DO have the Wondercaps, however, there's only one. not two like the one pictured.  I understand that there were several variations of this speaker over the years with driver changes, etc.

I got one speaker fully assembled and hooked it up just to see what the fuss was all about and I have to admit, I am completely disappointed.  Bass is muddy and fat, midrange is uninspiring, and the high end completely weak.  Considering these speakers have four tweeters in total, the high end was virtually non existent.  I checked the crossovers and they are very simple. 

There's no padding on the tweeters with the exception of the L-pad for "Brilliance" and the L-pad for the super tweeter mounted on the back.  All the L-pads work and I cleaned them with DeOxit. 

The tweeters make noise, they are just completely overpowered by the terribly bloated bass.  So I looked at the low end connections.   According to the marketing, the two woofers are supposed to be crossed over at different frequencies, which I find impossible because there's only one choke in the crossover.  I haven't measured it yet, but both woofers are running in parallel off this choke.  So they are crossed at the same frequency in mine, and by running in parallel.  I cannot imagine this is right.

First, does anyone have a crossover schematic that they can post here or email? 

Second, would these speakers benefit from a recap?  The Wondercaps and other caps are all film type and should not degrade.  But maybe they do?

Third, the wiring inside this speaker is a complete mess.  The Low Loss Monster wire is so thick that the connection points are comprised of blobs of solder.  Has anyone rewired and/or replaced this ridiculous Monster wire with something more reasonable that's easier to handle and solder?


Thanks again!

ZAKski288

Re: VMPS SuperTower/R Question
« Reply #22 on: 27 Jun 2016, 03:07 am »
As far as the rewiring . 14 gauge ANALYSIS PLUS CABLE (purple, black) is what is used in later VMPS speakers. Zak

baco99

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Re: VMPS SuperTower/R Question
« Reply #23 on: 27 Jun 2016, 03:49 am »
Thanks

Any help with a schematic?

The crossover points are supposed to be as follows:

15" = 22-200 HZ
12" = 200-600 HZ
5"x2 = 600-4500 HZ
1" x2 = 4500-15000 HZ
Ribbon = 15000-47000 HZ

I only see one choke for both the 15" woofer and the 12" midbass coupler.  Other than that, there's no upper range cutoff for any of these drivers. I've measured Morel MDT28 tweeters to 22khz. A proper choke would need to be used for a second order cutoff at 15k as the manual claims.

Any help would be great.

ST86

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Re: VMPS SuperTower/R Question
« Reply #24 on: 27 Jun 2016, 02:21 pm »
I suggest checking some basic things. 

Are all drivers wired in phase?  You can trace the wiring to check this, or I can send you the wiring check instructions where you use a 9V battery to see which way the drivers "thump" when the battery is applied to test points.

The bloated bass could be from the passive not being tuned, also did you listen with the cabinet empty or stuffed with fiberglass?

Dull midrange and treble could be from L-pads turned down or miswired.  Start off at "default" settings of around 12 o'clock, then turn each L-pad fully counter-clockwise then fully clockwise.  You should hear a significant volume difference from one extreme setting to the other.  The "default" setting is a good starting point to dial things in.  If things sound bad from there then there likely is an issue somewhere.



Ed

baco99

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Re: VMPS SuperTower/R Question
« Reply #25 on: 27 Jun 2016, 02:41 pm »
Hi Ed
All of the L-pads function as they should with the resistance shift as indicated on the body of each L-pad.  All the wiring looks to be in order.  The woofers are wired in phase with one another.   And I listened with the PR in place, weighted to 3.5oz, which is about half the original.  And the cabinets stuffed with fiberglass.  Trust me, this wasn't a "splitting hairs" kind of critical listen.  This was a "within a half second" notice that these thinks sound "EW!" as my daughters would say. 

To be honest, it just looks like a sloppy job all around.  I've taken apart and refurbished hundreds of speakers, and for the price these things got, I'm simply in shock.  Trying to suspend disbelief.

Also, thank you for the thread with your schematic.  It confirms that the wiring is in fact, intentional.  Just sloppy.











Huge gobs of solder everywhere and some cold solder connections. 

ST86

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Re: VMPS SuperTower/R Question
« Reply #26 on: 27 Jun 2016, 03:02 pm »
The woofers in these pictures appear to have no surrounds.  I don't know if that is part of the bad sound you are hearing but if you've rebuilt a lot of speakers you'd already know this.

Other than a setup or wiring error I can't think of much else to check at the moment.  Bad crossover? Most everyone that owns/hears the Supertowers is pleased and even impressed with the sound.  What you are describing is way off, I don't know what could be amiss.

Here's something else to check:  How much and with what are the midrange chambers stuffed?

Ed

baco99

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Re: VMPS SuperTower/R Question
« Reply #27 on: 27 Jun 2016, 03:11 pm »
I haven't opened up the mids yet, but I will check.

I noticed in your schematic that there a 15 ohm resistor in line with the 12" mid-bass coupler.  I don't see that installed here.  Maybe that's where all the muddiness is coming from.

And yes, I took the pictures before refoaming all six drivers.    :green:

baco99

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Re: VMPS SuperTower/R Question
« Reply #28 on: 27 Jun 2016, 03:49 pm »
Ed
Mid chambers are empty.

ST86

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Re: VMPS SuperTower/R Question
« Reply #29 on: 27 Jun 2016, 03:54 pm »
The chambers should not be empty.  The chambers should have either fiberglass or lambs wool.  Brian recommended lambs wool for midrange damping.

ST86

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Re: VMPS SuperTower/R Question
« Reply #30 on: 27 Jun 2016, 04:50 pm »
Please check the upper terminal cup wiring and compare it to my posted schematic.  It appears to me the speaker cable polarity on the toggle switch is swapped from where it should be.  The coil for the woofer should connect the negative speaker terminals and be on the same side of the toggle switch as the negative speaker cable from the other terminal cup.  It looks like the *positive* speaker cable from the other terminal cup is connected there instead of the negative wire.

Ed

baco99

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Re: VMPS SuperTower/R Question
« Reply #31 on: 27 Jun 2016, 05:17 pm »
Thanks Ed - I will check on that.

baco99

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Re: VMPS SuperTower/R Question
« Reply #32 on: 29 Jun 2016, 10:50 pm »
Here's a summary of what is wrong with these speakers....

1) each cabinet missing all acoustic fill for the bass drivers

2) each cabinet missing all the specialized lambs wool fill for the midrange enclosures.

3) woofers and mid bass couplers in one cab are wired out of phase with the other drivers (all drivers are wired in phase according to the schematic)

4) woofers and mid bass couplers in the other cab not connected at all.

5) 12" mid bass couplers missing a 25 ohm resistor ahead of them which alters the crossover points for all drivers since the mids are connected in a series circuit. Ah!

6) The midrange cap measured at 5.4 uf, not the prescribed 49 to 54.5 uf in the schematic. 

Once I fix these things, we might have something useful to listen to and evaluate further.  Thanks Ed (ST86) for the assistance here!

Also, some of the absolute worst soldering I have ever witnessed.





What a mess!




Also, I tested the caps and they are still well within rage, with the exception of the single Wondercap, which is supposed to be 2.5uF (I think) and reads 0.9uf.  But I need to verify when I get a hard copy of the schematic.

ZAKski288

Re: VMPS SuperTower/R Question
« Reply #33 on: 29 Jun 2016, 11:19 pm »
baco99, I don't think these were factory built speakers. Also is that a fuse holder in your second picture next to the L-pad. Zak

ZAKski288

Re: VMPS SuperTower/R Question
« Reply #34 on: 29 Jun 2016, 11:32 pm »
baco99
         "The midrange cap measured at 5.4 uf, not the prescribed 49 to 54.5 uf in the schematic."

My midrange caps measure 5.59uf and the tweeters caps  measure 1.43uf .


baco99

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Re: VMPS SuperTower/R Question
« Reply #35 on: 30 Jun 2016, 12:34 am »
Weird. The schematic that Ed posted shows a 54.5 cap in front of the mids.

I think this was a factory build because the serial numbers are sequential and stamped on the paperwork attached to the back of the speaker. I think someone got clever and f-d everything up later on. 

And yes that's a fuse holder.

ZAKski288

Re: VMPS SuperTower/R Question
« Reply #36 on: 30 Jun 2016, 01:55 am »
baco99 , Not to sure if the fuse is a factory thing, I've never seen it on another pair of VMPS. I think my speakers crossovers are somewhat similar to yours. All my drivers were updated sometime (2011-2012)

ST86

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Re: VMPS SuperTower/R Question
« Reply #37 on: 30 Jun 2016, 02:37 am »
I concur the fuse is not a factory thing, that looks like a mod added by someone.  Never seen it on any VMPS speakers of that era and a fuse is not listed in the parts list or on the schematic for my Supertowers.  With all the other problems found I would be surprised if these cabinets left the factory like that.

My schematic called out 54uF for the cap value for the original grey poly mids.  When I bought the updated 12" Misco woofer and 5" mids (Brian called them "classic" mids) from Brian he specified changing the woofer inductor to 2.8mH and keeping the midrange cap value at 54uF.  This is for the mids that I bought from him.  I'd say different mid drivers require different cap value.  The ones shown here are not the same as mine.



Ed

ZAKski288

Re: VMPS SuperTower/R Question
« Reply #38 on: 30 Jun 2016, 03:25 am »
Also the white damping material on the  cabinet, I don't think is a factory job, because the drivers and crossovers would not have been there then the coating was applied.
 
Hello Ed, I think your right about the red and black wire on the switch, they need to be switched around, or better yet take the    switch out. Zak

RSorak

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Re: VMPS SuperTower/R Question
« Reply #39 on: 30 Jun 2016, 04:14 am »
Many VMPS speakers were also sold in kit form....This could explain many of the problems found in these speakers.