[klapse]

Hi, from the VMPS archive site http://pointillistic.com/vmps-audio/technical.htm I found the following description of the FST

"Free swinging tweeter" is the latest true-ribbon tweeter used throughout VMPS line. It is one of the best tweeters available today. It's advantages over previous spiral ribbon tweeters were easily audible and cost is not overly prohibitive. We use custom version (8 Ohm, custom transformer and diaphragm) of similarly looking Aurum Cantus tweeter. The FST tweeter has 30 degrees of vertical dispersion, less than 25 mm dome tweeter, but does not become directional at 11 kHz like a 25 mm dome. Horizontal dispersion is broad and even up to 25 kHz.

Looks like the Cantus G2Si http://www.parts-express.com/aurum-cantus-g2si-ribbon-tweeter--276-400?AID=1457483&PID=5567334&SID=skim23608X823435X6aa26b5067b0fea3c239cfb95d4b41af is not a 1:1 replacement. Has anyone replaced a FST with an aurum cantus? Will it work with the crossover in the VMPS or is it not suitable at all?

Wondering whether to send my AC G2Si tweeters purchased for spare parts back to parts express...

[Stimpy]

Hi Klapse,

Not to sound contrite, or uncaring, but at this point, what choice do you have?  Short of finding someone parting out a pair of VMPS speakers, and finding the exact tweeters, all VMPS owners have no choice, but to look for aftermarket drivers and hope that they work.  While I don't know if your AC G2Si tweeters are exact replacements, I do know that I'd rather have those tweeters, than none at all!  Plus, with the trim pots, on your speakers, you can at least adjust the output to match the stock tweeters.  As such, I'm sad to say, with no Brian,  "that's as good as it gets!"

Good luck!

Hi, from the VMPS archive site http://pointillistic.com/vmps-audio/technical.htm I found the following description of the FST
Looks like the Cantus G2Si http://www.parts-express.com/aurum-cantus-g2si-ribbon-tweeter--276-400?AID=1457483&PID=5567334&SID=skim23608X823435X6aa26b5067b0fea3c239cfb95d4b41af is not a 1:1 replacement. Has anyone replaced a FST with an aurum cantus? Will it work with the crossover in the VMPS or is it not suitable at all?

Wondering whether to send my AC G2Si tweeters purchased for spare parts back to parts express...

[Early B.]

Wondering whether to send my AC G2Si tweeters purchased for spare parts back to parts express...

Send them back.

It doesn't make sense to pop in a tweeter that isn't designed for the speaker. If you can't find the exact tweeters, then buy another set of speakers and trash the old ones.

[Jon L]

Plus, with the trim pots, on your speakers, you can at least adjust the output to match the stock tweeters.  As such, I'm sad to say, with no Brian,  "that's as good as it gets!"

Good advice here.  The main difference is likely the "custom transformers" which was likely used to adjust the stock 6 Ohm impedance to 8 Ohm.  This should not be insurmountable since you have trim pots on speakers to play around with.

BTW, what's wrong with the original FST tweeters?  Unless something horrible happened to it, many issues tend to be due to the ribbon element, which is easily replaceable by user, likely with Aurum Cantus ribbon replacement kits, leaving the housing intact. 

[klapse]

[EDIT] Thanks for the replies, particularly Stimpy and Jon L.  The impedance mismatch hopefully wont be too much of a problem since I can dial back the L.Pad.

I want a complete spare set of drivers to keep my RM2s running for a long, long time I find them to be incredibly good speakers. I've browsed through all 68 pages of the VMPS Speakers circle and don't think I will ever need to upgrade, though I would love to hear RM40s, 60s, 626r etc someday. (Any VMPS owners in Germany? I'd love to meet you!)

I guess I will keep the Aurum Cantus GSi, until/unless I find someone selling original FSTs.

Just wanted to let people know that they are not an exact replacement, according to that website.

Customer satisfaction for VMPS speakers is pretty huge, considering the last posted number of customers was 23,000 and Stimpys "sale" thread only lists ten or so each year!

[YoungDave]

I have replaced a FST with a G2Si.  Physically an exact replacement.  IIRC, dc resistance was the same.  I cannot state how it worked with the original crossover because my RM40's do not have a crossover.  I removed the crossovers years ago and triamp the speakers.

I must say, though, that the tweeter itself is very nearly indestructible.  Sure, you can damage the ribbon, but 5 minutes (well, OK, maybe 30 minutes) with aluminum foil, scissors, and hand tools is all that is needed to replace the ribbon.  I do not keep spare tweeters on hand for that reason - and that I learned some years ago to operate the tweeters with a modest-powered amp.

Cheers!

[Rocket]

Hi,

Was there a problem with the FST tweeter that couldn't be fixed.  These tweeters should last for a very long time.  If it is the ribbon they can be replaced without too much trouble.

Contact John Casler he might be able to provide further information for you regarding compatibility.

Cheers Rod

[Stimpy]

As far as I've read, the OP's RM-2 speakers are fully functional.  I just think klapse wanted back-up drivers for emergency purposes.  To keep his VMPS up and running for many years to come!  A worthy goal...!   

Hi,

Was there a problem with the FST tweeter that couldn't be fixed.  These tweeters should last for a very long time.  If it is the ribbon they can be replaced without too much trouble.

Contact John Casler he might be able to provide further information for you regarding compatibility.

Cheers Rod