[John Casler]

With all the NuFORCE Buzz going on, I was "jogged" into remembering a bit of "tuning" procedure for any and all who who use VMPS floorstanders with the NuFORCE amps.

Gentlemen....Check your putty!

I had a friend/client stop by but wanted to hear the RM30s in STEREO and I have everything set up in a TriNaural config

Well in any event we did go stereo and while I didn't actually have the speakers set up for the best bass (which is what he was looking for) in stereo it wasn't as bad as I thought (this is without the subs)

Except there was this "resonance" on a transitional and very low female voice that was lousy.  

It was a recording I was not familiar with, so it didn't "jump out" at me, like it did him.  Also the "problem" didn't seem to manifest itself in any of the other tracks that had good bass in them.

I chalked it up to a room resonance that was covered or amiliorated when I added the subs, which is how we heard it some time ago and it seemed fine.

Well after we shut down, and my friend left, I began thinking about the reasonance and I thought maybe I should switch my RM30s so the woofs fire "out" instead of in, since I hadn't tried this much.

So I did, bada bing, bada boom, (and I do mean boom) lower, cleaner, bass and more of it.  Now this is from the RM30s "only".

Did it clean up the reasonance?  I didn't know since he had the CD cut and I don't even remember what it was.

Then another realization        

I had the putty set for the Son of Ampzilla and had just switched to the NuFORCE.

So what?  Well that IS one of the main reasons to "adjust" your putty.

What was I thinking (or more accurately, NOT thinking)?

Since Damping Ratios of amps differ, when changing an amp, you might need to adjust the putty.  Generally this will be to "add" putty if the damping ratio gets larger, or slightly subtract if it goes lower.

Well the Son of Ampzilla had a damping ratio around 250.  The NuFORCE is around 4000!!!!

So I just added a pea of putty to each RM30 and voila an immediate difference.  Will it cure the specific resonance from yesterday (very likely) but what it did do is make the bass meatier, deeper, and more textured.

Just how I like it.

So all you out there making the NuFORCE move on your VMPS, don't forget to add a bit of putty. to damp the PR a bit more.

Happy Listening

[Brian Cheney]

"Magic putty" don't mean a thing, just hype, everybody knows that.  

John, where'd you put those curves I ran showing a 90% reduction in THD in the bass region from  1/2g  PR mass adjustment?

When I get my Ref 9 I will post impressions and instructions. Already have Dusty Vawter's D200 (Nuforce sibling but with linear power supply) warming up.

[John Casler]

"Magic putty" don't mean a thing, just hype, everybody knows that.  

John, where'd you put those curves I ran showing a 90% reduction in THD in the bass region from  1/2g  PR mass adjustment?

When I get my Ref 9 I will post impressions and instructions. Already have Dusty Vawter's D200 (Nuforce sibling but with linear power supply) warming up.

B,

Look here and see if the graph(s) you seek is/are in this group.

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=75

[warnerwh]

Thanks John!  I'd been wanting to see these again.

[John Casler]

B,

If one or any of these are the right one(s) let me know and I can post them.

[warnerwh]

When you do post them make sure it's easy for everybody to understand. Thanks

[KJ]

So all you out there making the NuFORCE move on your VMPS, don't forget to add a bit of putty. to damp the PR a bit more.

Actually, VMPS owners should modify the putty mass with ANY component change in their system.  Based upon my brief conversation with Brian, altering the electrical impedance presented to the speaker itself is the key factor that will slightly change the sonic characteristics.  Because the Nuforce amps use switch-mode power supplies, I imagine swapping out an amp with a linear power supply will be more drastic than a like for like swap.  Therefore, amps will most likely have the largest impact.  However, if your hearing is that good I imagine even a change in pre-amp or source would have a minute effect.

-KJ