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Vandersteen 2Wq subwoofers with M5-HP crossovers - help needed

I have been happily using a pair of Vandy 2Wq subs with single-ended M5-HP crossovers for a few years now. My system was dialed in the way I like it (bass a bit on the full side, but still tight and defined). I just had my amplifier repaired and upgraded, and the new input impedance is 22k ohms vs. the 10k ohms before the upgrade. I followed the Vandersteen recommendation for the jumper settings in the M5-HP (6 and 7 only, "on" or not open), and the bass is just about MIA altogether. As per the Vandy web site, I disregarded the chart on the case of the M5-HP and followed the chart on the web site.  Because I am an idiot, I didn’t bother to mark down the settings of the jumpers prior to changing them. Anybody have any suggestions for me that will restore the bass? I am pretty sure the issue is the jumper settings. Thanks in advance!
bondmanp
hifiman5's avatar
hifiman5
1,832 posts
 
@bondmanp   Be willing to bet you need new batteries in the M5-HP!  Your batteries may not be dead but could be too weak to work effectively.  The next time I replace mine, I am gonna send Vandersteen two Duracell Quantums.
bondmanp OP
1,810 posts
 

@hifiman5 - it is possible, but what a coincidence that they both seemed fine when I pulled the main amp for the upgrade, and are both dead three months later upon the amp's return.  Also, even though I got better bass out the mains run full range, the level of bass was still way down from what AI have heard these speakers do when run full range in the past, before the amp upgrade.


But if all else fails, and after the amp has run in some more, I will have to try new batteries.  But with the soldering, that's a real PITA. 

audioconnection
1,271 posts
 
Harbour Freight has nice big red 23 dollar Voltmeter.
 It sounds like your meter is shorting your amp's speaker outputs provoking it into protection.

You need to find out where this newly modified amps input impedance really is.
We have seen modifiers install transformers at the input stage,
changing the amps input impedance thinking they are making a masterpiece and muck up the whole picture.
  
Also, your older pre-owned Hi pass units 2012 batteries should be changed immediately and have the 10-year lithium Batteries installed by Vandersteen or a real tech,..and performance verified.
 Best JohnnyR
  
bondmanp OP
1,810 posts
 

@audioconnection - Well, the amp was modded by the original manufacturer, so I will have a conversation with him about the input stage.

Once I have this conversation with the manufacturer, I will re-evaluate and look into battery replacement.    Thanks!

gdnrbob
4,444 posts
 
Yup, 2012 batteries are probably kaput. Don't they have the expiration year written on them? All the ones I have, have a date written in magic marker, so no question when to replace.
B
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