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VSA VR-4: problem with midrange drivers

I recently bought a pair of original VR-4's. They sounded great except when playing certain discs at higher volumes. Then I had some distortion from one or both mids. I am driving the top end with a 200 wpc B&K ex442, same for the bottom (bi-amped). Called VS and they were helpful, thought that the voice coils had probably been overheated at some time...I replaced them yesterday with the upgraded drivers.
Again, with certain discs I seem to be hearing some clipping at higher volumes...say about the 11:00 position on my AR LS3B pre. Sounds potentially like my amp is clipping.
Question is, if I use a lower powered amp on the top end ( I have a 100 wpc Aragon not currently in use) would that make any sense? I will also have the B&K checked out to see if there are any issues with it, but I'm concerned that sending 200 watts to the upper and 200 to the lower speaker modules is why I'm having the issue. The VR4's are rated at 250 wpc.
pjnad

Showing 3 responses by bdgregory

bdgregory
1,708 posts
 
I would start by using another amp entirely. Have you tried them in NON-biamped config? That's where I would start before replacing speaker drivers, or sending amps in for service. Also, if you have identical amps I would vertically biamp them, though this shouldn't effect the issue you have.

I have VR4 gen III's and they don't require 200 watts to sound good (indeed they sound wonderful with a 35 watt tube amp (non-biamped), and I normally drive them with a 140 watt ss amps in vertical biamp config. So testing them with your lower power amp shouldn't be an issue at all. Also, unless there's a significant sensitivity difference with your top and bottom amp, driving the mid/hi module with the EX442 shouldn't be an issue either.
bdgregory
1,708 posts
 
VSA manual does suggest that they will sound better bi-wired or bi-amped.
Also, I am not clear as to how to vertically bi-amp. My speaker cables are not identical, I'm using MIT on the bottom end and Synergistic on the top.

I called VSA when I bought my VR4s - Albert answered the phone personally on the second ring! I asked him about biamping or using a single high powered amp (I was considering having my Eagle 4's converted to Eagle 11 mono blocks. He said they're best when biamped. I've since tried them with several different amps and none best Eagle 4s in vertical biamp config.

Vertical biamping is easy - but you need identical amps. One stereo amp goes to one speaker, the second to the other. Connect one channel of each amp to the mid/hi, one channel to the bass. You can use different cables for mid/high if you like. There is a biamping thread in the archives where Steve McCormack describes at length why vertical biamping preferred when you're passively biamping. It's worth a read Here.. he also discusses using different cables . . .
bdgregory
1,708 posts
 
as for interconnects - you can run one IC to each amp and use a Y splitter at the amp, or you can use the Y splitter at the preamp (or if your pre has 2 outputs use those) and run 2 IC's to each amp. My IC's are long so I do the former using some good quality Audioquest splitters. I have my amps sitting next to my speakers so I can have short speaker cables

If you're brave, you can also open up your amp and solder a short jumper between the + terminals of the 2 RCA connectors, but then you need to be careful to remove it before you use the amp for stereo again. This may have an advantage technically over splitters and double IC's. This isn't something I was comfortable with though.

I'm not sure how loud the VR's will play and have never put a db meter on mine, but mine will play louder than I'm comfortable listening at . . . this I know.
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