The question I posed to AMMRL about the new Varian Direct Drive console (VNMRS) had a few responses and I got some data from Varian. It is relatively new (Feb 2005 I believe). Thank you to those of you who responded. Below are the original question and the responses. The bottom line is that those with it are impressed with its flat baseline and filter performance which is what I saw in the data I got from Varian. Other advantages are listed in the responses.
Original Question :
Dear AMMRL Members:
I am considering upgrading our Inova 600 console to the new Direct Drive version but would like to hear from anyone who has experience with it. If you have the new console, what real advantages have you seen in your spectra, any increase in sensitivity (how much), etc.? Have you seen any drawbacks to the new console?
Any comments would be appreciated.
Best regards,
Patrick Hays
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Responses (edited to preserve anonymity):
We have a new Direct Drive console running on a 600. The data haven't seemed to have any great advantage over our INOVA systems though the instrument it is running on is only doing simple organic spectra at the moment. We haven't tried it with 3-D protein work. The console itself is very nice. The tuning is much simpler with fewer cables to move. As far as disadvantages, the greatest one is that it only runs VNMRj 2.1A (no classic view available) that is quite bug-ridden at the moment.
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Our new 900 has the new Direct-Drive console. Our 800 will be retroactively upgraded in the spring to the new console. The new console offers lots of advantages, the main one being a nearly perfect time-compensated digital filter algorithm that gives nearly perfect
FIDs, with no baseline distortions often associated with digital filtering. In addition, since the data is not acquired in quadrature there is 100% elimination of quadrature artifacts. Varian did a good thing, however, in that the FIDS are saved as normal, complex FIDs do there is no difference in the data format.
Since there is no longer a digital backplane (i.e. VME bus), many of the annoying problems many of us have had (or continue to have) with the Inova systems (such as FIFO-underfloes, Number of points not equal to np, things going inactive for no reason, and a bunch of others) shouldn't be a problem any longer. Most of the recent "flakiness" of the Inova consoles has been due to timing issues on the digital side of the console. The new system of a CPU on every board, with gigabit Ethernet communication between them seems much more stable. However, our system is new enough that we really can't
make any definitive statement about stability.
One thing I can say is that our most difficult performance test (that is written in our purchase contract) is the spin-echo difference test. We've never had an instrument pass 20 out of 20 times (our spec. is 10for20). The 900 has passed this test 100% of the time. If you have the resources, and considering Varian's apparent desire to move support to the new console as quickly as possible, I would do the upgrade.
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DirectDrive vs. Inova: We have several Inova's and 2 direct drive [vnmrs] systems. I certainly like the baseline of the vnmrs systems over the inova's. But, the realtime dsp in inova does a pretty decent job if the spectrometer is setup correctly. The vnmrs system allows you more flexibility in this regard. Apart from that I havn't found something that I can do with vnmrs that I cannot do with Inova. We do have some future ideas that could be uniquely bett
Received on Tue Nov 15 2005 - 10:48:18 MST