Varain Pre-amp.

RDUDLEY (rdudley@ARSERRC.Gov)
Mon, 11 May 1998 09:36:56 -0400 (EDT)

We have a Varian Unity+400 NMR spectrometer. It has a single preamp
for both proton and x-nucleus. Recently we had our 5mm id BB probe
repaired and upon return we checked the specs. We were unable to meet
the proton signal to noise spec (350/1). We thought that it might be
the probe. On the 5 mm BB probe we were able to meet the C13 signal
to noise spec (150/1). Varian thinks that we have a bad pre-amp. We
have a third party service contract and they think it is the AMT
amplifier. I find this had to believe, but I am troubled by thinking
that the pre-amp is bad. Has anyone else had a similiar experience on
a Varian Unity, Unity + 400 Mhz and less? Please e-mail me directly

Bob Dudley
rdudley@arserrc.gov