[QuadList] tube record amps...

[Guy Spiller]

This discussion of record issues on the TCRs and the frequency response 
of the record amps reminds me of a question I always wanted to ask the 
respective design engineers.
Both Ampex, in the VR-2000, and RCA, in the TR-70, decided to go with 
tubes in the four record amplifiers.  They both had other machines in 
their lineup that used all solid state amplifiers, but they opted for 
tubes in their high end machines of the day.
I don't know if all 2000s came with tube amps, but the one I worked with 
certainly did.  RCA apparently later offered a solid state direct 
replacement for the tube record amps in TR-70s.  Was there such a 
retrofit for VR-2000s as well?
At some point, RCA switched to the solid state amps on the production 
line....possibly during the later 70B run or with the 70C.  My 70A has 
always had the tube amps.  The 70B I have has solid state amps 
installed, but came with four of the tube amps in the assorted boxes of 
parts that I suspect to be the originals.  All my 70Cs have original 
solid state amps, as the S/N of the machine is stamped on each one.
I am assuming that the performance of the tube amps at the time of the 
introduction of the 2000 and the 70 was superior to solid state designs 
at the time, but it would be interesting to hear exactly what the 
decision was based on.
Also, did the TCR use standard TR-70 record amp modules, and if so, were 
they the solid state ones?
Guy

-- 
Guy Spiller
email: quadruplex at verizon.net
phone: (804) 379-2050
website: www.GuySpiller.com
Midlothian, VA