FRANCISCO%FILIP0.LIPUC.RCCN.PT@CUNYVM.CUNY.EDU (FRANCISCO FRAGA) (03/12/91)
During the last few weeks I have been using some of the new
conrad-johnson preamplifiers PF1 (fet) and PV11 (tube) and their
new amplifiers, MF80 (fet) and MV52 (all tube).
I have owned for about a year a PV10 and was quite pleased
with it. Due to its high gain and somewhat high noise levels
cartridge, amplifier and speakers matching is critical. If the
output from the cartridge is too high you will finish using the
volume control only in the first fifth, needing very small
adjustments to get in the desired position. Hopefully, the
excellent quality and feeling of the potentiometer helps a little.
I got some good results with a cartridge of 500uV at 5cm/s output.
(Kiseky ruby). With high gain amplifiers or very sensitive speakers
one can get residual hiss levels too high for late nigh quite
listening. But this preamplifier is a bargain and with proper
matching its sound quality is comparable with much higher priced
preamps. The strong areas are the low coloration and very good
dynamics, which are not easy to get together in low cost products.
Components and building quality are good and the circuits are so
simple that I think that the unit must be quite reliable. Even the
transistors used in the regulated power supplies are well known and
reliable Motorola high voltage types. Tube quality must be
critical, it is a non feedback triode based design, but they use
common tubes.
When I looked at the specifications of the PV11 (no feedback,
triode based, less noise and less gain than the PV10) I thought
that it would have the same sound as the PV10 with an easier system
matching. Wrong! It is much better! Bass is better, stage sound and
depth are much improved. Small details in the music are easily
found but they do not jump in front of you.
The MV52 sound is quite different from the previous model, the
MV50. The medium frequencies have the same characteristic warmth
and voices are quite good, the bass is no longer fat and
underdamped as in the cj MV50. May be because of this the amplifier
sounds much more transparent and uncolored. But real bass is
missing (what should one expect from a 45W stereo tube amplifier?)
I read somewhere that the power supply uses no electrolytic
capacitors as in all their preamplifiers but I am not sure of this
point.
I am still trying to make my mind about the new fet based
models. I am already sure of one aspect: the longer they warm-up
the best they sound. After a few days warm-up I disconnected them
for some hours. It took a few days to bring them back to the
previous warmed-up state!
Just one question to finish : I heard briefly the MV100 (not
in my system). I was quite impressed. Any news about a future
replacement of the MV100 by a MV102 or something similar?
........................................................
Francisco A. F. Fraga
Dept. Physics
Univ. Coimbra
3000 Coimbra PORTUGAL tel. 351-39-34668 fax 351-39-29158
FRANCISCO@FILIP0.LIPUC.RCCN.PTsimond@uunet.UU.NET (Simon David) (03/14/91)
> During the last few weeks I have been using some of the new >conrad-johnson preamplifiers PF1 (fet) and PV11 (tube) and their >new amplifiers, MF80 (fet) and MV52 (all tube). > I am still trying to make my mind about the new fet based >models. I am already sure of one aspect: the longer they warm-up >the best they sound. After a few days warm-up I disconnected them >for some hours. It took a few days to bring them back to the >previous warmed-up state! I have a PF1 and find the same thing. The sound stage expands dramatically after only a few hours but still improves for few days after this. I thought about the tube equivalent (PV10 I think) but a home dem of the two in my system showed the PV too noisy. My cartridge is a Koetsu Red Sig and I had to have the volume right up to get any sound. The PF1 sounded less muddled and had better bass and imaging too. > Just one question to finish : I heard briefly the MV100 (not >in my system). I was quite impressed. Any news about a future >replacement of the MV100 by a MV102 or something similar? Has anyone used a PF1/MV?? Combination. I am looking for a power amp and have heard that the the MF100 & MF200 (fet) are not as good value for money, soundwise, than the highly rated (in the UK) PF1. Simon David Informix UK Tech Support simond@informix.com simond@informix.com