Path: utzoo!news-server.csri.toronto.edu!rutgers!usc!rpi!uwm.edu!csd4.csd.uwm.edu!info-high-audio-request From: FRANCISCO%FILIP0.LIPUC.RCCN.PT@CUNYVM.CUNY.EDU (FRANCISCO FRAGA) Newsgroups: rec.audio.high-end Subject: conrad johnson Message-ID: <10143@uwm.edu> Date: 12 Mar 91 13:48:09 GMT Sender: news@uwm.edu Lines: 59 Approved: tjk@csd4.csd.uwm.edu Originator: tjk@csd4.csd.uwm.edu 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.PT