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In Reply to: RE: conrad johnson pv10 compared to older"warm transparent"preamps posted by n.buzzard@hotmail.com on February 12, 2015 at 19:57:28
Mine is an original 10 w/phono, not 10a or b. I had the gain lowered with a resistor and the line stage 5751 changed to a 12AU7. I also had Vampire jacks installed along with Discovery hook-up wire.
The pv10/McCormack does provide warmth/richness with balls, and enough detail for me. The Prem. 3 is definitely a better phono stage, not sure about the line stage in 'em.
I've really enjoyed my pv10, but the pv10, pv5, and Prem. 3 all have too damn much gain in the line stages for a sensitive power amp like mine. Past time for an upgrade/change for me and my next preamp is gonna be something that has much lower gain, and probably one that employs 6SN7's.
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McCormack amps have a LOT of gain, making them difficult to pair with high gain preamps. Add to that a hot source, like a cd or dac that outputs 4v, and you have very little volume control even with a medium gain preamp.
Yep, reminded of the gain issue just last week. Brought the old CJ Premiere 3 out for a little exercise. I'd went from an 88 db speaker to a much more efficient 95 db speaker in my HT/casual set up. Without thinking, I set the volume control just below the nine o'clock position as I usually did with the 88 db speaker. When the music started, I was nearly blown out of the room. Had to dial it down to BELOW 8 o'clock. Fortunately I have a tube buffer upstream with a volume pot. I used this the trim things out to where I had a little room on the CJ .....at least enough to where I could take it to the nine o'clock position. If one had something crazy efficient like a big horn, I think there'd be some output with the vol. pot all the way down. Yep, this issue was present in my PV 5, PV8 and even my A.I.Mod 2B. Beyond 9 o'clock was verboten. Apparently this was a design flaw they couldn't seem to rectify back in the day?
~!
The Mind has No Firewall~ U.S. Army War College.
I just happened to have a pair of Wright 2A3's years ago. With the CJ Premiere 3 as a pre-amp in fact. The vol. never went beyond 9:30 as I remember.... maybe 10 when using a cartridge with around 1 mv output. Speakers used were Spendor 2/3's. The only active tube pre-amp from that era I could ever take to 12 o'clock or slightly beyond was a Music Reference RM-5 III which had an adjustable gain feature. The lowest gain setting allowed this range.
CJ 5 driving George Wright monoblocks... into Khorns.
I have a Baldwin 6L6 that is even harder to drive whereby was @ 3 o'clock.
At any rate the gain structure of that preamp {the Premier 3 is almost the same as PV-5} would not allow me to go over 9 o'clock with a Dyna 70... the point being some amps are far harder to drive.
The Mind has No Firewall~ U.S. Army War College.
another great post in this thread. Tweaking can be great. I am totally with you on the excess gain in so many line stages. With todays sources almost all 2V out or more a ;line stage w/ 6-12db gain at less than 1K ohm output impedance (lower is better esp for long cable runs) is plenty, maybe even over kill.
E
T
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