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Preamplificatore |
Finale |
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Prodotti che
hanno fatto la storia dell'hi-fi e che rimangono ancora attuali e
performanti , preamplifcitore valvolare dal suono sopraffino e finale
push pull di el 34 . Ottima la costruzione e molto comoda la
regolazione bias per le valvole finali.
Pre PV 10
Finale MV 50
Pre PV 10
Finale MV 50
Lo schema del pre
click per allargare
Una recensione
sul preamplificatore PV10
http://www.epinions.com/content_94304374404
For several years, the main
pre-amplifier in my stereo system was a conrad johnson PV 10. I bought
mine in 1990 or so, and used it with a conrad johnson MV 50 power
amplifier as well as a B&K 202. Speakers used with my PV 10 included
Vandersteen 2Cis, DCM Time Windows, Spica TC-50s, and Snell EIIIs.
The PV 10 has evolved since its introduction in 1989 or so: the version
shown here on Epinions, the PV10A, came into being in the early '90s,
and the latest version is actually called the PV 10B. The
design and tube complement have changed slightly over the years (and the
price has increased), but the sonic signature of the PV 10 has remained
quite similar.
First, the basics: The PV 10 is a no-frills tube preamplifier. Mine had
only a selector knob, a balance knob, and a volume knob on the front
panel, as well as a tape monitor button and a "balance out," the latter
of which removed the balance control from the circuit entirely.
In later versions of the PV 10A (as well as the PV 10B) the balance
control was done away with completely. The version shown on Epinions is
an earlier PV 10A, similar in appearance to my basic PV 10.
What matters is the sound. Audiophiles know that tube pre-amplifiers and
power amplifiers reproduce music with a "naturalness" that even the best
solid state equipment can not match. Solid state equipment generally
produces deeper, tighter bass, and perhaps more extended highs, but in
the critical midrange, tubes sound more natural and effortless. Imaging
is more three-dimensional with tubes, and the music seems to have more
life to it. The PV 10 is not perfect, but it DOES have some of
what makes tubes magical. Especially if mated with a good tube power
amplifier, the PV 10 can provide a very satisfying musical experience.
What are its sonic characteristics? First of all, the midrange is quite
lush and beautiful. Especially when mated with the conrad johnson MV 50,
musicians sounded like they were in the room with me. The sense of each
musician being a three-dimensional entity, rather than a "cardboard
cut-out," as audiophile reviewers like to say, was also really good.
Overall imaging is also really good. The PV 10 can generate a wide and
deep soundstage with good speakers (a PV 10 might work well with Thiel
.5s, which I recently reviewed).
Clarity and detail are NOT as good as with the best tube pre-amplifiers.
In fact, I think that the presentation of the little Jolida 102 tube
integrated was a bit more delicate and detailed, and a tad clearer, than
that of the PV 10/MV 50 combination, though the Jolida was lacking in
heft and warmth, relatively speaking. Bass through the
conrad johnson PV 10 is good, but it was not as firm and authoritative
as when I switched to my passive solid state pre-amplifier. The highs
may have been ever so slightly rolled off as well, though this didn't
detract from the musical experience for me. I believe that the high end
roll off is less pronounced with the PV 10A and PV 10B.
A minor problem I had with my PV 10 was that I had to tweak and re-tweak
my phono ground wire to minimize hum. Even at its best, there was
slightly more hum when playing records than with my passive
pre-amplifier. But the sound through the phono section was excellent.
Phono gain was also quite high; I only used the first 110 degrees of my
volume control when listening to records. The PV 10 was quiet with other
functions, though there was a barely audible hiss present if I put my
ears right up to the speakers with the volume turned up.
Tube microphony was also a minor problem. If you have tube equipment,
you want to isolate it as well as you can. The PV 10 runs fairly warm,
but it didn't burn up tubes particularly quickly. I generally re-tubed
every couple of years or so, ordering my tubes directly from conrad
johnson in most cases. As for human engineering, I really
like the way the conrad johnson PV 10 looks and feels. The unit is very
attractive, and the three knobs and two buttons operate smoothly. The
back panel is laid out logically, and the thing has a simple elegance
that is really pleasing. All versions of the PV 10 have auto-mute, to
supress noises that might occur as the unit warms up. It takes about 30
seconds to warm up (no sound during that period), though the sound
improves the longer you have it on.
To summarize, the conrad johnson is a solid tube pre-amplifier. The most
liquid and musical amplification I've had in my system was the PV 10/MV
50 combination. Female voices in particular sounded wonderful through
this combination. I ultimately returned the MV 50 (but kept the PV 10)
because the MV 50 could not control the woofers of the Vandersteen 2Cis
I was using at the time, and acoustic guitars (which HAVE to sound right
in my system) sounded too bloated. With the PV 10 and B&K 202, things
were much better in this regard, though the 202 is not as liquid through
the midrange as the MV 50.
The retail price of the conrad johnson PV 10 was about $1000 when I
bought mine more than ten years ago. I think I paid about $800 for a
demo. conrad johnson products are not heavily discounted, but you can
find vintage units an the used market for pretty good prices. The retail
of the latest version (with phono) is about $1600, which is getting up
there. According to Sam Tellig, in a 2002 Stereophile article, the
characteristics of the latest PV 10 (the PV 10B) are quite similar to
the earlier versions, but he warns of a slight upper-midrange emphasis,
meaning that a power amplifier with similar characteristics should be
avoided.
If you are trying to put together a system based on tube amplification,
I might try to find an older PV 10, and mate it with an older conrad
johnson or VTL tube amplfier. You can save some money this way, and
though you'll give up a bit in resolution and deep bass relative to the
best out there, you'll have that magical tube midrange at a decent
price. Older PV 10s can be had for between $300 and $400 on the used
market.
For those who are interested in such things, the tube complement of my
older PV 10 was as follows:
V1 & V2: 12AX7
V3 & V5: 12AT7
V4: 5751
Replacement Tube Set RT10
For the PV 10A, the model listed here, the complement is as follows:
V1 & V2: 12AX7
V3: 12AT7
V4 & V5: 12AU7
Replacement Tube Set RT10A
If you want to experience the sound of tubes without having to buy a
separate pre-amplifier and power amplifier, check out the Jolida 102 and
202 integrated amplifiers. If you like the idea of separates, or if you
happen to have a tube power amplifier on your hands, and are looking for
a suitable mate in a pre-amplifier, the conrad johnson PV 10 is one of
the most cost-effective options. Given the rise in price over the last
10 years, I might check the used market before diving into a new PV 10B,
but I invite comments about the latest version.
Happy listening!
http://www.stereophile.com/tubepreamps/790/
http://www.hi-figuide.com/standard/amplificazione/finali/conrad_johnson/index.html
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