PV9 v PV10-AL

[NorthernLights]

Hi again forum. I haven't dared show my face after my last posts but I am hoping for some advice!

I currently have a 10-AL and MV-55 combo which I really love. I stream and play digitally from a server.

I've been planning - next year now, I think - to upgrade the AL to BL and add teflon caps in the MV-55. This can be done here in the UK through Audio Freaks and they seem well regarded. So I'm looking forward to that.

In the meantime a one-owner PV9 came on the market and I've put a deposit to hold. It has a phono stage which I won't be using. I'm curious if anyone has any insight into sound difference, if any, from a PV10-AL. Or say a 12, which I see come up for sale more frequently. I don't see much about the 9 on the net - is there a nice sonic improvement from the pre-amp I have?

My current set-up sounds great. I guess I'm just curious to try an inexpensive alternative to see if it makes a positive difference. Knowing I can always sell one of the units without taking a drastic loss. I'm kind of thinking it would be fun just to A-B the two preamps just for the hell of it.

Oh - is there database to check manufacture dates based on serial numbers? This 9 they say was new in 2003 but the literature on CJ has dates way back. I'm curious to find out how old the actual unit is.

Thanks in advance for any thoughts.

[admin]

Hi NortherLights,
Good to hear from you again.

I can't speak directly to the comparison of the PV9/10/12 but I did use a PV-12AL for a number of years. It's a great preamp and really one of the highlights of that CJ era. Although I don't have sale numbers, I think it was one of their more popular units as we just see a lot of PV-12's for sale than many other in that series. I think this is for good reason, it was a very solid performer. They did sell some PV12's with a phono stage which I have heard are very good quality, although hard to come by.

All things being equal, I would definitely go with the PV-12 vs the PV9/10 if given the choice.

BTW, the PV9 was introduced in 1988, the PV10 in 1989, the PV12 in 1993 (with the PV-12A version in 1997, which is the version I would recommend pursuing if considering a purchase).

CJ's site states the PV10B was released in 2000 as "new model" but I'm not exactly sure what the differences are. This topic talks a little about PV10A/B differences so maybe ask in there: https://www.conradjohnsonowners.com/vie ... php?t=2080

[AnotherJohnson]

The 9 and 10 were lesser units between the 8 and 11. The 12 was a legitimate heir to the 11.

If it were me, I’d stick with what you’ve got (if you like it and it sounds good to you). If a 12 comes along, it might be worth a move. Actually, if it were me, I’d wait for an ET3SE to come along. That would be your real game changer.

[NorthernLights]

Thanks so much, I really appreciate the insight from you both.

[roberto]

Hola,

AJ and Admin had pointed out for the PV-12. AJ added the ET-3SE, and I am sure this ET-3SE belongs to another higher level. The ET3SE comes with Teflon caps and metal foil resistors. These components offer a more accurate quality sound and more transparency. The S/R is impressive. I am totally in favor of the ET-3SE. Totally newer design and of course shows the signature quality sound of Conrad Johnson. You can't go wrong with this model...

Happy listening!

[tonye]

I have had a PV9 since the beginning...

...about three years ago, while on a repair visit to the factory to fix the zener diode to the soft start (mute) circuit, I had them go over the whole thing and upgrade it to the teflon caps.

It wasn't cheap, but if you have one of the old CJ preamps, you should RUN to get this done. It transforms the sound.... my wife says our main 2 channel stereo sounds like music, not an audio system.

The teflon caps change the sound... the noise level drops (OK, I have also done some significant changes to the turntable -LP12- and amps -Aleph 2 ) but anyone who dumps on the PV9 is simply not following the factory upgrade path. The soundstage opens up (running Maggie 1.7s now), the treble shimmers, and the midrange -instruments become palpable.

BTW, the PV9 with its 20v output will easily drive a First Watt F4 and it;'s very quiet (at least my upgraded unit can easily drive it with no noise). In that low power setup, running a pair of Elac monitors, not very loud mind you, the sound is holographic. The peaks are only 90db but the noise disappears and the F4 allows the full sound of the preamp to shine through.... the F4 itself has NO sound of its own... so if you want to hear a preamp, that's the ticket... and the PV9 does fantastic, with flying colors. Even at lower levels, the soundstage doesn't collapse, does not miniaturize, it just sound as big, but not as loud. BTW, I can not recommend enough the PV9-teflon caps-F4 combo... It turns the preamp into an SE integrated...

The only complain I've had about the PV9 is the high gain of its phono preamp and non adjustable load (100 ohms). But most of that has been on my head... the sound per se, specially after the teflon caps, is impeccable. I have driven low output Grado References for about 15 years now, quite successfully.

Recently, my head had the best of my wallet and I had a DIY custom two box Pass Pearl 2 phono preamp built for me (FETs) with full adjustable load/impedance/gain. The Bill Of MAterials alone was scary... but the sound is just a bit better: mostly a lower noise level Mind you my Pearl 2 is only one of two in the entire World build with such parts and adjustability... and to buy an equivalent commercial product would be nuts ( the BOM run $1400 bucks, with plain aluminum cases for PS and amps... ). So, that gives you an idea of how good the PV9 can be - again... with the teflon caps.

[AnotherJohnson]

That great that it worked out so well. Congratulations!

[admin]

Doing these kinds of upgrades decades down the line can truly revitalize these units. We are often quick to recommend upgrading to more recent offerings but if you really enjoy a classic piece, these upgrades are viable options.

Congrats on the (new) PV9!

[Big Dog RJ]

Good stuff matey!
Keep those tubes a'glowing and keep those tunes playing!

Certainly sounds like those Teflons and minor mods hit the spot! Sounds like T's PV9 based system has reached its threshold, in which case why change?

Just enjoy it to the fullest!
Woof! RJ

[roberto]

Oh yes, upgrading the PV9 is a good idea. Good to know that yours worked that good and best way. Teflon caps really offers a fantastic great sound quality. The signal to noise ratio is improved too.

Having said that, I really don't see a reason why change it.

Happy listening!

[NorthernLights]

Happy New Year everyone and just seeing the new posts now. Actually, I was just coming on to update - I did buy that PV9 in December, I figured there wasn't much downside and it came with a full set of replacement valves also. I think it was a later version but CJ dumped all their old serial numbers from their internal database (can only go back 6 years now); not sure why but that's what they told me.

Tonye, was interested to read your post. Although a lot of technical stuff above my pay grade! Yes the gain is higher than the PV10 and I am loud without moving the volume control as much. That much I did notice. By doing crude a-b I think I'm hearing the sound is fuller/richer/more fleshed out with the 9. Not drastic but it's almost like the instruments sit back with the PV10 and the voice is a little forward from them. The PV9 seems to bring the instruments up to parity so it's a different kind of presentation - one I like a lot. And there's something sweeter to it all. It feels like it's got a better grip on the music for a completely non-scientific viewpoint. I continue like the sound of the PV10 but it's maybe a little politer and thinner in places, still a great amp in my mind and I could go back to it for sure. So I would recommend these PV9 units are definitely worth trying if anyone has the option. The CJ dealer in the UK believes them to be a real gem from times gone by. And, if I can afford the Teflon upgrade down the road then that's something I will definitely have a think about. It does sound damn good already.

[tonye]

One thing about the PV9... it is VERY quiet, while it swings quite a bit of output voltage (20V) and gain - both phono and line stage. Indeed, likely too much gain in phono for a MM. My 1mV Grado is pushing it.

Recently I got the FW F4 so I needed more efficient speakers. I splurged and bought new speakers (used of course... about 90db/w).

Now, I can crank the PV9 to fully drive the amp ( a FW F4, which is a current amp, not a voltage gain ). This requires a single ended swing of 14.4V.

To reach that, I have to turn the volume knob to 3 o'clock. (my source swings enough voltage).

That's a lot of gain... yet, if I hold my ear to the speakers with no signal driving it, I don't hear anything. Both on phono and line stage.

[NorthernLights]

That's interesting - I'm not with the stereo currently but I'm not experiencing the same as you, although I haven't really had a chance to play around. Perhaps your amp and teflon upgrades have something to do with it?

My impression, from recent memory, was that it was almost as if the signal was bursting to break through at any slight volume. So there was a low level static/hiss sound even at volume "off" (when close to the speakers). Once it was turned up I don't notice it over the music so it's not like it interferes really. But the PV10 is quieter in that sense, so far. One thing I don't have is an annoying high-pitch whine my PV10 has from time to time. The only way I've resolved that previously is to power down the pre-amp and turn it back on. That I haven't had a chance to troubleshoot with a tech so far due to distance to someone that can service.

If the PV9 "off' is at 6 o'clock - and I don't remember if that's actually accurate - then I'd say at 8 or 9 o'clock it's decently loud. I haven't really tried to crank it. I have 92db re-configured HPD315 Cheviots. Really great speakers from a top notch guy here in the UK (can't speak highly enough of them) - https://www.referencefidelitycomponents ... dspeakers/

Will have to explore more when time allows.

[tonye]

It could be your amplifier or you might need new tubes or a cleaner AC source?

I live in suburbia and installed a dedicated 20A, 120V home run between the stereo and the fuse box. Nothing else is plugged into the line, not even digital audio products... only analog.

When I run the PV9 into a "normal" amplifier, ie: a voltage amplifier, with normal speakers (more on that anon) I seldom turn up the volume past 10 o'clock.

When I run the PV9 into Aleph 2s running the Maggies, I will turn it up to 11 or 12 o clock. The Maggies are rather inefficient so they push the amp to drive past 100 watts rather often! That needs some serious voltage amplification by the amp.

Now, neither of such amps though requires all the gain the PV9 is capable of ( 31db amplification on the line level and a max 20V output). I would figure that when driving voltage amplifiers the preamp is likely not driving more than 3V.

However, When I run the PV9 into a First Watt F4 ( no voltage amplification at all ) and into 90 db/watt, 6 ohms speakers, I can turn the PV9 up to 3 o'clock (with a ~2v input) with no noise at all. The F4 is driven to full current at an input of 14.4v... which is about ~35 wpc, and it has NO gain... so that means I am really using the PV9 to amplify the signal to a full 14.4V. The F4 has NO noise of itself.

Now then, I'm in the US and the plug of my PV9 is a two terminal prong... not using the ground, only the Hot and Neutral.

It sounds to me like you might need some noise filtering in your AC "mains".

[NorthernLights]

Thank you again for your reply and suggestions - ok, well I have an unused set of valves that came with it, so maybe I'll start there. I don't have the same sound with the PV10 and the amp so feeling like it must be the PV9 as the "new" addition. The PV10 issue I mentioned is way, way more annoying for sure, this PV9 hiss you don't really hear unless you are up beside the speaker. I'm sitting a good bit away. The other preamp's issue drives you nuts it's like you're having a bad tinnitus attack - it's totally intermittent though.

Understood on your Magnepan speakers, I haven't heard them before but obviously quite different from my speakers. I guess the volume on your normal speaker experiences are in the world I'm talking about, also. Makes sense.

I'm really out in the sticks although I don't (think) I have a dedicated line to the socket. It's an old house so god knows what's going on behind the walls! I do have all my stuff running out of a Plixir BAC 3000 AC conditioner, which brought a nice smoothness, stability and a bit more depth overall.

Hope you are staying dry, I know you've had a lot of rain in SoCal this year. I was 20+ years in LA and it never seriously rained like that - that I can remember at least.

Cheers.