Mini System with PV-14L and MV-55

[admin]

So for awhile I have been thinking of building a small second mini system downstairs in our sunroom. It's a room that we use for work on the computer, reading, storing plants in the winter, and just generally "hanging out." However, as this is not in a dedicated listening room, my wife and I did not want to put a stereo system in that would be one that attracts people's eye. Hence, it had to be relatively subtle. I also did not want to spend significant sums as I would rather put money into the main stereo system upstairs where I do my "serious listening." We also have some ceiling speakers in the room and outside of the room in the main house. We use this as "background music." The source is the computer you see in the picture and powered by the small Kenwood receiver (which is stacked under the CJ units but there are not direct connections between the two systems). The speakers for that are some dinky generic RCA's that came with the house. I have to admit that sometimes the audio quality makes me cringe.

I had some stipulations when considering the build:

1) Bookshelf speakers. Nothing big that would not fit on the shelf already in the room.
2) Keep the total cost under $2,000.
3) Ok'd by wife.
4) At least some CJ gear.

When the oppertunity came up to attain a PV-14L and MV-55 at a very reasonable price I went for it. I was also able to purchase a set of preowned Martin Logan 35TXi book shelf speakers from my local high end audio store. The audio source is a Wiim Mini that I already had but was not using. Interconnects and speaker cable are no-name brand generics.

As for the sound. Actually very nice and pretty amazing for the price point. When I first listened to some music on the new setup even my wife mentioned,... "wow, that sounds a lot better." No, they don't compete with my Magnepan 20.1's and ET7s2 and ART amps, but they are in a completely different league than the ceiling speaker setup. You can't tell from the picture as I took it from an angle but the left and right angles are identical from the seating position. They are a little higher than ideal height and the right speaker is 2.5 inches higher than the left but again, I had to make due with the limitations and criteria of the room furniture. Interestingly, I don't appreciate any vertical sound difference from the listening position. I can always put something under the left speaker to raise it up a little if I do start noticing a vertical sound discrepancy. I may also try to get better interconnect cables but there is not too much left in such a tight budget. The wife was happy and approving as well. I was able to stack the preamp and amp onto the already present in the room Kenwood stereo receiver and the Wiim mini is smaller than a hockey puck. The only extra space taken up is the two bookshelf speakers.

Overall, I'm very happy with the build and the ability to listen to high quality music down in this room that we spend a considerable amount of time in every day.

[AnotherJohnson]

I’m glad to hear that it has come to a good start.

Think of the wood you’re going to save by running tubes there. The wood stove will wonder if winter has been postponed.

Paulo has posted on WBF that he has a PV5 and MV 55 coming, so he’s set too (he was second to respond to the classified, but too late).

FWIW, the Kenwood should sound better on the new speakers too. Although it may have its own issues.

[AnotherJohnson]

Actually … I am going to suggest something now that I’ve looked at the picture beyond noticing the wood stove.

I would be hesitant to stack a tube amp on top of a tube preamp. Maybe it’s just my tendency toward caution, but the ventilation by natural convection for the preamp is thwarted, and the heat that transfers out of the preamp is moving into the lower casework of the amp, accelerating the thermal aging of insulation and other susceptible components.

That’s really a perfect location for a CA150 (solid state), but probably not within the budget constraint. I get the impression that this system will see a fair amount of daily use … it’s in an area where you spend time most days, not a vacation home.

Maybe you could build a little riser to give 4” to 6” clearance above the preamp.

Or maybe you could just see how it goes … but because I’ve seen fires started by lack of ventilation around tube gear, I’d definitely keep a close eye on it.

[admin]

I thought of the heat issue as well. Interestingly, the PV-14L produces very little heat with the two tubes. The top of the PV-14L is only vented all the way in the back and even that is a very little area. The MV-55 is not only less wide, but also less deep so the vents of the PV-14L are not actually under the MV-55 but behind it. The MV-55 produces very little heat inside the chassis as all the tubes are above and the transformers are outside as well. Before I brought the units up into this position, I had them on my work bench (when I working on finding the static noise and replacing the tubes. The top of the PV-14L didn't seem to get "hot", only very mildly warm. I'm going to keep an eye on it and increase the separation if there is any heat dissipation issue.

I did get some listening time on it today and for now I really like the sound and should serve it's purpose. Not my "reference system" but very enjoyable and a lot better than it has any right to be for the total cost.

[admin]

I was thinking more about the heat dissipation issue today so I took a closer look at the setup today and did some experimentation with a probe thermometer.

First, there seems to have been design thought put into the PV-14L above just the "lets put some vents on this thing." There are vents right in the bottom front housing and then some more on the back top. This creates a consistent airflow from the front bottom of the unit to the back out. I presume this was done to keep the front control components nice a cool, move the air over the tubes and out the back near the power supply. As mentioned before, the back top vent is in no way covered by the MV-55 which has less depth than the PV-14L. I also put my probe thermometer between the center point of the two units and took a temperature reading after about 30-40 minutes of playtime. The top of the PV-14L housing read at 90 F (ambient room temp was 74 F). In other words, very limited heat production or it's simply venting well. I don't know what the overall power consumption of the PV-14L is, but I'm presuming those two small tubes are not generating too much heat. There is a good 3/4 of inch space between the two units so I think for now I'm not going to take any intervention and keep an eye on it.

[AnotherJohnson]

Make sure you’ve got the correct plate fuse(s) installed in the MV55. In fact, check the other fuses too.

The problems come in when something fails. If the fuses are correct, they should blow before anything runs away.

[AnotherJohnson]

According to the owner’s manual the PV14L dissipates 20 Watts and 2” clearance with an unobstructed back are recommended.

[Big Dog RJ]

Good stuff Admin, always nice to see another side of the humble spectrum in audio gear.
110% agreed with AJ on the set-up, I would definitely not stack any power amp directly on top of a preamp, that's a big no no for me.

One is heat dissipation, the other is cross talk between the two units, hums, buzzes etc , and finally although this is vintage and simple gear, it's still highend audio! Therefore, both these units need proper placement. Unless you're entire stack was a Kenwood or Pioneer SS for that matter then going up on top of each other is fine.

Definitely not CJ gear, regardless of model.

The one and only record store I buy all my music from, which is also the only store in Melbourne to carry audiophile recordings, the owner actually has a MV55. Driving a pair of Watmough floorstanding speakers, a very nice TT rig by Dr. Feickert- wp and a Cyrus preamp, all placed on dedicated shelves and totally isolated sounds quite good for vintage value.

Anyway, I understand that you want to keep the expense to a minimum, so most probably won't make any adjustments.
That's fine, as long as there are no long term issues since this particular rig is being used longer than the other one.

Now do enjoy those fine tunes!
Cheers, RJ

[AnotherJohnson]

I would have brought up the emi/rfi interference potential, but I thought enough of admins ears to let him decide without my input.

But … obviously it’s an elephant in the room. You would NEVER intentionally put output transformers so close to the input stage of the preamp.

When CJ said that 2” of clearance above the preamp was necessary, it was partly to keep the components from being stacked.

I am stacking two stacks. One has the Node sitting on top of the MDA200. The

The other is the Sennheiser Headphone amp sitting on top of the Marantz ND8006, which is sitting on the Ruby SA-KI. All are solid state, none dissipates much heat, and like admin’s stack, none are for critical listening.

[admin]

110% agreed with AJ on the set-up, I would definitely not stack any power amp directly on top of a preamp, that's a big no no for me.

One is heat dissipation, the other is cross talk between the two units, hums, buzzes etc , and finally although this is vintage and simple gear, it's still highend audio! Therefore, both these units need proper placement. Unless you're entire stack was a Kenwood or Pioneer SS for that matter then going up on top of each other is fine.

I would have brought up the emi/rfi interference potential, but I thought enough of admins ears to let him decide without my input.

But … obviously it’s an elephant in the room. You would NEVER intentionally put output transformers so close to the input stage of the preamp.

When CJ said that 2” of clearance above the preamp was necessary, it was partly to keep the components from being stacked.

I have to say that I am kind of in a pickle. This system has a very powerful limiting factor on how I can arrange the components. I promised Mrs. Admin that it will not look funny or out of place. There really is no place to put them side by side so it's stacked or nothing.

Luckily, I don't notice any cross talk RFI interference. Before I put the system in the room, I had it on my work bench where they were side by side and the sound was identical. So those big transformers don't seem to be having any influence on the PV-14L output.

I don't know how I feel about the temperature. Again, the measured temperature on the PV-14L after running for a considerable time was only 90 F. That is lower than ambient room temperature in many climates. But admittedly under normal circumstances I would never stack an amp on top of a preamp like in this setup. I also wouldn't have one speaker 2 inches higher on the vertical than the other. Again, this is a system of compromises and was never meant as the "ideal setup."

After some consideration I think I may try some active cooling options. I actually use a small blower fan on my Onkyo SR-875 Receiver in my home theater setup. That can get so hot you could boil an egg on it and literally burn your hand. However, with active cooling it's only slightly warm to touch. Active cooling is much more efficient than passive and may provide the thermal protection I am looking for here.

Maybe something like this: https://www.amazon.com/GDSTIME-75mm-Blo ... 427&sr=8-4

Could be small enough to fit in the 3/4 inch gap and be placed on the side or back where it is out of view (and Mrs. Admin approved). This would increase air flow more than any riser would.

I will have to examine the situation further.

[AnotherJohnson]

You may find it perfectly acceptable as it is. SWMBO has already acknowledged the sound upgrade. That’s part of the battle. A little riser on which to mount the amp would be simple enough to make. Or just leave it alone and enjoy the tunes.

RJ alluded to this next thought … this is not a “cheap” system. It was very close to SOTA at the turn of the century. It is going to sound far better than anything you could buy new for the same money. You lucked out here, on the same level as your ART amps. Buy low …

[AnotherJohnson]

You may find it perfectly acceptable as it is. SWMBO has already acknowledged the sound upgrade. That’s part of the battle. A little riser on which to mount the amp would be simple enough to make. Or just leave it alone and enjoy the tunes.

RJ alluded to this next thought … this is not a “cheap” system. It was very close to SOTA at the turn of the century. It is going to sound far better than anything you could buy new for the same money. You lucked out here, on the same level as your ART amps. Buy low …

And implied in this post, (a) adding a fan begins to build a kluge. Noise, power, more “stuff,” probably not necessary, and (b) this system is worthy of a better location with better speakers. You could flip this and have more than enough for a used CA150. Or even a new Japanese sourced SS receiver which would work fine for your purpose. You might even have money left over to augment your travel budget.

[Big Dog RJ]

Yes, nice Yamaha or Luxman integrated amp would have been marvellous!

To place those beautiful CJ tube products stacked like that onto top of one another is like cattle ready for the slaughter house ... I would say it's a shame.

The MV55 is a glorious tube amp. For what it offers and the level of musicality from the EL34's is fantastic! Plus the PV14, that preamp has those wonderful Mullard M8080 tubes. These are the same input tubes used in the ART monoblocks. They're a superb quality of musical finesse used in the pv14, pv15, and CJ's last Classic/SE preamp. Only after those models CJ ventured back towards the 6922's as their standard input & driver stages.

If it was me, I would place these two golden beauties on a dedicated stand to highlight those golden years that CJ was known for. After all, products like these were the hall mark of CJ. Just beautiful gear.

Anyway, it's upto Admin to decide on further steps...
Cheers, RJ

[admin]

Hmmm. Sounds like I'm committing sacrilege here.

I have to look at options. Unfortunately, I am really limited on what I can do here. The location of the components is restricted. I would love to put the entire thing in appropriate rack/stand but I don't have the room. I'm going to see maybe I can get some risers to put between the components to give them separation. I also ordered that little fan so I'll see how much heat dissipation it would augment.

Keep in mind that from the beginning I knew this system was going to have compromises. I don't want those compromises to potentially damage the equipment, so heat management is certainly something of a priority fix, but I probably will not be able to solve all the limitations.

[AnotherJohnson]

Don’t worry about it. It is a first world problem.

“Oh No!!!! My $3k worth of amp and preamp are too precious for my background music space!”

It’s your stuff. Enjoy it as you wish.

It just kind of humorous. Sort of like using a $500 yard sale find $10k gold antique French clock on your kitchen counter because you need a clock in the kitchen and if you want something else there, you have to buy it.

It’s all good.

[Wildcat]

Good score on the PV-14L! The only tubes I've had luck with have been the Mullard CV4058/M8080. I was buying them from a source in the UK, who matched them in pairs. They were a good seller, also--I had one of the tubes get noisy after a couple of weeks, and they offered me a new pair gratis. Because of that gesture, I ordered another set as a backup so they could ship the two replacement tubes with my order. They currently have "close pairs" for £40, plus shipping. My 14L arrived with Phillips/ECG 6C4s, and I had tried a replacement set of NOS Tung-Sol 6C4s, and both sets were microphonic even at average volume. I've never had the M8080 become microphonic.

The eBay UK seller was jmg744. Colomor Electronics.

My PV-14L does not get very warm either. I actually put the EV-1 back in the system again, and have it stacked on top. If the PV-14L is just warm to the touch, the EV-1 (with more tubes) is maybe ten degrees warmer at the most. It's nothing I'm worried about. (A neat visual party trick is that the PV-14L and EV-1 have the same front panel design, so the vertical machining lines up perfectly.) I recently used one of the sections from my rack as an amp stand, so the Premier 11 sits off to the side now.

For my desktop system, I had considered finding a CAV 50, as it's the older, less expensive "control amplifier" C-J made for a while. But I don't think I've ever seen one come up on the used market. CAV 45s are somewhat more common but also cost more. At any rate, both were too large for the hutch on my desk. I had a cheaper "Chi-Fi" amp I was playing with for a while, but I finally broke down and bought a pair of KEF LS50s and a Sprout100, with a Martin Logan Dynamo 700 under the desk, and it is fine for listening when I am not by the main system.

And speaking of the heat, when the Sprout100 is powered up, it is warmer than the PV-14L! I've been meaning to try it on my stats one of these days, just to see how it does.

[admin]

I may try to do some tube rolling with the PV-14L once the tube crises abates. I'm going to hold off for now. Also, I promised myself to limit the budget on this setup to $2k so it really doesn't leave any wiggle room. On my upgrade list is to get some better interconnects as I using some generic brand currently (which I really didn't like when I used it for testing purposes in my main setup).

I've been experimenting a little with the heat issue (or lack there of). I did get one of those mini-usb fans and it blows a lot of air between the units but also makes fan noise which I didn't like. Almost all the heat comes from the MV-55 and the PV-14L is really mildly warm to touch, if that. I'm going to employ some spacers to give a little more separation but I really think that will be more than adequate. I'll keep experimenting.

A CAV45 would have been an excellent choice in this setup, but the price point would have been at a different level than what I had set for myself.... maybe one day.

The sprou100 is a different beast all together. Not surprised it puts out considerable heat as the spec pages report that it can use close to 300 watts and the unit itself is much smaller so more heat on a smaller radiating surface. It is an incredible unit for all it does and the price point is amazing considering it is PS Audio.

[Wildcat]

I wouldn't be overly concerned with the PV14L's heat--the only thing separating mine from the EV1 are a set of three IsoAcoustics mini pucks, and like you say, it is only mildly warm to the touch. And I have not noticed it getting any warmer. If heat were an issue, there probably would be more venting along the top. The EV1 basically has the same case to it (same size, with the same three rows of vents on top), and it is a warmer-running unit due to having four tubes inside vs. two.

My Sprout100 I wasn't too clear about--when it's turned on and idling (not playing anything), it gets warmer than the PV14L. It is a nice unit for either a desktop system or a small system in a spare room--I'm glad I got it.

Anyhoo, with the warmest unit on top (in your case, the MV55), I think you'll do just fine. In fact, more heat might be radiated out the bottom of the MV55 than out the top of the PV14L! (My whole Premier 11 gets nice and toasty.)

I had no luck tube rolling with the PV14L largely due to microphonics. But I only have experience with two other tubes (the Philips/ECG pair, and the NOS Tung-Sols). A 6C4 is not as common as a 12AX7 or 6DJ8, but it has other electrical equivalents (EC90, CV133, M8080/CV4058, 6100, etc.). I usually start on a site like the following and start digging. Maybe you'll be "the one" to find that magical replacement we've all missed? (You would think that with all the substitutions and different brands available, there might be *something* out there that could work!)

https://www.radiomuseum.org/tubes/tube_6c4.html

From what I've read, even here on the forum, is that the M8080s sound the best so far.

https://www.conradjohnsonowners.com/vie ... php?t=1369

And a similar discussion on Audiogon:

https://forum.audiogon.com/discussions/ ... line-stage

Rolling the small signal tubes in the MV55 at some point in the future might be fun also.

Enjoy the new setup!

[paulCJ]

Congrats on your PV-14L and MV-55. While I don't always have my MV55 connected in order to save on tube life (I have other gear too), it does seem extra special when I do connect my PV10AL to the MV55 to listen to jazz and female vocals that bloom.

[tonye]

Nice set up.... how do the ML speakers do? Did I miss your front end? Some DAC? What kind of music do you listen in that set up?

I daresay that upping the speakers and the front end will give you the most bang, as the preamp and amp are very much fine.

Have you tried the Elac Unifi-2 EB52? Or the Elac Carina bookshelves?

Sure, sure... you only want to spend $2K... but you know how it is. And at this price point just a few bucks will make a huge difference.

Good listening.