Hi All. I've been pretty happy with my Pro-Ject Tube Box DS using Tung Sol tubes, although the treble occasionally seems a bit harsh and the sound stage could have better depth. But, since I upgraded my preamp last year to a Vincent SA-T7 and love the sound (still with stock tubes), I've been eyeing the PHO 701 and reading your informative posts. The list price is (or was) $800 USD, but Audio Advisor has been selling it for $600. Last week, they had a demo for $436, so I jumped on it. As always, their demo products arrive in near-new condition. This unit was only lacking the manual, which I easily downloaded from Vincent. I've been playing it with the stock tubes. I noticed an immediate improvement in the two things I noted above. The treble is more silky, and the soundstage has more depth. Also, the instruments generally have a richer timbre. I do notice a mid-bass bloat on some recordings. I'm surprised at how good it sounds even with the stock tubes. I bought a Mullard for $25 from an Amazon seller. It's probably a knock-off, but I'll try it anyway. I also immediately replaced the power cord with a Pangea AC-14 per your recommendations. I've been using the same cord on my other sources for a while with no complaints. I'll report back as I get more hours on it, and after I try some different tubes.
I forgot to mention noise from the proximity of the two boxes. I put mine on top of my digital player, as far apart as possible. There's about 7 inches clearance between them. I detect no noise.
Curious what kind of noise issue you were having. I’ve had the power and tube chassis stacked one on top of the other since I set it up. The stack sits on a shelf, not on top of another component. It’s dead silent.
I haven't had any noise issue. Others reported some hum with the boxes stacked on top of each other or close to each other. See posts 4 and 5 on this thread for mention of it, but I read some more comments elsewhere, but don't remember where. I just mentioned it to state that I haven't had any hum.
Gotcha. I misunderstood what you meant. I think noise/hum other people are hearing may be coming from poor grounding of the TT, a cartridge prone to hum (think Grado), or some other issue in the chain, rather than the proximity of power chassis to tube chassis. Other than this thread, I’ve not heard of hum being an issue with the 701.
I recently bought the Vincent PHO-701 and since I inserted it into my system, I have a constant hum. This is only when I plug the device into AC power. Once I actually turn the device on, I start picking up what sounds like a distant radio signal. I can hear voices and songs playing faintly in the background amidst static. My Schiit Mani was dead silent. No him, hiss or otherwise. As soon as I plug the Vincent back in, the hum is back. I tried going directly to the wall outlets, using an extension cord to another outlet, going through a surge protector and unplugging all other items to ensure no crosstalking. I’m at a loss to know what’s going on. I’m disappointed after reading so much positive about this phono stage.
I also forgot to mention that I tried all the aforementioned spacing including separate shelves and several feet apart.
I had a hum on a Vincent PHO-700, which I tried. The only way that greatly reduced the hum ( I had no radio interference) was disconnecting the ground of the TT/cart, . Possibly, grounding created some weird loop?
I was a little irritated with the radio interfereance at first but you can only hear it if you turn the volume really loud and put your ear next to the speaker, shouldn't be there...
Good that it is (almost) inaudible! But it could still sound better, if it were to be eliminated, like lowering a noise floor. Do you perhaps use some unshielded phono or tonearm cables that could act as an antenna?
I wonder if replacing the power cable helps. I've only used mine with a Pangea AC-14. I didn't even try it w/ the cable provided by Vincent.
Tonight I replaced the stock tube with the Mullard (not NOS). I'll let it settle in for a while, but in the first hour or two I notice more forward treble and less pronounced, tighter bass. Due to this, it seems to have shallower depth. However, where I noted the bass bloat on side 2 of Tangerine Dream's 'Le Parc' before, it's now more controlled. I'll probably splurge on a better NOS Mullard or Telefunken.
I just bought the PHO-701 and SV-237MK and have been battling hum and radio signals since day 1. Love everything else so far, but can't seem to reduce the noise, especially at higher volumes. It's noticeable during playback. My TT is wall mounted, and proximity doesn't seem to be the issue. I have AQ Big Sur + AQ Saturn Ground cable from Pro-Ject Classic SB to the PHO. Perhaps I try the Pangea AC-14 power cable next. Tube rolling starts when I solve the hum/radio signal issue! Hum definitely coming from the TT.
I got no hum but the radio signal is there at very high levels. I have to put the ear next to the speaker to hear it though.
Have you tried not grounding the PHO and or the TT at all? Sometimes grounding can create loops as well. Another option is to ground the PHO directly to wall socket ground with a “ground only” cable.
Thanks! Hasn't been a horror story at all really, more a nuisance but I'm confident it can be dealt with. Symptoms are nearly identical to the OP's, just frustrating because I feel like I've done everything right. I test drove a Parasound Halo Hint 6 right before getting the Vincents, and it was night and day difference. The Vincents blow the Hint 6 away in my set up, definitely a great investment, just have to chase this hum away. Will post when I find a solution. Apologies to the OP for the thread jack!
None at all. No sweat. Asides from the radio interfereance i say that the Vincent is a beautiful sounding phonostage.
since the Vincent comes with separate PS and does all its rectification on a different board, my guess it is not the power cable ... try changing the phono cable from the TT to the Vincent with min double shielded ones with low capacitance. I bought mine from Yannis cable which are hand build competently. Make sure the ground is connected only to Vincent and the Vincent output is to the LINE input of the pre-amp. Yannis Tome Analogue Audio Cables web shop
Last weekend I switched back to the stock tube from the 'Mullard' I was trying. I think I like the stock tube better, but my opinion might change like the weather. Last night I listened to a couple of LPs, and they sounded wonderful. It was a vintage evening. First, side one of last year's Vertigo soundtrack release, which is 34 minutes of stereo recordings made in 1958. Then, side two (Variaciones Concertantes) of this stereo Ginastera LP from 1968: Ginastera* / João Carlos Martins, Boston Symphony*, Erich Leinsdorf - Concerto For Piano And Orchestra (1961) / Variaciones Concertantes
