you can write to Yannis and see what advise he gives.... he recommended me to use Belden double shielded ones or Quad shielded ones which I end up with the Silvercord cables costing more than Schitt Mani. so far no regrets, cable performs as claimed, zero noise from Mani not even a hiss at max vol. I take it as a long term investment where this part of the chain I won’t touch no more.
The AudioQuest Big Sur cables I'm using are double shielded (allegedly) and "Prevent captured Radio Frequency Interference (RFI) from modulating the equipment's ground reference..." but I switched them out with the stock cables and found there was hum/radio without the TT being connected at all, so the trouble is with the PHO itself. This leads me back to the power cable. Been using a new WAudio W-3900 power purifier which had no effect, and will now be spending another $100 for a Pangea AC-14XL MKII to cover all the bases. The AQ Saturn ground cable so far has been most effective from the TT to the PHO, as normal. I won't be mentioning the $100 power cord to my wife just FYI.
Say, did you ever find a solution to your PHO's humming? I just received my new PHO-701 about a week ago and it has a 60hz hum. I determined the hum isn't related to my Technics SL-1500 as the hum occurs when the TT is turned off. The PHO is connected to my Hegel H90 amp. When the two are the only devices powered up, plus the speakers, this occurs. When I power up first the PHO followed by the H90, the hum kicks in concurrent with a little clicking sound in the H90. It becomes audible at volume 50 (the H90 goes 0 - 99) and increases from there. I've separated all the power cords from the interconnects to eliminate the possibility of an issue there. The interconnects I use are from World's Best Cables -- "3 Foot – Directional Quad High-Definition Audio Interconnect Cable Pair, Using Mogami 2534 Wire and Eminence Gold Locking RCA Connectors." I also have about 2.5' separating the PHO from the H90. And I'm using the power cords that came with the PHO and with the H90. I hope you solved your issue and your solution may guide me in my own quest for silence!
60Hz hum isn't usually related to turntable power, it's generally caused by a ground loop, meaning more than one wire providing AC return path and causing an AC voltage to develop between the ground and signal lines. Assuming you are using a turntable ground wire connected to the phono preamp to keep the tonearm structure grounded? Is this old 1500 or new 1500C? You can try disconnecting one of the phono cables to see if that breaks the loop, and maybe reverse polarity on one of the AC power cords, if possible. Sometimes need to add an additional ground wire from one of the components.
Thanks Davey. So disconnecting one of the phono cables (I tried each) had no effect. THEN I disconnected the ground wire that runs from the Technics SL-1500C to the PHO-701 and -- voila! -- no noise went away! And this was with the TT off. So I powered up the TT and no noise. I checked to ensure the ground wire was attached properly to the 1500C and it was. It appears the ground wire was the culprit. I should add that, per a suggestion from PS Audio where I purchased the PHO, I put a "cheater" (3 - 2 prong) on the PHO's power cord, and that also helped reduce the noise, about 5 db. In fact, when I now just removed the cheater, the noise level jumped ... so it appears that the largest part of the hum reduction was inserting that cheater, and removing that ground wire removed the rest. The hum is now barely audible when volume is at 77 with the Hegel H90.
Yes, definitely! Using the Phono Out (for use with a preamp), not the Line Out (to use the 1500C's built-in phono stage). It's weird that even with the 1500C powered off, that ground wire running out of it to the PHO still causes that hum.
I see a typo in my first reply to you that changes the meaning! I *meant* to say:a THEN I disconnected the ground wire that runs from the Technics SL-1500C to the PHO-701 and -- voila! -- no noise! And this was with the TT off. Sorry if that caused any head scratching
How do you actually go about opening the PHO-701 up to upgrade the tube? I recently got the 701, but the manual didn't have any information on how to change the tube, so I'm not sure if that means this is something they don't expect you to do, or it's not as easy as it seems or something else entirely. Any advice would be great. Thanks.
I don't have one, but seems like you just remove the screws that hold the cover on, then pull the tube out and put the other one in... maybe leave the screws out so you can go back and forth until satisfied with the change...
You're correct, Davey. It's a little tricky to get the tube in/out with that semicircular metal piece, but I've done it a couple of times.
I didn't eliminate it completely, but found a very livable workaround. I concluded the hum was coming from the PHO, so I upgraded the AC cable to Panagea AC14 and took out the removable ground prong. This helped reduce hum quite a bit. I usually start records at little/no volume at needle drop, then increase volume once a song/signal begins. This way, I hear zero hum in quiet parts and in between songs. If playing at high volume, I'll start to hear hum again once the record is over. It's weird, but it works. I don't really consider it an issue anymore. Still using original tubes FWIW.
Yup. For me, it was just detaching that ground prong from the PHO and the hum disappeared. The folks where I purchased it -- Upscale Audio -- were kinda surprised ("Yes, sometimes you can actually remove grounds as opposed to add them, and somehow break the loop") but admitted if it works, good enough! Thanks for the reply.
I found that removing the 8 screws, especially the 2 at the front, a pain. I had to use a crescent wrench to get 'em loose. After that, pulling the tube that came with it and replacing it with the ECC82 Tungsram was a cinch.
Hi, fellow owners of this beautiful and performant phono-stage! A few questions and comments from my side. My setup is very similar to @TimWare - Technics SL-1500C is my TT with stock Ortofon 2M Red stylus, wired to PHO 701 (stock tube as well) with Supra 1m cable. My questions are: 1) Vincent's manual says that the unit operates best if left powered on constantly. Also, specs say that power consumption is 15W. The question is - is it OK to leave the PHO 701 ON all the time? I mean, from the safety point of view mainly, as 15W will not hurt the electricity bill much. 2) Does it count for the burn-in time for the tube if i simply leave the unit on for long time? Or, it needs to be fed a real signal from TT? 3) I would not like to go much into tube rolling, especially for some tubes which are hard/costly to get in Europe. But, what about this one - https://www.thomann.de/se/tad_vorstufenroehre_12au7.htm? I've not seen brand "TAD" mentioned much here in the topic. But seems like it have nice reviews on that web-page. 4) What is recommended combo of capacitance switches for Ortofon 2M Red? Ortofon's recommended load capacitance - 150-300 pF. Do I need to discount the capacitance of the cable, which is 57 pF/m (I have 1m exactly, so it is 57 pF)? I've tried to set switch 2 to ON, which corresponds to 235 pF capacitance, but then I heard that "over-capacitance undercut for highs". Now, i have switch 1 to ON, which corresponds to 115 pF. Does it match your set-up? 4) A comment about hum. I was also affected by it. I tried many options as suggested - moving PSU around - no difference, trying stock Technics cables - no difference, disconnecting ground wire - made it much worse. I listen in the headphones, by the way, so hum is exceptionally noticeable and bothering. Then, i simply plugged all the power cords - PSU, turntable, and headphones amp - to a different power outlet on the other side of the room and voila! - it's dead silent even on max volume. I'm super happy with it now, as now i can start experimenting with different cartridges, which was the main purpose of buying PHO 701. Maybe it will help someone to solve the humming issue.
For your first 4 questions, I'd suggest you email the company from which you purchased your PHO-701. I bought mine from Upscale Audio and had some email exchanges with Sean-Paul there who was quite willing to help ([email protected]). Regarding the hum, as I said above, removing the ground wire from the PHO actually eliminated much of the hum. HOWEVER, just yesterday I finally solved a hum caused by the PHO that I couldn't get rid of. Before purchasing the PHO, I'd used the Technics SL-1500C's built-in phono stage. Of course, when I got the PHO, I switched the RCA's from the Line Out (to use built-in phono stage) on the 1500C and used the Phono Outs instead. BUT, I neglected to change to OFF the External Output switch next to the Phono Outs. Once I switched it off all hum disappeared.
Thank you for the suggestions, but can't you share what is your PHO 701 modus operandi, namely - do you keep the unit ON all the time, and, in connection with SL-1500C and Orto 2M Red, which capacitance settings do you use on PHO 701?
I do not. I only turn it and its accompanying tube integrated amp ON when in use, which is usually once a day for 2-4 hours.
Until this past weekend, I'd been using the stock tube. I briefly tried a new Mullard, but it was too bright. I've been happy with the stock tube, but it is a bit dry. I finally splurged on a vintage Telefunken smooth plate that I bought from Brent Jessee. That purchase was a wonderful experience. It was shipped very quickly and carefully, and the tube is immaculate. I've only put less than 3 hours on it, but I love it. The treble is very clear, yet not too bright. The midrange is much more rich and detailed than the stock tube. At first the bass was a bit plump, but that seemed to disappear after the tube warmed up a bit. I'll listen to that carefully over time. Overall, the tube enriches the instrumental timbres and decay tracing. It also enhances the wide, high, and deep soundstage of this preamp. I highly recommend Brent Jessee. Thanks to whoever recommended him on this forum. I had read up on the Telefunken on his website. His website is poorly designed, and it takes some work to find what you're looking for. I actually purchased via eBay, which was easy.
Now that it looks like hum has been sussed out... Anyone mind if we derail this a bit to experiences with different tubes and the Vincent 701? Interested minds want to know. Good to know about the Telefunken...I’m still using the included tube but getting curious. Also, did you encounter any problems while rolling?
I upgraded the stock tube with a Psvane 12AU-7 Mark II tube about 2 years ago and i couldn't be any happier. The tube is very detailed and clear but the real magic is in the low end and mid range. Low end became much more tight and weighty. Mid range became very lush and rich but not overly colored by the tube. These tubes are not that warm sounding but do impart a slight tube roundness and punch. Very musical. Highs are tame, clear and detailed with excellent separation.
I decided to go with your advice and give it a go. I picked up a Amperex Telefunken smooth plate too. I think it's the right one, mine says 12AU7A on the top though. It works and sounds very nicely. First play is The Wonderful Sounds of Female Vocals. Got the tube on the auction site from a lady in FL. So pulling out the old one works by the suggestion of slowly rocking the old tube back and forth with a little force going up. Also just unscrewing the 8 Phillips screws and the cover comes off cleanly and easily. Sorta stoked to pull the trigger on more single 12 AU7 tubes if I come across any. Thanks!
Hi PB. I'm glad you're enjoying it. In the short time I've had mine, the sound has changed quite a bit. Where I thought the bass was a little bloated, it's now gotten very tight. I guess I still have less than 30 hours on it.
Sorry for the delayed response. I don't keep the PHO on all the time, just when I'm actually using it. As for the capacitance, I have it set with just the 1 switch on, all others off. Seems like the right balance.
