I would first do everything possible to make things work for the turntable at its current location. If this is not possible, I would suggest moving the preamp along with the turntable to the new location. The phono stage's voltage output (at line level) is not so much the issue but rather, the preamp (line stage) output stage is likely to be able to better "handle" driving long ICs to the amp than a phono stage's output to drive the same ICs to the line stage input. But still, there is no guarantee this will be a success.
John |
Have read fairly consistently that after about 15 to 20 feet, some say longer, a balanced interconnect is better than an RCA. If you have to go 30 feet, go for balanced, if your pre-amp allows for it,though you can get balance to rca adapters, but that just adds one more chain in the link, where to my mind the shortest link works best with the fewest connections works best. |
I think total capacitance would be way too high.
30' is getting into an iffy range even for line level signals, where I've seen balanced cables recommended for anything over 10 meters. |
Both components have only unbalanced connections.
Thirty feet is really pushing it, but fortunately the phono stage output impedance is only 100 ohms (which in fact is considerably lower than the preamp's output impedance of 440 ohms). That should be low enough to eliminate the possibility of upper treble rolloff due to interaction of cable capacitance with the output impedance.
The remaining concern would be noise pickup. There is no way to predict that other than by trying it, since it is dependent on the noise environment of your particular setup. But in addition to the noise environment, success or failure would be dependent on the quality of the shields in the particular interconnects you would be using (both shield coverage and shield resistance), so I would try, if possible, to arrange trials of several different cables, with return privileges.
Regards,
-- Al |
Just to chime back in here, I ran a 30 feet RCA Purist Dominus IC from line stage to amps for a couple years and had no hum/rfi issues at all. What people echo from what they have read vs. what they have experienced are very different things. Pushing the requirements for balanced ICs is an unnecessary issue. And converting to/from balanced with bogus adapters will accomplish nothing as well. All of this aside, I still would put every effort into making the current turntable location be a success. |
You can try a couple of things to isolate the table from vibration. You could try a sandbox designed by Galibier Design and built by Timbernation. In my system, it worked very well. You could also suspend the table from the ceiling on a platform hung with chain. There are solutions that don't require 30 foot cable runs. |
As for Timbernation buyer beware: Timbernation and Timbernation TooBetween spotty workmanship, long delays, and some people not receiving their items it should make one think twice about ordering. My own personal experience mirrors that of some of the posters in these threads. Luckily for me I was able to do a charge back on my credit card. Outside of that the idea of the sand box or alternative isolation methods is worth exploring. A 30 ft. run of ICs is too long IMO. |
I agree with Clio09 about Timbernation. Even though I recommended the Galibier Design sandbox, I wouldn't commission Timbernation to build one (and they built mine).
The plans and specs for the sandbox are available online from Galibier Design. Any competent carpenter/cabinet maker can build one. |
As far as I heard, most cable manufacturers don't recommend phono cable longer than 2 meters. I would either better isolate the table or try longer IC between preamp and power amp. Phono signal is so low that it is susceptible to noise such as RFI. |
Audiolui -- Although it wasn't made completely clear in the original post, and I too was initially confused, the connection in question is between phono stage and preamp, not cartridge and phono stage.
Regards,
-- Al |
Hello Gentlemen, thank you for your responses.
Right now the stylus, when playing is approx. 20" from the side of the left Vandersteen. As I am getting a wobbling deep bass feedback as the volume get's up there, I have to assume that the tt is too close?
Please tell me if I'm wrong, and I will work on isolating from the speaker.
The floors are really springy as well, and after trying different isolation products from herbie's that I had on hand, I am thinking I have to wall mount the tt. I am reluctant to mount a wall rack in the tables current location, only to find the proximity to the speakers is still an issue. Without turning our living room upside down, The best place is 30ft away. What I am hearing is that is too long. I cannot move the preamp, it and everything else are plugged into dedicated circuits. So, upon reviewing your answers, I have 2 options. A 30 ft run, or a wall mounted turntable 20" from a speaker.......or sell it?
Thanks,
Mike |
A 30 ft run, or a wall mounted turntable 20" from a speaker.......or sell it?
Thanks,
Mike
Hanaleimike (System | Answers) If you're settled on only those two options, then I'd sell it. 30 ft is too long, and 20" is too close. |
For a few hundred bucks you can have an electrician install some more dedicated outlets on the side wall farthest from your speakers. Then with an understanding wife and some rearrangement of furniture, you can move all your front end stuff, most of all including the turntable, to the far end of the room. You are better off with long runs between your preamp and amp than with long speaker wires, so IMO leave the amps nearby the speakers. Perhaps for some reason this solution is not possible, but it does suggest itself. I am not sure what is the "it" that the other guys and you are talking about selling. By all means don't give up vinyl because of this problem. You would be far better off with true balanced components in this situation, but it will be ok. |
Do you have balanced equipment amp/preamp? |
Hi, Marakanetz, no I do not have balanced components,
Tvad, I have moved some furniture around (in my head ) and have another option. If one chair magically disappears, I can wall mount the turntable placing it approx. 45" from each speaker. With a 30ft run now out of the question, I am left with this new wall mount option, and I obviously don't want to sell it, but maybe another turntable would be less susceptible to feedback? Is a Thorens td-147.
One last possibility, although I can't do it immediately, the side wall is a possibility, but will cost more and involve a new wall mounted tv, but if 45" is still too close, It may be my last option.
Thanks again for all your thoughts. |
That might work. You should first try placing it there on a stand to see if the placement is going to be sufficiently far enough from the speakers to avoid reacting to the energy emanating from the drivers...especially the bass. It won't be perfect, but you should get an idea if the placement makes an improvement. If it does, you might be in business. The Galibier sandbox made a significant improvement in my system, and the buyer of it told me it did the same for him.
I take it since you haven't commented on the method that suspending the table from the ceiling is not an option. |
Almarg,
Thanks for correcting me. Even between phono stage and preamp, long cable is also not a good idea IMHO. I believe long cable (if done right) is fine between pre and power amp.
Another thought is to replace the Vandersteen with some small monitor speakers and a subwoofer that can be placed away from the turntable. If you love the Vandersteen, then this won't work of course. Just a thought. |
Alright Gentlemen, lots to think about, the ceiling mount is a possibilty, but it would still be about 45" from each speaker. I will look into the Galibier sandbox, and Audiolui, you may be onto something as I blew the bottoms out of my Vandersteens sunday afternoon.
Thanks, I will post back with my solution.
Mike |
Hanaleimike
maybe, just maybe what I did in terms of a wall mount (not grown on my own tree) could work for you too. Have a look at my system.
The tt is jolly close to the speakers going easy to 35Hz and I get no feedback to my pick-up what ever, I promise.
The idea with this is to have a sturdy mount, but VERY little in the way of low frequency 'getting a grip' so to speak on the support.
The idea came for some VERY high-end tt mounted in a system on display some time ago with Image HiFi (high-end German mag.)
The wall needs to be of course VERY solid, as it is in my case e.g. brick and mortar.
Please let me know what you think.
Axel |
What table are we talking about and where do you have it currently with respect to your system pictures? Are you thinking of moving that stuffed chair and placing the table there, next to the truss? |
Mike what about moving the chair to the right away from the A-frame beam and mounting the support, sandbox and TT on the beam. |
Hi Dan, it is a thoren td-147, I currently have it where the c-30 is in the picture as I have upgraded my preamp, but not my systems photos. I am thinking about moving that chair to the right.
Sam, I thought about it, and it would probably be the easiest, but there are 2 ceiling fans across that beam, when I put my hand on the beam I can feel their vibrations, I don't think that would be good, but the vibrations are at a much higher frequency.
I understand there is going to be some trial and error, I am trying to minimize the number of holes I drill into the wood wall. You should see my floor. |
Sorry to highjack my own thread, but this is turning into a turntable isolation thread.
Tvad, I am having a hard time finding info on ceiling hanging, is this better then a wall shelf, would I use heavy chain, and a slab of granite? poured concrete? I have moved the speaker and added 2 more isolation platforms and now I can stomp my foot close to the turntable without skipping, most of the time. I recently blew my 10" acoustic coupler voice coils on my Vandersteen 3a's, so the deep bass is not there right now, but I think it goes to about 35hz, and I am not getting any terribly noticeable feedback, but I think I could do better. I used the hi-fi new lp and my cartridge resonates at around 12 hz, so even with the couplers back in after repair, the speakers shouldn't cause an issue at 20or 25 hz. It would be nice to be able to completely isolate from the floor, and the wall is not bearing, and is underneath a 10ft window. It shakes when I bang on it. |
Resonant frequency of the arm/cart has nothing to do with acoustic feedback, so don't let that fool you. Anything from about 200Hz down can cause issues.
You definitely have your hands full with springy floors and a somewhat tight space. I'm not sure how the Vandy's will react, but pulling them out from the back wall another foot might help with the pressure that is building up along that wall. And, if possible, it might be better to pull the table out from the wall as well.
Can you brace the floor from underneath? |
I designed a shelf for my table, and emailed it to a local welder, then today while awaiting a reply, I decided to make one myself, just to make sure it would work. It did. I used 2" Mahogany, 4 1/2" stainless screws, glued, clamped and screwed. It's not fine furniture, but it is solid, goes with the equipment stand and room, and best of all it was free as I had all the materials on hand. I can jump up and down right in front of the turntable and it does not skip. My son and I tested it out well.
I tried the Hi-fi news test lp again, and It tracked the torture track with only the slightest distortion from the right channel, best yet. I moved the speakers into the room a bit, and while I don't have my super deep bass right now, I can play as loud as I want without audible feedback distortion. Depending on what the quote from the welder is, I may just keep my version and spend the rest on records. I am now looking to put a slab of granite, Mango wood, or a poured concrete slab ( like a countertop) and probably a sandbox, with the galibier metal inserts into the sand, and I think I'll be done for a week or so.
Thanks for all your help. |
Sounds like you're going in the right direction.
The Galibier metal inserts are simply 1" aluminum angle strips purchased at any hardware store, cut to size, and screwed into the underside of the top shelf. Filling the sandbox is a several step process because you need to fill it about a quarter or third at a time, place the shelf on the sand, and whack the shelf with a rubber mallet to compact the sand. Repeat the process until the sandbox is full and the platform is level. This is what I was instructed to do by Thom Mackris. |
Mike, is your suspension on the tt working properly or is it getting hung up? I seem to remember the 147 as a sprung mount suspension. |
I am using a 15 foot IC between my phono and amp and I don't use a preamp at all. I have used a couple of phonos; Pass, Herron and a couple of home rolled tube units w/o a hint of a problem. |
Hello again,
I thought I'd post an update. I replaced the repaired woofers in my speakers and now have the full bass again. I built the wall shelf, placed the table ( I got a vpi scout during this whole process ) on a slab of granite which is sitting on isoballs, moved a couch, spread out the speakers, and I have no problems with footfalls or feedback at any volume level. Life is good.
Thanks for all the help.
Mike |
