Long distance run ok for turntable analogs?

mchuckp · « **on:** 17 Mar 2010, 02:52 pm »

I'd like to shelf mount my turntable and best place is going to be approximately 15-20 feet from the preamp. Anyone feel this is a bad thing to do due to signal distance over RCA cables? I've ran at approximately 8' before and seemed fine to me. Someone told me once that a turntable cable distance should be as short as possible because it is a low level signal. Not sure I concur.

Thanks,
Mike

Sonny · « **Reply #1 on:** 17 Mar 2010, 02:58 pm »

Well, that someone is correct, the shorter is always better, but it's not necessarily true in all cases. With my experience, it's mostly were the phono stage is located that's it picks up RFI or other interference. You can always try it and see what happens. Make sure the cable you use is very low capacitance and resistance...that'll help the signal....

Tuan

gerald porzio · « **Reply #2 on:** 17 Mar 2010, 03:57 pm »

15 to 20 ft. from T/T to phono preamp is too long by 1/2 @ least. It'll roll off the highs, IMO.

Wayner · « **Reply #3 on:** 17 Mar 2010, 04:01 pm »

To put it in a different light, let's say your running a 5mv output MM cartridge. That would be .005 volts, which ain't very much. Now, let's say you were running a .5mv MC cartridge. That would be .0005 volts, unless you run it to a phono pre or a SUT close to the turntable.

Very small voltages, that can be easily influenced by many different outside sources. Tuan is right, the shorter the interconnect, the better.

Wayner

Stu Pitt · « **Reply #4 on:** 17 Mar 2010, 04:03 pm »

If you have an external phono pre-amp,maybe have that close to the TT and long interconnects from the phono pre to your pre-amp?

I agree with what's been said - keep the interconnects from the TT to the phono stage as shorth as possible. The signal is pretty delicate.

mchuckp · « **Reply #5 on:** 17 Mar 2010, 05:58 pm »

Thanks everyone for your responses so far. I'm in a slight dilemma. Currently my TT is on my rack and about a foot from my preamp (Van Alstine T8+ w phono). I just ordered an Ultravalve tube amp from Van Alstine and It was recommended to not put my TT above it due to heat. So if I follow that recommendation, I am going to move my TT off the rack and put the amp in it's place.

I could move the amp elsewhere instead. Again, still have a longer run. Issues this causes besides the run, is inconvenience to turn the amp on that will be used daily vs my TT that gets used occasionally.

turkey · « **Reply #6 on:** 17 Mar 2010, 06:09 pm »

Quote from: mchuckp on 17 Mar 2010, 05:58 pm

Thanks everyone for your responses so far. I'm in a slight dilemma. Currently my TT is on my rack and about a foot from my preamp (Van Alstine T8+ w phono). I just ordered an Ultravalve tube amp from Van Alstine and It was recommended to not put my TT above it due to heat. So if I follow that recommendation, I am going to move my TT off the rack and put the amp in it's place.

I could move the amp elsewhere instead. Again, still have a longer run. Issues this causes besides the run, is inconvenience to turn the amp on that will be used daily vs my TT that gets used occasionally.

I guess you should just try moving the turntable and using the longer patch cords. You might find it works ok. If it doesn't then at least you'll know for sure and can make a better decision about moving the amp or not.

gerald porzio · « **Reply #7 on:** 17 Mar 2010, 07:01 pm »

Try to get a pwr. strip w/ the on/off switch located on a separate pwr. cord, & use that to turn the amp on & off if you don't want to put it in the rack. Cost will probably be $20 to $50.

Wayner · « **Reply #8 on:** 17 Mar 2010, 07:07 pm »

Quote from: mchuckp on 17 Mar 2010, 05:58 pm

Thanks everyone for your responses so far. I'm in a slight dilemma. Currently my TT is on my rack and about a foot from my preamp (Van Alstine T8+ w phono). I just ordered an Ultravalve tube amp from Van Alstine and It was recommended to not put my TT above it due to heat. So if I follow that recommendation, I am going to move my TT off the rack and put the amp in it's place.

I could move the amp elsewhere instead. Again, still have a longer run. Issues this causes besides the run, is inconvenience to turn the amp on that will be used daily vs my TT that gets used occasionally.

Hang on a minute. Frank suggests that as a general rule, which is a great rule. If your cartridge is prone to hum, I suggest moving the amp to a distance of 4 feet, by the way the crow fly's. If it's a really well shielded cartridge, then leaving a space of 12" should be more then enough room.

If your rack has 3 or 4 shelves in it, I would put the TT on top (obviously), below that on the next shelf, the T8 and below that, the amplifier. If your rack is an open design, there should be plenty of air around each component as to not cause a problem.

If you don't have a spot for everything, I'd suggest moving the amp out of the rack, to perhaps a floor standing amp stand. That could be as cheap as an old breadboard with 4 hockey pucks underneath,,,,what ever.

Wayner

mchuckp · « **Reply #9 on:** 17 Mar 2010, 08:05 pm »

Quote from: Wayner on 17 Mar 2010, 07:07 pm

Hang on a minute. Frank suggests that as a general rule, which is a great rule. If your cartridge is prone to hum, I suggest moving the amp to a distance of 4 feet, by the way the crow fly's. If it's a really well shielded cartridge, then leaving a space of 12" should be more then enough room.

If your rack has 3 or 4 shelves in it, I would put the TT on top (obviously), below that on the next shelf, the T8 and below that, the amplifier. If your rack is an open design, there should be plenty of air around each component as to not cause a problem.

If you don't have a spot for everything, I'd suggest moving the amp out of the rack, to perhaps a floor standing amp stand. That could be as cheap as an old breadboard with 4 hockey pucks underneath,,,,what ever.

Wayner

Here's a few pix of what I'm working with.

Frank's comment to me had to do more with the heat from the amp likely not being good for the TT longer term. He didn't comment about possible interference. The rack I have has shelves that are 7" or 9" and are interchangeable. My thought was to put the new amp on a 9" shelf just below the TT as to only cause "warming of one component. I'd love to keep it on the rack but definitely don't want to hurt any of my gear physically or performance of. BTW, the rack is open on all 4 sides with metal frames with 3/4" MDF shelves.

You can see from the one angled shot of my room, that there is quite a bit of room to the right of my right speaker. That is where I was thinking of putting the TT. I have some room around my speakers but hate to work my way around them to get to the TT. I also like a clean looking set up and like to let my speakers "breathe".

Wayner: You thinking yay or nay on putting the Ultravalve and TT on the same rack? Other opinions?

BTW, my table is a Rega P1 using an Ortofon 2M Blue MM cart. It has rubber feet, MDF platform, and glass platter. I plan on upgrading my table within the next year but not sure what yet. Trying to get the rest of my gear in place first as I think it sounds pretty dang good for a budget table.

BTW, my camera was crooked. Not my rack.

Mike

Wayner · « **Reply #10 on:** 17 Mar 2010, 08:16 pm »

Mike,

I don't like the idea of the Ultravalve right under the turntable, not because of heat, but am concerned about magnetic interference from the Ultravalves 4 transformers. Thanks for the pictures, now I can see what's going on. I like the table right where it is. I assume the component below it is a DAC. I'd put the DAC and the Oppo on the shelf below the TT and stick the Ultravalve on the shelf where the T8 is, and put the T8 where the Oppo is. I don't really think you will have any problems with everything on this rack, unless the Oppo and DAC don't fit on the same shelf, but it does look like they will.

Wayner

mchuckp · « **Reply #11 on:** 17 Mar 2010, 08:26 pm »

Quote from: Wayner on 17 Mar 2010, 08:16 pm

Mike,

I don't like the idea of the Ultravalve right under the turntable, not because of heat, but am concerned about magnetic interference from the Ultravalves 4 transformers. Thanks for the pictures, now I can see what's going on. I like the table right where it is. I assume the component below it is a DAC. I'd put the DAC and the Oppo on the shelf below the TT and stick the Ultravalve on the shelf where the T8 is, and put the T8 where the Oppo is. I don't really think you will have any problems with everything on this rack, unless the Oppo and DAC don't fit on the same shelf, but it does look like they will.

Wayner

Actually what you are calling a DAC is actually my AVA 240 amp in the smaller chassis. I'm selling it to a friend of mine to get the Ultravalve. I could easily rearrange my rack as you suggest and no need to worry about stacking anything. I have a PS Audio DLIII DAC that is out on loan (to same friend) and not planning on getting it back anytime soon as I love my Oppo Special Edition.

I think I will plan on getting the amp and giving it a try. If I get concerned, I'll move it after that.

Thanks again.

Wayner · « **Reply #12 on:** 17 Mar 2010, 08:38 pm »

I can put my hands over the output tubes at 2 1/2 inches above and keep my hands there for ever. If you have that much space to work with get your order in! That total height (including 2 1/2 inch space) would be about would be about 9 inches, from amp surface to underside of next shelf. If your spacing is 9" from top to top surface (then being 8 1/4" between, I recommend you place a metal sheet on the underside of the shelf that is above the amp, to keep the MDF a little cooler.

Wayner

Scottdazzle · « **Reply #13 on:** 17 Mar 2010, 08:52 pm »

I agree with Wayner that putting the tt close above the amp is probably not a good idea. Hum, EMI, and who knows what else.

doug s. · « **Reply #14 on:** 18 Mar 2010, 02:21 pm »

personally, i do not think you will have any problems w/the new amp yust below your turntable - looks like plenty of clearance to me. if it is an issue w/either heat or rf/emi, you can swap out one of the taller shelves below, for the one the turntable is on, put a piece of sheetmetal or foil under the turntable/under the turntable shelf, raise the turntable on footers, (even hockey pucks will work well), etc etc, etc - you really have many options other than moving the 'table across the room...

doug s.

mjcmt · « **Reply #15 on:** 18 Mar 2010, 03:43 pm »

Quote from: mchuckp on 17 Mar 2010, 02:52 pm

I'd like to shelf mount my turntable and best place is going to be approximately 15-20 feet from the preamp. Anyone feel this is a bad thing to do due to signal distance over RCA cables?

The best scenario for you at that distance, is to consider installing a phono preamp with balance output in close proximity to your TT, to amplify the small cartridge voltage and sensitivity to hum. (PS Audio GCPH comes to mind, but there are others) Then run nice shielded balanced cables (Belden Star Quad, mic cables, or high-end cables) to your stereo preamplifier. This will give you the best sound and least distortion, hum, and signal loss.

doug s. · « **Reply #16 on:** 18 Mar 2010, 04:38 pm »

Quote from: mjcmt on 18 Mar 2010, 03:43 pm

The best scenario for you at that distance, is to consider installing a phono preamp with balance output in close proximity to your TT, to amplify the small cartridge voltage and sensitivity to hum. (PS Audio GCPH comes to mind, but there are others) Then run nice shielded balanced cables (Belden Star Quad, mic cables, or high-end cables) to your stereo preamplifier. This will give you the best sound and least distortion, hum, and signal loss.

that would be the best scenario, if mike didn't already have a fono stage he wants to use, built into his preamp.

doug s.

mjcmt · « **Reply #17 on:** 18 Mar 2010, 04:56 pm »

Quote from: doug s. on 18 Mar 2010, 04:38 pm

that would be the best scenario, if mike didn't already have a fono stage he wants to use, built into his preamp.

I was addressing his question about a 20' run from a cartridge to a phono preamp. My offering is the best way to satisfy a long run of a very low output. A 20' run from a cartridge to a phono preamp is not recommended.

gerald porzio · « **Reply #18 on:** 18 Mar 2010, 05:33 pm »

You can use unbalanced for a 20 ft. run from phono preamp to line in as long as it's shielded.

doug s. · « **Reply #19 on:** 18 Mar 2010, 07:15 pm »

Quote from: mjcmt on 18 Mar 2010, 04:56 pm

I was addressing his question about a 20' run from a cartridge to a phono preamp.

you were addressing his question about a 20' run from a cartridge to a phono preamp? why would he be wanting to know about a 20' long run from cartridge to fono preamp, if his fono preamp were in direct proximity to his turntable?

Quote from: mjcmt on 18 Mar 2010, 04:56 pm

My offering is the best way to satisfy a long run of a very low output. A 20' run from a cartridge to a phono preamp is not recommended.

i agree, but there's much easier/cheaper ways to do this - ie: leave turntable where it is, properly shield it from the amp, and use the short cable run you already have - than to buy another fono stage when you already have one you like.

ymmv,

doug s.