signal loss on long RCA runs?

nooshinjohn

I am looking to set up my Denon DP-52f, and so far the only spot I have for it is about a 30 foot run from where the rest of my gear is located. My question is about signal loss over a run of that distance. Will there be a problem having the table so far away from my preamp or should I find a better way of housing my rig. I currently have my sunfire on top of my rack as it is easier for me to care for it there. As always thanks for the help.:)

danz1906

It doesnt look like you could use balanced cable,XLR cables are very good for
running long runs.

nooshinjohn

I thought about that, and about using an XLR to make the run and using RCA adapters on both ends of the run but I don't know if would make a difference. Thank you for the idea.

CoolJazz

It's a question of high frequency roll off and whether it's enough to be audible.

By knowing the output impedance, the input impedance at the preamp and the capacitance of the cable, you can calculate the roll off frequency. At 30 feet, you'll need a favorably low output impedance to high input impedance and low capacitance cable.

Adapters and balanced cable would do nothing for you to help outside of a different capacitance value for the cable. However, a buffer could improve the situation if necessary. It's possible, you may have the 3 factors already in your favor though...and need nothing!

CoolJazz

nooshinjohn

thanks Jazz. How would I go about finding this data and making the calculations? Mathematics is my best subject:eek: and without a calculator I cannot count my fingers...

mhardy6647

So, this Denon DP-52f is a (turn)table? Does it have a built-in MM preamp? If not, you'll have severe HF rolloff from the cable capacitance.

You can add a cathode follower to a line-level output. This is a time-honored trick for longer cable runs. Those "tube buffers" that folks are inexplicably enamored of may also serve the same function. (EDIT: I guess in the solid state world, cathode followers are called voltage followers http://en.wikipedia.org/wiki/Input_impedance )

A quick Google on the topic "input output impedance" turned up this, which might be helpful.
http://www.kpsec.freeuk.com/imped.htm
http://www.tape.com/resource/impedance.html

nooshinjohn

here are the specs for the table. I do not know anything about MM preamps and such.

Rating of a mode
Form Full auto player
<Phone motor part>
Drive system Both-directions servo direct drive
Motor AC servomotor
Speed control system The speed servo and phase servo by frequency detection
Number of rotations 33 1 / 3 or 45rpm
Wow and flutter 0.01%w.rms (rotation system)
0.02%w.rms(JIS)
Number-of-rotations deflection Less than 0.002%
Speed change mechanism Soft touch push button
Signal to noise ratio 78dB or more (DIN-B)
Starting time less than (33 1/3) 1.8 seconds
Load characteristic 0% (the needle pressure 80g outermost circumference)
Brake Electronic brake
Power-supply-voltage characteristic It is 0% to change of 90-110V.
Turntable Aluminum die-casting 30cm
Moment of inertia 200kg-cm2 (turntable sheet included)
<Tone arm part>
Form Dynamic balance and exclusive use shell exchange type low-mass straight-way type
Electronic dumping servo full auto arm
Active length 244mm
Overhang 14mm
Tracking error Less than 2.5 degrees
Needle pressure variable range 0-3g
Conformity cartridge tare About 3g - 12g
Head shell Type PCL-50 only for the product made of special hard resin: About 3.3g
Output cord 1.2m of low capacity cord abbreviation
An attached mechanism Electronic formula anti skating mechanism electronic formula servo lifter
<Cartridge part>
Form MC type (DL-52)
Output voltage 0.3mV
Play frequency range 20Hz - 50kHz
Compliance 10x10 to 6 cm/dyne
Needle point 0.1x0.2mm angle solid diagram special ellipse needle
Conformity needle pressure 1.8±0.36g
Exchange needle Main part exchange (10,000yen)
<Synthesis>
Power supply voltage AC100V, 50Hz/60Hz
Power consumption 14W
Dimensions Width 455x height 130x depth of 424mm
Weight About 9kg

mhardy6647

If you need to hook it to a phono input on a preamp or amplifier, it has no preamp for the moving magnet (MM) cartridge. If you can connect it to a line-level input (AUX or TAPE IN) then it has one.

EDIT: oops, it has a low-output moving coil (MC) cartridge, with 0.3 mV output! You must be using a "head amp", step-up transformer ("SUT", some call them) or an "MC PHONO" input, then?

nooshinjohn

It plugs directly into the phon inputs on my reciever if that's what you mean...

CoolJazz

Oops. Didn't catch that it was a turntable!! Yup...30 feet is a real problem in that case!!

CoolJazz

mhardy6647

get a separate phono preamp (there are zillions at all price points from tens to thousands of dollars) and then you might (might) get away with 30 feet of cable from its outputs to a line-level input on your amp. You'll need considerable gain for a cartridge with 0.3 mV output (this is less than a tenth of a typical moving magnet cartridge).

Note that the specs (which are sort of transliterated Japanese) mention "Output cord 1.2m of low capacity cord abbreviation". That's about as long as they can be!

nooshinjohn

mhardy6647 wrote: »

get a separate phono preamp (there are zillions at all price points from tens to thousands of dollars) and then you might (might) get away with 30 feet of cable from its outputs to a line-level input on your amp. You'll need considerable gain for a cartridge with 0.3 mV output (this is less than a tenth of a typical moving magnet cartridge).

Note that the specs (which are sort of transliterated Japanese) mention "Output cord 1.2m of low capacity cord abbreviation". That's about as long as they can be!

so what you are saying is run the output of the turntable into an external phono pre and then make the run to the reciever. Any suggestions on a decent one?

mhardy6647

Yes. Again you'll need one with enough gain to accommodate 0.3 mV output (according to the specs you posted).

I use a Bottlehead Seduction (kit) and like it very much... but the output impedance may not be a good match for a long cable run (I dunno). www.bottlehead.com

The Hagerman Bugle is a very nice, inexpensive solid state phono preamp... but it is sold as a semi-kit and may be a little tricky if you're not used to pure-play DIY! www.hagtech.com

I really cannot comment on any of the others on the market. Some folks like the ProJect Phono box and TubeBox phono preamps; some don't. The NAD PP-3 is reputed to be decent and is inexpensive. Grado makes one. I wouldn't recommend the hybrid Bellari VP-130. The Manley Steelhead is really nice (a little pricey, though).

Here're some:
http://www.needledoctor.com/Online-Store/Phono-Preamps?gclid=CKyAs5yJ6ZoCFQQrFQodzDPUBw
Here're some more:
http://www.musicdirect.com/category/24
http://store.acousticsounds.com/category.cfm?section=equipment&id=67


You should check with the dealer or mfgr. for any of these to ask whether they'll drive a 30 foot cable run, though.

jimmydep

Back in the 70's (1977) I had a similar problem when the TT was about 20' from the receiver, I added a cheepo phono pre-amp and connected it to the aux input on my Marantz receiver. As I recall it worked just fine.

Face

Here's a decent phono pre that's not too expensive: http://www.cambridgeaudio.com/summary.php?PID=29&Title=Summary