How long can my Turntable interconnects be?

Or I guess the more accurate question is; How long can the interconnects be from my Bottlehead Seduction preamp to my Linestage preamp?
The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

Sony Playstation 3 for CD and Streaming
Thorens TD320
Modified Carver C-1
Carver TFM 42 and 45 Amplifiers
Polk RTA15TL Speakers w/Decato mods
White Lightning Moonshine DIY Speaker Cables and Interconnects

Comments

  • mhardy6647
    mhardy6647 Posts: 32,926
    edited December 2017
    depends upon the output impedance of the Seduction (which I don't know, even though I have one). One to two meters would be no problem -- EDIT -- the issue with the Seduction (and its replacement the Reduction) is that it has no output stage per se (e.g., a cathode follower), so it's probably a little more sensitive to the I/C load than would be a preamp with an output/buffer stage.

    I say this mostly based on the comments on Bottlehead's Reduction, which isn't all that different in terms of its basic topology than the Seduction.

    https://bottlehead.com/reduction-phono-preamplifier-kit/
    The phono preamp has a gain of approximately 36 dB at 1 kHz and is intended for use with phono cartridges of 2.5mV and higher output, with 5mV output being the design center. Higher than 5mV output is certainly fine, and one may also use lower output cartridges with a suitable step up device. Input impedance is 47.5K ohms, input capacitance is 50pF. Remember that your phono cable’s capacitance will add to this figure and increase your cartridge’s capacitive load somewhat. Frequency response exhibits +/- 0.3dB RIAA curve accuracy. The Reduction is designed to operate into line stages with 50K or higher input impedance through interconnects of 1M or shorter length. At 4.5mV input THD is 0.12%, THD+noise is 0.6%

    FWIW -- I think 2 meters is fine, empirically ;)

    Oh, the other "issue" with the Seduction/Reduction is the relatively low gain (see the quote above pertaining to the Reduction; I think that the Seduction is more or less identical in terms of gain -- I could check if someone really wanted me to! ;)).

  • mhardy6647
    mhardy6647 Posts: 32,926
    By the way -- and you probably know this already (but just in case) -- the output signal from a phono cartridge is much more delicate than the output of the phono preamp! The interconnect's capacitance must be low and/or the length of the interconnect should be short (as short as possible) to ensure no degradation (mostly in the form of treble roll-off).

    The line-level output of the phono preamp is considerably more robust (although not arbitrarily robust, as I tried to say my earlier post!).
  • trav0810
    trav0810 Posts: 1,056
    I knew that I would want the cables between the TT and the phono pre to be as short as possible, but I'm using the standard factory installed cable on the Rega, so I don't have much choice on that. For the layout of my room and available shelves/stands, my TT and phone pre will be about 8 from my Linestage
    The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

    Sony Playstation 3 for CD and Streaming
    Thorens TD320
    Modified Carver C-1
    Carver TFM 42 and 45 Amplifiers
    Polk RTA15TL Speakers w/Decato mods
    White Lightning Moonshine DIY Speaker Cables and Interconnects
  • mhardy6647
    mhardy6647 Posts: 32,926
    edited December 2017
    Is that 8 feet? Well -- try the preamp with shorter cables vs. long-enough ones & see 1) you hear a difference and 2) if you do, does it bother you?

    Bottlehead would say 8 feet is too long -- my knee-jerk assessment would be that it's borderline.

    I would say if you're lookin' at 8 feet - either make your own I/Cs or get some made to the right length (if you go the store-bought route). I.e., don't default to 3 meters (nearly 10 feet) if you need eight.

    Cheap in the long run to do it as 'right' as possible.

  • If you make your own cables use RG62u for the lowest capacitance per foot.
  • trav0810
    trav0810 Posts: 1,056
    I'll certainly make my own. And I don't know if this makes any difference or not, but they are going to be converted to XLR at the Linestage
    The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

    Sony Playstation 3 for CD and Streaming
    Thorens TD320
    Modified Carver C-1
    Carver TFM 42 and 45 Amplifiers
    Polk RTA15TL Speakers w/Decato mods
    White Lightning Moonshine DIY Speaker Cables and Interconnects
  • trav0810
    trav0810 Posts: 1,056
    Ok, thanks for the heads up.
    The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

    Sony Playstation 3 for CD and Streaming
    Thorens TD320
    Modified Carver C-1
    Carver TFM 42 and 45 Amplifiers
    Polk RTA15TL Speakers w/Decato mods
    White Lightning Moonshine DIY Speaker Cables and Interconnects
  • mhardy6647
    mhardy6647 Posts: 32,926
    Ken can probably speak to the net impact of that -- I can't, I'm afraid.

    I'm an unbalanced kinda guy, mostly -- except when necessary (i.e., pro-style hardware, like my Otari and a few other bits and pieces here).
  • tratliff
    tratliff Posts: 1,651
    edited December 2017
    I would give HeliPilotDoug (Doug) a shout. He is very helpful in cable planning and can give you a recommendation on what would be the best approach.

    www.douglasconnection.com

    I have not seen him around lately...

    2 Channel Rosso Fiorentino Volterra II, 2 REL Carbon Limited, Norma Revo IPA-140B, Lumin U2 Mini, VPI Prime w/SoundSmith Zephyr MIMC, Modwright PH 150, Denon DP-59l w/Denon DL-301MKII, AudioQuest Thunderbird Speaker and Interconnect Cables, AudioQuest Niagara 7000 w/Dragon and Hurricane Power Cables
  • mhardy6647
    mhardy6647 Posts: 32,926
    tratliff wrote: »
    I would give HeliPilotDoug (Doug) a shout. He is very helpful in cable planning and can give you a recommendation on what would be the best approach.

    www.douglasconnection.com

    I have not seen him around lately...

    It's a good idea and I do believe I've seen him post recently.
    I'm sure he's contactable (is that a word?) via his website, regardless.

    http://www.douglasconnection.com/Douglas-Connection-Analog-Interconnect-Cables-DCFAIC.htm
  • trav0810
    trav0810 Posts: 1,056
    I do business with Doug frequently. I've already talked to him a little about making me some XLR to RCA's!
    The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

    Sony Playstation 3 for CD and Streaming
    Thorens TD320
    Modified Carver C-1
    Carver TFM 42 and 45 Amplifiers
    Polk RTA15TL Speakers w/Decato mods
    White Lightning Moonshine DIY Speaker Cables and Interconnects
  • mhardy6647
    mhardy6647 Posts: 32,926
    why the heck were you asking us, then? ;)
  • trav0810
    trav0810 Posts: 1,056
    He'll build what I need, but I don't think he is a big Vinyl guy.
    The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

    Sony Playstation 3 for CD and Streaming
    Thorens TD320
    Modified Carver C-1
    Carver TFM 42 and 45 Amplifiers
    Polk RTA15TL Speakers w/Decato mods
    White Lightning Moonshine DIY Speaker Cables and Interconnects
  • txcoastal1
    txcoastal1 Posts: 13,124
    trav0810 wrote: »
    He'll build what I need, but I don't think he is a big Vinyl guy.

    Doug's old enough to know better :p
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
  • Viking64
    Viking64 Posts: 6,646
    Turntables in helicopters cause skipping records. :p
  • tratliff
    tratliff Posts: 1,651
    He built my phono cable and I couldn’t be happier. Doesn’t look I have a picture of it on my phone. I will send a pic in the morning when I’m on my pc.
    2 Channel Rosso Fiorentino Volterra II, 2 REL Carbon Limited, Norma Revo IPA-140B, Lumin U2 Mini, VPI Prime w/SoundSmith Zephyr MIMC, Modwright PH 150, Denon DP-59l w/Denon DL-301MKII, AudioQuest Thunderbird Speaker and Interconnect Cables, AudioQuest Niagara 7000 w/Dragon and Hurricane Power Cables
  • tratliff
    tratliff Posts: 1,651
    Here is the one Doug built me earlier this year.

    4agqns7ct7wa.jpg
    2 Channel Rosso Fiorentino Volterra II, 2 REL Carbon Limited, Norma Revo IPA-140B, Lumin U2 Mini, VPI Prime w/SoundSmith Zephyr MIMC, Modwright PH 150, Denon DP-59l w/Denon DL-301MKII, AudioQuest Thunderbird Speaker and Interconnect Cables, AudioQuest Niagara 7000 w/Dragon and Hurricane Power Cables
  • trav0810
    trav0810 Posts: 1,056
    I have ZERO doubt in Doug's build quality. I just wasn't sure if he would know about the cable length I could use, unless he had experience with the particular phono preamp I'm using. That is why I came here. Not to get a cable, but to find out the length I would be able to get away with.
    The difference between genius and stupidity is; genius has its limits.” -Albert Einstein

    Sony Playstation 3 for CD and Streaming
    Thorens TD320
    Modified Carver C-1
    Carver TFM 42 and 45 Amplifiers
    Polk RTA15TL Speakers w/Decato mods
    White Lightning Moonshine DIY Speaker Cables and Interconnects
  • soundfreak1
    soundfreak1 Posts: 3,374
    If it helps, I had a concern about that as where my TT needed to be (10ft away from preamp) researched cables for loss and basically found anything under 20 ft (using really good cable) was irrelevant for all practical intents.
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable