Might help to list what you tried.
Every time I say 'I just' or 'lets just' it seems to be the start of a long journey
Balanced tonearm cable
- Thread starter analog2analog
- Start date
The problem you first have to address is the capacitance of the tonearm interconnect. This has to be kept low and the input to the amplification should have a low capacitance as well. Otherwise you can get into all sorts of difficulty with an electrical resonance caused by the inductance of the cartridge being in parallel with the said capacitance!
Noise might be one problem but you may run into others as well depending on the frequency of the resonance.
Microphones avoid this by running their signal through a transformer which drives the balanced line. That setup is low impedance so you'd need a really long cable (over 200 feet) before you got in trouble with an electrical resonance (which would likely be outside the bandwidth of the input transformer at the receiving end).
IMO the best way to solve this is to have a phono section at the turntable location. Then from it send a balanced line to wherever you are going. To do this, the balanced line source (the output of the phono section) should support the balanced line standard and its important to understand that most high end audio equipment simply does not. If you don't pay attention to this issue you probably will have noise issues!
I have my preamp located by my turntable and the entire system is balanced. The preamp supports the balanced line standard (AES48) so no worries driving the 30 feet of interconnect cables going to my power amps, which sit by the loudspeakers. The turntable and preamp are not in the same room as the speakers (its in the dining room) but its not that far from the listening position due to the layout of the house. The preamp employs a direct coupled output that supports the low impedance aspect typical of balanced line systems. So the interconnect cables are almost irrelevant as far as the sound of the system is concerned.
If I can get this to work, then I will need to do the same at my brother's house, which is even simpler in that he's only using the phono pre input on his receiver. I know that the level of quality for what we're talking about can be almost infinite, so let me say that in my scenario, I'm looking for cheap; I want the signal from the turntable to get to my preamp (or receiver); I'm OK with good, and don't expect the most pristine of signals.
Here's a few of the more promising tests I've tried:
• cartridge --> twisted pair cable --> passive balanced-to-unbalanced transformer --> phono input
• cartridge --> twisted pair cable --> active balanced-to-unbalanced transformer --> phono input
• cartridge --> --> microphone transformer --> twisted pair cable --> passive balanced-to-unbalanced transformer --> phono input
• cartridge --> --> microphone transformer --> twisted pair cable --> active balanced-to-unbalanced transformer --> phono input
• cartridge --> --> microphone transformer --> twisted pair cable --> microphone preamp --> phono input
Thanks!
Here's a few of the more promising tests I've tried:
• cartridge --> twisted pair cable --> passive balanced-to-unbalanced transformer --> phono input
• cartridge --> twisted pair cable --> active balanced-to-unbalanced transformer --> phono input
• cartridge --> --> microphone transformer --> twisted pair cable --> passive balanced-to-unbalanced transformer --> phono input
• cartridge --> --> microphone transformer --> twisted pair cable --> active balanced-to-unbalanced transformer --> phono input
• cartridge --> --> microphone transformer --> twisted pair cable --> microphone preamp --> phono input
Thanks!
One of the problems you're up against using transformers is they have to be properly loaded to express their turns ratio. If they are running into a high impedance and are designed for low impedance they might only express the inter-winding capacitance.
Since transformers transform impedance, this also means that the impedance of the cartridge affects what loading the transformer requires at the output. A mic transformer would probably work alright at the sending end, but at the receiving end where the phono input is 47K, its likely that a mic transformer would be a country mile off as far as loading is concerned. Hard to imagine how that would work well...
Most people balk at what I'm trying to do, especially when I say "cheap", so thanks for chatting it out.
Silly me: I thought I had rewired the turntable that I'm using for my tests, but that was a different turntable. I rewired this one to have a balanced signal output from the cartridge and retested a bunch of different devices and wiring schemes over 100' of STP cable. Here are the ones that worked perfect with no hum/noise/buzz:
• cartridge --> twisted pair cable --> passive balanced-to-unbalanced transformer --> phono input
• cartridge --> twisted pair cable --> active balanced-to-unbalanced transformer --> phono input
• cartridge --> DI box --> twisted pair cable --> balanced-to-unbalanced transformer --> phono input
Most of these will take care of my brother's scenario, since he's just going into his receiver's phono pre. Since I have a phono pre, I can put it at either end, so I may go with one of the options above, but I have a few more tests I'd like to perform. I ordered a RDL ST-PH1, which has a balanced output, so my wiring would look like this:
• turntable out (unbalanced) --> ST-PH1 --> twisted pair cable --> passive balanced-to-unbalanced transformer (RDL TX-A2D) --> line input
I was also thinking about experimenting with an analog to digital converter and using either optical or RG6 cable to send the signal to the digital input on my receiver. It would look like this:
• turntable out (unbalanced) --> phono pre --> A/D --> optical or coax cable --> digital input
Does anyone have any experience or thoughts on this (besides the obvious that I'm converting beautifully warm analog vinyl to digital)?
Thanks so much y'all!
There have been a few phono preamps using dsp to acheive the eq section and some folks have done it diy using digital crossovers so it can certainlybe done. If your system favors digital who knows maybe this could sound better? Anyways at this point you could also give in and put an analog phono preamp in the turntable location
Thanks for the tips. The way the room is designed with the built-in shelves, I have barely enough room for the turntable in one small section. Plus there's some major WAF that deters me from having a phono pre. But, if the RDL ST-PH1 sounds good and can transport a clean balanced signal to my receiver, then I'll just install it inside of the turntable and call it done.There have been a few phono preamps using dsp to acheive the eq section and some folks have done it diy using digital crossovers so it can certainlybe done. If your system favors digital who knows maybe this could sound better? Anyways at this point you could also give in and put an analog phono preamp in the turntable location
Can you point me toward any of the DSP phono preamps or DIY stuff you referred to? Thanks!
Look into Channel D Pure Vinyl software. They outline a number of ways to set it up.
Ok! I think I should report back. I made two Balanced phono cables and both works flawlessly.
For first cable, I used I 2.5 feet of Van den Hul D-501 SILVER HYBRID cable, Zavfino TAD-3 Tonearm Connector (DIN) and Neutrik NC3MXX-EMC XLR connectors. At XLR connector's side, I connected shield to pin 1, positive signal to pin 2, negative signal to pin 3. At Din connector's side, I connected shield to pin 3 (middle pin). I tried it with Elac PPA-2 phono pre-amp’s balanced input and it is all good. At full volume (no music paying) there is some hum/buzz with RCA input but no hum/buzz with XLR input on Elac PPA-2 phono pre-amp. All good!
Then, I built a second cable, everything same but changed the cable to Canare L-4E5C Star-Quad Microphone Cable (it is thinner version of standard Canare L-4E6S). Canare L-4E6S is marketed by Canare as the best configuration to fight any outside noise, “Canare L-4E6S Star Quad is used for environments with a higher noise factor and where audio signals are in the low -50 dB or less range. The 4-conductor Star Quad arrangement, cancels electromagnetically induced noise from SCR dimmer packs, fluorescent lighting ballasts and AC power transformers.” Seems like a match made in heaven for a tonearm cable. However, I did not notice any noise improvements over Van den Hul D-501 SILVER HYBRID cable; perhaps I don’t have noisy enough environment thus one point for Van den Hul. Sound quality was similar to Van den Hul at fraction of the price thus two points for Canare.
For first cable, I used I 2.5 feet of Van den Hul D-501 SILVER HYBRID cable, Zavfino TAD-3 Tonearm Connector (DIN) and Neutrik NC3MXX-EMC XLR connectors. At XLR connector's side, I connected shield to pin 1, positive signal to pin 2, negative signal to pin 3. At Din connector's side, I connected shield to pin 3 (middle pin). I tried it with Elac PPA-2 phono pre-amp’s balanced input and it is all good. At full volume (no music paying) there is some hum/buzz with RCA input but no hum/buzz with XLR input on Elac PPA-2 phono pre-amp. All good!
Then, I built a second cable, everything same but changed the cable to Canare L-4E5C Star-Quad Microphone Cable (it is thinner version of standard Canare L-4E6S). Canare L-4E6S is marketed by Canare as the best configuration to fight any outside noise, “Canare L-4E6S Star Quad is used for environments with a higher noise factor and where audio signals are in the low -50 dB or less range. The 4-conductor Star Quad arrangement, cancels electromagnetically induced noise from SCR dimmer packs, fluorescent lighting ballasts and AC power transformers.” Seems like a match made in heaven for a tonearm cable. However, I did not notice any noise improvements over Van den Hul D-501 SILVER HYBRID cable; perhaps I don’t have noisy enough environment thus one point for Van den Hul. Sound quality was similar to Van den Hul at fraction of the price thus two points for Canare.
Mogami makes a balanced 'console cable' that is low capacitance and therefore suitable for phono use. Running with the hookup you described, I've yet to hear any 'high end' cable sound better or different (which is the point of balanced line in the first place, so its all good).
The only exception to Ralph’s recommendation of attaching the shield of both XLR output pin 1s along with source chassis ground (DIN pin 3) comes from Carlos Candeias of B.M.C. Audio.
Stated in their Phono MCCI manual, “Tonearm DIN to XLR connection is to be noted particularly that the tonearm ground is connected from the middle pin (3) of the Tiffany?plug only to ONE channel XLR pin 1, otherwise risking hum noise due to a ground loop.”
Various examples provided: http://bmc-audio.com/tl_files/bmc_audio/pdfs/Manuals/PHONO-MCCI-Manual-Web-EN.pdf
Stated in their Phono MCCI manual, “Tonearm DIN to XLR connection is to be noted particularly that the tonearm ground is connected from the middle pin (3) of the Tiffany?plug only to ONE channel XLR pin 1, otherwise risking hum noise due to a ground loop.”
Various examples provided: http://bmc-audio.com/tl_files/bmc_audio/pdfs/Manuals/PHONO-MCCI-Manual-Web-EN.pdf
You would not get a ground loop if the ground were tied to both channels. If you think about it, it is anyway, since pin 1 of either phono section input is (or should be) tied to ground. Since there's no signal current through it, a ground loop can't be formed.
You are 100% correct. Unfortunately, this is not always the situation as I mentioned by B.M.C. Audio.
The popular 1995 AES paper (Audio Engineering Society published standard AES48-2005) by the late Neil Muncey addressed most Pin 1 issues and inconsistencies that run rampant in our real audio world.
A very nice option to having when realizing inherent Pin 1 issues.
When you are dealing with a passive source like a phono cartridge, you simply will not have any issues with pin 1. That's only an issue when active devices (such as a tape recorder) are acting as a source.
How a ground loop is going to occur when we're talking about left and right hand channels from a phono cartridge?? Plain and simple, it won't. That is why the shields can both tie to pin 3 of the DIN connector and also pin 1 of each channel's XLR connection to the preamp with no worries whatsoever.
FWIW Atma-Sphere first worked out this connection back in 1988, prior to the release of the world's first balanced line tube preamp, the MP-1. Since the XLR connection is the de facto standard for balanced connections this was really more of just a logic thing. At any rate, you will never encounter a ground loop with this sort of phono connection!
If there is a ground loop in a system with this connection, it will be found to be caused by other equipment, not the turntable/tonearm or its connection to the phono section.
You really shouldn't get ground loops in a balanced system since a balanced system ignores ground. This is by design to that ground loops can''t get amplified. Its only when a designer does not understand how this works that you get into trouble. IMO that is all too common in high end audio.
It’s rather remote possibility using a MM cartridge with this kind of phono but some MM cartridges have a jumper between negative signal pin and cartridge body. In that case cartridge body can ground negative signal pin through head shell and tonearm. It’s not a ground loop but can be perceived as ground loop due to hum.
So far not encountered any issues with that, but if it did occur a small set of diagonal cutters can solve that issue.
I built two working balanced phono cables where ground is tied to each side and to each channel's Pin 1. I don't have any hum or ground loop. And I don't believe I should have any either. I also use balanced cables based on Canare L-4E6S between preamplifier and amplifier and between DAC and preamplifier; ground is tied on both ends for both channels.
Network cables, CAT 5, 6... work on this principle. This is true for all IT cables. You can check any CAT or USB cable; ground is always tied to both sides. CAT or USB cables do carry differential signals just like balanced cables. In IT field a cable with only one sided ground is considered an RF antenna, which is true because that is how an antenna works.
I have heard (no personal experience) that Rega Tonearms cannot be used with balanced cables because internally they tie the -ve signal to ground. Frankly, it is broken wiring. Just to accommodate a wrongly wired MM cartridge or a tonearm, we should not standardized and perpetuate broken wiring standards.
I have turntable with a tonearm that has a 5pin din output. I own an Eleac Alchemy PPA2 phono preamp that has a balanced input.
Unfortunately, there is no sound coming through the Right channel. I asked for support at Eleac. They told me to bridge pin 1 (ground wire) and pin 3 (negative) of both the XLR3 connectors. I have no issues when I connect the turntable unbalanced to the phono preamp.
Unfortunately, there is no sound coming through the Right channel. I asked for support at Eleac. They told me to bridge pin 1 (ground wire) and pin 3 (negative) of both the XLR3 connectors. I have no issues when I connect the turntable unbalanced to the phono preamp.
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