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Home made interconnect

Postby timbloke » 30 Dec 2011 20:27

I'm fed up with some of the crazy prices being asked for phono interconnects and wanted to make my own from cut cable and those heavy gold plated plugs that Maplin in the UK now stock. Which is the best type to use and can anyone recommend a good supplier of suitable cable in the UK?
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Re: Home made interconnect

Postby bogle111 » 30 Dec 2011 20:44

The only problem with doing this is that you won't know if the sound will be to your liking in making up a cable. What equipment are you using to connect to?

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Pete
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Re: Home made interconnect

Postby timbloke » 30 Dec 2011 21:32

Hi Pete,

Thanks for the quick response. That's a good question and also a very good starting point.

The three sources are a Thorens TD160/SME3009 II improved. The arm has been rewired and SME phono sockets added. The arm was rewired with silver wire but I'm not 100% about the sound of it as it still sounds a little bright to me, particularly with substandard pressings. The cartridge is a Shure M97XE which has improved the sound of the turntable as I found the Denon DL-160 I had on there previously way too bright.

The other main source is a Revox B226 CD player. I also have a Samsung flat panel TV I want to connect (but I guess this forum isn't the place to discuss such things) The amplifiers are Audio Research SP9 and D130 pre and power amps hooked up to ProAc Studio 100s. The preamp is a hybrid type with valves in its output stages and the power amp is a mosfet type. The adjectives that probably sum up the system's sound are clear and open and warm.

Again, probably not the place to say this but the combination of the Revox B226 and the amps & speakers really does it for me. I've used both Van Den Hul D-102 III interconnects and some OFC leads that Audio Origami made for me when he rewired my 3009. Both sound pretty good. The Van Den Huls may sound slightly better with the CD player though I may have been in the wrong mood when I plugged the OFCs in.

Is what they say about IBM cat-6 network cable as interconnect true?

Thanks, Tim
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Re: Home made interconnect

Postby awty » 31 Dec 2011 02:23

I made phono interconnection cables using pure silver 28 AWG Teflon coated. Something in the 33AWG-28 will do, Single strand is better, but multi will do. Silver plated copper is OK to, but you need to shield phono cables other wise they'll buzz. The plugs should be similar metal (silver plated copper).

I used single strand 24AWG silver plated teflon coated cables for amp inter connectors. They didnt need shielding.

Got all that off of Ebay. As far as sound goes I feel that is subjective and depends on the individual.

Have you tried altering the VTA on your tone arm or other adjustments? Can you change the loading on your pre amp?

What do they say about "IBM cat-6 network cable as interconnect"
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Re: Home made interconnect

Postby timbloke » 31 Dec 2011 03:41

Thanks Atwy,

That's really useful information on the cables, thank you.

The Vta on my arm looks fine according to the tone arms manual and I don't have the facility to adjust the loading on my pre. These adjustments would effect the bright treble of my turntable set up?

There's a few articles on the web about using cat 5 and cat 6 networking cables as phono cables. I just googled it.

thanks,
Tim
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Re: Home made interconnect

Postby awty » 31 Dec 2011 07:10

Thats for just basic leads that wont cost much and do the job.

I believe adjusting the VTA might improve things, worth a try. Adjusting tracking force may help to.
From what I've read the shure is slightly on the bright side, especially when new, may get better with use.

I just fitted a new Acutex 312 cart and its anything but bright, great bass, but then again my old at 110e wasnt very bright either......nor am I #-o .
The acutex are pretty cheap http://www.ebay.com.au/itm/TESTINA-ACUT ... 3a6e0c5699

Anyway I'm sure someone with better knowledge than me might be able to help solve your problem.
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Re: Home made interconnect

Postby awkwardbydesign » 31 Dec 2011 14:30

Have a look at TNT, they show some interesting designs. http://www.tnt-audio.com/
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Re: Home made interconnect

Postby cafe latte » 03 Jan 2012 03:20

At the risk of this becoming another cable dedate.. Good quality maplins plugs, some low capacitance quality shielded rca cable and they will be fine. There is no such thing as directional cable, and if there was with an ac signal it would be a very bad thing!! Silver in a tiny tiny tiny anount more conductive than copper, but the idea it has a sonic signature is hogwash. As far as I am aware nobody has sucessfully in a controlled double blind test EVER managed to pick the better cables. Interesting no manufacture has EVER set up such a test to prove their products. This speaks volumes to me. Years ago in a mates hifi shop we tried to blinfold pick the grand cables against ones I had made, it is not possible. Lastly our inperfect brains cant remember what it heard a fraction of a second ago in quality terms (sad but true), so those who listen to a cable, then remove the wire and fit the new cable cant for sure remember what the old wire sounded like, we also have our own bias to what we have just bought which is unavoidable.
Flame suit on 8-[
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Re: Home made interconnect

Postby LPspinner » 03 Jan 2012 19:46

Hi Guys…

At the risk of getting flamed myself I also think that far too much importance is attributed to the interconnect cable. Like CL said, choose a good quality – low capacitance cable; good quality does not mean silly and expensive.

I use a twin-core and shielded type microphone cable wired in quasi-balanced configuration and terminated with good quality metal-bodied plugs for all my line level signals. The plugs and cable are available from most electronic hobby shops for less than 5 dollars each. If the cable is for carrying the signal from a cartridge rather than a line level signal 50 or 75-ohm coaxial cable is also very good, it has a very low capacitance as well as low signal loss.

Happy listening
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Re: Home made interconnect

Postby timbloke » 04 Jan 2012 01:00

I'm in agreement with what Cafe Latte and LPspinner just said. I actually had the chance to compare cable types as my Revox 226 CD player has two sets of analogue outputs so I could directly compare cable types. I couldn't detect any noticeable difference between the OFC and the silver cable. I also tried some brand name readymade cables- Some lower end Chord Company cables with plain looking sliver ends (not silver plated) and some Van Den Hul D102 mkiii hybrid. I couldn't detect any real difference between any of the cables apart from maybe the Van Den Huls stereo separation was slightly wider.

LPspinner, would I get better sound from my turntable if I made some dedicated leads from 50 ohm coax?
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Re: Home made interconnect

Postby LPspinner » 04 Jan 2012 03:54

timbloke wrote:
...LPspinner, would I get better sound from my turntable if I made some dedicated leads from 50 ohm coax?


Hi timbloke …

In reality probably not … it’s just that the microphone cable will have a slightly higher capacitance due to it being a twisted pair wrapped up inside the outer shield. The Co-axial cable on the other hand, is a simpler, single core and shield with a greater distance between the shield and the core. The more distance between the core and shield means lower capacitance.

In theory, the higher output impedance of the cartridge will be more sensitive to cable capacitance than the lower and more predictable output impedance of a pre-amp or stand alone phono-stage. In reality the HF “roll-off” caused by the extra capacitance will probably be well beyond the audio frequency range and of no real consequence, unless you are planning to run many meters of cable. Then again: it won’t cost that much to try and you can practice you soldering skills along the way.

I mentioned the coax simply because I feel a little more comfortable using it in this application where capacitance may become an issue. The coax also makes good digital interconnects if you are running an outboard DAC on your CD spinner.

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Re: Home made interconnect

Postby awty » 04 Jan 2012 05:07

If you use single core co ax cable try to get plugs to suit, else wise it can be a b****r to solder the outer foil to a tag suited for wire. Plugs with a crimp over the outer foil are easier to use.

It only cost a few dollars per foot for 24 awg silver coated wire (obviously the shielded stuff for phono cables is a bit more), so no great expense and 5% is 5%.

There is plenty of DIY you tube vids you can check out to see how its done.
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Re: Home made interconnect

Postby jlbruyelle » 05 Jan 2012 11:43

Hi, just jumping into the conversation to bring my 2 cents worth of professional knowledge. Such general assertions like "microphone cable has a high capacitance because it is a twisted pair" or "50 ohms cable has a low capacitance because is it is done for HF", very often prove wrong. It entirely depends on manufacturing parameters that vary widely between types.

But then there is a way to actually know: all the cable types have a data sheet available on the manufacturer's site. Check the capacitance in pF/m (or pF/ft depending on the country you live in), multiply it by the length you plan to cut, and voila, you have the capacity of your cable. Contrary to a common belief, a balanced cable can very well have have a low capacitance.

To concur and expand on LPspinner's post, here's how interconnects are done in studios where your records / films / TV shows are made (I know because I've done it). OFC, silver or 24K gold wire are not even considered, because they add cost for no known benefits. All the pro cables just use copper, sometimes tinned for protection.

- Low capacitance, well shielded cable for the phono sections. It is difficult to get these two qualities at the same time, so the cable may be a little more expensive. Note that the shielding is also specified in the data sheet, so you don't have to guess. Note that phono-level interconnects are rare except in community radios, usually the preamplifier is integrated in the turntable. Well, vinyl is a thing of the past anyway, so why bother to mention it (just joking! But as far as radios are concerned, well... that's the sad truth :cry: ).

- Well shielded cable for the line level interconnects. Balanced is better, even for short runs, since it reduces ground-induced hum (not that grounding doesn't matter even then). Capacitances does not really matter, except maybe for very long runs but then the induced noise becomes a nuisance before the trebles loss, especially on unbalanced links. Note that the extra circuitry involved by balanced interconnects is considered less harmful than unbalanced ones - of course YMMV, but this is how things are seen in the broadcast circles.

- In digital: 75 ohms cable for SPDIF (any plain video type, 10 metres max length), and 110 ohms balanced cable for AES/EBU (not an ordinary balanced cable). A specific connector of the same impedance is not required, because its influence on the signal is so low.

- Gold contacts are liked because they don't get oxidized, which reduces problems and maintenance. Nickel is standard too.

...And that's how your records/films/shows are made. No exotic gadgets involved, just commonsense engineering and manufacturing quality. Widespread cable brands are Belden, Canare, or Gotham. And Neutrik or Switchcraft for the audio connectors (no hierarchy implied, no affiliation). Neutrik NY273 is well regarded as a high quality, low cost RCA connector; their insanely expensive model with a retractable ground contact is often used in mobile applications, just because it is reliable and does not cause a noise burst when inserted.
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Re: Home made interconnect

Postby cafe latte » 05 Jan 2012 12:41

Rubbish.
When the distance from the center of the conductors increases the capacitance drops, when it reduces it rises and inductance drops, it is how things work, sorry. Gold is not a good conductor, copper is the second best very very very closely behing silver. Capacitance is very very important in phono cables as a high capacitance caple with a MM cart will alter the freq curve of the cart a lot, It is why all carts give a capacitance loading that the cart works best.
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CL
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Re: Home made interconnect

Postby awkwardbydesign » 05 Jan 2012 13:33

"Neutrik NY273 is well regarded as a high quality, low cost RCA connector; their insanely expensive model with a retractable ground....."
My insanity seems to be bigger than your insanity; I think they are quite cheap!
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