length of interconnects for passive preamp

It applies after the passive.  The source to passive is actively driven so that's going to be less sensitive. It's the R that the passive puts in after that that makes the signal more susceptible to cable performance. 

Just as a rule, 1 meter cables are very versatile if you have your gear in a tight rack. 6 icnh or 1 foot cables are single use only. Move your gear and those are scrap. Buy a cable that has room to grow if your stack changes.

I have been running 25' of Mogami Gold balanced cables from my dac to a passive volume pot. Another 25' of Mogami to my amp for years without problem. Had a Lightspeed Attenuator at one time and longer runs I couldn't get hi volume from that though . Must be system dependent.

 I am running 6 meter from a Prometheus TVC to my amp with no ill effects. 

I think it largely depends on if you're connectors are single ended (RCA), or balanced (XLR).  If you're running RCA IC, then you probably want to keep them at 1M or 2M.  For XLR, the length becomes more irrelevant.  

I like 1/2 meter between my passive pre and amp...

I use .5 meter Audience Au24 from my phono stage to my Tortuga Audio pre

@majorc - In my rack, the minimum length of interconnect I could use due to shelf spacing is 1/2 meter (20"). So i use a 24" Custom cable for some added "wiggle room".

For a passive stage - I would want to use the very best cable possible to maximize signal transfer.

I highly recommend Zavfino cables like these two

1. A cable that employs UP-OCC copper
   • https://zavfinousa.com/collections/audio-interconnects/products/arcadia-pc-occ-interconnect-cable
2. or their silver cable
   • https://zavfinousa.com/collections/audio-interconnects/products/the-fusion-solid-pure-silver-occ-copper-hybrid-rca

Take a look at their website - they have great products

Hope that helps - Steve

Many thanks to all; I'll go with 1/2 meter. I did not realize the quality of IC mattered more with a passive preamp. The IC that was recommended was made with mogami 2549 cable and neutrik rean connectors.  I'm very much looking forward to seeing what improvement there is going from  3 meter to .5 meter. 

@williewonka 

For a passive stage - I would want to use the very best cable possible to maximize signal transfer.

Can you intimate what “The very best” translates to in terms of specs?

@holmz - the cables I provided links too in my previous post are great examples of a very good commercial cables. There are better, but these provide best bang for the buck from a commercial brand

However the "specification" for the DIY cables I have developed (with the help of many others) would make an excellent cable because they employ

• either UP-OCC solid copper or UP-OCC solid Silver signal wires
  • these are the best conductors available for DIY projects at present
• With oversize Teflon tube insulation
  • the internal diameter needs to be 25% to 30% larger than the diameter of the wire
  • using an oversize tube allows an air gap between the wire and the Teflon
  • the resulting effective Dielectric Constant value is very close to air at 1.1
    • this produces a very low noise floor cable
• UP-OCC solid copper Helix coil neutral
  • the Helix also helps lower noise floor of the cable
  • it minimizes induce noise between signal and neutral conductors
• silver coated pure copper low mass RCA plugs
  • KLE Innovations Absolute Harmony
  • or Perfect Harmony RCA’s
• see this link for the Helix DIY cables
  • My Audio Alchemy (image99.net)

The problem with Bulk cables is they employ a conventional cable geometry with insulation that are bonded to the wires. This all contributes to noise being generated by the actual cable.which clouds micro details

Bulk cables also tend to use OFC copper, but the best metal for the wire currently (i.e. for DIY purposes) is UP-OCC silver and UP-OCC copper

If you want to read aabout what others think of the Helix cables take a look at this thread

https://forum.audiogon.com/posts/2350463

If you want to proceed with a bulk cable than I would recommend this one

• https://wp.neotechcable.com/ic-up-occ-copper-cable/

Hope that helps - if you have any questions about the Helix design just ask - I;m glad to assist

Regards - Steve

None of that makes any sense.
Maybe it might, but with a spec, the one can determine something.

• capacitance is given in Farads (milli, micro, nano or Pico farads)
• inductance in Henrys (Milli, Micro, nano, Pico)

What you give seems sort of like BS… in nice words.

And that link that you posted does not have any specs… so going with Mogami, Canare, etc. would let people base their purchase on some meaningful specs.

Shorter is also a good practice with a passive-Pre to get the capacitance and inductance numbers as low as possible.

@holmz - My apologies - what I provided are the Phyical cable specs, which to me are the most important - i.e.

• type of wire
• type of insulation i.e. dielectric characteristics
• cable geometry

But since you asked so nicely, here are the electrical specs

Helix Interconnect Cables - 3 ft long - using the 1mm dia Mundorf Solid Silver/Gold wire with the cotton sleeve insulation

• Capacitance = 32 pF
• Inductance = 0.8 uH
• resistance is negligeable

WRT your statement

What you give seems sort of like BS… in nice words.

When you have time - take a look at the In-akustik website, because they display their geometry in detail and so does Zavfino.

Also, take a look at these links that talks to the many aspects of cable design

https://www.psaudio.com/article/cables-time-is-of-the-essence-part-1/
https://www.psaudio.com/article/cables-time-is-of-the-essence-part-2/
https://www.psaudio.com/article/cables-time-is-of-the-essence-part-3/

I have provided my opinions as to what goes into designing and building excellent cables. They are based on exeprimentation and observation over many years and with the input from many other people

• you are free to do what you want with the information I have provided
• If you believe it is B.S. so be it
  • I am NOT here to convert.

BTW - I stopped using Mogami, Canare and even Van den Hul many years ago because they did not provide the level of performance that I was looking for !

They are quite good for live performances - where high gain amplification is used, BUT they are NOT the best solution for Home audio

• they are however very affordable, which will attract many people.

Regards - Steve

Thanks @williewonka I’ll try to keep my tone civil.

Geometry:

• One of the 3 PS links mentions woven cables, which sound like what the Kimber 4TC and 8TC are.
• And you also mention the silver gold Mundorf.
• Is that a single solid core?
  • and… are you saying that the multi strand is something you shy away from?

Insulation

• I see PTFE and also bare wire.
• Are you using a different cotton over the bare wire?
• And then in your earlier talk about an air gap… Are you “twisting the pair”?
  • Wouldn’t that reduce the gap to zero where the +/- sit ‘side by side’?

The other thing that the 3 part PSaudio mentioned was time errors. Does reducing some of the cable issues even help in a speaker that is not phase or time coherent?

https://www.mundorf.com/audio/en/shop/Cables/MConnect_SGW/

@holmz - WRT wire types - i.e. Stranded vs. Multi-strand vs. Solid

Stranded wires do not provide the same level oif dynamic performance and clarity that solid wires do, but that does not mean I do not use them - I use them for the neutral conductors of Speaker and Mains cables because they improve cable flexibility

Stranded wires

• In stranded wires, each strand has a finite numer of valence electrons availlable to provide for the transfer of electrical energy
  • as that limit is approached (due to increased power levels), electrons start to jump between trands,
    • this generates HEAT and NOISE
    • and is why stranded wires do not perform as well as solid wires
• A solid wire has a much higher current carrying capacity than the same gauge stranded wire
  • so it is better equiped to handle those large transient peaks
  • This is why I choose to use solid wires for the signal (or Live) conductors in all cable types
• But stranded wires ARE very good for the delicate signals in Tonearm wires/cables
  • because all they are really "conveying" is very small changes in voltage
    • i.e. the current is extremely small
    • the smaller the current, then the impact of the dielectric effect of the insulation on that wire becomes negligeable
    • hence - crystal clear transfers are achieved
• I have tried stranded wires for the signal (or live) conductors in all cable types, but the solid wires sound significantly better
• But when the use of a cable requires better durability e.g. my more mobile guitar amps - then I scafrifice cable perofrmance for safety and durabliity

Multi Strand conductors

• I make this distinction, because I have compared a Single solid wire to conductors made from multiple solid strands (i.e. up to 4 strands of solid wire) in both power cables and interconnects
  • The optimum appears to be 2 strands - for reasons I am yet to understand, but I have tried the following...
    • Tightly twisting two strands of bare wire before inserting the wires into a single Teflon tube
    • inserting each wire into their own Teflon tube and twisting them in a more relaxed twist (i.e. one complete twist every 3-4")
    • the latter providing the best performance

Single solid wires

• My initial cables used just a single strand of wire for both signal and neutral conductors and then another Audiogon member suggested I try the "Double Shotgun" approach
  • i.e. using two wires for each conductor, referred to as the Double/Double
  • This proved to improve overall performance
• But being curious, I decided to try a two wire Signal conductor with a single wire neutral conductor known as the Double/Single
  • I also tried a larger gauge neutral to compensate for the loss of gauge in the neutral conductor
  • Whilst provding very good performance it did lack a little body comapred to the Double/Double
    • But it is cheaper and easier to fabricate
• which brings me to my latest adaptions
  • A Double/Double cable that has...
  • for the signal conductor
    • 2 x 20 gauge solid UP-OCC silver wire
    • each bare wire is inside it’s own Teflon tube and twisted together in a relaxed twist
  • for the neutral conductor
    • 2 x 18 gauge solid UP-OCC copper wire
    • each bare wire is inside it’s own Teflon tube and formed into the Helix coil
  • this geometry provided stunning performance that exceeded my expectations
  • I also tried a second Double/Single cable that has a neutral Helix Coil made from 1 x 16 gauge solid UP-OCC copper wire
    • to my amazement I could not discern any significant improvement on my system and with my ears
    • This may not be the case on systems with higher resoultion capabilites

INSULATION(s​)​​​​​​

I started investigating insulations a couple of years ago after trying Duelund Tinned Copper, becasue it made no sense to me that people preferred Tinned Copper over Solid silver

• it was at that time that I discovered some content on the web that explained about Dielectric Contant (Dk) of different insulations and their impact on signal propagation
• this was an eye opener and explained why the Dulund wire was prefered - the Cotton/Oil insulation proved better clarity and imaging
  • the followigis a list of Dk values of different insulation tyoes
    • Vacuum = 1.0
    • Air = 1.1
    • Cotton 1.3
    • Foamed Teflons - 1.45
    • Teflon - 2.2
    • PVC’s, rubber ect.. > 4.0
• Fast forward to the bare wire in teflon tube
  • provided you use a tube that has a 25%-30% larger inside diameter than the diameter of the wire, the teflon tube does not collapse around the wire when a gentle twist is used - there is only ever one very small point of contact
    • this makes value of Dk very close to Air at 1.0
    • this technique provides exceptional clarity of signal tranafer, which translates to more details
    • having more details also improves imaging - not only in a larger more well defined image
      • but it improves the clarity of the various layers of instruments and artists within the image.

WRT

Wouldn’t that reduce the gap to zero where the +/- sit ‘side by side’?

The DIY Helix cables take a very different approach to Cable Geometry

• the +ve and -ve conductors DO NOT sit side by side
• the neutral conductor is wound into a helical coil (or Helix)
• the signal (or live) wire is inserted down the center of the coil
• this means the coiled conductor crosses the Signla conductor at close to 90 degrees
  • this mitigates any/all NOISE that would otherwise be induced into the neutral conductor from the signal conductor
    • NOTE: Any noise on the neutral wire is actually transfered back into the neutral side of the connected component’s circuitry, which causes distrtions in the signal that are amplified by that component
  • The mechanics are more fully explained in this link
    • My Audio Alchemy (image99.net)

WRT:

Does reducing some of the cable issues even help in a speaker that is not phase or time coherent?

This type of problem could be due to

• crossover design
• choice/combination of drivers
• enclosure design

But having said that - cables that have parametric extremes (either low or high) in levels of Capacitance and/or Inductance might display this type of degraded sound when used with with speakers having similar high values of Capacitance or Inductance.

Speaker Design is one area that I tend to shy away from just because of the complexities involved.

But when I try new speakers (which is NOT very often) I take along my cables and amp 

But the Capacitance and Inductance parameters of the Helix design tend to be "middle of the road" and I have not yet learned of any problems in systems to date

The only restriction of the Helix design is

• they DO NOT provide optimum performance in the following cases
  • Speaker cables should NOT be used in conjunction with amplifiers that have adopted a symmetric balanced design
    • i.e. where the speaker +ve and -ve terminals carry the same signal, but 180 degrees out of phase
  • Power cables should NOT be used in conjunction with Power supplies or providers that have Balanced Outputs
    • i.e. where the Live and Neutral carry the same signal, but 180 degrees out of phase - this includes:
      • Certain power conditioners adopt this approach
      • Norway, where the entire power grid is balanced

NOTE: With the Helix Cable geometry

• There appears to be no impact related to the shortness of a cable.
  • e.g. I have used Digital RCA cables as short as 18"
    • But I did use the KLE Innovations Harmony RCA plugs
  • I also know of USB cables that are 36" long and work extremely well
  • I also have a mini System that has 12" long speaker cables and a 30" power cable and the improvement in sound was amazing

My apologies for the very long post - but as you can see it gets very compoicated

Regards - Steve

OK Steve lets get back onto the topic of: “Length of interconnects for passive pre.”

1. I see no great point for multi stranded wire in the interconnect.
   1. But I suppose if there is some 20-28 gauge stranded wire then why/why not? (I have no opinion on geometry, just length and specs)
2. The output impedance of any passive pre is “gawd awful”
   1. So length should be minimised
   2. Capacitance should be minimised
   3. inductance should be minimised

I would not be considering using a passive pre, unless I was considering playing that system pretty damned loud.

And secondly if one wanted to use a powered sub woofer, like a vandersteen, then it would not work at all given the impedance changes with output knob level in a wild (but predictable) way.

And lastly; I would not consider it unless I had spoken to the amp people to get their opinion on the topic.

The only benefit I can see is if one had a super sensible speaker, and controlling thermal noise was the primary goal.

They look great on paper, up to a point… only in the simplest of cases.

@holmz - My experience with passives is pretty limited

• My NAIM 5i MKII had a passive pre, but it was integrated so the complications of an interconenct did not exist
  • However - I purchased it for the natural, uncouloured sound it produced
  • it was incredibly detailed and performance improved as my cables improved
  • hence my statement from my first post about using the very best cable to allow the passive pre to do what it does best
• I also had a friend that had a seperate passive in his system
  • it was not the same brand as his amp
  • he used a high quality 1 meter cable in order to capitilize on the benefits of a passive
    • i.e.to convey the best details possible
  • his cable had "middle of the road" capacitance and inductance, but because of the geometry of the cable and the wires used, his passive sounded amazing.

Granted - using as short a cable as possible will reduce capacitance and inductance

• but opting to use "some 20-28 gauge stranded wire" will NOT achieve the best perofrmance that a a passive pre is capable of.

So I guess my point is

• Passive’s are great for neutrality, details, imaging, dynamics etc, but those attributes can only be achieved by using a well designed cable..
• using any old piece of wire is defeating the purpose of having a passive pre in the first place

Regards - Steve

@williewonka don’t do this:

• using any old piece of wire is defeating the purpose of having a passive pre in the first place

That is a straw man misquoting, as I said I had no opinion on geometry and size.
I also said I only care about “length and specs.”

1. I see no great point for multi stranded wire in the interconnect.
   1. But I suppose if there is some 20-28 gauge stranded wire then why/why not? (I have no opinion on geometry, just length and specs)

Whatever piece of wire the OP uses will result in the tonal quality changing with volume-knob level. It does not matter if it is copper, silver, steel or gold. And it does not matter if it is multi-stranded solid, or whatever.

The higher the capacitance and inductance, and the longer the wire… then the larger the tonal change will be as the volume knob goes to lower and lower volume levels.

Do we agree on the physics (electronic aspects) that the length, capacitance and inductance of the interconnect are important?

Or is your position that the specs do not matter in favour of the materials, constructions and geometry?

My passive sucked the life out of my system when I was using very inefficient speakers and monoblocks, which required  3 meter ICs. I recently switched to very sensitive speakers (horns) and a stereo amp  and the passive sounds great even with the same ICs. the reason for my q was I want to purchase shorter interconnects to get it to sound even better (and the fact that I do not require this length). I will purchase 1 meter or .5 meter ICs - question is what brand - to be honest I do not quite understand the specifics of some of the previous posts but want to express my thanks and appreciation for your contributions. 

My passive sucked the life out of my system when I was using very inefficient speakers and monoblocks, which required  3 meter ICs.

Ideally we change only 1 thing at a time.

I recently switched to very sensitive speakers (horns) and a stereo amp  and the passive sounds great even with the same ICs.

I suspect that the input impedance of the power amps play a role, and the gain of the amplifiers also okay a role.

the reason for my q was I want to purchase shorter interconnects to get it to sound even better (and the fact that I do not require this length). I will purchase 1 meter or .5 meter ICs - question is what brand - to be honest I do not quite understand the specifics of some of the previous posts but want to express my thanks and appreciation for your contributions. 

I would purchase the cheapest Amazon cable, or what you already have in a Red/White/yellow set.
And use that as a baseline in an A/B test.

The Wonka mentioned these earlier 

Personally I would not be using anything that is more $ than that, and they are at my edge of what I can tolerate in terms of marketing foo.

It would be best if you could try them before committing.
And whether you hear a difference or not… it would be good see your feedback.

@holmz - as I said in my previous post

Granted - using as short a cable as possible will reduce capacitance and inductance

So I guess we agree ! - to some extent 🖕

BTW my statement 

• using any old piece of wire is defeating the purpose of having a passive pre in the first place

I was not quoting you,  I was just trying ot highlight the point - my apologies for the mis-use of bolded text

Regards - Steve

@majorc RE:

I want to purchase shorter interconnects to get it to sound even better

A better qulaity cable like those offered by Zavfino of 0.5 or 1 meter long will help to achieve your goal.

Also - what speaker cables are you using?

Regards - Steve

The speakers cables were made for me by a local tech and I do not have the specs. I will report back after I try the shorter ICs. Regarding my prior 3 meter ICs I I started with cardas microtwin, which seemed to "round out" the sound and were a little muddy,  then I changed to a more expensive cardas - I can't recall the specific model - which was a step up - and then I had 3 meter ICs made by Stephen Sank, who is a tech/modifier of equipment based in Arizona -   they are unshielded and were inexpensive - but were MUCH better than the other 2 - so I may purchase shorter ICs from him or send the 3 meter back and have him make 2 pair of shorter ICs.  

So I guess we agree ! - to some extent 🖕

I guess we are getting the finger onto the pulse ^here^?

Back to your twisted wires with the oversized insulators and also the cotton.
There is a lot of talk focussing on the materials and the geometry. It is possible that those affect the electrical parameters directly, and that one could talk about the parameters that are desired rather than construction.

It makes sense when we talk about a cake or a bottle of wine to talk about whether it is chocolate or Pinot, and not talk about the chemicals. But electrical things have only three things (resistance, capacitance and inductance. They are not like flavours.

they are unshielded and were inexpensive - but were MUCH better than the other 2 - so I may purchase shorter ICs from him or send the 3 meter back and have him make 2 pair of shorter ICs.  

^That^ sounds like a wise plan. IMO.