Transformer for Preamp powersupply

For low current application based on opamp, the advantage of lower noise from toroidal would be ideal.

However when a EI core is properly made...it will definetly sound better...but where would you source it from.

I get my toriods from RS components...expensive but reliable. I used to source - locally from a company called Miracle - which was quite disappointing.

Regards
Siva.

Read some stuff on dc offset within the AC mains power generated by the difference in loads on the phases of the electric feed that feeds your home. Can't quite get how that's possible.

Will try to explain.

Below is a pictorial representation of a Sine Wave, of the AC power delivered to homes worldwide.


The Vertical axis is the Instantaneous Voltage. This is Zero where the sine wave starts from the horizontal axis, goes up to its peak value, then descends to zero and then turns Negative, forming a negative peak and returning to Zero.

The Horizontal axis is Time, and shows how the voltage ( as explained above, varies with time.





You will observe that the Sine wave is perfectly symmetrical around the Horizontal axis which is also the 0 Volt level of the vertical axis.

Now if the Sine wave is Not perfectly symmetrical around the horizontal axis, the area of the Top Half of the Sine wave will not be equal to the area of the lower half. The difference between the Upper portion's are and the Lowerr portion's area is interpreted as a DC component or Offset or unbalanced part.

This shift actually implies that the Zero Volt line has shifted i.e. the Neutral is Not at Perfectly Zero volts.

Thanks siva. Yes I know rs is expensive but they also assure some dort of consistent quality. Yes it is an opamp based preamp.

I did find one guy who is reputed to be decent. Website is torotrans.com basd in pune. Check him out if you like. He seems to cater to single consignments if courier charges are paid. Name is mahesh. Let you know once I get the tranny delivered. On the EI core there is one guy that was very well recomended by my uncle who used to deal in hospital equipment. Very good trannys from argo transformers, lam road, opp minerva cinema, mumbai. They have a workshop at lower parel. I have had my step down tranny made of 1kva and its heavy as hell ! Backbreaking to carry but very quiet.
What about those plitron india guys based in the south ?

Thanks for the education dinyaar as always.

Manek

Universal Transformers on SP Road in Bangalore is a great place for EI core transformers.

Excellent quality. Solidly built stuff.

My rambling on the Issue.

Manek, you are correct, there are 'Camps' for EI & Torroidal.

Ayre ONLY Uses EI Core Transformers in all its products. They Phoo-phoo toroids.

From a marketing and drum beating perspective, toroids are great. They also offer low stray field and high peak current delivery.

As Siva has pointed out, the Low stray field could be a small advantage in your pre, though High Peak current capability is irrelevant. That is a significant factor in Power Amps.

Even small transformers in a Pre amp's PSU ( such as the 4 Op Amp Pre that you are building) will offer 5X or even 10X the current that you will need.

I would suggest that you dont spend sleepless nights on EI vs Torroids ;). Your resourses would be better spent on:

1. Decoupling the Op Amps VERY Close to their Power Supply pins.

2. Use of a Shunt Regulator instead of 3 Terminal regulators.

3. Good interconnects for internal wiring ( why not avoid sockets and directly solder onto the PCB ? )


Incidentally, I agree with you, ARGO makes SUPERB Transformers, and there are several good transformer suppliers in Mumbai and Pune. Thetre is also a good source for R Core transformers in Ahmedabad.

I have often seen round Potted ( Blue Colour, with fins) transformers in High End Audiophile products. If the pic resolution is good, and you zoom in... they are made in Pune ! Indian Transformers are GOOD !

Hi ampnut

Decoupling the opamps would mean a bypass cap very close to the power pins ? If so that's done.

Shunt regs I will do in the next version of the power supply board.

Nope, I am bot spending sleepless nights on the debate but just curious.

My preamp is being built pretty cheap along with a donor chassis of an old amp so nit much money is being blown on it, so don't worry. As ab exercise I will connect the torroid(small one (50va, 1amp) and not too expensive) and check out the diff if any :-)

What I will need help from you guys next is on proper pcb design.This one is on vero board and an experiment. Once I have finished messing with the vero baord I will get the proper pcb. The power supply circuit is on a proper pcb already.

Regards

Manek

....And yes, local trannys are good and a few very good vendors around. I am not surprised you saw the pune tag. A few products use indian tranny's

Viren likes the tranny's from delta in delhi and they do look neat, good build.

Siva, you may save a bundle with good local options.
And you will never know until you try others out.


Manek

Manek schrieb:

....And yes, local trannys are good and a few very good vendors around. I am not surprised you saw the pune tag. A few products use indian tranny's Manek

W.r.t Amp_Nut's & Manek's point about the use of Indian xformers in US products, I did notice very clearly that the Bel Canto DAC2 used 2 of those blue cover with fins xformers!

Manek schrieb:

Read some stuff on dc offset within the AC mains power generated by the difference in loads on the phases of the electric feed that feeds your home. Can't quite get how that's possible. Manek

Per my understanding, DC offset on the AC mains appears to be less of an issue for xformers =< 300VA because the DC resistance of the primary is high enough that a large portion of the DC offset gets dropped across that resistance. As a result very little current (due to DC offset) is created in the primary.
DC offset seems to be more of an issue for xformers >= 500VA because the DC resistance of the primary windings is much less. Hence, a large portion of the DC offset voltage gets thru & creates a (larger) DC current in the primary windings.
Basically, DC current in the primary windings has the bad effect of satuaring the core.
Toroidal xformers are notorious for reacting badly to DC offset because these type of xformers intentionally do not have an air gap in their core. Thus, when the core saturates, the inductance (of the primary windings) drops drastically & the current increases drastically. (Remember the equation of the inductor: V = L * di/dt? 'V' here is the DC offset, which is fixed/constant on the AC mains. Then, the product of the value of the primary winding inductance times the rate of change of current over time = constant (DC offset voltage). So, if the inductance value falls (during core saturation), current has to increase over time so that voltage remains constant).
OTOH, EI transformers have an air gap in their core hence they resist core saturation much better than toroidals. This seems to be exactly what you have read, Manek.

You can get an asymmetrical load on the AC mains - some appliance such as a hair dryer or something else that does not always do a full wave rectification of the AC mains i.e. does a half-wave rectification only. In such a case the half-wave rectification (asymmetrical load) interacts with the finite impedance of the AC mains (which is 500mOhms - 1000mOhms) to create different peak voltages of the rectified AC during the positive & negative cycles of the AC. Since the rectified peak voltages are different, the average DC is not zero i.e. you end up having a DC offset!
Another way to get DC offset in the home environment is to have unequal loading of the 2-phase AC that comes into your house. One phase might have more load on it than the other. For example, you could have your washing machine, dryer, microwave, fridge all one one phase. On the 2nd phase you could have all your electrical lights, other lighter loads & your 2-ch. The loads are asymmetrical - when the fridge/washer/dryer/micro come on Phase 1 versus just your 2-ch drawing current on Phase 2, you have an imbalance & a high probability of a DC offset!
DC offset on the mains can be transient i.e. last for a few cycles to a few minutes & then go away but it can also be present for a longer time. Often, the victim of DC offset on the AC mains is powerless to get rid of it on the incoming AC itself because somebody else is creating that DC offset unknowingly! You have to use a DC blocking capacitor in the power supply unit to get rid of it.

Manek schrieb:

A question for the diy gurus here.... Would a toroidal or EI core transformer be the best candidate for a opamp based preamp/headphone amp ? Which one would you pick and why ? Do shed some light please. There is some stuff on the internet but I finally found it inconclusive. Read some stuff on dc offset within the AC mains power generated by the difference in loads on the phases of the electric feed that feeds your home. Can't quite get how that's possible. Hence EI type is supposed to be better as it resists dc saturation better. Regards Manek

Manek,
here is a really nice, simple read explained in layman's terms.
"The High-End Mythology of the Toroidal Power Transformer" by Doug Blackburn of Soundstage

Manek,

If you can get the R-cores from Delta...they are really good. I use them in my 845 SE & also in my own personal tube DAC and tube-pre. Only for the 5-Amps heater of the 845, i thought the toriods behaved better..

I got my EI core's from a local vendor in Bangalore...but wait time is quite high. PM me with what you need and i can help.

However Delta - as Viren recommended - should be your first option

Regards
Siva.

bombaywalla schrieb:

Manek schrieb: ....And yes, local trannys are good and a few very good vendors around. I am not surprised you saw the pune tag. A few products use indian tranny's Manek W.r.t Amp_Nut's & Manek's point about the use of Indian xformers in US products, I did notice very clearly that the Bel Canto DAC2 used 2 of those blue cover with fins xformers! :)

They are just toroids....nothing spectacular about thier sonics though...they do look good.

Tks bombaywalla for your patience.

Siva thanks for helping.

Good to know you have a local source and a genuine one at that.

Looking for some lessons on pcb design.

So much of this was learnt in college and all of it forgotten ! Its all coming back slowly yet steadily. :-)

Manek

...And I have noticed that the proto boards I use are extremely resilient to repeated soldering and desoldering...didn't find it in the power supply pcb.

Now what is it about these boards that make them so resilient ?

Manek

Thicker copper tracks, better bonded to the subsctrate

Ampnut, I assume regular pcb's can also be made the same way or better and its just a matter of finding the right person to do the job I think.

Any pointers to good pcb makers ? You know the kind that will take orders sizes of one/two pieces but build a kick ass pcb. Would they also turn a schematic into a pcb design ?

Etching my own pcb's at home is not an option currently.

Manek

Manek, you are correct. You CAN get good, 1 off PCBs made at a reasonable price, As Long As You Provide The PCB Track Artwork !

CK electronics, in the same lane, down from Champion Rubber will do it for you, in approx 3 days. They will happily make 1 PCB also. There is a fixed cost to make the film ( not much ) and then the cost for each PCB.

Costs are typically computed per sq cm, for the film & PCB.

They will make the film and PCB ( with drilled holes) from even a Xerox copy, but be VERY Careful that the Xerox copy is a 100% scale reproduction from the magazine or website download. Most Xerox copies are Not 100%. As a result, the IC may not fit on the PCB, since the lead spacing is a tight parameter.

You can even get your PCBs glod plated or solder mask. Multi Layer PCBs also possible.

However, getting a PCB designed from the Circuit diagram is another story all together...


Exen good PCB designers and software typically optimise a PCB for zero jumpers.... not signal routing or track width.

It may not even be fair to say that they dont know the rules for a kick ass (audio) pcb....

There really are No cut and dry rules and opinions vary. As an example, while most companies show off Very neatly laid out ( All components laid out perfectly horizontal or vertical ) PCBs, Mark Levinson believes that PCBs for audio applications should be laid out Non Symetrically, with a (preferably) random layout !

... was just reading the May 2009 Stereophile review of the Simaudio Moon Evolution W-7 amp.

Says .... " was a bouch bright & forward when it was first turned on" and required a break-in period becaue of the "heavy, pure-copper circuit board traces "

FWIW .... Keep that DIY vero board kit cooking

How about gold plated tracks .. serious

Any good reason for that ?

Yes I know ck. I but my caps, resistors, pots from him.

Sometimes he is grumpy but most times willing to help.
Now I need a good pcb design to give him so that's a new project for me. Help welcome :-)

Btw, my amp works, tested with headphone. Now I will sort out the rats nest, resolder a few wires, route them properly, get proper rca connectors, secure the boards on the chasis.

I will then connect it to a power amp and check it out the real performance.

Next step is to turn this amp into a headphone amp with additional circuitry.

Regards

Manek

Amp_Nut schrieb:

... was just reading the May 2009 Stereophile review of the Simaudio Moon Evolution W-7 amp. Says .... " was a bouch bright & forward when it was first turned on" and required a break-in period becaue of the "heavy, pure-copper circuit board traces " FWIW .... Keep that DIY vero board kit cooking ;)

Amp_Nut, how did the Stereophile reviewer make a one-one correspondence between the heavy pure copper PCB traces & the initial bright & forward sound?

Bombaywala, I too found that very 'interesting' but I guess that is best for the reviewer to answer....


Actually, I think it was based on what the manufacturer told him !

The more I hear about these things the more I now tend not to believe in the break-in phenomenon :-) I still feel 20 odd hrs is just right for everything to settle in after that its just voodoo.

But that's my personal opinion and belief and I have been wrong before :-)

Manek

I agree with you, Manek... while there is a Burn-in phenomena, I suspect its our brain that also needs to be 'burnt in' , and get a-climatised to the sound.

It our own personal 'burn-in' was not a factor, I am sure most manufacturers would have burnt in their equipment / cables before shipping

Many cable manufacturers have a delivery time of 45 days, and a recommended burn in of a few hundred hours... ie about 10 days of continious use. They could easily add that 10 days before shipping ( keep in mind the almost absurd price some demand ! )

Correct....and that holds true for mechanical parts like speakers as well.

Btw I know some manufactures do burn in stuff for 24hrs and then ship. That and a handfull of additional hours is all the burn in you need.

Like the cars of old had a run in period of a 1000kms with a governer ! Needed the valves and other moving parts to bed in properly cause they couldn't manufacture them precisely enough and had more than necessary friction that would cease the engine if not carefull. Some manufacturers even today tell you to be carefull in the first 1000km and drive in traffic more rather than the highway but not with a governer.

Parts today are manuafctured more precisely and closer tolerances, more precise functioning right out of the box etc....

Now if someone tells me a particular equipment takes over 100 hours to burn in I smell a rat !

And worse, many guys propose a continuous use of equipment during the so called burn in period like connecting two speakers out of phase facing each other cover em with a blanket and blast them for 4-5 days straight ! God ! That's a sure to do some damage to the equipment speaker, amp and cdp ! My thoughts are if the equipment is not running in its optimal parameters don't stress it ! Be gentle with it !

Manek

Amp_Nut schrieb:

Any good reason for that ? :?

Skin effect & Impedance...some also say resistance and durability.

Does gold offer lower skin effect & impedance than copper ?

Is gold also reported to sound better than copper ?

At the end of the day, so specific aspect can be singularly important for sonics. It is the collective implementation of many such nunances that improves the sonic.


Please read the above as

At the end of the day, no specific aspect can be singularly important for sonics. It is the collective implementation of many such nunances that improves the sonic.

sivat schrieb:

How about gold plated tracks .. serious

while sivat has done much more DIY stuff than myself & I consider him more knowledgeable on the above matter, I found this from my own research:

copper and gold tend to undergo solid state diffusion into each other (with copper doing so at a faster rate); the process is accelerated by increased temperature. Copper on a trace surface oxidizes, resulting in increased contact resistance (copper migrating into the gold can cause the gold to tarnish and corrode). This can be minimized by plating a barrier layer between the copper and gold. Nickel is commonly used as a barrier layer to prevent the gold migrating into the copper on the tracks. (The nickel barrier helps to reduce both the number and the effect of pores compared with plating gold directly over the copper base.) The nickel protective coating provides several benefits. It serves as a backing to the gold for extra hardness as well as providing an effective diffusion barrier layer between gold and copper. The nickel/gold provides a finish that is heat and corrosion resistant, environmentally stable, wire solderable and durable (the nickel underplate enhances the wear characteristics of gold) albeit at a higher cost than simple solder finishes.

From my research I understand that Nickel plating is bad for signals in the 1GHz region because

Nickel is a ferromagnetic material and its magnetic permeability results in a higher skin effect resistance than that of copper. copper's resistivity (at room temperature) is 1.7 x 10-8 ohm metre, with that of nickel over four times greater at 7 x 10-8 ohm metre.

The audio signal is limited to 20KHz hence the effect of the Nickel barrier should be minimal/negligible/non-existant.
FWIW.

The audio signal is limited to 20KHz hence the effect of the Nickel barrier should be minimal/negligible/non-existant.

If you check Audiophile sites, Nickel is ABSOLUTE Phoo-Phoo for audiophile applications.

NO audiophile Mains cable will use Nickel plated plugs.

Tweaks for using regular plugs, suggest that the Nickel coating be removed, before use, and polishing the tarnished Copper plugs from time to time, if you Must use regular plugs.

For audiophile applications, Rhodium or Palladium is suggested And implemented for Mains cords.. NEVER Nickel.

Gold also has a 'Thumbs Down' generally for audiophile applications. Supposed to lend a Hard, edgy sound. Some have experimented with a mix of Gold and Silver for the interconnects, keeping only a trace of gold to bring out more detail in the sound... the mix / balance is critical, and still not many like gold at all.

Gold has MUCH poorer conductivity ( hence worse skin effect too ) than Copper. It is used on the 'contact fingers' of industrial application PCBs where they are slotted into edge connectors. Used because gold does not tarnish. It provides POORER contact than copper, but because it does not tarnish, it is used to provide a consistent, long term (reasonable ohmic value) sliding contact via the edge of the PCB. Its a Compromise for long term consistency.

Atleast in recent years, neither Gold nor nickel are encouraged for audiophile applications....

Just my 2 cents...

Amp_Nut schrieb:

The audio signal is limited to 20KHz hence the effect of the Nickel barrier should be minimal/negligible/non-existant. If you check Audiophile sites, Nickel is ABSOLUTE Phoo-Phoo for audiophile applications. NO audiophile Mains cable will use Nickel plated plugs. Tweaks for using regular plugs, suggest that the Nickel coating be removed, before use, and polishing the tarnished Copper plugs from time to time, if you Must use regular plugs. For audiophile applications, Rhodium or Palladium is suggested And implemented for Mains cords.. NEVER Nickel. Gold also has a 'Thumbs Down' generally for audiophile applications. Supposed to lend a Hard, edgy sound. Some have experimented with a mix of Gold and Silver for the interconnects, keeping only a trace of gold to bring out more detail in the sound... the mix / balance is critical, and still not many like gold at all. Gold has MUCH poorer conductivity ( hence worse skin effect too ) than Copper. It is used on the 'contact fingers' of industrial application PCBs where they are slotted into edge connectors. Used because gold does not tarnish. It provides POORER contact than copper, but because it does not tarnish, it is used to provide a consistent, long term (reasonable ohmic value) sliding contact via the edge of the PCB. Its a Compromise for long term consistency. Atleast in recent years, neither Gold nor nickel are encouraged for audiophile applications.... Just my 2 cents... ;)

Agreed, Amp_Nut that for AC power cords & plugs having any Nickel is a bad thing.
But, we are talking about the construction of PCB traces here.
It is my understanding that the methodology of gold-plating copper PCB traces is standardized & that any PCB manuf will put down a Nickel barrier over the copper trace before gold-plating. It is my understanding that you cannot get away with anything else no matter how much Nickel is "phoo-phoo'ed".
Without the Nickel barrier the gold plating will tarnish due to the copper tarnishing underneath. Hence, the money paid for the gold-plating will be all in vain over time. There'll be no way to polish the tarnished copper once the PCB is installed inside the chassis & populated with components.
I *think* that you mixed up the issue & applied the rule of thumb for AC power cords & plugs to PCB traces.

I *think* that you mixed up the issue & applied the rule of thumb

Hardly, Sir !

The point I am making is that neither Gold nor nickel find favour with audiophiles for even Power, leave aside as a path in signal transfer. Gold + Nickel in an audiophile path will be worse than the individual evils.

Gold on PCB Fingers itself is a Compromise.

No reason for an audiophile product to utilise such compromises. Plain Copper and good solder are FAR better, for power cables, interconnects, PCB tracks or connections between a PCB and another component / circuit.. The same applies across the board.

I am NOT disputing your contention that Gold can only be used with Nickel, when plated on PCBs.

To be explicit, I am saying that its not a good audiophile solution.

Amp_Nut schrieb:

I am NOT disputing your contention that Gold can only be used with Nickel, when plated on PCBs. To be explicit, I am saying that its not a good audiophile solution.

Ok, Amp_Nut, I get it now. Thanks for the reply post clearing this up.

I wonder what some of those Mark Levinson products sound, then, with all the heavy gold-plated PCBs?? They seem to make a big hoo-haa about their gold-plated PCBs, no??
I saw the same heavy advertising for DACT attenuators saying that their contacts are gold-plated. People seem to like the sound of DACT attenuators (I've never heard one so far).....

DACT attenuators have to withstand continuous abbrasion due to repeated switching. Gold provides a long lasting connection... (a compromise none the less in terms of ultimate sound quality, compared to bare silver or copper), The compromise has been made for long term durability, which is a Prime consideration in this (switching) application.


For PCBs, I can only wonder how much BETTER they would sound with rhodium, palladium, or best of all, a design with no edge connectors, and good solder joints instead of Gold.

If the Tracks ( rather than edge fingers) are gold plated, then it would seem that a simple film over a good copper track, to prevent copper oxidation, would be better by current audiophile leanings..

No other way to know but to try it out no ?

Manek

bombaywalla schrieb:

I saw the same heavy advertising for DACT attenuators saying that their contacts are gold-plated. People seem to like the sound of DACT attenuators (I've never heard one so far).....

I Haven't heard one either yet..someone's asked me to build them an electrostatic headphone amplifier with balanced inputs..the DACT attenuator has been ordered already.

Too rich for my blood still at 229$ for the quad ganged one.

My 2134 opamp based preamp works, and shall I say works well.

It gave me a scare when I plugged in a very el el el cheapo dvd source line out but then I mustered up the courage to connect my pioneer dvd player after some basic checks and lo and behold...good clean sound and those opamps do drive the senn hd580 to loud volumes without distortion. Its not as transparent as when I plug my phones drectly into the source directly but close, so I am a gonna give it a few hours to run. Do remember this is a preamp and not a dedicated head amp by design but not bad, not bad.

Its quiet, not hum, and I found a source to get the opamps in mumbai. Have used polypropylene caps and metal film resistors throughout but somehow compromised on the rca fenale connectors expecting some resoldering and tweaking but am happy with nickel plated mx rca's. Extremely entry level :-) and loving the cheapness of it. Have used cat 6 wire for internal wiring. A very ordinally transformer with polycab mains voltage wiring.
Unbranded volume and balance pot.

What can I say, I am really enjoying the cheapness of it all !

Ah. That song "isn't she lovely" just came on....well yes she is !

Post some more later.

Manek

Got my torroid from torotrans in pune. Mahesh from torotrans is very helpfull. Got mine with a 50va rating 230v primary, 15-0-15 secondary.

Was delivered in good shape.

Now to. Put it in and play !

Manek

The amp still works ! I am amazed it has made it thru 50 odd hours of playing without any fixing :-) hoping for that century.

I did make one change, I put terminal blocks at the inputs and outputs of both stages. Wanted the flexibily of experimenting with wiring.

Got some basic solid core wire from one manufacturer in two avataars, one pvc insulation and other teflon. I am told its the same wire in both forms. Ampnut your passion for teflon I can now understand and hear :-) teflon stays ! Subtle but evident.

I plugged her into a power amp a week back in pune. I got a hum, not too loud to distract and some high freq noise again only noticable with ear to speaker and pot over 12 o'clock. Funny that I don't hear it on the phones so it must be picking it up from somewhere. Other equipment no such disturbance at pune. Need to figure out this puzzle later. It played well, good imaging, good sound separation, remained composed at higher spl and complex passages.
I know I need to work out a quality power supply, shorten the signal path and quality pots. I am going to sink my fingers into that later.

Manek

Manek schrieb:

Got some basic solid core wire from one manufacturer in two avataars, one pvc insulation and other teflon. I am told its the same wire in both forms. Ampnut your passion for teflon I can now understand and hear :-) teflon stays ! Subtle but evident.

Hey anyone heard of the triboelectric effect ? http://en.wikipedia.org/wiki/Triboelectric_effect
apparently teflon/copper rubbing together can produce static electricity...apparently small vibrations can also trigger it
Cotton does not. would love to hearr if anyone has heard any positives from a cotton dielectric Vs a teflon

???

Wow this potentially can make my amp go up in flames !
:-)
this certainly is new to me arj....interesting article, thanks for info. A lot of older tube amps used to be made with solid core wire with cotton insulation sleeves...why the old xformer I pulled out of an old solid state amp I owned has leads with cotton insulation sleeves....maybe there is something to be learnt here ?

Manek

apparently someone called Be Yamamura took this theory to practice in his brand of cables. after he stopped his work ART cables and Prana Wire do follow his philosophy. He now consults for Acrolink.

Not sure of the theory part but I just tried out the Yamamura Digital IC and it has an amazing smoothness and ease to it.

Hmmmm.....

Cotton you say ? I may have a sleeve o two around :-)

There are a few cable recepies on the internet that use cotton if I remember correctly but that was to damp the cables, which I also did with my power cord....cotton as a dielectric is something else....worth trying.......just got an idea !

Manek

maybe you add teflon OVER cotton for 1 experiment..in that case the teflon and copper will not "set the sparks flying"

While I have not read the reference in GREAT details ( I have skimmed thru it ) my high school knowledge of this phenomenon tells me that the 2 mediums rubbing against each other and generating static MUST be electrical insulators. A conductor would 'drain' (conduct) away the static and there CANNOT be a static buildup,

Since here Copper is involved ( one of the best electrical conductors, how can static build up ??

Also, did I miss any specific ref in the Wiki article on Teflon-Copper being particularly potent static charge generators ?

On the other hand, I would urge anyone whp has a turntable to conduct this simple experiment....

Switch to your Turntable as source on your pre / integrated amp.

Dock the TT arm.

Turn the Volume to MAX ( ! )

Now tap the Phono cable with a pencil.

You will hear LOUD Thumps in the speaker, clearly showing how 'microphonic' cables are

Arj

I not making anything, on the contrary I thought I saw a cable with similar construction....don't remember clearly....

But I do remember rethm using bare cables with cotton separators for demo in mumbai av show....

Manek

Amp_Nut schrieb:

While I have not read the reference in GREAT details ( I have skimmed thru it ) my high school knowledge of this phenomenon tells me that the 2 mediums rubbing against each other and generating static MUST be electrical insulators. A conductor would 'drain' (conduct) away the static and there CANNOT be a static buildup, Since here Copper is involved ( one of the best electrical conductors, how can static build up ?? Also, did I miss any specific ref in the Wiki article on Teflon-Copper being particularly potent static charge generators ?

ill start with the disclaimer that i myself am not really sure of the theory and neither am i an expert

my understanding was any 2 materials can generate static which is an EMF..the conductor, if connected to a "circuit" can actually produce a flow due to the EMF generated which will be along. (AN thats what you have also said..but in the end isnt there an impact due to this on the signal flow ?)

from the article on Wiki, there is a table on the right which gives the potential of various materials to generate this effect. both copper and teflon are mentioned

i went a bit crazy trying to read about it via a simple google of "triboelectric effect audiophile"

Apparently It has been mentioned in some professional papers especially in the recording industry and for Power cables. but again not sure of the magnitude of the impact as it s apparent in poorly made cables but ideally should not be present in most good cables.