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Old 1st July 2003, 12:56 AM   #11
jam is offline jam  United States
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Frank,

Where have you been hiding? You seemed to have gone missing from the 'off topic' forum.

Regards,
Jam

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Old 1st July 2003, 01:18 AM   #12
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Hi Jam,

Stickin' me flamin' neck out once more in that bleedin' ediot cable discussion once again.'Cuse me Cockney...
That's where I've been.

Bats are blind and moles are deaf, or are they? Bla, bla, bla....

That kind of thing and it ain't pretty...

Ah well, wat helpen kaars en bril als den uyl niet zienen wil. (old Flemish saying).

How are you ole chap?

Must say you're the cartoon master.
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Old 3rd July 2003, 09:30 PM   #13
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Default MORE OT.

Hi,

Quote:
Data I've found on the web talks about gold-plated endcaps, but the data sheet the disti sent me doesn't mention this in any way.
Nah, just plain goold old copper.

Since Meggit took over you now have magnetic resistors (steel increases tensile strength) in all kind of shapes and sizes as you'd find from most resistor companies.

If it's any consolation, finding non-magnetic resistors has become hard throughout the world.

The non-magnetic Holcos had a rep for good sound although not exactly neutral across the board, this becomes especially obvious when you use nothing but Holcos throughout a project, ther tonal balance seems to counterbalance some CDP suffering from digititis nicely.
Not that I advocate that type of electronic cooking, it sure makes for a nice big rug to put the nasties under.

They acquired a rep of being fragile, which IMO they're not, as long as you don't put them under mechanical stress...which is something one shouldn't do to any (passive) component anyway.

I sometimes spot coupling caps and resistors with their leadout wires sharply bent mounted on PCBs which is bound to put the component under stress and damage the crystal structure of the leadouts as well... not something that'll improve sonics.

Now the more recent Holcos have a more modern looking printing on their body which you'd easily spot once you've seen the older ones.

If it were me in the market for a good and cheerful allround resistor I'd consider Beyschlag or Roederstein Resista from Europe, Caddock and Vishay from the U.S....
While looking into it in detail you'll also notice that independent manufactures are becoming extremely rare...

You'd be surprised how much I learned about these multinationals when working for Siemens...and I wasn't even involved in electronics.

Cheers,
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Old 4th July 2003, 06:22 AM   #14
ALW is offline ALW  United Kingdom
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Default Frank

Thanks for that Frank, the sonic signature that many have mentioned w.r.t. the Holco's worries me a bit, I have to say. Most say they are 'soft' sounding.

I've been using some Dale / Vishay RN60 (CMF) parts that are totally non-magnetic, and they are a considerable jump in performance from the Beyschlag MRS25's I've used up until now.

As you say finding these non-ferrous components has become much harder, I do have a source for some 'better than Dale' resistors, with 1/3 the noise figure, but buying 250 of each value at 30p each isn't my idea of fun, when I need a range of values.

Importing the Dale's looks like the best option at present, something that's still likely to get me hit for VAT and customs and excise duty on the way in.

It's VERY frustrating, I'm going to try some other Beyschlag parts, as although the construction looks identical to most of the metsl films, I have an idea that some of the lower tolerance version may sound better (SFR25?).

Don't even get me started on audio-grade caps and their limted availability (and the rip-off prices charged by the audio tweak guys)

Andy.
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Old 4th July 2003, 07:17 AM   #15
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Hi!

What I find interesting, is that Germany's Thel Audio (T. Hartwig, a very well respected developer and provider of high end diy audio modules, www.thel.de) is marketing Welwyn RC55 resistors (which have steel caps like any other resistors, therefore are inductive) says on his page about those resistors (http://www.thel-audioworld.de/bautei...wyn/welwyn.htm), that all those non-inductive resis are often being destroyed upon manually bending and soldering (internal breaking), and really had no advantages above the Welwyn RC55, except for high frequency circuits.

The steel caps of the RC55 would not matter electronically, as they were not getting any current through them.

His biggest competitor in Germany (for providing DIY electronic parts) is Schuro (www.schuro.de), and they state somewhat the opposite opinion, and had Vishay-Dale produce a non-inductive resistor series (guaranteed to be non-inductive) especially for them (http://www.schuro.de/preisl-cmf-55-1.htm).

So even in "professional" audio circles the matter of inductive and non-inductive is a question of belief...


Bye,

Arndt
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Old 4th July 2003, 09:19 AM   #16
ALW is offline ALW  United Kingdom
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Default Inductive?

I'm not sure inductance is the issue.

Almost all metal film R's are spiral cut and therefore inductive - the endcap material is of very little relevance here. There certainly is current flowing through it - it has to be able to get from lead to resistive element

There are a number of other issues that are, in my experience, more likely to be the problem, and that is thermoelectric (thermocouple) potentials between dissimilar metals.

The downside to this argument, based on my limited knowledge is that SMD resistors, which also seems to have a similar signature to the mag leaded types use nickel barriers that would seem, at first glance, to be a better match to the NiCr resistive element.

I've seen little data on this though, I may have to do some fundamental research of my own.

Andy.
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Old 4th July 2003, 09:31 AM   #17
UrSv is offline UrSv  Sweden
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Quote:
Originally posted by Cradle22
Hi!

What I find interesting, is that Germany's Thel Audio (T. Hartwig, a very well respected developer and provider of high end diy audio modules, www.thel.de) is marketing Welwyn RC55 resistors (which have steel caps like any other resistors, therefore are inductive) says on his page about those resistors (http://www.thel-audioworld.de/bautei...wyn/welwyn.htm), that all those non-inductive resis are often being destroyed upon manually bending and soldering (internal breaking), and really had no advantages above the Welwyn RC55, except for high frequency circuits.

The steel caps of the RC55 would not matter electronically, as they were not getting any current through them.

His biggest competitor in Germany (for providing DIY electronic parts) is Schuro (www.schuro.de), and they state somewhat the opposite opinion, and had Vishay-Dale produce a non-inductive resistor series (guaranteed to be non-inductive) especially for them (http://www.schuro.de/preisl-cmf-55-1.htm).

So even in "professional" audio circles the matter of inductive and non-inductive is a question of belief...


Bye,

Arndt
I think you mean magnetic?
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Old 4th July 2003, 11:42 AM   #18
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Hi,

Quote:
I think you mean magnetic?
That MUST be magnetic.

BTW, it seems from reading that page at thel.de, as if they've bought a huge supply of those Welwyn resistors.

At 2 Euro a pop they'd better be good...however I somehow doubt that.

The Dales form Schuro are likely the better sounding ones of the two.

Quote:
Almost all metal film R's are spiral cut and therefore inductive - the endcap material is of very little relevance here. There certainly is current flowing through it - it has to be able to get from lead to resistive element
Most metal films I know of are not spiral cut, just a metalfilm sputtered on top of a ceramic body.
While most wirewounds are spiralled and therefore inductive, you can find them in non-inductive form also.
They use Ayrton-Perry winding techniques for that which cancels inductance out. Essentially it requires twice as much the resistive material.
At a price.

And of course the endcaps are going to carry any current the resistor sees, how could it not?

Any resistor is bound to have some stray inductance just as any other piece of wire but through the width of the body it will have slightly more inductance.

IME, it's only of importance for high powered WW resistors where it may potentially play havoc with high frequency response, linearity and circuit stability.

Cheers,
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Old 4th July 2003, 11:48 AM   #19
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Hi!


Yeah, I meant that those resistors will attach to a magnet, but I think that this also implies that they are sensitive (in an electrical way) to magnetic fields, therefore inductive...

As for the price of those Welwyns at Thel: I only picked the site because T. Hartwig has made a statement about resistors with or without those end caps, and the sound of the Welwyns.
If I would buy them (which I actually do!), I would take a look at Farnell... Farnell's not cheap, but 0.93 € per resistor sounds better than 2,- ...

And Farnell also has the cheaper version, Welwyn RC55C...


Bye,

Arndt
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Old 4th July 2003, 12:33 PM   #20
ALW is offline ALW  United Kingdom
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Quote:
Most metal films I know of are not spiral cut, just a metalfilm sputtered on top of a ceramic body.
This isn't true, unfortunately.

The resistive film is sputtered to the substrate but a spiral cut is then performed to produce the value required.

You can make non-inductive variants with an interdigital cut.

First page: -

http://www.bccomponents.com/Uploads/...ts/sfr1625.pdf

Andy.
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