Holco H8 resistors

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
A question for those who know.

I believe the earlier version of the Holco H8 resistors were of a totally non-ferrous construction, but that later versions had steel / ferrous endcaps ?

Can anyone offer any means of determining which type is which, without resort to actually obtaining some and giving them the magnet test.

I have a disti that's closing out what may be old stock. I've asked for data sheets and they onle mention the lead material, not the end-caps - does anyone have an old data sheet for comparison?

Any help will be gratefully appreciated.

Andy.
 
You are correct that the older Holco are non-ferrous. Welborne Labs still has a stock of some of these and may be a source of info.

Also, this is extremely non-scientific, but of the Holcos I have, the newer magnetic ones have the black coating applied over the endcaps and spilling onto the leads. My NOS ones have clean leads.
 
I think I'll have to buy some to try

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.

I think I'll buy a few and test the waters, you wouldn't believe what a pain buying non-mag resistors is in the UK!

Andy.
 
Andy,

One caution about the old style Holco, they seem more fragile mechanically than most and sonically a bit soft on the high end, otherwise they were an excellent choice.

Regards,
Jam

P.S. I have now swiched to Dales and am very happy with the results.
 
One caution about the old style Holco, they seem more fragile mechanically than most and sonically a bit soft on the high end, otherwise they were an excellent choice.

Jam,

Thanks for that, the Dales are great, and I've only heard one type that's better (a special audio-grade device that's new to market and generally unailable at present), but the Dale's are a pain to buy in the UK too, unless anyone out there has any ideas for sensible priced disti's. I'm looking to buy in the US (Mouser), but import duties and carriage can be a pain.

I've been using the RN60 series but these are not guaranteed non-mag anymore, the new parts in primary values have steel endcaps - you have to buy odd values, or mil-spec parts (RNC / ELR or ERC) at MUCH greater price to be certain.

I'd be VERY grateful for ideas and alternatives though, this is driving me mad at present, the sonic signature of the Beyschlag parts I normally use is so obvious after the Dale's.

Andy.
 
Jam,

I've looked at SMD too, as I have no problems working in that form, but the initial trials of some Neohm 0805 1%, 1/8W ones was unconvincing.

The layout opportunities are a big bonus, so I wonder about the larger format devices (1206 upwards).

Most use nickel as a barrier though, those that don't are intended for bonding, not soldering.

DACT use NM SMD devices in their attenuators though, but I've not determined the type.

Andy.
 
diyAudio Senior Member
Joined 2002
Hi,

One caution about the old style Holco, they seem more fragile mechanically than most and sonically a bit soft on the high end, otherwise they were an excellent choice.

As far as the sound of these Holcos go I agree 100%, they tend to sound too sweet for comfort.

Bet that does show up on a scope either?

Ah well, it's their loss no?

Cheers fellows.;) ;)
 
diyAudio Senior Member
Joined 2002
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). :rolleyes:

How are you ole chap?

Must say you're the cartoon master.:)
 
diyAudio Senior Member
Joined 2002
MORE OT.

Hi,

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,;)
 
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.
 
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/bauteile/welwyn/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
 
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.
 
Cradle22 said:
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/bauteile/welwyn/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?
 
diyAudio Senior Member
Joined 2002
Hi,

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.

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.:bawling:

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,;)
 
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
 
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/Datasheets/sfr1625.pdf

Andy.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.