Resistors

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izzy wizzy
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#1 Resistors

Post by izzy wizzy »

I normally don't bother about resistors too much. Mills for higher power stuff, or Welwyns W range in the power supply. I have in the past tried and liked Vishay S102 (cartridge load) but I have some sitting around from past projects and there lies the problem. It can be expensive as there are just so many values. Plus I keep changing things; it's pointless to spend on decent ones.

But some things are no longer changing and have come to realise, the phono hasn't changed in years nor likely to so maybe it is worthwhile updating. Traditionally I use any old metal film I can get. Not fussy at all, never compare resistors so here I am asking the panel for thoughts. It would seem carbon films like those from Kiwame and Takman might be a good bet instead of garden variety metal films for the grid and cathode. Anyone with preferences? I've heard metal films can be a bit hard sounding in comparison. Then again, I read some have issues with the carbon films; mushy sounding. Very confusing.

Has anyone experience with the nude Vishays? I understand they can be ordered with precise values (well from Michael Percy). This would be my preference for the RIAA EQ parts but it ain't cheap. Are there alternatives that anyone likes for this? Can they be ordered with precise values in the UK?

Edit: I would imagine Allen Bradleys to be good for stoppers. Does it matter? I've used any old CC thing from Farnell.

Thanks for any thoughts on this.

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Stephen
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Nick
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#2 Re: Resistors

Post by Nick »

I use and like Takman resistors from HFC (carbon mainly, but metal for the front end of phono stages), but for RIAA EQ I use 0.1% TE Metal Film from RS. I used a Charcroft as the 47k Load in the ref phono. I don't know if any of that makes a difference, but its what I have ended up doing.
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#3 Re: Resistors

Post by izzy wizzy »

Nick wrote: Thu Apr 30, 2020 9:07 pm (carbon mainly, but metal for the front end of phono stages),
Is that for noise reasons?
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#4 Re: Resistors

Post by Nick »

That was my reason yes. Again, not sure it matters, but its what I did.
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#5 Re: Resistors

Post by izzy wizzy »

That 0.1% TE metal film series could be just the ticket for the values I need in the EQ. Thanks Nick.
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#6 Re: Resistors

Post by IslandPink »

I purged the last metals films ( Holco's ) from my phono amp after JC advised me to do it, and I haven't regretted it.
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#7 Re: Resistors

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IslandPink wrote: Fri May 01, 2020 12:08 am I purged the last metals films ( Holco's ) from my phono amp after JC advised me to do it, and I haven't regretted it.
Well you see ... that's the other side of things. What did you use?
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#8 Re: Resistors

Post by steve s »

Back in the 90s l built quite a few ladder type attenuators, there was a hifi world article that set me off.

I started with 1/2 watt metal films, (which I like the sound of..) but the signal running through a ladder of them was degraded, I then made a ladder type with vishay bulk foils. It sounded the same as running through one 1/2 watt maplins metal... no degradation.
The next one was built using 2 watt (maplins) metal films, that sounded very close to the vishay loaded attenuator.

My ears have been educated since the 90s and the standard of my kit has improved, but that vishay one has been built into my latest px4 amp, still sounds very open. I found my stash of 12 & 24 position switches the other week, so I will be building another, but not ladder type and be using metal films.

In the 90s I bought quite a few vintage amps and 'upgraded' them, they where all originally built with carbon, replacing them with 1/2 & 2 watt metals always improved them, removed a softness from the presentation, which to me sounded unrealistic.
I now have boxes of various well made resistors by all the top makes, there is nothing in them when there is ony a few in the amps power supply and grounding, but I have not built a phono stage.. Yet
All just my limited experience..
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#9 Re: Resistors

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izzy wizzy wrote: Fri May 01, 2020 9:40 am Well you see ... that's the other side of things. What did you use?
In the current unit I've got a Mills and a Kiwame as anode loads. There are carbon composition ( from Rapid ) for grid-stoppers and probably those on cathodes, although one of the cathodes might be a tantalum. In the RIAA I think I have a tantalum one leading into the RIAA and the others I will have to check , it's possible one is a Holco ( old one ) to ground so that may be a metal film of sorts. I took out any of the standard blue metal films a while back, they are the ones to avoid in my books.
My grid-leak on the input ( = loading ) is a Vishay precision bulk foil I got from old circuit boards at work !

So, it may be that I get more drift of RIAA with temperature than is ideal, but I know the treble cleaned up stage by stage as I tried the choices above.
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#10 Re: Resistors

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IslandPink wrote: Fri May 01, 2020 1:20 pm In the current unit I've got a Mills and a Kiwame as anode loads. There are carbon composition ( from Rapid ) for grid-stoppers and probably those on cathodes, although one of the cathodes might be a tantalum. In the RIAA I think I have a tantalum one leading into the RIAA and the others I will have to check , it's possible one is a Holco ( old one ) to ground so that may be a metal film of sorts. I took out any of the standard blue metal films a while back, they are the ones to avoid in my books.
My grid-leak on the input ( = loading ) is a Vishay precision bulk foil I got from old circuit boards at work !

So, it may be that I get more drift of RIAA with temperature than is ideal, but I know the treble cleaned up stage by stage as I tried the choices above.
That reminded me I have a copy of your phono and you document your choices on it. You seem to have just about every type jammed in there. I suppose that's one way of avoiding a build up of one "flavour" ;)

I suspect you may have kept a metal film in there, the 3.2k coz you couldn't get that value in anything else. And this is part of why I'm asking.

At the moment, I have S102 cart load, Mills anode, schottky cathode, a bunch of unknown metal film stuff in the EQ and bias for diff stage.

The two weird values I need are 3.18k and 13.8k. I get good sim results with 0.1% values of 13.7k and 3.16k in metal film. If I was to do it with anything else, I use either two in series like 12k + 1.8k and 3k + 180R or some parallel combo. I've always gone for series connections in the past coz in my head, I keep all the electrons flowing in the same pipe - probably nonsense. Has anyone tried series vs parallel resistors when not bothered by power? I might be making things more complicated than need be; wouldn't be the first time.

Or I could try and get the nude Vishays in the exact value I need which is looking favourable albiet expensive but certainly not the most expensive option. I mean, silver no mag tantalums? Blimey, are they really that good? (thinking out loud)

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Stephen
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Greg
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#11 Re: Resistors

Post by Greg »

Why not just calculate what combination of resistors you need either in series or parallel to achieve the specific value you need?
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#12 Re: Resistors

Post by izzy wizzy »

Greg wrote: Fri May 01, 2020 10:41 pm Why not just calculate what combination of resistors you need either in series or parallel to achieve the specific value you need?
Yeah not a problem. Would prefer one device over two. Just having time to think about things. Maybe too much. Thinking out loud. Canvassing opinions.
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#13 Re: Resistors

Post by IslandPink »

You're right Stephen I think I spoke too soon, I probably have at least one or two holcos in the RIAA. I remember having a holco as the lead-in resistor for the RIAA, then a carbon comp, then a tantalum. I remember there was a difference between the holco and the carbon composition, but nothing much between than and the more expensive (AN) tantalum. The first one ( in a typical all-in one RIAA ) mainly affects the 20Hz bend, and I have played around with the value on that years ago, it's not critical by ear to a level like 1% , but the others ( and the caps ) certainly are.
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#14 Re: Resistors

Post by izzy wizzy »

Thanks Mark. I've got a cart building at hiFi Collective with Kiwame and will use two values in series for the EQ. Nothing like trying for yourself. Wasn't after "the best" whatever that is but types do have flavours hence my interest. And just for giggles will try Kiwame and Mills in the anode of stage 1 to see what that does.

I've read in two places now where AN Tants have been used as grid stoppers. That's too rich for me but both said, good results. I was surprised at this low level. Just because they're there, I'll stock up on ABs for grid stoppers from HFC. Again, be fun to see if it makes any difference.

Only time I ever tried swapping resistors was a bunch of metal films for hi spec Rhopoint wirewounds IIRC, and they lasted not very long. Sucked the life out of everything. That was an expensive mistake and really put me off but that was 20 years ago.
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#15 Re: Resistors

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The first one ( in a typical all-in one RIAA ) mainly affects the 20Hz bend, and I have played around with the value on that years ago, it's not critical by ear to a level like 1% , but the others ( and the caps ) certainly are.
YMMV, but I have found a 2.5% change in that first cap value can make a huge difference in the phase accuracy of the sound.
Little known fact, coherent thought can destructively interfere with itself leaving no thought at all, that’s why I prefer incoherent thought.
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