[AndrewFischer]

Here is the datasheet for the parts in the OP:

http://www.vishay.com/docs/31019/ptf.pdf


Like the RN55 and RN60 the PTF series are available in several tolerance and ppm ranges. Mouser carries a few of the .05% 5ppm parts along with a few more of the .1% 10ppm parts.

http://www.mouser.com/catalog/629/507.pdf

At > $1.00 each, I've never used them.

 

[Garbz]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif snip

Don't get me wrong. I agree they are designed to take a beating. But you said it yourself, talking about mil-spec is something different than normal resistors.

Mil-spec devices have a standard (usually it means somethings like a much wider operating temperature, lower MTTF, etc), but a 1% 1W resistor is still a 1% 1W resistor. The reason they would go an extra mile if you put more power through them is their 1W rating must hold at a new much higher ambient temperature (part of the extra-ordinary conditions of milspec)

My point is just to use the milspec purposefully, like for extra ambient operating conditions, and not as part of the equation to stretch their tollerance beyond normal levels.

Either way, the RN60s are still damn good resistors for the price.

 

[Joshatdot]

I like em cause you can read the vaules much EZ'er than color bands.

 

[splaz]

I don't find colour bands that much of an issue if the manufacturer uses fairly distinct colours. I've seen some where red, brown and orange all look a like. Also sometimes the colour of the body makes it hard to see blue, grey or white if it's the usual light blue ones.

However if you can see it clearly I don't have a problem and the more common values like 1k, 4.7k and so on I can all identify fairly easily.

 

[ericj]

Quote:

Originally Posted by ezkcdude /img/forum/go_quote.gif I use the PTF56 which are 0.1% precision and 10ppm. If you need better matching than 1%, and you don't have a good DMM (or enough time to hand match), these are a good choice. And yes, they also look cool.

Care to elaborate on when, in an audio circuit, you need greater than 1% precision?

 

[threepointone]

lazy bum who doesn't want to bother matching resistors?

 

[Chops]

I'm kind of partial to PRP resistors myself. They're very easy to read, and in my amp, they made a rather large improvement over the cheap blue generic ones that came stock.

And adding some Audio Note tants in the input and output sections added that much more to the improvements. The Kiwames are there for anode duty, which ultimately effect the sound in some way I'm sure.

All in all, I can honestly say that upgrading to quality resistors really can improve sound quality. I didn't think they would, but they certainly did.

After reading about the V-D's, I think I might try them when I eventually build my SET tube amp. Why not, right?!

 

[AndrewFischer]

Quote:

Originally Posted by Chops /img/forum/go_quote.gif After reading about the V-D's, I think I might try them when I eventually build my SET tube amp. Why not, right?!

RNxxD's might save you a few hundred dollars.

I've thought about using Caddock MK-132s as they are far more compact than RN65 or RN70s. But the price keeps chasing me away.

 

[hYdrociTy]

would replacing all the resistors inside a gilmore lite help? or are they already hand matched?

 

[Pars]

Gilmore Lite: They should already be matched close enough (if your DC offset is low, you are fine). Matching resistors past a certain point is a waste of time, and should be of no sonic benefit.

I've used Vishay-Dale RN series, PRP, BC and Roederstein. The Roedersteins are probably my favorite, but are discontinued and not available in many values. The Vishay-Dales don't seem to be any tighter than the others when it comes to matching (at least that I have seen), but they are good resistors. When I was a tech 20+ years ago, we used to use these. Course, they just said Dale on them

.

 

[ezkcdude]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif Care to elaborate on when, in an audio circuit, you need greater than 1% precision?

Yes, just take a look at the differential-to-single-ended topology of my DAC output stage (see the website in my sig). Matching can be very important for decent CMRR.

 

[cotdt]

the problem with cheap carbon resistors is that the higher frequencies are not linear. replacing them with metal oxide or metal film resistors improve the sound quality. it has nothing to do with matching.

Vishay Dale S102 are the resistors to get for a no-holds-barred setup. Pretty much an ideal resistor.

 

[Pars]

Quote:

Originally Posted by cotdt /img/forum/go_quote.gif tVishay Dale S102 are the resistors to get for a no-holds-barred setup. Pretty much an ideal resistor.

At what, $7-$10 a pop? That would make a really expensive Dynahi

 

[tomb]

Quote:

Originally Posted by Chops /img/forum/go_quote.gif I'm kind of partial to PRP resistors myself. They're very easy to read, and in my amp, they made a rather large improvement over the cheap blue generic ones that came stock. And adding some Audio Note tants in the input and output sections added that much more to the improvements. The Kiwames are there for anode duty, which ultimately effect the sound in some way I'm sure. All in all, I can honestly say that upgrading to quality resistors really can improve sound quality. I didn't think they would, but they certainly did. After reading about the V-D's, I think I might try them when I eventually build my SET tube amp. Why not, right?!

Actually, NO. If you read my post, the V-D's are exactly the wrong thing to put in a tube circuit. They will not mask any tube noise or harshness whatsoever. Your experience with Kiwame's and the other ones are not analogous to using V-D's.

Quote:

Originally Posted by cotdt the problem with cheap carbon resistors is that the higher frequencies are not linear. replacing them with metal oxide or metal film resistors improve the sound quality. it has nothing to do with matching.

This was listed among the many reasons to use V-D's in the first few posts. "Nothing to do with matching." is not true, though. As you note, the non-linear response is solved by going to metal film or metal oxide, not specifically V-D's. So, there are other advantages with the V-D's - as in matching and better quality assurance.

 

[Chops]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Actually, NO. If you read my post, the V-D's are exactly the wrong thing to put in a tube circuit. They will not mask any tube noise or harshness whatsoever. Your experience with Kiwame's and the other ones are not analogous to using V-D's.

Whatever. It's all subjective and personal tastes. There's NO right and wrong when it comes to such things as this.