[sputnik13]

I'm making plans to build a DIY amp. Starting with the mini3 from amb.org. Does it really make a difference to the sound quality what brand resistor I use?

I ask because the description for ALO's "double mini3" is claiming to have superior sound quality because they "changed a few resistors in the signal path with a brand that we believe offers a less grainy top-end and has more extension and is more effortless sounding" in addition to having a Black Gate capacitor rather than "stock" capacitors.

The part list on amb.org says use xicon resistors, but I get the feeling some people think Vishay Dale RNxx resistors are very high quality from some of the posts I've seen touting the fact that they used "the highest quality parts" and listing Vishay Dale. So does it really make a difference? Anyone have first hand experience they can speak from?

 

[sputnik13]

Oh for that matter, if black gates are so great, why isn't one recommended for use on some of amb.org's designs? I guess that's more a question for amb than the public at large.

 

[EFN]

Because Black Gate caps are out of commission for a while. The only available stocks now are old leftovers.

 

[sputnik13]

Quote:

Originally Posted by EFN /img/forum/go_quote.gif Because Black Gate caps are out of commission for a while. The only available stocks now are old leftovers.

Does that mean I should stock up on them while I can?

Any thoughts on the resistor question?

 

[fordgtlover]

The Mini³ uses mini resistors. I don't think the RN55 resistors will fit properly. As for the black gates in the Mini³, I think it was discussed somewhere that these are not in the signal path, so are unlikely to really improve anything.

And, for the record, I never thought the Mini³ had a grainy top end.

The fancy resistors sure do add some bling, but whether they improve the sound is probably a decision you need to make for yourself. Personally, I'm happy using metal film 1% resistor. I often do use the RN55 because it's just as easy to get them when I order other parts.

 

[sohels]

I would think that the closer a resistor remains to its specified value over a reasonably wide range of temperature, the better it is. So if your build requires closely matched resistors, I guess you should invest in better resistors.

I do not know much about specific brands though.

 

[Beefy]

Quote:

Originally Posted by sputnik13 /img/forum/go_quote.gif Oh for that matter, if black gates are so great, why isn't one recommended for use on some of amb.org's designs? I guess that's more a question for amb than the public at large.

Black Gates are very good for specific purposes. In most cases, this is as coupling caps directly in the signal path. None of AMB's designs have coupling caps in the signal path, thus no need for Black Gates.

The current habit of throwing Black Gates into everywhere that they will fit is silly. It is a waste of a finite resource now that they are out of production, and in many cases other much cheaper capacitors would be better and more sensible. Unfortunately, sensible choices rarely make for good marketing......

 

[sputnik13]

Thanks for all the great responses. I'm curious about the RN5x still (I'm not dead set on them or anything, I just want to understand), the RN50 is on the list of alternatives resistors for the mini3 and the RN55 is in the part list for CK2III (which I'm thinking of building after the mini3), so are they in fact superior to other resistors in performance? I've not seen posts anywhere else talking about the difference in sonic qualities of resistors so I was baffled by the aforementioned post that touted using RN55 as use of premium components... I wish I could remember where I read it.

 

[Beefy]

The whole Vishay Dale RN series are premium components. They are really good resistors at a really good price, and the unofficial default for DIY projects. This isn't to say that other cheaper resistors aren't also an acceptable choice, or that you can't get even better resistors at higher prices.

But to obsess over such a small point is silly. It is safe to say that if AMB recommends it, he has a reason for it, and it will be an excellent choice.

 

[NelsonVandal]

IMO Mini3 has a slightly grainy top end and a slightly exaggerated mid. As a whole a bit aggressive. I don't think it has anything to do with design or passive parts. Since amb shows square waves and RMAA tests, we can be absolutely sure the amp has a flawless design and layout. It's just the way AD8397 sounds.

The placebo effect is very strong when you modify stuff yourself, and especially if you pay serious money for the parts, and even more if the parts look nice. In this kind of topology with an active ground channel, and the opamps running at quite high bias current, capacitors have very little impact on sound quality.

When it comes to resistor "sound" some claim there's a difference. If there is, it's very minor. IMO it's the active parts that really make a difference, like opamps and transistors, and capacitors if they're in the audio path.

 

[rds]

Not only can black gates be a waste of money, imo there are superior options for everywhere but (perhaps) the signal path. I would rather go with a cap that has a complete datasheet with specs and tolerances ...do black gates even have a datasheet?
Black gates are like glow sticks at a rave - people just stick them everywhere in a euphoric delirium (it is fun though)

EDIT nice thing about glow sticks is they're cheap. Sometimes I'll put on a glow bracelet just chillin at home

 

[FallenAngel]

Hold on, I must really be missing something. When did Rubycon start making resistors? Rubycon makes (or "made" but that's questionable always) Black Gate capacitors.

For resistors, I look at the thermal drift, noise level and tolerance of the resistor and for 99.9% of the time, I use the Vishay/Dale RN or CMF lines of resistors. In the design for the Mini^3, I go with the Panasonic ERO series "mini" resistors, just for their small size and the fact that the design is fairly strict with parasitic capacitance in the resistor leads (read as DO NOT USE VISHAY DALE AS YOU MAY GET AN OSCILLATING AMP).

Although there is much debate about "audiophile" resistors, unless I want to really go down that road and use PRP or Holco resistors, I just stick with what I know works "best" or at least what is most recommended by those who know "best".

 

[Ferrari]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif ... I use the Vishay/Dale RN or CMF lines of resistors. In the design for the Mini^3, I go with the Panasonic ERO series "mini" resistors, just for their small size and the fact that the design is fairly strict with parasitic capacitance in the resistor leads (read as DO NOT USE VISHAY DALE AS YOU MAY GET AN OSCILLATING AMP)....

Can you elaborate a bit more on that "parasitic... thing" ???

 

[fordgtlover]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif snip... It is safe to say that if AMB recommends it, he has a reason for it, and it will be an excellent choice.

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif snip... I just stick with what I know works "best" or at least what is most recommended by those who know "best".

Quote:

Originally Posted by NelsonVandal /img/forum/go_quote.gif snip... When it comes to resistor "sound" some claim there's a difference. If there is, it's very minor. IMO it's the active parts that really make a difference, like opamps and transistors, and capacitors if they're in the audio path.

It is unlikely, IMHO, that you will find better advice on this matter.

 

[Earwax]

Quote:

Originally Posted by Ferrari /img/forum/go_quote.gif Can you elaborate a bit more on that "parasitic... thing" ???

Not because the resistors are bad, but because they are too large to fit the board and to mount them they have be "tombstoned" with one long lead and it's the long lead that can cause problems. [unwanted inductance (not capacitance) according to AMB's mini3 page]

I can see high-spec resistors making a difference in a high current/high heat application. But in a battery powered amp?

I once built a cmoy with carbon film resistors instead of metal film, just to see what would happen. It really did sound bad.