Best place to throw some money in an Aleph 5 (excluding PSU) - diyAudio
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Old 16th June 2006, 08:33 PM   #1
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Default Best place to throw some money in an Aleph 5 (excluding PSU)

Hello,

after learning a lot about the different resistor and capacitor types available (or rather I should say, after reading through a lot of marketing texts on products costing about 10000% of their industry standard competitors), I was worrying about the best way to go with my Aleph5-on-a-budget project. I already intend to spend a fair amount of money on the PSU, so I'd rather keep the spending to those few places where it actually makes a difference. So let's look at the schematics (I'm linking this pic from Holger Barske's website):

Click the image to open in full size.

What I thought would make a bit of sense would be to use some high quality resistors and some high quality caps directly in the line of the input (R2,R3, R7, R9,R10,C5,C6 and C8). Now this might be a terribly naive attempt as I frankly have no real idea what adverse consequences a metal film vs a tantal film resistor (or an ordinary WIMA MKS5 cap vs a Mundorf MCap) might have on the signal qualities, and especially not on which place in the circuit those differences would be the most noticeable.
I could also imagine that the very low ohm resistors parallel to the output would be worthwhile to improve, but unfortunately it seems very hard to find ANY sub-1-Ohm resistors for me, not to mention high quality ones. Of course I could use 9x 1Ohm resistors to arrive at almost the same ohm rating, but I can hardly see me buying 20+ high quality resistors for €4 a piece in the near future...
By the way, (and again, please excuse my naivity) is this resistor arrangement (R22-25) representing the actual compensation for the "single-ended nature of air", as explained in those famous articles by Nelson Pass?

So would anybody who knows these amps (and it's obvious that some people on those boards do) care to give me some advice on how to spend my hard(ly) earned money the best way?

Chris
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Old 16th June 2006, 08:53 PM   #2
MikeW is offline MikeW  United States
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Top ten ways to a better Aleph?
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Old 16th June 2006, 09:10 PM   #3
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is this resistor arrangement (R22-25) representing the actual compensation for the "single-ended nature of air", as explained in those famous articles by Nelson Pass?
Read "The Zen Variations - part 2", it explains the Aleph current source and the function of those resistors, or even better, read them ALL starting with the oiginal ZEN article.
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Old 16th June 2006, 09:11 PM   #4
steenoe is offline steenoe  Denmark
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Dont expect a resistor and a cap, here and there to make any diffence Regarding the sub 1 ohm resistors, we all suffer from that What makes this circuit sing is the layout

Steen
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Old 16th June 2006, 09:15 PM   #5
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I must disagree - feedback resistors make diffrence.
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Old 16th June 2006, 09:20 PM   #6
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Originally posted by steenoe
Regarding the sub 1 ohm resistors, we all suffer from that
Speak for yourself !
Mundorf craps is a waste of money,imo, spend on the biggest sinks you can find.
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Old 16th June 2006, 09:23 PM   #7
steenoe is offline steenoe  Denmark
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What I was trying to say was: If you build the circuit as proposed, there is next to nothing to be won, using exotic components You can make an Aleph with normal components, and it will outperform any average system"!!!!!! If you have the right speakers!!

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Old 16th June 2006, 09:46 PM   #8
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Hmm.. after reading through the Zen V2 pdf, I realized (as opposed to the last time I did so, when I stopped after getting the concept of constant current source as explained on the first page ) the meaning of those 0.47 Ohm resistors - or at least I could somewhat relate what was described in the pdf to what I see in the Aleph 5 schematics

Uchi Deshi, which one would that feedback cap be in the schematics? R6 (680pF) by any chance? Because I already noticed that this one is missing in the PCB layout I'm using (BrianGT's), and I did already get worried about this a while ago...

Anyway, thanks for the replies so far! This is such a great forum!

Chris
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Old 16th June 2006, 10:05 PM   #9
MRupp is offline MRupp  Germany
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I am not exactly shure how big your budget is but at any rate you'll find it pretty difficult to buy just a few "exotic parts" because you won't even get beyond the minimum order of most suppliers. A good supplier that has all the parts that you need would be schuro, here's my suggestion:

You can get pretty decent Metallband MPC71 5 Watt resistors for 50-60 cents (they also have manganin metal foils but they are already 4 EUR).

Next get their Vishay-Dale CMF-55-143, non-magnetic version !!!, for the signal path / feedback network at 50 - 80 cents: R7-10 (for single ended input), plus R52-54. Anything more exotic will cost ten times more.

As there are no caps in the signal path (let's not quibble about the definition) you can use WIMA for most foil caps, C6 Wima FKP2, C7 MKP4 or MKP10. C8 they don't have but you could create one out of a pair of twisted wires as explained in ZEN variation 4 (I think)

C5, 9, 10 you can use Panasonic-FC at 50 cents.

If you still have money left you can get more Vishay-Dale though it may not make a noticeable difference R4, R6 (not sure why you need both), R14, R21, R28-30, and so on.
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Old 16th June 2006, 10:07 PM   #10
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In the 'true' feedback loop there is only C9 10pF cap, purpose of C6 is diffrent.
Anyway, in my post I've meant feedback resistors R5 and R7. If I can often I use Caddock(series R7)and Riken(to ground R5) in others amps .
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