New direction for RudiStor!
Sep 1, 2010 at 2:07 AM Post #61 of 123

burnspbesq

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Just curious, Mr. Spritzer.
 
In your ever-so-humble opinion, has anyone other than yourself ever made any positive contribution to headphone amplifier design?
 
You may think you come by it honestly, but pompous and condescending doesn't play well.
 
Even if you really are the smartest guy in the room, that doesn't give you the right to treat people like garbage.
 
Grow up, willya?
 
Sep 1, 2010 at 4:25 AM Post #63 of 123

jjinh

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Quote:
Just curious, Mr. Spritzer.
 
In your ever-so-humble opinion, has anyone other than yourself ever made any positive contribution to headphone amplifier design?
 
You may think you come by it honestly, but pompous and condescending doesn't play well.
 
Even if you really are the smartest guy in the room, that doesn't give you the right to treat people like garbage.
 
Grow up, willya?

 
Spritzer, like all of us, will give credit where it's due. Anyway if it looks like garbage...
 
Sep 1, 2010 at 5:34 AM Post #64 of 123

spritzer

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It was Sovshiller brought up what I had done for the community, not me.  I felt it was only fair to respond to those accusations.  As for putting my self on some pedestal, I simply don't, I do how ever aspire to do things well and I truly think others should do as well.  I do give credit where it is due but the sad fact is that we are surrounded by overpriced garbage. 
 
As for great designers, there are a few about and one of the most respected being Nelson Pass.  Something like his Pass XA.5 amps are miles ahead of what other people are doing and the measured performance is just art.  Another pair that springs to mind is Naotake Hayashi, the founder of Stax, and his son Takeshi.  Naotake came up with very simple designs in the 60's which are, with some modern touches from Takeshi, still state of the art today.  Takeshi also did some truly great speaker amps which inspired designs like the Mark Levinson ML-2's.  Plenty of others that I simply don't have time to list. 
 
That said, Rudi isn't a designer no more than Mikhail was one.  He didn't invent any of the Single Power circuits, they are just copied from elsewhere and often with horrible results.  Change a resistor value here, add a trimpot there, change to different transistors does not a designer make IMHO. 
 
Quote:
Does Class A mean better sounding ?


Indeed it does, the various classes have to do with how the devices are run.  Class A means they are always on, always conducting which means a lot of wasted power (i.e. heat and a lot of it) but by far the most linear state.  Switch to Class B and then you have an amp that consumes a lot less power since the devices are only on 50% of the time.  Less heat but you get the nasty effects of old transistor amplifiers such as crossover distortion and other non linear effects. 
 
With headphone amplifiers and preamps there is no excuse not to use Class A.  The amount of power is always relatively small so no massive heat issues such as with speaker amps.  Due to the heat problem most speaker amps are Class AB which means the devices are on for more than 50% of the cycle which lessens the issue of crossover distortion.  There are some high power Class A amps out there such as the Krell beasts which use a very clever way of remaining in Class A while minimizing heat output. 
 
Sep 1, 2010 at 6:19 AM Post #65 of 123

winzzz

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is it ? i think someone who sells a cmoy for 600 deserve being treated like that 
tongue_smile.gif

 
Quote:
Just curious, Mr. Spritzer.
 
In your ever-so-humble opinion, has anyone other than yourself ever made any positive contribution to headphone amplifier design?
 
You may think you come by it honestly, but pompous and condescending doesn't play well.
 
Even if you really are the smartest guy in the room, that doesn't give you the right to treat people like garbage.
 
Grow up, willya?



 
Sep 1, 2010 at 7:20 PM Post #66 of 123

Sovkiller

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Quote:
Does Class A mean better sounding ?



For heaphone amps, there is no reason to go other than class A as the power is very low, so the efficiency is not an issue, and in theory you will have a more linear sound, nor the head dissipation, though battery life may suffer considerably in portables...
Now on speaker amps, that is a different story, I would say that in books, and theoretically, yes, they should sound better...But in nowadays designs, this difference between class A and AB (and now with the "digital" amps out there) is getting thinner, and those anomalies that are present in the class AB, are hardly detectable by the human ear, and in the worst scenario you will have a lot other problems, speaker related, that will have a lot more weight, to worry about...
 
As I stated above Marantz amps nowadays are not class A, with a few exceptions, and they sound very good, and in some cases are said to sound better than the previous versions of Class A...
 
Sep 1, 2010 at 7:33 PM Post #67 of 123

Sovkiller

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Quote:
Just curious, Mr. Spritzer.
 
In your ever-so-humble opinion, has anyone other than yourself ever made any positive contribution to headphone amplifier design?
 
You may think you come by it honestly, but pompous and condescending doesn't play well.
 
Even if you really are the smartest guy in the room, that doesn't give you the right to treat people like garbage.
 
Grow up, willya?



Even if he is right, the other opinions, or designs, for wrong that he believes they are, may be right for others, with different points of view, or simply with different ears, and IMO, they have the right to coexist with the ones he considered "right". That is what life is about variety...What I do not understand is the constant bashing to everything that is not designed by Kevin Gilmore, and why is he so afraid that other people may like other ideas, designs, and sound, and the absolute need of trying to completely exclude what he considers is not right, even while others like the "wrong ones" as well...it is like pretending that now the whole world should be Christian, or Muslim, or that everybody need to drive a Lexus or a BMW... 
 
Sep 1, 2010 at 7:45 PM Post #68 of 123

rhythmdevils

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Quote:
Actually, the line isn't all that mythical. If you can identify parts in an amp, you can develop a parts list and use several well-known suppliers that pretty much everyone uses to find out how much the parts cost. These suppliers will tell you the quantity price breaks, too, so you'll know how much is saved by buying in bulk.


Next, if you've built a few DIY projects, you can get a good idea of how long something takes to build, and thus calculate labor cost. Further, adding the basic overhead isn't too bad if you've taken some accounting.


Add up those costs and you'll get a rough number of what something costs to manufacture. You won't know for sure, but a range of numbers is OK.

Most businesses would consider a 12% return very good. So if something costs $200 inclusive of parts, labor and overhead, then you could sell it for $225 or $250 and do well.

When profits get into the hundreds of percent, that's screwing a customer. I give businesses a little leeway since I can't see their books and don't know exactly. If someone is getting 20% and I estimated 15%, I don't care too much.

But if profits get into the 300%, 400% or more range, that's anal sexual intercourse without consent.


I agree, but you're leaving out quantity of sales.  The percent profit that is viable for a successful company depends on how many units they sell.  If they sell fewer, the prices go up.  If an amp builder was doing a completely custom design, for example, and was only to sell 1 of the amps, he would have to charge thousands of dollars to cover all the R&D with that one sale. 
 
However, I imagine all the amp builders out there sell about the same quantity, so this doesn't explain why one amp would cost 600 and another 250.
 
Sep 1, 2010 at 8:46 PM Post #69 of 123

cegras

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All the MOTs I've heard here like to keep things proprietary, but honestly speaking the audio community is small enough that counterfeiting is pretty much impossible. There will always be people from China who are willing to take oscilloscopes and possibly electron microscopes to your chip if they want to clone the design and proprietary or not you won't stop them.
 
Sep 2, 2010 at 6:45 PM Post #70 of 123

Sovkiller

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Quote:
All the MOTs I've heard here like to keep things proprietary, but honestly speaking the audio community is small enough that counterfeiting is pretty much impossible. There will always be people from China who are willing to take oscilloscopes and possibly electron microscopes to your chip if they want to clone the design and proprietary or not you won't stop them.



We saw here, not long ago a case where an amp from Dr. Meier (Corda Audio) was copied by another manufacturer, for profits...
 
About the clonning of chips, Gilmore stated the same once, while he noticed that Ray covered the chips with red epoxy, and that he could x-ray it and this and that....That is not so simple, even for designers of chips, to just copy one chip or find out what chip is, based in an xray and measuments from any osciloscope...you need also parameters and values that are not shown on the xray, or measuremnts, otherwise the clone of Intel and AMD chips would be more practical, as...they are far more expensive than any audio one....also what for? If there are thousands of good sounding chips around, just pick one of your liking, and build an amp around it...period...all that hassle to copy an opamp??? That will be really funny...it will be better to pay someone to chase the carrier that deliver Ray packages, and pay him good money to open the box to see what chips is he pruchasing...LOL...   
 
Sep 2, 2010 at 7:33 PM Post #71 of 123

Uncle Erik

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rhythmdevils, good point. That is elastic. The problem is that if your expected sales push the price above reason, you aren't going to get many, if any, sales. If my product had to be priced far above the competition, I'd seriously rethink whether or not it makes sense to produce it in the first place.

Not all MOTs are secretive about their builds. Some produce DIY designs that are completely open. The biggest hurdle with amps is usually the casework - it takes a lot of time. Because of that, it is possible to sell an open design at a profit. I also think that open designs are full of benefits. First, it keeps manufacturers honest. You can't charge enormous prices without it being obvious and opening yourself up to competition. Also, the DIY designs have been seen by many eyeballs - problems and deficiencies have been rooted out by builders. You end up with a more robust circuit. Just my thoughts, but this is why I tend to go for DIY circuits and amps that come with schematics over something secretive.
 
Sep 3, 2010 at 7:16 PM Post #72 of 123

Sovkiller

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Quote:
rhythmdevils, good point. That is elastic. The problem is that if your expected sales push the price above reason, you aren't going to get many, if any, sales. If my product had to be priced far above the competition, I'd seriously rethink whether or not it makes sense to produce it in the first place.

Not all MOTs are secretive about their builds. Some produce DIY designs that are completely open. The biggest hurdle with amps is usually the casework - it takes a lot of time. Because of that, it is possible to sell an open design at a profit. I also think that open designs are full of benefits. First, it keeps manufacturers honest. You can't charge enormous prices without it being obvious and opening yourself up to competition. Also, the DIY designs have been seen by many eyeballs - problems and deficiencies have been rooted out by builders. You end up with a more robust circuit. Just my thoughts, but this is why I tend to go for DIY circuits and amps that come with schematics over something secretive.



But consider that even while they have been for years and years around, and they are indeed proven designs and sometimes even good sounding ones, and despite the price, case, and parts used, none of them have stopped many of us to keep on looking for other things, and none of them is consider as the final word on amplification, despite the efforts of some few fellows to push them to no limit, and despite the implementation, and parts used...and what is funny is that in the majority of the cases, after some time of owning them, they are simply replaced by brand name amps, considered as many times inferior by these DIY designers, there must be a why don't you think?
 
 
 
Sep 3, 2010 at 10:08 PM Post #73 of 123

jpelg

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Quote:
I for one think the amp should be able to drive any headphone you throw at it regardless of music choice or the impedance of the transducer. 
 

 
I disagree with that statement, and believe that amp+driver synergy is very real. Given the wide variety of headphone designs & driver specs, it is certainly plausible that amplifiers can be designed to cater to the needs of one end of the spectrum or the other. One size does not fit all.
 
Quote:
I've had two of the older models here.  NX-02 or something like that was one of them and I can't remember what the other one was called as this was years ago.  Sounded quite bad on my HD600...


Case in point. The NX-02 (the lowest priced home desktop amp Rudistor ever sold) was designed specifically for the Ultrasone PRO750/2500 headphones. The NX-02 sounds great with them, as well as other similiarly-speced low-impedance cans (Denons, Grados, etc.) It was never designed to drive a 300-ohm load, and certainly cannot be chastized for not do so very well, any more than you could downgrade a flea-watt SET amp for not being able to drive a pair of Maggies. Btw, Rudi's OTL models sound quite nice with Sennheisers.
 
Sep 3, 2010 at 11:12 PM Post #74 of 123

Nebby

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Actually it's not that difficult if you have access to an x-ray, since you can ID the exact chip used and then buy it directly from a distributor like Mouser or Digikey. There's no need to custom fabricate something like an opamp when you can just buy it.
 
Quote:
About the clonning of chips, Gilmore stated the same once, while he noticed that Ray covered the chips with red epoxy, and that he could x-ray it and this and that....That is not so simple, even for designers of chips, to just copy one chip or find out what chip is, based in an xray and measuments from any osciloscope...you need also parameters and values that are not shown on the xray, or measuremnts, otherwise the clone of Intel and AMD chips would be more practical, as...they are far more expensive than any audio one....  


Counterfit Intel and AMD chips are a different story, as they're normally originally chips made by Intel or AMD except they've been overclocked to a higher speed chip and then labeled/packaged like the higher speed chip. 
 
Sep 4, 2010 at 7:15 AM Post #75 of 123

spritzer

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Ahh the ever elusive synergy defense to make up for buying badly made gear.  It's a particular pet-peeve of mine as you see this used to do just that, justify bad engineering practices where two minuses are supposed to make a plus.  This never happens though so you end with some non-linear mess which might sound pleasing but high end it ain't. 
 
Rudistor pairing up with Ultrasone is particularly funny since Ultrasones are widely regarded as the worst headphones money can buy.  As for any impedance matching in the circuit (let's give a good shout out to people who post detailed internal pics in their reviews) there is none but it looks like the amp is running at very low rail voltages which would minimize the voltage swing but it is still more then  portable amp has to offer.  This is only from a quick look though, I'll have to do some more digging. 
 

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