Rivendell61

Don't under-rate the laptop! It can be used as the center of a system as good as any high dollar audiophile one. They have been used to make some of the best recording out there. It is all in set-up, and associated components. It should sound ok for you now--but think of it as the core/starter of a potentially excellent system (although.....a 'desk-top' might be a bit cheaper/easier, if you don't need the mobility). Computer based audio is commonly misunderstood as either inherently poor quality, or an easy, 'perfect', signal transfer, digital solution. In reality it is somewhat tricky to do well (if you are looking for a 'best quality' result), so the output is often far from perfect in practice--but it certainly CAN be done well. Using an integrated amp is a good idea!--because of.....Computer Audio Tip #1: Let the media player organize/select the music but use a post D/A conversion analog control (the integrated) for volume adjustment. In most computer audio applications you do NOT want to use the 'media player' (esp. i-tunes/OS-X) software to modify the signal (e.g., change vol)--it will add distortion. Mark

That's me! Maybe one reason I am less concerned about the heavily limited stuff is I don't ever listen to it-- Around the turn of the 18th century music starts to become a little too John Cage for me :-) I've seen that PWK letter posted here. If I recollect correctly--he seemed to think recording had no use for more then 50-60 dB dynamic range. Those numbers were perhaps SOTA in 1984 but they are *way* out of date now. Doug Sax re-mastered DSOM for SACD--among many other things......uses Benchmark DAC1's too..... Mark

Two points: 1) This is not an analog/digital issue. Geoff Emerick was smashing/compressing Beatles stuff through a Fairchild about 40 years back--and the old fogeys hated it then too. Today musicians are lined up to have Vlado Mellor (at $495/hr), or Sterling Sound, or whoever-- clip their mix through an AD-122, because that is the sound they want. Now....different 'loudness' issues are being conflated here but the really smashed sound so prevelent today is Artist driven -- done by big studios and independants. And lots of engineers are scrambling to catch on the loudness learning curve that bands are demanding. 2) It is a bit unfair to characterize PWK's CD views via a single 22 year old conversation. Despite what he said at that moment in time--he did eventually listen to CDs at home. Mark

Islander: The specs you quote are not good but.....no, there is not a topological reason for Class D amps not to perform well.....there are however *lots* of poorly designed Class D amps. Here are specs from a good 'high-end' Class D amp spec sheet: 350W 8 ohm/600W 4 ohm/1200W 2 ohms. When actually based on measurement even high-quality linear amps do not usually fully double. For instance-- Bryston 14B: 690W/8 ohms and 1000W/4 ohms. Or Mark Levinson #431: 234W/ 8 ohms and 400W/4 ohms. Here are two Class D amps (measured): 290W/8 ohms and 540W/4 ohms (Logic MC-20) Another: 110W/8 ohms and 200W/4 ohms(CIAudio). So.....they perform reasonably well when compared to actual AB amp ratios. Mark

Could that be 'Iconic'? Link for them: http://www.iconicspkrs.com/stonehenge.html Mark

Well, no. Again you seem to have mis-read or not read. But I'll let you have the last word. If you actually believe what you have been saying why not take the questions to his forum and ask him? As noted above he has designed the best performing digital control Class D amps extant (not to mention converters and analog Class D). You might learn something..... I'm done. Mark

Not true. If DrWho were designing a digital amp, he would be employing the skills he learned in college concerning the implementation of a well behaved DAC while taking into account the importance of output impedance. So if feedback is the best solution to the problem, then that is what will be implemented. However, feedback is most certainly not the only tool, nor is it free from tradeoffs, and finally nor does its presence negate the digitalness of a circuit. I would love to share some of the cool tools DrWho has learned about, but he's paid good money for that education and needs a bit more experience experimenting with the various tools to see which he likes best. If you want to draw the box around the chassis of the "amplifier" then sure, it's an "analog" device. You can use the same analogy for the complete signal path of a CD too. Better yet...feed a digital signal into a digital amplifer and draw the box around the chassis and now the "digital amplifier" is really just a "digital to analog converter". I'd like to draw smaller boxes though and have someone show me where the D/A stage happens...you're going to find that it's after the point where the digital signal is represented by a larger voltage swing... I would be curious how many here have actually measured the current behavior of digital circuits...the claim is far-fetched. Voltage and current are directly related by the impedance of the load (Ohm's law anyone?). I agree. All that matters is that you've got switches (*cough* switching amplifier *cough*). The transistors are being operated in their "switching mode" which is akin to saying they are being operated in their "digital mode". On and Off - that's a digital circuit. The largest significance of this description is that the digital signal is subject to aliasing and timing errors... Or simply described in one sentence as a switch. [] It's either off or on, 30V or 0V. A digital circuit does not allow the output to fall at a voltage inbetween. A digital amp (PWM or SDM) will only output one of two voltages. How many more different ways does it need to be said? Or is the problem that the naysayers don't understand the ramifications of the switching behavior? The ramifications are why the description exists in the first place! To say that a digital amp is not digital is to say that it is free of digital ramifications. I would love to see how the analog model accounts for the aliasing that occurs when the sampling rate is too low. lol, you're fired [] LOL DrWho. I liked your (content free) attempt to criticize the Voltage vs Current argument. I hope you were not serious. You have not read the paper have you. The secret knowledge bit (2nd para) was good too--the best way to avoid answering what you can not. No comment--aside from my prior posts--on the rest. Hope your amp works.... :-) Mark

Very good news. I could use a pair. Thought they were no more. Just a thought....if new drones are on hand.....would it be because a Forte III is forthcoming? Oh boy! That I would buy in a flash-- Mark

Mdeneen, I agree...but the definition is fairly harmless in the context of the consumer world, and the misnomer of "digital' has won the day in marketing if nothing else. The only 'downside' may be for DrWho--if designing a Class D amp "as though it was digital", i.e., no feedback--he will have an amp without output impedance control (none of the 'digital' Class D amps do). Hmm, why does that seem ironic? DrWho, whether you choose to think Class D amps are digital or analog is between you and the sonic results of your amp building exercise. Quote from article: "It stands to reason that the myth of the 'digital amplifier' would have never taken off if it had been as common to show current wave forms as it is to view voltage wave forms". And yet you say "it has nothing to do with digital amps being digital.....". Really? Simply because an amp has a bit of digital 'looking' behaviour going on does not make it 'digital'--ref your own odd statement above re converters not being analog simply because they have analog components. The question of definition is resolved by how they actually behave (here is a quote from the author of the previously cited article): **** "OK. Back to electronics. You have a device with all sorts of signals in it which you're tracing a signal with a scope. How do you tell it's digital? It might look very digital, for example a square wave, but by now you know that form and content are not to be confused. Well, simple. Add some noise. Amplitude-modulate it. Add a small amount of time-variant delay. And make sure you can vary the amount of error you introduce at will. Then look at the output of the device. There are two possible outcomes. 1)The first is that the output of the device remains to-tal-ly unchanged for all types of error. The signal is digital. Only when you crank up the noise level, suddenly very dramatic errors occur in the output. That's when the symbols could no longer be read. 2)The second possible outcome is that no matter how small the error you put in, you'll see it in the output to some extent. Some errors may have very little effect (e.g. amplitude modulation) while other errors (e.g. jitter) may have a clearer influence. Of course, if you make the error smaller, its effect on the output is smaller too, but it is never completely gone. The signal is analogue, even if it looks like a square wave or a serial bit pattern." **** End quote. That definition may seem a little 'difficult' because it seems counter-intuitive re converters, etc. But it is formally correct and is an 'engineers' definition in that it forces a functional understanding of the behaviour of the circuit involved Which.....brings me to DrWho's question: "Please define 'mixed signal' ". In light of the above you can see the phrase 'mixed signal' is used as an obscuring term of art to avoid causing confusion for those who can not understand that Class D amps (and converters) are correctly described as analog.... :-) Mark

Treating a fundamentally analog device like a Class D amp as digital can lead to some design problems and performance compromises (compare specs on the 'digital' ones vs the analog ones). I think you mentioned that you were intending to play with some Class D amps so you might find some good info (there is lots) in this paper (given at AES last spring)--on Analog vs Digital in Class D amps. http://www.hypex.nl/docs/allamps%20hypex%20layout.pdf The primary author designed the Hypex amps (analog) but he also designed the best performing (by spec) digital controlled Class D amp: http://www.aes.org/e-lib/browse.cfm?elib=11439 Mark

Certainly there is some wow factor in the tiny plastic thing sounding good. Don't forget that not all are cheap. The same Class D modules are in amps that will cost well over your $3995 figure (some many times over) and these also get the rave audiophile subjective reviews (perhaps for the inverted reason!?). Mark

If you take an A/D feed it to a D/A it is both analog in and analog out... surely you are not going to tell me it isn't digital? Shawn I will! They are not....they are 'mixed signal' devices. Thinking of them as 'digital' gets people into trouble. You see comments like "don't worry about the converter: it's digital--either it works or it doesn't"--and there are many of varients of this. A bit OT but the vast majority of the engineering problems which must be resolved to create a good converter (vs a middling one) are analog. Can the manufacturer find a good engineer with expertise in 'mixed signal' applications? And how many months can you afford to have him work on one circuit board? Mark

Andy, Here is a (4 page) thread with some general acoustic guitar mic technique info: http://recforums.prosoundweb.com/index.php/m/125980/0/ The search function over there will get you info on specific mics (Oktavas, Royers....), mic positioning for guitar, etc. Searching with 'classical' in the Subject will gets lots of good stuff. Mark

Pauln, you are not missing anything. Class D amps--all amps--are analog! Parts of the signal in a Class D amp may look digital but you can not distinguish analog from digital by looking at a signal. How does it behave? There are amp makers who do try to treat Class D amps as digital--but as a rule these amps will perform poorly compared to Class D amps which utilize normal analog control techniques (feedback, etc). If you are interested I can find and post some links to a discussion and an AES paper on this subject. Mark

Did you look at the link in my post on the last page for the BeoLab 5? Mark

Re Meridian: the new G95 (surround receiver) uses 5 100 watt Hypex amps: http://media.meridian-audio.com/datasheets/g_series/G95ds-a4.pdf As Shawn says there are lots of higher power Class D amps out there. Like these guys: http://www.d-amp.com/ Kharma has new --very nice--monoblocks (Hypex) that are 350W at 8Ohm and 1200W at 2 Ohm. Dr Who, Have you seen these? If you read the text/specs at the bottom of the cut sheet I think they are along the lines of what you were describing : http://www.abtelectronics.com/images/products/PDF_Files/BeoLab5_CutSheet.pdf They use some interesting ideas from these guys too: http://www.sawonline.com/overview.shtml Mark

Tripath literature is somewhat hyperbolic--the 'learning algorithm', etc is Tripath talk for feedback. Mark

Yes exactly! You put your finger on the primary sound difference (there are some others but not likely to be so noticable). The Tripath based Class D amps want to boost the highs a little (they are reactive into speaker load: see the Tripath data sheets or, for instance, the Stereophile measurements ). The slight 1-2dB lift is really not a bad thing--it gives 'air'--a very 'audiophile' sound quality. The Hypex does not react to load so is flat--less interesting.... The only downside to the Tripath sound is that it is an 'amp sound' and not a 'recording sound'. That tends to bug me slightly--but obviously not too much since I own 4-5 of them..... Mark

FYI: if anyone is interested in the 'Tripath' sound, etc but wants more power--an option is to convert a car amp like this Blaupunkt which uses a Tripath chip and seems to be rated at 150 watts into 4 ohm: http://www.cardomain.com/item/BLAPA2150 Some folks over at diyaudio have played with these--you can search the forum there for info. It is currently out of stock at that place--but there are other amps and sources. Tripath is now bankrupt so it is a bit unclear what will happen to them, or if stocks will be replenished. There are also various opinions about which Tripath chips sound 'best'--not sure how this one fits in that classification..... Mark

Max ya nut. I saw something you posted a while back about it not working out very well--but did not get a chance to respond. What you described was clearly a 'build' problem. You should be able to check the output specs on the thing, do some diagnosing, maybe talk to Hypex, and get it fixed (or maybe it is too late?....). The Hypex is well enough known and there really are no problems like you encountered--quite the opposite. That MXD1 is not *too* bad (a bit Heath Robinson). The Hypex should sound almost identical--just a bit better :-) Very, very 'neutral'--which is not too everyones liking though. It will drive the same low impedance loads, etc. There are a few bits of gear which use the Hypex--and will be around in Europe this summer--if you still have an interest in hearing one (correctly put together [A]). Unfortunatly all pricey, and more cost wise than the MXD1--but should be at some shows. Mark

Leo, I think there was some confusion because you used the term 'SACD' which is unrelated to HDCD. Mark

Well, I did not intend to imply that if it WAS modded it would sound subjectively lousy either. Most 'modders' only damage DACs--yet they are liked. In the listening comparisons you see most commonly on boards like this (stand alone, or 'shoot out' style) the correlation between quality and preference tends to be an inverse one. You will often see converters that by any standard are 'broken' and putting out very poor quality signal (like filterless NOS DACs) be hailed as better ("very analog"), etc. Take a good DAC, put lots of jitter on it, and many will like it better (at least in the test 'short term' time frame). Mark

Hi, I'm not a 'Mac' person but I can try to answer.... Remember, you don't need the DAC--at least initially. An external DAC can/will be higher quality but starting by using the MAC built in converter is always an option. So....assuming you want to use a good external DAC: You need to get the digital signal out to the DAC. A Mac is very good in this regard because it comes with lots of digital output options: Firewire, USB, and the optical/SPDIF mini-cable thing (which is a mystery to me as a PC user). That gives you lots of options for DACs. Generally Firewire or USB would be better than optical (because optical generates more jitter)....IF the DAC is well designed ala Benchmark to be unaffected by jitter, line noise, emf, etc., then the connection options are less gear dependent. OTOH fewer DACs come with FW or USB. So you find a DAC you want and select the appropriate cable option. I have no idea what your budget is but here is one Firewire option: http://www.sweetwater.com/store/detail/MiniDacFW Better would be the new Benchmark USB DAC--also more expensive. There are many cheaper options, easy to Google--and more expensive options..... Re remote--there are lots of ways to do 'remote' once you have a computer as a source. There are remote touch screens, etc..... I know nothing about them--but they are out there and used in audio. A wireless laptop by your chair works too. If you eventually rip everything to your hard drive it makes your 'mega changer' obsolete..... Mark

ib, You can get excellent sound quality from your computer. There are a few important configuration rules for best SQ--one is: Don't use the digital volume control in iTunes (or the operating system), set them both to 100%--and use the analog vol. control after the DAC (in your case I think you mentioned a Blueberry). Mark

***, I would strongly suggest NOT doing that mod. The DAC you are looking at (Benchmark) is very good! Really nothing will beat it in consumer DACs (sorry Mark Levinson) and you would have to look at high end Pro 2 channel converters before the DAC1 gets a real challenge--and they are going to be many thousands of $ more (like c.9k). Re the mod--3 points: 1) Why do it? They don't seem to have identified any 'problem' they just say they are 'upgrading'. Uh Uh. They claim 'objective' improvement. Just for fun you could ask to see some spec plots showing an improvement over the stock DAC--taken on an audio analyzer capable of measuring a DAC, which I suggest they do not have--and I would also suggest that they will be unable to provide those plots. 2) Their main objective seems to be removal of the NE5532s. That is almost a litmus test for 'not ready for prime time'. I would not want them inside my DAC.... 3) Most important: Benchmark has remarked on several opamp substitutions for the DAC1. They say the OPA627 offers no advantage and will likely increase high frequency distortion. So why buy a great DAC to have someone mess with it? Mark