Hey look a pre-amp .....
Dan D'Agostino Master Audio Systems Momentum line preamplifier | Stereophile.com
I am always astonished to see how some designers can use so many parts to accomplish so little. 8 dB of gain and 7 cards, motherboard and connector panel. Most be well over 100 parts for the audio path in each channel. And for all of that the measured performance is not exceptional by just the standards set by the products published in Stereophile. Perhaps the quantity of parts limits the audio performance. And I would not call 600 Ohms punishing. Virtually every "audio" opamp is rated into 600 Ohms making it not an exceptional performance.
Its quite possible that aspects not measured (power supply isolation, EMI resistance, leakage current from the power transformer) could contribute to improved sonic experience, certainly exceptional conventional measurements don't. However it does meet the JC target of no visible (above -130 dBR?) higher order harmonics/ IM products.
Well ... looking around, I see you're a real fan of soft dome tweeters,
... guess what, these are the babies that started it all for me, http://i242.photobucket.com/albums/ff70/uvtube/BW.jpg - still have them, but the magnet of one of the mid/basses decided to have a wander sideways ...And the tweeter was never a problem, did cymbals beautifully - amazed me when it first conjured up the 100% disappearing trick ...
Damian, i don't think out of audible range distortions can affect our perception. It is time to compare in and out signal of any audio electronic supposed to be linear on real musical signal (transients) to see the differences. Sampling them, as a method.
I believe our actual (old) measurement methods are totally inadequates.
yes... i hate them... just able to make some hisses on my opinion... so far from my 1" compression driver with a big wooden spherical horn, where i can hear all the body, metal weight and shock of the stick on them...as in real life. With nos 'trebles' feeling, like in real life...I see you're a real fan of soft dome tweeters,
In fact, i tried to add tweeters (even compression ones) to those medium high units, with no success. May-be it is the 'tweeter' concept with the requested crossover at high frequencies witch is inaccurate ? Or the differences of directivity at crossing frequency (acoustical energy) ?
My actual crossover frequency is around 1.5KHz.
Nb: My waf home version was not so good than my studio version of the same driver with a bigger horn and a crossover around 700Hz. Both are damn flat up to 15Khz with a flat impedance curve (up to 40KHz) too. Both have the same surface and directivity curves at crossing frequency than the bass speaker.
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Here's my effort
Ovation Symphony Line Preamplifier
I'd love to do a DBT against DA's pre and Doug Self's latest as well. I'd agree with the earlier comments that the drive on DA's pre is a bit wimpy, but I suspect the proof will be in the listening.
What is really nice to see are the tone controls - hopefully this will be the start of a trend to see them back in gear. I think this is where the Japanese high end brands have got it right.
Ovation Symphony Line Preamplifier
I'd love to do a DBT against DA's pre and Doug Self's latest as well. I'd agree with the earlier comments that the drive on DA's pre is a bit wimpy, but I suspect the proof will be in the listening.
What is really nice to see are the tone controls - hopefully this will be the start of a trend to see them back in gear. I think this is where the Japanese high end brands have got it right.
Preconceptions against PC evils ?
Or , indeed, galvanic evils with grounds leakages ?
Or, in your case (optical link ?), the miss of a very good reclocking ?
There is so many reasons why some can make, form a local mistake, a general law !
The Dan pre is full discrete , i believe the Boulder takes the Scotty route ....
Not sure why Everytime we do the CD comparison the PC IS bettered by the CD player ...
Agree with the implementation of tone control .....
Of course my take is that the hissy nothing you were getting is due to the amplifiers, and other electronics reaching the level where they, not the drivers, were very obviously misbehaving. If you took the chain where the compression driver was delivering good stuff, and deliberately reduced the effective sensitivity, by adding a dummy load which soaked up most of the power being delivered to the drivers, I suspect you would hear the same problem return. The Perreaux I had back then, in raw form had a plateau of output, where beyond that the cymbal sound also fell to pieces - only after major surgery was it capable of delivering cleanly at higher levels ...
Point source gives best imaging but is difficult to implement. Line source is at best second best, but easier to do at required SPL's.
Sounds like an interference problem to me - sound from digital source is a mongrel to keep clean when there's muck around; my own experiences lately are that music servers are in front of CD players, if just the normal, reasonable things have been done to optimise.
Cant agree , a good linesource images vastly superior to a point source, has better dynamics and lower distortion ...
Not my experience even with 15-20k of pc setup vs quality CD PLAYER ....
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A true line source as usually implemented has a vertical window of only a few degrees. A few inches too high or too low and all the HF is GONE. I was part of a team that blew through about $3M proving that point. We needed to add a single tweeter to make them work. There is some really good simulation software that shows the effect. If this does not make immediate sense think about the speed of sound and the difference in distance between the listener' ear and the top, center and bottom of the line source, and interference.
In pro applications the "line source" is always curved to get some vertical dispersion. At which point is it really a line source or something else?
I have had better results from a dedicated "computer" based player than the best CD transports I have had access to. Not to mention that high resolution audio does not come from a CD. Its not an afternoon's worth of PC tweaking however. I'm happy to charge $20K for one but it needn't cost 10% of that. While you can get good results from Windows and OSX I think a desktop OS is the first hurdle to overcome. A headless system with a well executed SPDIF/AES card or USB interface can deliver exceptional results. First important trick, use the least amount of PC processing power that will support the task. More processor, faster processor = more junk to deal with. Second trick, as much power and radiated noise suppression as possible.
In pro applications the "line source" is always curved to get some vertical dispersion. At which point is it really a line source or something else?
I have had better results from a dedicated "computer" based player than the best CD transports I have had access to. Not to mention that high resolution audio does not come from a CD. Its not an afternoon's worth of PC tweaking however. I'm happy to charge $20K for one but it needn't cost 10% of that. While you can get good results from Windows and OSX I think a desktop OS is the first hurdle to overcome. A headless system with a well executed SPDIF/AES card or USB interface can deliver exceptional results. First important trick, use the least amount of PC processing power that will support the task. More processor, faster processor = more junk to deal with. Second trick, as much power and radiated noise suppression as possible.
in the home "true line source" can illuminate the whole vertical listening region
Bohlender Graebener RD75 Planar Transducer
still may have hf issues but not "vertical window" related
Bohlender Graebener RD75 Planar Transducer
still may have hf issues but not "vertical window" related
For what its worth here is a good treatment of line sources, focused on pro sound reinforcement. Its sales oriented but Igor is very responsible and the core info is accurate: http://www.slsloudspeakers.com/RLA1WPRev3.doc.pdf And software to play with: SLS Audio LASS Line Array Simulator Software
If you look through the info you will see the narrowing at high frequencies I mentioned.
If you look through the info you will see the narrowing at high frequencies I mentioned.
Demian ,
I did say CD PLAYBACK , the PC advantage is when doing high resolution , the last one demoed for me (PC) had separate psu and looked liked an amplifier , quite and fast , turn on playback was like using a CD PLAYER , noise non existent, non Desktop OS , DAC used Lampi.
As to Linesource speakers, ribbon dipole, not monopoles , The line has to have sufficient height to not have any narrowing, the shortest i would use for domestic use is 50 inchs and overall height should not be lower than 74 inchs to eliminate height issues , baffle width is very critical , get the ratio's right and no point source speaker gets close and i will gladly build one and charge 3m to prove it ...
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