I was at the house warming party of a brother in law yesterday afternoon.
Private equity guy in his late '50s, who now spends half each month in the south of France, after buying a 2nd home there.
He then figured he doesn't really need the very large 1st home in a prestigious small village east of Utrecht.
So he bought a 2000sqft appartment in the most prestigious street in Amsterdam (also where all the prestigious criminals are shot, Apollolaan)
Then had it renovated wall to wall with matching whitewash tropical wood floors and cupboard doors in every room.
In his former house, he had wall to wall floorstanding B&O audio installed, the wireless 8002 shiny pipes.
When asked, he told me he had sold the audio system with the house.
He now has a multiroom HD/streamer server installed somewhere in the entry hall, all cablework everywhere installed inside the walls.
Proudly said he can now control the audio of every room with his HTC One cell phone, even in the bathroom.
Each room in his house now has two loudspeakers hanging at/on the walls, 7 feet high, about a feet distance to the ceiling and side wall.
These : | M-SERIES REFERENCE | scheek-loudspeakers
(I counted a total of 8 of them, ~$1250 each)
As I was not familiar with them, I read the site yesterday evening.
It mentions that the M-series loudspeaker model became available on the 1st of October, and had a 'review' in a lifestyle magazine barely 2 weeks ago.
Unlikely that the designer of the loudspeaker knows what this client was after.
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Sorry Ed I mis-spoke, the harmonic structure of symmetrical vs. asymmetrical distortion is algebra 101.
Thanks for your thoughts dvv 
All the arguments for and against have holes in them. Your NAD player could be a product where the "sum of all the parts is much greater than the individual parts in isolation"... it just works and has a "rightness" about it. Much equipment does.
I believe Sugden used the OPA2604/604 and fairly recently too, at least I'm sure I remember seeing it some of their products. Their reputation for sonics is sky high. I've a friend with two Sugden systems and so have a great benchmark.
Imo, there is no holy grail of opamps, or any audio component come to that. Its the listener that decides that for himself. A hundred others listening to the same components will disagree and choose something else.
I have a suspicion too, that in systems that use many opamps there could be much to be gained by using more than one device type. To have multiple devices all with a good spec but similar distortion spectra doesn't seem smart to me. Another avenue of exploration
(and in my own amp I used OPA2604 originally for many years, then switched to OPA2134's. Over many months I was aware that it was not as enjoyable to listen to. For no specific reason, it just wasn't. I switched to LM4562's and found these to be very satisfactory indeed but I still wonder if the OPA's had a bit of something that is missing with the 4562's)
All the arguments for and against have holes in them. Your NAD player could be a product where the "sum of all the parts is much greater than the individual parts in isolation"... it just works and has a "rightness" about it. Much equipment does.
I believe Sugden used the OPA2604/604 and fairly recently too, at least I'm sure I remember seeing it some of their products. Their reputation for sonics is sky high. I've a friend with two Sugden systems and so have a great benchmark.
Imo, there is no holy grail of opamps, or any audio component come to that. Its the listener that decides that for himself. A hundred others listening to the same components will disagree and choose something else.
I have a suspicion too, that in systems that use many opamps there could be much to be gained by using more than one device type. To have multiple devices all with a good spec but similar distortion spectra doesn't seem smart to me. Another avenue of exploration
(and in my own amp I used OPA2604 originally for many years, then switched to OPA2134's. Over many months I was aware that it was not as enjoyable to listen to. For no specific reason, it just wasn't. I switched to LM4562's and found these to be very satisfactory indeed but I still wonder if the OPA's had a bit of something that is missing with the 4562's)
Completely agreed on OP 37, unfortunately, so far I haven't managed to get hold of any 637, so obviously I cannot comment.
Yes, OP 27 is unity gain stable but comoensated and 2.7 V/uS "fast", while OP 37 is its evil twin, uncompenasted, stable for gains of 5:1 and over, but 15 V/uS. Actually, OP 37 can be unity gain compensated, but then it becomes effectively OP 27, thus making no sense.
Both very low noise. Damn good stuff.
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Unlikely that the designer of the loudspeaker knows what this client was after.
Is Sheek a real word or a homophone for chic as in the socks-less guitarist in formal wear?
Thanks for your thoughts dvv
All the arguments for and against have holes in them. Your NAD player could be a product where the "sum of all the parts is much greater than the individual parts in isolation"... it just works and has a "rightness" about it. Much equipment does.
I believe Sugden used the OPA2604/604 and fairly recently too, at least I'm sure I remember seeing it some of their products. Their reputation for sonics is sky high. I've a friend with two Sugden systems and so have a great benchmark.
Imo, there is no holy grail of opamps, or any audio component come to that. Its the listener that decides that for himself. A hundred others listening to the same components will disagree and choose something else.
I have a suspicion too, that in systems that use many opamps there could be much to be gained by using more than one device type. To have multiple devices all with a good spec but similar distortion spectra doesn't seem smart to me. Another avenue of exploration
(and in my own amp I used OPA2604 originally for many years, then switched to OPA2134's. Over many months I was aware that it was not as enjoyable to listen to. For no specific reason, it just wasn't. I switched to LM4562's and found these to be very satisfactory indeed but I still wonder if the OPA's had a bit of something that is missing with the 4562's)
Exactly so on all counts.
In the end, it all comes down to personal hands-on experience, you just have to know it to know what you can expect of it. There's no going around, no short cuts.
As you say you have learnt with your own gear. THAT'S the way to go.
Sjiek is. (pronounced exactly as you do sheek)
(Scheek is a Surinam origin last name. Keeping a straight face at tea parties is pretty hard nowadays)
Scott,
You got me to look up the syllabus for EE first courses at a number of places. Turns out there is quite a variance among which colleges (Oops everywhere is now a University...) teach what for intro courses. Some start with popular gizmos and labs and either work down to basics or expect the students to pick them up on their own.
Now as to algebra 101, seems in the better schools that is a remedial course, so I guess it fits some here quite well. But I really expect the differences in question to better covered by a third level course in the sophomore year.
Now as to low level distortion mattering, the issue I think you keep missing is something that is a real biggie in my types of systems. That is gain structure. If I have a microphone preamp capable of 60 db gain going into a mixer with 20 db of gain going into an amplifier with 26 db of gain (All voltage gain numbers, ignoring resulting power) what do you think happens with a close mic'd large diaphragm condenser microphone? Most mic preamps and mixer gain stages run on 15 volt rails!
Now from a commercial stand point the first DSP boxes were 12 bits and found to be unacceptably noisy even by the touring concert guys. (Sorry if I offend anyone but at that time I was unaware of any touring gals...) The products only were considered adequate at the 15 1/2 bit level.
Now for the math challenged 106 db of gain is 10 exp 5.3 or AV=200,000. Now a close talked microphone can have an output of 10's of mV. So a 1 mV signal would be 200 Volt signal, which into an 8 ohm loudspeaker should be 5,000 watts per loudspeaker, as there are multiple amplifiers and loudspeakers. This would result in increasing the rated impedance from 8 ohms to confetti.
If you turned down the power amplifier input by a factor of 3.16 you would limit the signal to 500 watts which is almost reasonable and by a factor of 10 which would handle a loud close talker the system would still be horrible, as the prior gain stages would still be hard into clipping.
If you took all the gain out in the mic preamp then the system would be noisier than if the mix gain were set to 0 and the preamp gain then adjusted for maximum input = power amp output clip level.
ES
P.S. I just finished an arena where the consultant made a major effort to tune the system. We took 25 db-ish out of the LF to get it to work properly. Guess there is more to it than looking at flat response in an empty room.
True, I did know the series expansions for sin and cos as well as the trig identities in high school.
I'll take your word on the rest, would it make any difference?
Mooly, my experience is that the lesser you change the signal, the better it sounds. In that sense, a perfect instrumentation amp is good enough for me
I am in this camp for two reasons..... learning what distortions sound like and learning what real acoustic instruments sound like. Lower distortion comes closer to the real sound of musical instruments. That appeals most to me.
THx-RNMarsh
Mooly, thanks for posting your circuit.
Talking about the OPA2604, I have an old Proceed PAV that I recently removed the top cover on.
Much to my surprise, there were a LOT of OPA2604's and Wima caps inside.
Apparently Levinson must have liked its sound at the time.
Afair, Madrigal had the scent of stick shifting to a new engineer every couple of years in the '90s. Going from 5534+LT1010 one moment, to OPA604 the next. (as if the exterior design of the first product line wasn't a dead giveaway)
No, it's not like that. I mentioned it so that those with similar experience would understand what I was talking about. It took me years to realize and understand that. After years of chasing the best amplifiers in the world and at the same time building loudspeakers and also learned an important thing that no good system can be had without great speakers.
Also, after I have practiced a lot to listen to "fatigue" I knew that what sound "sweet" is really really fatiguing.
The first time I hear vocal floats in the air, I was so impressed. Later I found out that it was so stupid. The real sound has the right size of soundstage.
I think the key is to have a great speaker. Because with cheap speakers, some amplifiers (tube, class-A) really sound better than others. Once the speaker is "changed", all amplifiers sound (almost) "the same" and the lower the distortion the better the sound. (Of course, there is still some "secrets" with numbers-sound relationship
)
You MIT guys. Sheesh.
I taught freshman pre-calc and calc at a public university; series expansions (Taylor, Maclaurin) came either in the first or second semester, depending on whether you had to have pre-calc or placed out of it. Fourier series were second semester or first semester of soph year, same deal. First semester physics, though, core of Intro to Mechanics.
It mentions that the M-series loudspeaker model became available on the 1st of October, and had a 'review' in a lifestyle magazine barely 2 weeks ago.
Unlikely that the designer of the loudspeaker knows what this client was after.
hmmm. Usable frequency response. Wazzat then.
You have those too. Tea and buns
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