I was impressed by the one preamp's slew rate spec of 330V/ns. That's triggered spark gap territory.
It really does read "330V/ns" unless I am totally losing it. But I presume that it was a typo.
The claim is that the designers decided a lot (?) of negative feedback was o.k. as long as the delay time was very short.
Yep, how about 50GHz per volt (simplified single pole but gives you the idea that we are supposed to be able to recognize a three order magnitude typo).
Thanks
-Antonio
Am I alone in thinking that many of the exciting developments in audio power amplifier design over the last few decades have emerged out of the amateur 'DIY' community?
Damping factor above 10000 - wow! (Valin's review) Useful if you have superconducting loudspeaker cables? A sign of crass ignorance in the reviewer for everyone else?bcarso said:
I am thinking discrete power amplifiers, and particular some of the advances made in compensation design in amongst others. Beyond that, a lot of the stuff done by JLH and Baxandall for example was done 'after hours'
I just don't buy this professional/amateur thing when some of the amateurs happen to be leading lights in the field in their own right.
I just don't buy this professional/amateur thing when some of the amateurs happen to be leading lights in the field in their own right.
Scott,
We really got to disagree on this one. There is no way a JFET/IC op-amp composite could meet all the same specs. Although it may match or even better all the presumed common measurements, there is one spec it would never match... the price.
ES
price is easy to adjust upwards - limited only by case appearance/weight/finish
not quite so nose bleed but look inside Ray Samuels Audio products - US$3k Dark Star headphone amp is 4 bridged OPA541 power chip amps - worse audio specs than LM3886
but really nice machining on the case, separate ps box, cones...
another example is a US amp manufacturer who contemplated closing, as last gasp effort went from sheet metal to machined cases, careful matching anodize apperance, integral eye candy heatsink machining, "jewelry" connectors - and 3-5x price increases
in an hr presentation at BAS they never once mentioned actual circuit design changes - now a regular buyer of full page Stereophile ads - doing great business
not quite so nose bleed but look inside Ray Samuels Audio products - US$3k Dark Star headphone amp is 4 bridged OPA541 power chip amps - worse audio specs than LM3886
but really nice machining on the case, separate ps box, cones...
another example is a US amp manufacturer who contemplated closing, as last gasp effort went from sheet metal to machined cases, careful matching anodize apperance, integral eye candy heatsink machining, "jewelry" connectors - and 3-5x price increases
in an hr presentation at BAS they never once mentioned actual circuit design changes - now a regular buyer of full page Stereophile ads - doing great business
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Write-Off
A new 750 does $45K here, used ones go under 20
(gets even worse when the 750PSU unit is included. one might think coils are a bad investment)
Attachments
No, you just need to pot it in diamond inpregnated epoxy (for its thermal properties of course).
I see nothing but "8 legs" here what's up? Is that photoshop or did they go through the trouble to really mill off the markings?
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Sockets? I don't even see any gold! Shouldn't go for more the $24K! 🙂
Nice component choices. By some random chance the parts they are using are among the ones that measure well.
Well you're doing something wrong, those guys are laughing all the way to the bank rolling IC's. Costs a lot more than the BT and looks like a lot less work and TAS thinks it kicks butt.
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Slightly off topic. We are shipping out a small system this month. It is taking six trucks just to hold the loudspeakers. We book an entire truck to take our loads. Twice now, the truckers have tried to pick up our stuff and pack it tight enough so that they can pick up a partial load from someone else along the way and make a bit more money.
Our best technique to avoid that is that our crates are four and a half feet wide so that you can't put two next to each other and a standard four foot pallet won't fit either.
We do pay for the entire truckload for a good reason. The maximum insurance for a truckload is $100,000! So we have to keep each shipment under that.
So you would need a 53' truck just to carry two phono preamps! 🙂
Scott,
That means you could only get 7 ICs on a truck!
Our best technique to avoid that is that our crates are four and a half feet wide so that you can't put two next to each other and a standard four foot pallet won't fit either.
We do pay for the entire truckload for a good reason. The maximum insurance for a truckload is $100,000! So we have to keep each shipment under that.
So you would need a 53' truck just to carry two phono preamps! 🙂
Scott,
That means you could only get 7 ICs on a truck!
Where are the discrete parts? Are there dual transistors in the heat sinked DIPs? The pinout or what I can make of it doesn't match any discrete that I know of. Looks more like a power buffer like the LT1010. Fixed bias? They aren't even using IC's in cans or ceramic packages. Where are the coils? Are you sure this isn't just the servo?
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