$7500.00 chipamp revealed

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Most of you have probably already seen this but this is my first time through the BPA300 threads so I thought I would throw this out again for some others that may have missed it.
Ever seen the inside of a $7500.00 chip amp?
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http://www.shine7.com/audio/jeff.htm
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Check out the nice review.
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http://www.audioasylum.com/forums/amp/messages/7578.html
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Maybe I need to try these chips again and use a few more of them this time. I didn't pay attention at the time, what with all of the fervor surrounding them, but a gainclone with 1 LM3886 per channel is only making 38 watts into 8 ohms which may go a long way towards explaining why my TDA7250 amps sounded so much better.
 
With the right power supply and PCB layout, the LM3886 really are quite good. They do, however, need to have constant speaker loading for optimum performance due to the way feedback is used. I also recall a different topology somewhere in this forum.
 
TDA7250 output is running with cheap TIPs

jaudio said:



What output transistors are you using with the TDA7250?

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My TDA7250 amps are running with cheap TIPs. The Phillips were a little more open sounding than the STMicro. I know this will hurt many others here but that amps kills a single 3886 with the same power supply. I have the parts for a Sziklai but haven't tried it yet.
 
First they go for cheap ICE Power moduls and now $7500 for a box containing cheap power-op-amps! They should be ashamed!

I guess there is no limit of what the so called "High End Industry" will do to make some money!
I also just discovered, that Mark Levinson has launched a class-D amp. Probably worse than a ICE Power based amp, but at that price, people will no have the guts to dislike it.... :D
 
I don't think anyone is knocking chip amps, I think they are knocking the price. I can't believe that this is selling for $7500, I feel insulted somehow by that price. I may be in the wrong business, I should start selling t-amps in a CNC machined copper enclosure for $10,000. "The copper's magic allows the t-amp to produce it's lucid musicality" ROFL.
 
LM4702 application notes

jaudio said:



LME49810 or LM4702
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Now I found the nice application notes for the LM4702 which would also apply for the 49811.
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http://www.national.com/an/AN/AN-1490.pdf
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Great notes they put together for that chip. It actually discusses differences in the circuit based on listening! No wonder they fired all of those guys. We can't have any of that going on around here.
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I will probably give those a try as well before I commit to boards for the 7250. But so far, it has beaten all comers.
 
Sendler,

how about a 4-deck Jeff Rowland Model 12 with twelve LM3886T/Ch. for $14K, £14K, or €19.5K ?
Take a guess what the 2-decker with 10 chips cost overhere up till 5 years ago.
 

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Re: LM4702 application notes

sendler said:

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Now I found the nice application notes for the LM4702 which would also apply for the 49811.
.
http://www.national.com/an/AN/AN-1490.pdf
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Great notes they put together for that chip. It actually discusses differences in the circuit based on listening! No wonder they fired all of those guys. We can't have any of that going on around here.
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I will probably give those a try as well before I commit to boards for the 7250. But so far, it has beaten all comers.

Make sure you take a look at the nat semi thread -- as Bob Pease recommended a noise-gain compensation tweak which benefits the chips -- 4702 and its single cousin -- even further.
 
Re: The shine7 link shows a schematic

sendler said:

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The Shine7 link in the first post shows his schematic which would be pretty close to the Rowland layout.


Except that the Jeff Rowland design is not inverted and therefore most likely doesn't have the same risk for some problems as the Shine7-design. And also the Jeff Rowland does not use DRV134 to bridge the two half's, as the DRV134 can also be a problem and is not suited for the job.

Note that I write "can". Many may not experience problem's but there is a possibility.
 
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