BPA-200 servo problem

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#85
brillantes schematic is based on my project in elab forum site, I have difficulties of choosing alternatives components here in the Philippines because most of the primary components especially the opamp is not available here, only smd type is avalable, but is not my option. so I search for substitutes, luckily I found a good one, The Sound is really good for outdoor or indoor, I used 12" driver 27hz -1500hz frequency response, 94 dB spl dual impedance, dual impedance passive coil, 50 oz. magnet, and the sound is like a theater .
 
#90
There are commercial amps that spec a 30V/uS slew using 10V/uS chips. How can they do this? Do they bin the chips to find those at triple the rating or does the slew change when these chips are bridged? Sorry if I wasn't clear but that is what I meant by laterally (parallel) and vertically (bridged).
 
#92
Right, so the chip is stressed for more current delivery. Does this effect the slew rate? I thought there may have been a way to improve slew rate by paralleling chips via a speed component since the load becomes easier to drive. Thanks for the attention to my question.
 
#93
The typical value as shown int he spec sheet is 19v/us.
The 8v/us value is a worst case value.

The typical value is just that, it is what you should typically get per part produced.

The slew rate can be increased by using a composite configuration such as in the My-Ref design or even tomchr's latest design and his threads about it.

Here are some papers on the composite opamp configuration technique,

http://www.ti.com/lit/an/sboa002/sboa002.pdf

http://www.ti.com/lit/ug/tidu026/tidu026.pdf

http://cds.linear.com/docs/en/application-note/an21f.pdf

Of all of the square wave tests I have ever seen so far for a standard configuration look pretty darn good,

http://www.parttimeprojects.com/audio/diy/LM4780_Chipamp_page.php

And even better for a good composite design such as the scope traces found here from tomchr,

http://www.diyaudio.com/forums/vend...ifier-achieving-0-0004-thd-n.html#post4065794

and here,

http://www.diyaudio.com/forums/vend...ifier-achieving-0-0004-thd-n.html#post4068082

FWIW

jer 🙂
 
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#94
Yes, you double the slew when you bridge the chip like the application note but the circuit will probably take some slew back. How much depends on how good the design is. Jer, thank you for the link. This is very interesting way to use precision amplifier.
 
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