It is mains-powered in fact, mainly because of the power-hungry MAN's-display, but it could as well be battery operated without changing the function
No, and no
Apparently, the opamps are not in the signal path, they control bias voltages, and flipping them would result in latchup.
The amp itself seems to be only inverting
Not exactly spot on, but almost: just an integration away
No, just look closer and think about it
Hint: It is useful for certain fields of electronics, but also for mechanics (and maybe others, weavers perhaps?)
Yet another "fossil": this one is labelled "stabilité marginale", and that is indeed the case: when loaded with 3 ohm, part of the lower half-wave is festooned with VHF oscillation.
Easy to fix apparently: I probably didn't try hard enough the last time, an additional comp cap does the trick.
This one is really wideband: it uses paralleled BDX37's as OP, and it does give results: see the oscillogram (it is a 200KHz triangle, and the apparent defects near the top are not caused by the amp), measured on a 3 ohm load
Easy to fix apparently: I probably didn't try hard enough the last time, an additional comp cap does the trick.
This one is really wideband: it uses paralleled BDX37's as OP, and it does give results: see the oscillogram (it is a 200KHz triangle, and the apparent defects near the top are not caused by the amp), measured on a 3 ohm load
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I rarely give my "proofs of concepts" the opportunity to fry a speaker's voice coil...
This one is no exception
When eventually I decide to go further with a prototype, I make additional tests and checks, to make sure it is well-behaved and idiot-proof in every conceivable circumstance.
Otherwise, I simply limit myself to performance tests.
I just use this thang. I added a 4.7uF little green Nichicon ES bypass cap over that thing to pass the hf around it. Anyway, that outfit goes series to the speaker (series to groundside, speaker return, if a split rail amp). Its really good for a test speaker. Can put it at the speaker cabinet so that the amp is driving first the cable.
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Yes, it is a good idea to "formalize" such a device.
I sometimes use a flying cap for a test, but then I have to care about polarity (in some cases), or find a second one, all this discourages use.
When you have a neat little thing always ready, that makes things easier.
I will probably build a pair of them in the coming days.
I sometimes use a flying cap for a test, but then I have to care about polarity (in some cases), or find a second one, all this discourages use.
When you have a neat little thing always ready, that makes things easier.
I will probably build a pair of them in the coming days.
By default, I build all my test prototypes as DC-coupled, x11 (or x-10) gain blocks, which means they already have the maximum bass extension possible
Your statement is true at the amplifier; however. . .
During the loss of an output cap at a certain bass frequency, whereupon if one is a bit lucky (or stubborn, preferably both) for choosing the capacitance value, and before the loss becomes too severe, the electronic dampening of the woofer will become slightly looser, as if in a larger cabinet, so you can get more bass extension with an ac coupled woofer (when if the cap size is fortunate for a given speaker).
For me, it is typical that the capacitance value is sized for that particular purpose, and in every case it was done for practical benefit of greater bass extension. I have not yet witnessed any exceptions. It worked every time.
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