I simply bought some blank adaptor SOIC to DIP8 PCBs from Aliexpress (see HERE for example) and fitted the OPA1641 opamps myself.I've read your LDC circuit and I find it interesting thanks. I might as well try out your LDC circuit design through the stripboard method, but how will I get the OPA1641 /w sip8 to dip8 on the market? I found this on ebay, if it's even legit...
What the hell even is that second board supposed to be (doing)?
Could I use a NE5532 instead I have on me? It can only take a maximum supply voltage of 15v though resistors do need to be adjusted. Maybe not since I don't know how many volts in your LDC circuit flow into OPA1641.I simply bought some blank adaptor SOIC to DIP8 PCBs from Aliexpress (see HERE for example) and fitted the OPA1641 opamps myself.
Tiny piece of 'blu tack' type adhesive putty to hold the IC in place while hand soldering. Pin 3 of the adaptor left out, to allow the 1G resistor to be soldered directly to the adaptor pin 3 socket.....As I have shown in my photos...
(Makes it easier to keep that very high impedance connection point away from any flux or dirt.... )
You could of course test things out, using a standard TL071 DIP op amp if you're not keen on soldering the adaptor --- OK, it would be a little bit noisier than a OPA1641, but it should work well enough to allow you to check things out...
As you say, buying the pre-assembled 1641 on an adaptor from Ebay can be a bit of a lottery.....
As gyraf says - it needs to be JFET op- amp. And it needs to be a single amp - like the OPA1641 or even the TL071 - and NOT a dual opamp like the NE5532.Could I use a NE5532 instead I have on me? It can only take a maximum supply voltage of 15v though resistors do need to be adjusted. Maybe not since I don't know how many volts in your LDC circuit flow into OPA1641.
I've also noticed this circuit board pop up in another shopping platform I often used. I was skeptical about this product initially given the insanely cheap price.Howdy! I purchased and tested this set of mic boards with @metalockpick patiently looking over my shoulder. They manage both true condenser and electret condenser capsules. Overall, I consider they are uninspiring and dull, suffering what I perceive is poor articulation with lack luster treble affect. They are reasonably quiet, but NOT as inherently quiet as, for example, the popular OPA Alice boards. While I have not measured them with a proper, formal protocol, they seem noisy compared to commercially produced boards.
They are what they are: $10 condenser circuit boards. They would certainly do in a pinch. While the gold foil capacitors is lovely . . . they sorta look and fee sorta "cheap" - and there is substantial manufacturing artifact giving them an unfinished appearance.
Note: These boards do not easily fit a BM-700/-800 body. While they are sufficiently narrow, they are 80mm long, which is exactly the length of the internal mounting rails of a typical BM-700/-800 chassis.
I may edit this post and provide a comparative recordings in due course. Until then, in a word, "Meh." I will probably replace them with other, quieter, more dynamic and musically exciting boards.
Of course, this is just MY take; your mileage may vary. // James / K8JHR //
PS - I appreciate the input I received from
Mr. Metalockpick as I tried them out. JR
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So this is basically an Opamp based condenser circuit with a "polarization board" and various other passive filter components then?
Good Day Mr. @Khron - What would you like to see better? I am a better photographer than musician and can either examine or photograph them to discover what you need. JamesAny markings on the active components, by the way?
Here's my best guess: the second board was originally intended to be a voltage multiplier circuit, but someone wanted to save a couple of quid (without re-working the first board) so knocked this one up to make it look busy.
they shamelessly "Munce" the original circuit, removing as many components as possible while maintaining an acceptable level of performance
Um ... er ... ahem ... Oops -BUSTED! (Getting old ... memory fading ... falling asleep ZZzzzzzz.....) James
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