Indeed bias cancellation is a hidden evil in recent (and not so recent) audio opamps. It is simply omitted from the specs, and in the neat and ideal noise calculations with resistive generator impedances.

Thanks for spotting that for the OPA210. And like I said, even ignoring bias compensation it only gains you a mere 0.6dB SNR as compared with the 5534 in MM SNR.

And that is something in favour for the 5534 and 5532 still - no bias compensation. And still available in 8-pin DIL packages. I just wish that they had the comprehensive set of performance graphs of more recent devices.

Sorry to hear of what ever has caused the beach bum from quitting the beach. Following a five month chest infection that needed kick ass antibiotics to kill, I'm luckily back to firing on all cylinders.

Craig

------ Original Message ------

From "Richard Lee via " <ricardo_lee@...>

To MicBuilders@groups.io

Date 09/04/2025 05:00:30

Subject Re: [MicBuilders] FET OPAs for mikes

On Tue, Apr 8, 2025 at 01:21 AM, Craig Sawyers wrote:

And the only bipolar opamp to beat the NE5534 is the OPA210. 2.2nV/rootHz at 1kHz, an amazing 2.5nV/rootHz at 10Hz, and crucially for MM cartridges current noise of 400fA/rootHz (same as for the NE5534). It is just better in all respects than the Neanderthal NE5534

Thanks for these suggestions Craig.

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OPA210 has EVIL input bias current cancelling.? The damning evidence is its +/- input bias current spec.? These invariably have much higher noise for stuff with different impedances on each input pin like single OPA RIAA preamps.? You may remember us looking at the ???? preamps with Steve Sells and finding significant improvement replacing OP27 or OP37 with 5534 on their RIAA

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It's more than a decade since I last looked at this seriously

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Wayne (and NWavGuy IIRC) measured NJM 2068, sadly Unobtainium today, quieter than LM 4562 so env < 2.5nV/rtHz @ 1kHz and inv good enough in to beat 5534.? Of course da Jurassic NJM topology (dating back to Raytheon 4136 ie much older than 5534) can't give 1 ppzillion THD like more modern stuff but good enough for an old beach bum like me.

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BTW, I hope you are not suffering various health issues like me which may mean I need to give up the beach

On Apr 7, 2025, at 21:32, Richard Lee via groups.io <ricardo_lee@...> wrote:

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It's actually for a Jurassic application with of no modern importance;? RIAA MM preamps in DIYaudio.? I'm surprised that NE5534 is still one of the best for this; slightly beaten only by $$$ OP627 or Unobtainium NJM2068.

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In theory, a FET OPA with <3.5nV/rtHz & low 1/f, popcorn noise bla bla should trounce 5534

On Apr 4, 2025, at 14:20, Mic mauler via groups.io <ljelley1@...> wrote:

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Hey guys (and gals),

I just wanted to drop a line to say thanks to this community. This is my first post, but I have been reading the board for the past few weeks.

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I am a singer (amateur with mediocre talent) and am interested in recording some stuff at home. Most of my mics are dynamic and I have really wanted to get a decent condenser, but just cannot bring myself to spend the hundreds of dollars to buy a "good" mic. I have owned an MXLV67 for over a decade but have never been happy with the sound so it has spent most of it's life in it's box. A few weeks ago, I ran across a YouTube video of someone building a condenser mic and the bug bit me.

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After a bit of research on the internet, I found JLI and watched the build videos. I ordered the parts for a "Samantha" OPA Alice board with the 34mm electret capsule. I also got mounting kit, 34mm saddle, and 22nF caps for the XLR as instructed in the video.? I bought the cheapest CAD 1800 ($17) mic on Amazon just to get a donor body and after a couple days of tinkering, managed to build my first microphone. The first time I plugged it in was truly magical. For a little under $100 I have a great sounding mic with very little noise. I sang for several hours straight just enjoying it and playing with different compression, EQ, and effects settings. Despite my poor soldering skills, it turned out great!

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So of course, down the rabbit hole I go. My next project was to build with a true condenser capsule and following the JLI videos again, I ordered an OPA Alice board, the hex inverter board, the K47 capsule and installed them in a cheap U87 body I bought for $23 on walmart.com. It was on this project that I made my first major mistake. I overheated one of the xlr pins and bent it out of place, so I ordered some XLR inserts from amazon. Meanwhile, I finished installing the pcbs and capsule and waited for parts. As soon as the parts came in, I finished the mic and it worked the first time! My soldering is getting better now and I am more confident with it. This mic sounds great, but still has a bit of noise that I intend to chase down. Probably poor soldering hygiene.?

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While waiting for parts I came across this https://www.opic.jp137.com/index-multi.html webpage and started contemplating assembling a pcb from scratch. This led me to Mic Scharf’s PCBway shared projects (https://www.pcbway.com/project/member/?bmbno=8A368813-05C9-44). So I ordered the MP PCB, hex inverter pcb, and the opa alice handheld boards (5 of each). I had a lot of fear of the soldering required so I worked on a couple of practice soldering projects while waiting for the parts to come from China.

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In the meantime, I ordered parts from Mouser enough to complete 2 of the OPA Alice handheld microphones and 2 of the 25mm electret capsules from JLI. Last night I completed my first pcb and installed it in a KMS 105 clone I bought off amazon for $10. It worked the first time I plugged it in and it sounds amazing. This might be my favorite microphone yet. I need to see if it can stand being plugged into my PA system for a little karaoke with out it feeding back. I am skeptical cause it is ultra hot with very little gain on my Yamaha interface.

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So I started my journey back on 3/14/2025 with my first order to JLI. Here I sit three weeks later with 3 completed microphones and parts for another on hand. I spend way too much time surfing Chinese websites for cheap mic parts and am working on a Mouser order for my next project. Can we form a 12 step support group or something, cause clearly I have a problem.

Thanks again to Jules and all the others on this site who inspire ordinary folks like me to leverage this technology. Whole new worlds are opening up to me when I see what can be built from PCBway projects as well. I have a lot of interest outside of microphones like retro computing and I want to build some stuff for my commodore 64 now.