Dear all,

As a reference to the context why I'm asking this question:

I'm looking for the THAT1512 but it's hard to find and often the 20€ delivery is quite expensive for a 5€ part.
Moreover, the THAT1512 seems to be out of stock in a lot of places until June 2022.
I'm looking for an alternative to the THAT1512 and thought of the THAT1510 as it's within the same datasheet. Would the THAT1510 preserve the same quality as the THAT1512?

As i'm not an expert in this field, it's hard to find and assess the differences between the two.
For logistical purpose, I'm located in Belgium.

 

. Would the THAT1510 preserve the same quality as the THAT1512?

Yes, and so would the INA217 and INA163, and INA217 is in stock.
The THAT part is about 1dB quieter. [edit] and being fed from a telephone microphone with a SNR of only 65dB, who gives a damn about an extra 1dB of noise from the amplifier. A THAT1510 is wasted on it. A 15p op-amp will suffice.
https://uk.rs-online.com/web/p/instrumentation-amplifiers/6604251

 

1pcs THAT1510P THAT1510P08-U 1510P THAT 1510 IC DIP-8 | eBay
Good luck............

 

Yes, and so would the INA217 and INA163, and INA217 is in stock.
The THAT part is about 1dB quieter. [edit] and being fed from a telephone microphone with a SNR of only 65dB, who gives a damn about an extra 1dB of noise from the amplifier. A THAT1510 is wasted on it. A 15p op-amp will suffice.
https://uk.rs-online.com/web/p/instrumentation-amplifiers/6604251

Ok, thanks I'll have a look at these !

 

Why do you want to deal with an amp that requires a minimum of 10v supply (minimum recommended is +5 to -5v rails). Why not use a low noise rail to rail op amp that works at a single 5v supply?

 

Why do you want to deal with an amp that requires a minimum of 10v supply (minimum recommended is +5 to -5v rails). Why not use a low noise rail to rail op amp that works at a single 5v supply?

Exactly, and why spend £6 (plus the 5V to ±15V converter) on a studio-quality preamp for a telephone-quality microphone?
It doesn't even need a particularly low noise op-amp!

 

After the intro, the video's very first sentence: "Microphone design is more of an art than a science."

No, it isn't.

ak

 

1pcs THAT1510P THAT1510P08-U 1510P THAT 1510 IC DIP-8 | eBay
Good luck............

Thanks for the reply. The problem is not finding the parts.
It's mostly to know whether the part has lesser/same/better specs than the THAT1512

 

Exactly, and why spend £6 (plus the 5V to ±15V converter) on a studio-quality preamp for a telephone-quality microphone?
It doesn't even need a particularly low noise op-amp!

Correct me if I'm wrong but the suggested microphone capsule is studio quality I believe.
As said I'm not an expert, far from that actually. I'm just following what is advised in the video but I stumbled upon the scarcity of the THAT1512 and now I'm here.

 

Correct me if I'm wrong but the suggested microphone capsule is studio quality I believe.
As said I'm not an expert, far from that actually. I'm just following what is advised in the video but I stumbled upon the scarcity of the THAT1512 and now I'm here.

That That Amplifier with that microphone for your application (USB audio) is like putting a good shift knob on a rusted, oil burning 1968 VW bug.

 

That That Amplifier with that microphone for your application (USB audio) is like putting a good shift knob on a rusted, oil burning 1968 VW bug.

Ow like that.
Agreed but next part of the project would be to use this mic as an input to a Boss RC30 Loopstation. Mic would then be hooked up to an output with a XLR connection.

 

Is it? Reviewing the thread, we don't actually know what the intended use is for the amplified audio signal. The video has "USB" in its title, and there are multiple references to "telephone", but the TS has not said anything about the circuit's application. Rather than spend more posts flapping around, let's find out.

TS:

1. What is the intended end use for the amplified audio signal? Home recording studio? Youtube video narration? Intercom? A <gasp> telephone?

1a. If it is in fact to be digitized and run through a USB port, what are the characteristics of the digitizing circuit / device / system?

2. Is there a specific reason for a dual-rail circuit, or are you open to other, less complex approaches?

ak

 

Correct me if I'm wrong but the suggested microphone capsule is studio quality I believe.
As said I'm not an expert, far from that actually. I'm just following what is advised in the video but I stumbled upon the scarcity of the THAT1512 and now I'm here.

This is your mic:
https://www.jlielectronics.com/content/JLI-2555BXZ3-GP.pdf
This is a studio quality mic:
https://www.akg.com/on/demandware.s...87a/pdfs/AKG_CutSheet_C451B_Condencer_Mic.pdf
11dB difference in noise.

The JLI output is -42dB/Pa and the signal to noise is -65dB so the noise is at -107dB which is 4.4μV, and assuming it is white noise, that is 32nV/√Hz.
A TL071 at 20nV/√Hz is plenty good enough for the job!

Or if you use a PCM2912, it has a built in microphone preamp for a condensor microphone.
https://www.ti.com/lit/ds/symlink/p...74709&ref_url=https%3A%2F%2Fwww.google.com%2F

 

Is it? Reviewing the thread, we don't actually know what the intended use is for the amplified audio signal. The video has "USB" in its title, and there are multiple references to "telephone", but the TS has not said anything about the circuit's application. Rather than spend more posts flapping around, let's find out.

TS:

1. What is the intended end use for the amplified audio signal? Home recording studio? Youtube video narration? Intercom? A <gasp> telephone?

1a. If it is in fact to be digitized and run through a USB port, what are the characteristics of the digitizing circuit / device / system?

2. Is there a specific reason for a dual-rail circuit, or are you open to other, less complex approaches?

ak

1. In the video the end use is indeed through a USB-C to be used for all use cases with PC (gaming, narration, streaming, ...)
My own addition to the video is to start using the analog signal as such and output it through a XLR cable to my loop station for musical end use.

1a. It is digitised, I believe in the video they refer to it as the digital audio interface (https://www.amazon.com/Capture-Edit...0e0d6c8c93114&language=en_US&ref_=as_li_ss_tl)

2. No specific reason except for the aesthetics of the microphone. I just saw the video, looked cool so I thought I'd give it a go.

 

The JLI output is -42dB/Pa and the signal to noise is -65dB so the noise is at -107dB which is 4.4μV, and assuming it is white noise, that is 32nV/√Hz.
A TL071 at 20nV/√Hz is plenty good enough for the job!

Politely disagree. The TL071 opamp noise amplitude is over half that of the noise in the source, so it will add a clearly audible amount of noise to the signal. I can see using a 20 nV opamp in a line-level mixer, but not in a preamp. Several opamps from the early and mid 70's have significantly lower noise, as do some of the TL series from Texas Instruments.

Something I've observed over the years is that in opamp datasheet-speak, 10 nV and under is touted as low noise; but in the precision audio world, it has to be under 5 nV to be considered studio quality. The NE5534 is hungry, cranky, and has a (overblown) reputation for being a bit "brittle" sounding, but that puppy is quiet.

ak

 

Politely disagree. The TL071 opamp noise amplitude is over half that of the noise in the source, so it will add a clearly audible amount of noise to the signal. I can see using a 20 nV opamp in a line-level mixer, but not in a preamp. Several opamps from the early and mid 70's have significantly lower noise, as do some of the TL series from Texas Instruments.

Something I've observed over the years is that in opamp datasheet-speak, 10 nV and under is touted as low noise; but in the precision audio world, it has to be under 5 nV to be considered studio quality. The NE5534 is hungry, cranky, and has a (overblown) reputation for being a bit "brittle" sounding, but that puppy is quiet.

ak

Ok so I might have overstated my case.
A TL072 would give an output noise of of 37nV/√Hz, a noise figure of 1.4dB.
I should have chosen something to give a noise figure of <1dB, and I couldn’t think of one at the time.
Anyway, we need a 5V supply rail to rail output op-amp, and I think Microchip does quite a selection <15nV/√Hz which would give <1dB noise figure.
My main point is that 1nV/√Hz is an unnecessary expense.
NE5532/4 is an excellent device, every mixing desk is full of them, but they are no so happy on a 5V supply, their minimum is ±5V.

 

Ok so to resume:
Both the THAT1512 and THAT1510 are overkill for this application as a microphone for digital use to USB-C
Potential alternative is the INA217.

That sums it up?

 

Ok so to resume:
Both the THAT1512 and THAT1510 are overkill for this application as a microphone for digital use to USB-C
Potential alternative is the INA217.

That sums it up?

Ok so I might have overstated my case.
A TL072 would give an output noise of of 37nV/√Hz, a noise figure of 1.4dB.
I should have chosen something to give a noise figure of <1dB, and I couldn’t think of one at the time.
Anyway, we need a 5V supply rail to rail output op-amp, and I think Microchip does quite a selection <15nV/√Hz which would give <1dB noise figure.
My main point is that 1nV/√Hz is an unnecessary expense.
NE5532/4 is an excellent device, every mixing desk is full of them, but they are no so happy on a 5V supply, their minimum is ±5V.

Is it? Reviewing the thread, we don't actually know what the intended use is for the amplified audio signal. The video has "USB" in its title, and there are multiple references to "telephone", but the TS has not said anything about the circuit's application. Rather than spend more posts flapping around, let's find out.

TS:

1. What is the intended end use for the amplified audio signal? Home recording studio? Youtube video narration? Intercom? A <gasp> telephone?

1a. If it is in fact to be digitized and run through a USB port, what are the characteristics of the digitizing circuit / device / system?

2. Is there a specific reason for a dual-rail circuit, or are you open to other, less complex approaches?

ak

I am also interested in this project so was researching the components he references in the video.

You describe the capsule as only suitable for a telephone, is this really true?

 

I am also interested in this project so was researching the components he references in the video.

You describe the capsule as only suitable for a telephone, is this really true?

Yes.
The signal-to-noise ratio isn't good enough for studio quality, but the frequency response is quite flat.
Some of them have a low-frequency roll-off below 100Hz.
MEMS microphone are somewhat better.

 

Yes.
The signal-to-noise ratio isn't good enough for studio quality, but the frequency response is quite flat.
Some of them have a low-frequency roll-off below 100Hz.
MEMS microphone are somewhat better.

I have a rather low bass-baritone voice so was looking for a low cost replacement for my existing mics, like an SM57 which has a dramatic roll off below 200 Hz.

I don't need studio-quality but a good SNR and a flat frequency response is desirable down to about 60Hz, can you recommend a good MEMS component for the job?