INA217 Preamp

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Zakl

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Joined 2010
#1
I am planning on making a INA217 Mic Preamp for my first diy amplifier project. The datasheet has a schematic (pg7) for a circuit with phantom power. However, I do not want phantom power in my circuit.

I am not sure how many components to remove. Do I just take out the Phantom Power loop or can I also take out R1, R2, C1, and C2?

Also, how would i connect a 1/4" headphone plug cable to the output, would I just connect the tip(+) to vo and ground the sleeve?

Thanks for the help!
 
#3
Hi Zaki!

This looks a bit ambitious for a first DIY project! Anyway, if you don't want phantom power, delete R1, R2, R3 and the 47uf cap- You can also short C1 and C2 and delete all 4 diodes. You may connect a headphone direct to the Vo output as you suggest, but keep in mind that the output current from the amp may be a little less than what you want!
 
#5
2quad said:
Hi Zaki!

This looks a bit ambitious for a first DIY project! Anyway, if you don't want phantom power, delete R1, R2, R3 and the 47uf cap- You can also short C1 and C2 and delete all 4 diodes. You may connect a headphone direct to the Vo output as you suggest, but keep in mind that the output current from the amp may be a little less than what you want!
Click to expand...

Even though the protection diodes aren't 'needed', it's a good idea to have them in 'just in case'. Nothing sucks like being in the field to record and blow something up and find that the protection diodes might have saved the day. They cost next to nothing and only add a few pF to the input.

G²
 
#6
Zakl said:
I am planning on making a INA217 Mic Preamp for my first diy amplifier project. The datasheet has a schematic (pg7) for a circuit with phantom power. However, I do not want phantom power in my circuit.

I am not sure how many components to remove. Do I just take out the Phantom Power loop or can I also take out R1, R2, C1, and C2?

Also, how would i connect a 1/4" headphone plug cable to the output, would I just connect the tip(+) to vo and ground the sleeve?

Thanks for the help!
Click to expand...

Looking a little more at the datasheet I would make 3 very minor changes. Add a small value (22-100 ohms) resistor in series with the output to decouple the amplifier from the cable capacitance. This helps to keep it stable. You may also want to add a potentiometer level control on the output if you're running into a computer. The level controls on my Gigabyte motherboards occur after a buffer stage which can be easily overloaded.

Under very loud conditions that preamp can put out >25 Volts p-p which is not a problem in itself but into a PC could damage the input if the aforementioned level control is turned up. So, the 3rd change would be to add some stacked diodes to limit the output to <5 Volts p-p to protect subsequent devices.

I use a similar preamp for microphones and had to add the level pots to go into a PC but I still have to add the protection diodes. It's another one of those 'real soon now' things.

G²
 
#7
Ssm2017 ssm2019 lt1167 that1510 ina163 ina103

I note, that except the INA217 follow additional pincompatible IC's there are:
SSM2017, SSM2019, LT1167, THAT1510, INA163 and INA103

Here the data sheet URLs:
TT Semiconductor 1510/1512 - Preamplifier ICs
http://web.archive.org/web/20080608...p.com/1500-series_Audio_Preamplifier_ICs.html
http://www.thatcorp.com/datashts/THAT_1510-1512_Datasheet.pdf
SSM2017 | Self-Contained Audio Preamplifier | Obsolete | Analog Devices
SSM2019 | Self-Contained Audio Preamplifier | Audio Signal Processors | Audio/Video Products | Analog Devices
Audio Amplifier - Microphone Preamplifier - INA217 - TI.com
Audio Amplifier - Microphone Preamplifier - INA163 - TI.com
Audio Amplifier - Microphone Preamplifier - INA103 - TI.com
Linear Technology - LT1167 - Single Resistor Gain Programmable, Precision Instrumentation Amplifier
Low Noise Balanced Microphone Preamp

and here both commercial preamplifiers and diy projects arround this types:

Rod Elliot Sound Products
Low Noise Balanced Microphone Preamp (discrete solution for SSM2017/INA217)

Trichord Dino
Trichord Research Dino Phono Amplifier (THAT 1510)
http://www.stereoplay.de/Testbericht/28746488_b9f74ee127.jpg
Stereoplay, das Magazin fr Hifi, Surround und Musik - Phono-Vorverstärker Trichord Dino Mk II

Lehmann Audio "Black Cube"
krishu.de Lehmann Clone (SSM2019)
Lehmannaudio :: HighEnd vom Toningenieur :: Black Cube Statement (SSM2019)

Simaudio "Moon LP3"
Simaudio MOON LP3 Phono Preamplifier (INA163)
Stereoplay, das Magazin fr Hifi, Surround und Musik - Phono-Vorverstärker Moon LP 3 (INA163)

Clearaudio "Smart phono"
www.clearaudio.de/download/phonovorverstaerker/testbericht_smartphono_stereoplay.pdf (INA163 OPA2228 NE5534)

Hoerwege MC V2
hoer-wege PHONO-MC V2: symmetrischer PrePre für alle MCs (INA163)

Thel Phono X1
http://www.thel-audioworld.de/module/phono/Phono-X1.jpg (INA217P oder INA163P)
Phonovorstufe von THEL

Ulrich Böhmke Audio und Messtechnik Mini Pre II
www.xinxii.com/gratis/107498rd1242149359.pdf (INA163)

Tom Evans Audio Design"The Groove" Phono amp (THAT 1510)
Tom Evans Audio Design Groove phono preamplifier
Tom Evans Audio Design at Walrus Systems hifi website

German thred arround this subject
Unterschiede zwischen SSM2017 SSM2019 LT1167 THAT1510 INA217 INA163 und INA103 für MC/MM Input? - Phono - Restauration und Selbstbau - Analog-Forum
 
#11
I built INA217 mic pre for dynamic mike without phantom supply on a perforated board couple of years ago.
 

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#13
Yes, but the value of my input caps is too low. Just 1uF, polycarbonate. It should be much higher with 2k2 input resistors (from the application circuit). That was mistake I made in my built, but preamp sounds excellent even with these values. Probably because my initial motivation for building this mic pre was to use it with my Sennheiser E815S dynamic mike, only for voice (speech) recordings. Although it is budget priced mike, it's excellent. Great German build quality, humbucking coil, etc. I also used protective input diodes, although I do not intend to "hot plug" the mike.

I needed this mic pre because my father is now 82, and I wanted to have his voice recorded while he is still alive. He is very good and generous person, that I will miss very much when he is gone, so I wanted to hear him after his death. I used Audacity softeware to record his autobiography on my PC HDD.
 
#15
stratus46 said:
Add a small value (22-100 ohms) resistor in series with the output to decouple the amplifier from the cable capacitance.
Click to expand...

I deliberately omitted output series resistor because DS claims that INA217 is stable with up to 1000pF loads. I wanted to test the claim so I used low quality (=high capacitance) 2m long coax cable to my PC and experienced no problems with stability. But resistor will not harm the pre in any way.

Regulated PSU is with low power 7815/7915 + RC filter at the output (10R/1000uF). Some people prefer shunt regulators for this application, but 7815/7915 works just fine in my pre.
 
#17
 
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