INA 217 Mic Preamp Circuit
« on: March 07, 2019, 12:26:53 AM »
Hello I'd like to realize some INA217 mic preamps
On the net I found several circuits but I am not sure how they work
Someone can provide me a good tested  schematic?


Matador

Re: INA 217 Mic Preamp Circuit
« Reply #1 on: March 07, 2019, 12:38:17 AM »
Hello I'd like to realize some INA217 mic preamps
On the net I found several circuits but I am not sure how they work
Someone can provide me a good tested  schematic?
The datasheet has everything you need.

Re: INA 217 Mic Preamp Circuit
« Reply #2 on: March 07, 2019, 01:52:00 AM »
A thing I have not clear it is because some circuits have the OPA 137 and others no
What's the difference?

gyraf

Re: INA 217 Mic Preamp Circuit
« Reply #3 on: March 07, 2019, 02:24:56 AM »
Start out by reading and understanding the data sheet. As Matador says - it has everything you need to know..

Jakob E.
..note to self: don't let Harman run your company..

Re: INA 217 Mic Preamp Circuit
« Reply #4 on: March 07, 2019, 03:01:01 AM »
Unfortunately I'm not very experienced

iampoor1

Re: INA 217 Mic Preamp Circuit
« Reply #5 on: March 08, 2019, 07:43:59 AM »
Build the figure 16 circuit.

Harpo

Re: INA 217 Mic Preamp Circuit
« Reply #6 on: March 08, 2019, 09:35:39 AM »
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.  -Douglas Adams

Re: INA 217 Mic Preamp Circuit
« Reply #7 on: March 08, 2019, 12:45:55 PM »
In this site it is offered a PCB for this preamplifier, but it doesn't inclde the OPA 137

http://www.bluecomtech.com/Web%20Sites/OSH%20Park/oshpark.com/shared_projects/QbTViZlZ.html

Matador

Re: INA 217 Mic Preamp Circuit
« Reply #8 on: March 08, 2019, 01:50:07 PM »
If you look at figure 16, it says the OPA137 is part of an 'optional DC control loop'.  It is a DC servo that works to keep the output potential at DC 0V.

Do a Google search for 'dc servo tutorial' to learn more about it.  I found it wasn't needed when I built this circuit in the past.

Re: INA 217 Mic Preamp Circuit
« Reply #9 on: March 10, 2019, 04:01:25 PM »


Re: INA 217 Mic Preamp Circuit
« Reply #10 on: March 11, 2019, 01:26:55 AM »
Thank you

Re: INA 217 Mic Preamp Circuit
« Reply #11 on: March 12, 2019, 01:09:07 PM »
I have found this simpler schematic with THAT1510
Anyone knows if it is possible to add a transformer to the output?

Newmarket

Re: INA 217 Mic Preamp Circuit
« Reply #12 on: March 13, 2019, 07:09:04 AM »
I have found this simpler schematic with THAT1510
Anyone knows if it is possible to add a transformer to the output?

Of course it's possible . But the questions are why you want to and consequently what is the best way to implement it...

Re: INA 217 Mic Preamp Circuit
« Reply #13 on: March 13, 2019, 07:23:49 AM »
I want to add the transformer to balance the output ... without complicating the circuit

I'd like to use something not too expensive like OEP A262A2E

Consider I'd use these preamps essentially for external drum recordings
« Last Edit: March 13, 2019, 07:34:34 AM by Liutmod »

Matador

Re: INA 217 Mic Preamp Circuit
« Reply #14 on: March 13, 2019, 04:21:00 PM »
A DRV134 is a good option.

Re: INA 217 Mic Preamp Circuit
« Reply #15 on: March 14, 2019, 03:02:32 AM »
I know but I'd prefer to put a  transformer if there are no contraindications

In the output of the THAT1510 (pin 6) may be better to put a capcitor?

john12ax7

Re: INA 217 Mic Preamp Circuit
« Reply #16 on: March 14, 2019, 04:10:55 AM »
Yes you can put a transformer on the output.  Jensen and Cinemag are good resources for transformer application notes, as there some details that are important.

Re: INA 217 Mic Preamp Circuit
« Reply #17 on: March 14, 2019, 01:32:19 PM »
Do you think the OEP A262A2E specs are ok for the output of THAT1510?

john12ax7

Re: INA 217 Mic Preamp Circuit
« Reply #18 on: March 14, 2019, 05:06:26 PM »
It's not the best choice.  The main issue is ICs are generally not good at heavy lifting,  so you would be asking a lot of the 1510 by putting that on its output.  You definitely don't want a step up transformer (1:2), you could wire it 1:1 but you are then still limited  by its inductance.

You could get a  good 1:1 transformer for $30-40.

Edit: if you wanted something inexpensive to try A262A7E would be a better choice.  Though you would still have a good bit of low frequency distortion with these.
« Last Edit: March 14, 2019, 05:29:49 PM by john12ax7 »

Re: INA 217 Mic Preamp Circuit
« Reply #19 on: March 15, 2019, 01:52:51 AM »
Thank you John. I will follow your advice


 

Related Topics

  Subject / Started by Replies Last post
19 Replies
20800 Views
Last post November 10, 2010, 06:31:23 AM
by abbey road d enfer
25 Replies
11315 Views
Last post September 27, 2005, 11:27:11 AM
by TedF
0 Replies
899 Views
Last post January 19, 2011, 01:54:18 PM
by kambo
17 Replies
1225 Views
Last post October 11, 2018, 03:58:17 PM
by squarewave