Go Back   Home > Forums > >

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

New full diff amp OPA1637
New full diff amp OPA1637
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 18th April 2020, 12:17 PM   #1
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
Default New full diff amp OPA1637

TI continues to surprise us with top notch products. After the OPA1656 I 'discovered' the OPA1637. A fully differential amplifier with excellent audio specs.
Ordered the eval module to get a head start*. I can see several places where this would fit very well, like fully balanced post-DAC filtering and/or I/V conversion, fully balanced preamps, fully balanced active filters/xovers. And, my own target, an improved fully balanced AutoRanger.

Anybody here with similar ideas?

Jan

*If the international shipping system holds up, hopefully.
  Reply With Quote
Old 18th April 2020, 12:35 PM   #2
davidsrsb is offline davidsrsb  Malaysia
diyAudio Member
 
Join Date: Dec 2005
Location: Kuala Lumpur
The datasheet looks good, the inputs seem truly symmetrical. All too often differential amplifiers have very poor AC common mode rejection.

Your post reminds me, I want to build a decent connector board to bypass my PCs horrible 3.5mm jacks
  Reply With Quote
Old 18th April 2020, 05:58 PM   #3
phase is offline phase  United States
diyAudio Member
 
Join Date: Oct 2004
Odd pinout, will keep it from any fast swapping into existing devices.

Looks like a great part.
  Reply With Quote
Old 20th April 2020, 05:08 AM   #4
noviygera is offline noviygera  United States
diyAudio Member
 
Join Date: Mar 2009
Location: Chicago
Would it work in a phono pre amp?
  Reply With Quote
Old 20th April 2020, 08:07 AM   #5
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
It would be a nice project to base a phono preamp on it. I've seen some (discrete) fully balanced designs here and they were generally well regarded.
Hans Polak did one, there's a tread about it.

Jan
  Reply With Quote
Old 21st April 2020, 12:29 PM   #6
sgrossklass is offline sgrossklass  Germany
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
Same pinout as OPA1632, it seems, but a less hot input stage with added input bias current cancellation (no biggie in a true balanced application). This part would be intended for more normal surrounding impedances. You could use it in a fully balanced phono preamp, I guess, but the duplicated RIAA network in these is always a nuisance.

We're not exactly drowning in these fully-differential parts, so any new type is welcome I guess.

BTW, I never noticed that OPA1632 specs do not really add up. 2 ľA of input bias current (typ) but only 0.4 pA/√(Hz) of input current noise? You'd get 0.8 from shot noise alone. (Besides, even the lowest-noise bipolar opamps do not manage en * in substantially below 1. OPA1632 specs would indicate 0.6!) OPA1637 specs look way more realistic.
  Reply With Quote
Old 21st April 2020, 03:00 PM   #7
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
Fully agree on the 'more normal impedances' in the fb networks.
I'm still waiting for my eval board ... :-(
Fedex says 27 April, but you never know in these interesting times.

Jan

Last edited by jan.didden; 21st April 2020 at 03:02 PM.
  Reply With Quote
Old 21st April 2020, 03:14 PM   #8
billshurv is offline billshurv  United Kingdom
diyAudio Member
 
billshurv's Avatar
 
Join Date: Mar 2014
New full diff amp OPA1637
Quote:
Originally Posted by noviygera View Post
Would it work in a phono pre amp?

I've got an MM phono waiting for test with the OPA1632. TI website not working for me at the moment so cannot see how the specs compare.
  Reply With Quote
Old 12th May 2020, 12:39 PM   #9
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
Got some time to check out the OPA1637 EVM. Some EVMs have 0 ohm output isolation resistors in R4, R7 positions. The latest units will have small non-zero resistors there to guarantee stability with cap loads. In case you do see oscillations, check that these resistors are non-zero.

But, with that, the performance is absolutely stellar, see attached. Measured via a balanced twin-tee, down in the AP noise floor ...
And this is with a gain of 5, so for unity gain expect at least 10dB lower yet!

Jan
Attached Images
File Type: png OPA1637 via bal twin-tee.PNG (23.1 KB, 370 views)

Last edited by jan.didden; 12th May 2020 at 12:46 PM.
  Reply With Quote
Old 16th June 2020, 10:43 AM   #10
davidsrsb is offline davidsrsb  Malaysia
diyAudio Member
 
Join Date: Dec 2005
Location: Kuala Lumpur
How about the new THP210?
https://www.ti.com/product/THP210?jk...omepageproduct
  Reply With Quote

Reply


New full diff amp OPA1637Hide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Designing a universal diff-in/diff-out Head Amp Hans Polak Analogue Source 259 5th September 2020 12:08 AM
Diff drive bigwill Tubes / Valves 36 6th February 2009 06:33 PM
diff between dipole and IB bser Multi-Way 6 18th November 2004 10:23 PM
diff or parallel dac TJ Digital Source 6 10th November 2003 01:14 PM
help with diff. output Raj1 Digital Source 4 9th September 2003 06:03 PM


New To Site? Need Help?

All times are GMT. The time now is 10:50 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki