Search found 271 matches

by terkio
Fri Apr 05, 2019 2:25 pm
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 21816

Re: Op amp matching

Thanks, you save me a lot of time pointing to me in the right direction. The Deboo can be fine, depending of the application and one cap only is nice for a differential. I abandoned the Deboo in an application where I want the servo loop to give a very best servo error correction. I bumped on the re...
by terkio
Fri Apr 05, 2019 11:48 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 21816

Re: Op amp matching

@terkio We had a servo discussion that began with the OPA2188. I did a test check with slow op amps as simple integrators to see when/where they stopped being integrators due to bandwidth and load-driving. This exercise reinforced the point JR has made regarding the importance of passive input pole...
by terkio
Wed Apr 03, 2019 2:28 pm
Forum: Test, Measurement and Repair
Topic: Welcome to the Test, Measurement and Repair Forum
Replies: 11
Views: 32950

Re: Welcome to the Test, Measurement and Repair Forum

The WOM joke doesn't work on software people. A file may be Write Only.
by terkio
Tue Apr 02, 2019 3:17 pm
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 21816

Re: Op amp matching

Interesting: MCPV6V51.
CMOS Vdd 45V
Vos typical 2.4µV
Chopping clock rate of 100kHz
BW 2MHz
Low cost 1 buck
by terkio
Tue Apr 02, 2019 8:35 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 498
Views: 337008

Re: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851

Thanks a lot for your help.
I sure need a "round tuit", I have high grass waiting for me.
At that place in the countryside my grand father had a couple of goats, the goat keep is still there, ready for new goats.
by terkio
Tue Apr 02, 2019 12:22 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 498
Views: 337008

Re: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851

by mediatechnology » Sun Mar 24, 2019 8:07 am The measurement chain is: Soundcard Out > THAT1646 > -60dB U-Pad > ZTX851 Balanced Preamp > PCM4222EVM (96k/24b) >AudioTester Thanks for your detailed presentation of the THD measurements. How do you connect the PCM4222EVM (96k/24b) to the PC ? How does...
by terkio
Mon Apr 01, 2019 4:35 pm
Forum: Test, Measurement and Repair
Topic: Welcome to the Test, Measurement and Repair Forum
Replies: 11
Views: 32950

Re: Welcome to the Test, Measurement and Repair Forum

Audio1Man wrote:
Mon Apr 01, 2019 12:28 pm
Thank god the Signetics 25120 Write-Only-Memory (WOM) is still working.
Duke
Write Only Memories are great to implement overflow bit buckets.
by terkio
Mon Apr 01, 2019 9:20 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 21816

Re: Op amp matching

The advantage of the Birt is that the second op amp's noise appears in common mode, not differential. (Assuming good R match.) Interesting, good to know. Otherwise, I see no advantage in the Birt. We've talked a lot here about the advantage of passive input poles on servos which the non-inverting "...
by terkio
Mon Apr 01, 2019 4:02 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 21816

Re: Op amp matching

the two amplifiers can be thought of as being in series I see a Birt topology. I do not use the Birt to make differential outputs from differential inputs. I use twice the same op amp circuit, one to derive Outa = K x ( Ina - Inb) the other to derive Outb = K x ( Inb - Ina). This is perfectly balan...
by terkio
Sun Mar 31, 2019 8:18 am
Forum: Build
Topic: Common mode choke
Replies: 1
Views: 13808

Common mode choke

This is to use at the inputs of a mic preamp, for -hopefully- CMRR enhancement. Is this, good ? https://www.mouser.fr/datasheet/2/410/media-346070.pdf It is not specified as a CMC, but it has 1:1 turn ratio, is small, is specified over 20Hz 50KHz I was unable to find Common Mode Chokes, clearly made...