Search found 22 matches

by KMN
Wed Mar 20, 2019 12:52 pm
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 7
Views: 164

Re: Op amp matching

I just discovered the LMP2021. It has very low offset and it is pretty quiet.

I just couldn't get the choppers quiet in my circuit, though they are also working for me.

http://www.ti.com/lit/ds/symlink/lmp2021.pdf
by KMN
Tue Mar 19, 2019 3:46 pm
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 7
Views: 164

Re: Op amp matching

Lower offset but only slightly so...LT1001AM. @ 15uV max, guaranteed, is the lowest Vos off the shelf opamp I know about. If anybody knows of a lower Vos I would be thankful to you if you would share the info. https://www.analog.com/media/en/technic ... LT1001.pdf
by KMN
Sat Jul 21, 2018 10:36 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 53
Views: 17639

Re: Dielectric Absorption

Hmm, or maybe I should say humm... I hadn't thought of that. I don't know how I'd stop myself from trying it now. Great idea!
by KMN
Sat Jul 21, 2018 1:10 am
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 53
Views: 17639

Re: Dielectric Absorption

It'd be somewhere around a mH. In order to get the best emi immunity, wire gauge should be as small as possible to enable optimal constructions of a smaller loop area. Up to maybe ten ohms or so series coil R is acceptable. Multilayer is fine. What I've seen, off the shelf looks nowhere close to opt...
by KMN
Fri Jul 20, 2018 9:47 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 53
Views: 17639

Re: Dielectric Absorption

good point, and it will be differential noise too. Not to mention the coil would need to be very near to other circuitry it could easily interfere with. That is definitely on my mind. I'd be looking for a low loop area coil and possibly try and come up with some kind of small, grounded steel shield ...
by KMN
Thu Jul 19, 2018 11:19 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 53
Views: 17639

Re: Dielectric Absorption

I believe it is pretty much as you described. We have a nice impedance analyzer at work where I can frequncy sweep various parameters . The high ripple current output filter ael caps drying out is essentially what determines our product lifespan. I have been able to catch snapshots at varying stages...
by KMN
Thu Jul 19, 2018 1:11 am
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 53
Views: 17639

Re: Dielectric Absorption

^^^^ oh yeah. Sorry if this is the wrong place for this.
by KMN
Wed Jul 18, 2018 11:57 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 53
Views: 17639

Re: Dielectric Absorption

The love of those big, well built, coincidentally low DA, audiophile caps probably isn't completely irrational. Would the magnetic complement to dielectric absorption be core material hysteresis? If high levels of filter energy storage element linearity is the goal then why wouldn't air core inducto...
by KMN
Wed Jul 18, 2018 8:43 am
Forum: Test, Measurement and Repair
Topic: Classic Bead Tantalum Capacitor Failure
Replies: 5
Views: 1458

Re: Classic Bead Tantalum Capacitor Failure

If the fuses stop the explosions, it might convince me to consider straying from the flock. Hard to deal with, expensive parts that fail safe are better than not shipping due to long lead part sourcing problems. I've also experienced the cratering. Often the collateral damage seeming much more drama...
by KMN
Tue Jul 17, 2018 8:56 pm
Forum: Test, Measurement and Repair
Topic: Classic Bead Tantalum Capacitor Failure
Replies: 5
Views: 1458

Re: Classic Bead Tantalum Capacitor Failure

Tantalums are pretty well against my religion... I got tired of trying to figure out how to keep them happy in high current ripple applications. Though I hear the tantalum polymers are quite a bit more tolerant high ripple current...the little beasts are way to rich for my blood. Then there is the p...