Search found 53 matches
- Tue Mar 26, 2019 12:11 pm
- Forum: Pro Audio Design
- Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
- Replies: 499
- Views: 794414
Re: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
First, really nice job. Whether by wank, luck or unstated genius, that thing is quiet. From the schematic symmetry, this design looks to be a candidate for a "humbucker" board layout. My new word from another thread here on proaudiodesignforum. Please bare with my attempt to describe what ...
- Wed Mar 20, 2019 12:52 pm
- Forum: Pro Audio Design
- Topic: Op amp matching
- Replies: 44
- Views: 51424
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
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
- Tue Mar 19, 2019 3:46 pm
- Forum: Pro Audio Design
- Topic: Op amp matching
- Replies: 44
- Views: 51424
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
- Sat Jul 21, 2018 10:36 pm
- Forum: Pro Audio Design
- Topic: Dielectric Absorption
- Replies: 64
- Views: 189733
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!
- Sat Jul 21, 2018 1:10 am
- Forum: Pro Audio Design
- Topic: Dielectric Absorption
- Replies: 64
- Views: 189733
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...
- Fri Jul 20, 2018 9:47 pm
- Forum: Pro Audio Design
- Topic: Dielectric Absorption
- Replies: 64
- Views: 189733
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 ...
- Thu Jul 19, 2018 11:19 pm
- Forum: Pro Audio Design
- Topic: Dielectric Absorption
- Replies: 64
- Views: 189733
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...
- Thu Jul 19, 2018 1:11 am
- Forum: Pro Audio Design
- Topic: Dielectric Absorption
- Replies: 64
- Views: 189733
Re: Dielectric Absorption
^^^^ oh yeah. Sorry if this is the wrong place for this.
- Wed Jul 18, 2018 11:57 pm
- Forum: Pro Audio Design
- Topic: Dielectric Absorption
- Replies: 64
- Views: 189733
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...
- Wed Jul 18, 2018 8:43 am
- Forum: Test, Measurement and Repair
- Topic: Classic Bead Tantalum Capacitor Failure
- Replies: 17
- Views: 96384
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...