Search found 105 matches

by terkio
Wed Sep 04, 2019 4:41 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 60
Views: 29221

Re: Dielectric Absorption

Can we model DA as a voltage source of a high impedance parallel to a perfect capacitor ? For instance 1 volt througt 1 MegOhm. This would be consistent with the voltage that keeps coming back after shorts. With this model, could that explain the clicking issue about microphone preamps phantom power...
by terkio
Mon Sep 02, 2019 4:45 am
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 60
Views: 29221

Re: Dielectric Absorption

Most amazing about DA is the voltage coming back after the cap was shorted.
Coming back after shorts, again and again.
There must be some battery that has built inside, recharging the cap.
Who knows the physics and chemistry that is going on ?
by terkio
Fri Aug 23, 2019 6:05 am
Forum: The Peabody Lounge
Topic: how green is my shack?
Replies: 2
Views: 286

Re: how green is my shack?

Interesting for a hot place I know in Australia.
What is the heat sink of the heat pump ?
An outside air exchanger I presume.
Can a heat pump give an efficient air conditioning using water from a nearby creek ? At the cost of pumping water, though.
by terkio
Thu Aug 08, 2019 1:13 pm
Forum: Pro Audio Design
Topic: A Differential Deboo Integrator to Servo Mic and Low-Level Preamps
Replies: 9
Views: 14171

Re: A Differential Deboo Integrator to Servo Mic and Low-Level Preamps

I compared using a differential Deboo integrator, and a non inverting two caps integrator. Integrating capacitor(s) insulation resistor does result in DC offset error in both cases. With the Deboo the resistor mismatch brings a similar effect. With the non inverting two caps, there is no such resist...
by terkio
Thu Aug 08, 2019 9:21 am
Forum: Pro Audio Design
Topic: A Differential Deboo Integrator to Servo Mic and Low-Level Preamps
Replies: 9
Views: 14171

Re: A Differential Deboo Integrator to Servo Mic and Low-Level Preamps

There is a catch in the Deboo integrator, differential or single. It is sensitive to resistor mismatch. This can be important or not, depending of the application. When in need for near perfect integrators, one needs capacitors with very high insulation resistors. Using a Deboo configuration, the un...
by terkio
Tue Aug 06, 2019 7:30 am
Forum: The Peabody Lounge
Topic: Technology progresses
Replies: 19
Views: 1448

Re: Technology progresses

Some 50 years ago, I had an old washing machine that had gone, clang, clang, clang for years long. I changed the two roller bearings at the drum, then I had a brand new machine. Took about, an hour, the roller bearing shop was nearby. Nowdays, this shop doesn' t exist anymore and we change the machi...
by terkio
Tue Jun 25, 2019 5:15 pm
Forum: Announcements
Topic: Active topics.
Replies: 2
Views: 1468

Re: Active topics.

Great. I see it is enabled. :)
I hope, users will like it.
by terkio
Tue Jun 25, 2019 3:42 am
Forum: Announcements
Topic: Active topics.
Replies: 2
Views: 1468

Active topics.

The "active topics" ( in the quick links, top left ) does not work.
I see it working in another similar site, a very convenient feature.
by terkio
Wed Jun 12, 2019 8:18 pm
Forum: The Peabody Lounge
Topic: too cheap to fix?
Replies: 21
Views: 3104

Re: too cheap to fix?

pigskin goatskin, deerskin and sheepskin. I like goat as it’s very soft. It’s good for tactile feedback but not super durable. Deerskin seems to be the most durable. Pigskin works best in wet weather. Moose skin is exceeding durable, but apparantly a biatch to tan. I have a mooseskin wallet (from F...
by terkio
Fri May 03, 2019 5:24 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 10119

Re: Op amp matching

At the Integrator ( dual, non inverting ) with OPA2277 I have 30K 10µF for the time constant I need. From the data sheet OPA2277 Vos max is 50µV, Ios and Ibias max is 3nA I am not sure I understand correctly these figures, a bit confusing in the data sheet. With these figures: 3nA x 15K gives a 45µV...