Search found 72 matches

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: 13311

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: 13311

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: 471

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: 826

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: 826

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: 2246

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: 7198

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...
by terkio
Thu May 02, 2019 4:08 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 44
Views: 7198

Re: Op amp matching

I realize Ios and Ibias can be as important as Vos about the quality of an integrator. The capacitor isolation resistance IR must be hight, easy with film caps, but that is not enough, the capacitor should not leak via the op-amp input pin. The OPA 2277 has a 3nA Ios and Ibias. About this specific p...
by terkio
Tue Apr 30, 2019 12:21 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 490
Views: 179663

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

My tester for EMI, hum, thermal drift is a hair drier. A cheap tool that does it all. An anecdote about thermal stability: A design of mine about a test equipement to test TV reference monitors. When they put my proto, in thermal testing to check the compliance with requirements about stability of l...
by terkio
Sat Apr 27, 2019 8:06 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 490
Views: 179663

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

First off, thanks to show all this nice work.
I do want to get some mu-metal....and I'll try lining the metal Hammond box with it.
I am very interested about this.