Search found 304 matches

by terkio
Sun Jan 31, 2021 6:20 pm
Forum: The Peabody Lounge
Topic: beverly hillbilly storm windows and cybernetic heat control
Replies: 37
Views: 105307

Re: beverly hillbilly storm windows and cybernetic heat control

I have some spare GFCI outlets in my stash, so the outlet by my bed now looks like a good candidate for GFCI. JR I searched to know what a GFCI is. I found a lengthy description that keeps repeating it protects from faults but nothing really clear ( or I was not patient enough ). In France we have ...
by terkio
Thu Jan 28, 2021 3:38 am
Forum: Test, Measurement and Repair
Topic: how to test relays for phono signals
Replies: 15
Views: 69058

Re: how to test relays for phono signals

crin wrote: is there a particular reason why you suggest the 1510 instead of the 1512?
The datasheet is clear.
Here high gain is needed.
by terkio
Sat Jan 23, 2021 1:47 pm
Forum: The Peabody Lounge
Topic: digital thermometers.... arghhh
Replies: 21
Views: 45529

Re: digital thermometers.... arghhh

JR. wrote: Sat Jan 23, 2021 1:21 pm I notice that some new weather remotes track barometric pressure too (mine doesn't)... it seems temp, humidity, and barometric pressure should be enough information to predict weather.

JR
Barometric pressure is the most important.
by terkio
Fri Jan 22, 2021 3:36 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 325929

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

For the balanced only version, I would manage going from 4 caps to only one, by means of footprints to allow the cap to jump over the J1 node.
by terkio
Fri Jan 22, 2021 1:50 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 325929

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

I do not understand about J1 J2.
I see a balanced-only configuration as a underpopulated board, no J1 no J2 no VR2 but a strap, four caps become one.
by terkio
Thu Jan 21, 2021 8:20 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 325929

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Yes. A link given by mediatechnology in a previous post. http://www.janascard.cz/PDF/An%20ultra%20low%20distortion%20oscillator%20with%20THD%20below%20-140%20dB.pdf Very informative, a key source. With: Resistors are preferably 0.1%, 15 ppm/K through-hole types, capacitors are preferably polystyrene...
by terkio
Wed Jan 20, 2021 4:47 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 325929

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

I was amazed to see very good notch depth despite a +/- 10% capacitor. Thanks to the two trimmers adjusted in SE mode to accurately get Fc 1KHz, I get -96dB notch depth on the 6 cases I simulated. The trimmed 15.9k range is: 14.5k to 17.7k. The trimmed 15.9k/2 range is: 7.4k to 8.6k. So, I think you...
by terkio
Wed Jan 20, 2021 1:46 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 325929

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

I have done more work about the two ways to build a balanced notch filter. This is about J1 and J2. What is best two jumpers or one jumper. I had thought a twin H was better rather than a double Twin T. It looks good and can be built with all equal capacitors. Then I realized that this was not a rat...
by terkio
Tue Jan 19, 2021 4:57 am
Forum: The Peabody Lounge
Topic: digital thermometers.... arghhh
Replies: 21
Views: 45529

Re: digital thermometers.... arghhh

mediatechnology wrote: Tue Jan 19, 2021 4:43 am You need a "cotton region" shelter for your outdoor instruments...

https://proaudiodesignforum.com/forum/p ... f=12&t=476
Definitely. This is the real thing and it would look great in JR backyard. 😀
by terkio
Thu Jan 14, 2021 4:33 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 325929

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

So far, with simulations I found no difference. Virtual grounds connected or not, no difference detected. The unbalances, I tried: inputs amplitudes 0.25 0.75 ( iso 0.5 0.5 ) input resistance 1K 2K ( iso 1K 1K ) With or without differential output load 100K. Interesting. I found the same thing on t...