Search found 3480 matches

by mediatechnology
Wed Feb 20, 2019 5:50 pm
Forum: Build
Topic: Affordable umblicals.
Replies: 4
Views: 19

Re: Affordable umblicals.

billshurv wrote:
Wed Feb 20, 2019 9:04 am
Newark is part of the farnell group so probably is the same.

They grow up fast, its just with 20 years between eldest and youngest....
I'm amazed at how many ways they can brand the same company.

My older brother and I are 9 years apart; 20 is quite a span.
by mediatechnology
Wed Feb 20, 2019 5:39 pm
Forum: Test, Measurement and Repair
Topic: Red Pitaya
Replies: 2
Views: 15

Re: Red Pitaya

Thank you for posting that!

I hadn't heard of it and need to do a deep-dive. Looks really cool.
by mediatechnology
Wed Feb 20, 2019 8:46 am
Forum: Pro Audio Design
Topic: A Modern Loftech TS-1 Audio Test Set
Replies: 65
Views: 31786

Re: A Modern Loftech TS-1 Audio Test Set

in large scale production I have seen small specialty circuits come and go You mean like the 74C926? I have an idea: Why don't you code a PIC to emulate the 74C926 so that TS-1 owners who need one aren't orphaned. TS-1 Schematics: https://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=16&t=4...
by mediatechnology
Wed Feb 20, 2019 6:28 am
Forum: Build
Topic: Affordable umblicals.
Replies: 4
Views: 19

Re: Affordable umblicals.

That's a good price Bill. That CPC/Farnell site is new to me here in the US. It looks like the cables are the same ones we see here in the MCM brand at Newark. I've also used the Planet Waves umbilicals from Amazon when I used to shop there. They were good cables but a D to XLR breakout in that bran...
by mediatechnology
Tue Feb 19, 2019 8:03 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 308
Views: 140803

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

I haven't experimented using this servo with switched gains but I think it has advantages. Olaf alerted me to this technique in a mic preamplifier thread. Since I had a similar topology on my bench in the form of the MC preamp I decided to try it there. It worked so well I decided to use it even tho...
by mediatechnology
Tue Feb 19, 2019 6:18 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 308
Views: 140803

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

Negative resistors are a way to make oscillators ! You'll note that the positive feedback is rolled off at high frequencies (above fc) by virtue of it being an integrator. You can simulate the servo if you wish. I recall Gary Hebert of THAT doing a sim for me. I would use 1% resistors. The 2C integ...
by mediatechnology
Tue Feb 19, 2019 5:16 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 308
Views: 140803

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

I went back to my notes and remembered where the extra two bridge resistors came from. (R15 and R16). During my initial experiments I had the servo sense the INA output prior to the THAT1240 stages. There was nothing to pin the floating Deboo servo to ground so the added two resistors were required...
by mediatechnology
Tue Feb 19, 2019 4:09 pm
Forum: Test, Measurement and Repair
Topic: entropy continued?
Replies: 6
Views: 243

Re: entropy continued?

Breakers even better!
by mediatechnology
Tue Feb 19, 2019 4:08 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 308
Views: 140803

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

T-bias' benefit is the low frequency common mode rejection improvement. It is a capacitor value mismatch improver. I've never tried bootstrapping the CM in a mic preamp similar to InGenius. About the only complexity T-bias adds in a servo situation, where servo is injected into the inputs, is the re...
by mediatechnology
Tue Feb 19, 2019 3:22 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 308
Views: 140803

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

OK, just checked it and R15 and R16 can be eliminated.
R17 and R18 become 10KΩ.

The servo attenuation is now "2."

Good catch!