Search found 3598 matches

by mediatechnology
Wed Apr 17, 2019 6:14 pm
Forum: The Peabody Lounge
Topic: End of "The Telephone Flea Market"
Replies: 1
Views: 34

End of "The Telephone Flea Market"

DOVER — After 45 years on the air, WOKQ and WPKQ have pulled the plug on “The Telephone Flea Market.” The radio flea market was a tradition for many New Hampshire listeners who would tune in Sunday mornings to hear about the items callers were selling around the state and other parts of New England...
by mediatechnology
Wed Apr 17, 2019 2:15 pm
Forum: Build
Topic: Simple pcb design program
Replies: 27
Views: 33660

ExpressPCB now includes Gerber files with every order

ExpressPCB now includes Gerber files with every order no matter how small. You're only locked into buying the first set of boards and it can be a super-small order. I've opened their Gerbers in DFMNow! and they work just fine. Some PCB manufacturers use different file extensions but that is fixed by...
by mediatechnology
Wed Apr 17, 2019 2:07 pm
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 40
Views: 1223

Re: Op amp matching

Pulling numbers out of air: If I have 100 uV of preamp output noise above the servo cutoff frequency what good is 10 uV DC precision? Try running experiments in the real world with real components rather than simulation. If you connect a DC voltmeter to the output of a servo'd high gain preamp and m...
by mediatechnology
Wed Apr 17, 2019 5:36 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 40
Views: 1223

Re: Op amp matching

It may be ineffective to reduce Vos much further below 100µV given that the 1/f noise of the preamp will dominate.
by mediatechnology
Tue Apr 16, 2019 5:02 am
Forum: Pro Audio Design
Topic: was HYPEX amps cheap surround system
Replies: 42
Views: 28112

Re: was HYPEX amps cheap surround system

I have some Hypex nCore modues on my bench right now that are in a client's bass amp.

Do you see about 1V P-P of residual carrier on the output?
by mediatechnology
Tue Apr 16, 2019 5:00 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 393
Views: 150601

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

They are back-to-back and will be epoxied together.

The small metal "hats" I made from 3AG fuse ends I found worked pretty good.
I like wearing tin foil hats myself and the transistors seem to like it too.
by mediatechnology
Mon Apr 15, 2019 7:31 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 393
Views: 150601

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

I meant to ask as I got in some 2068DD in readiness before you finally decided on the 5532. I assume the differences are small enough as to be not a worry in use? I really don't know the answer to that but I suspect it may depend on the gain. The compensation allows for either the NJM2068 or the 55...
by mediatechnology
Mon Apr 15, 2019 5:12 am
Forum: Pro Audio Design
Topic: Op amp matching
Replies: 40
Views: 1223

Re: Op amp matching

I agree the OP07 is a bargain.

We should be saying the same thing about the NE5532 or, in some apps, the NJM2068.
Those two ICs were about the only 4" product JRC didn't EOL.
Unfortunately JRC did EOL the OP07.

The dual OP07 isn't such a bargain.
by mediatechnology
Sat Apr 13, 2019 2:35 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 393
Views: 150601

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

Thank you. What schematic capture/layout tools are you using? if you don't mind my asking, that is... I use the Kenner Easy Bake Oven (aka Express PCB). I manually route. Made some noise measurments: https://proaudiodesignforum.com/images/jpg/ZTX851_MC_Preamp_Output_Noise_62dB_Gain_800.jpg ZTX851 Mo...
by mediatechnology
Fri Apr 12, 2019 8:27 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 393
Views: 150601

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

Done! https://proaudiodesignforum.com/images/jpg/Flat_Balanced_Input_Moving_Coil_Phono_Preamp_ZTX851_PC_Board_800.jpg Flat Balanced Input Moving Coil Phono Preamp Using The ZTX851 PC Board Got the boards in today and assembled. Layout passes DC tests and has gain. The ZTX851 are not physically bond...