Search found 17 matches

by Audio1Man
Fri Jul 15, 2022 7:19 pm
Forum: Pro Audio Design
Topic: Discrete Op Amp clipping behavior
Replies: 6
Views: 729

Re: Discrete Op Amp clipping behavior

Phase reversal is very common in most FET IC when over driven. Try a non FET IC
Duke
by Audio1Man
Mon Jun 13, 2022 5:21 pm
Forum: Test, Measurement and Repair
Topic: PC Power Supply Failures After Running on a UPS
Replies: 6
Views: 1784

Re: PC Power Supply Failures After Running on a UPS

The power line may have had a big voltage spike. Lost the netural first (I lost a VCR in smoke)? Did some other devices fail? Check if surge protectors are GOOD.
Duke
by Audio1Man
Tue Oct 27, 2020 6:05 pm
Forum: Pro Audio Design
Topic: How Closely Do The Values Of Capacitors From The Same Lot Match?
Replies: 26
Views: 65548

Re: How Closely Do The Values Of Electrolytic Caps From The Same Lot Match?

The THD% in resistors that are shown in the table maybe misleading. What frequency & power levels did he use in testing the THD? During the development of the ATS2 (the first all SMD AP) I had 0.0006 THD% until the 10Hz test when it went sky high. At first I thought it was oscillating. Probing a...
by Audio1Man
Wed Aug 19, 2020 6:51 pm
Forum: Test, Measurement and Repair
Topic: Which Audio Analyser?
Replies: 26
Views: 64754

Re: Which Audio Analyser?

Hello AnalogJoe I have an APIB USB ADAPTER that drives the System One. System Two & Cascade under ApWin 2.24 that runs OS from XP, Vista, Win7, Win8 & Win10. My next batch is due from my assy. house 31 Aug. I should have some overages after filling my back orders in Sept. http://www.sound-lo...
by Audio1Man
Thu Jun 11, 2020 11:23 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 227
Views: 294393

Re: Phono Transfer System Construction Information

Hi Brian

If you have access to an Audio precision the RIAA curves & tests are part of the software tests.
Duke
by Audio1Man
Wed Jun 03, 2020 6:46 pm
Forum: Test, Measurement and Repair
Topic: Classic Bead Tantalum Capacitor Failure
Replies: 17
Views: 53052

Re: Classic Bead Tantalum Capacitor Failure

Hi AnalogJoe The AP S1 has Tantalum only as pass modes and they are common failures. Sometimes the 15 volt trace also opens on the SINP assy. When I repair/service them I replace them with Panasonic low ESR parts. Tantalum’s is also prone to failure where ripple currents are present. When we develop...
by Audio1Man
Sat Sep 14, 2019 11:40 am
Forum: Build
Topic: Audio RMS versus Peak
Replies: 21
Views: 52693

Re: Audio RMS versus Peak

In Pro Audio I would not use rail to rail op amps. Look @ the THD/SPECTRUM of the output as output level increases. Many op amps will go nonlinear when the output gets near to 3 volts from the rails voltage. To get clean 8v rms the op amp rails need to be slightly larger than 15 vdc.
Duke
by Audio1Man
Sat Apr 27, 2019 6:12 pm
Forum: Test, Measurement and Repair
Topic: HP3582A
Replies: 3
Views: 24267

Re: HP3582A

The HP3582A was a great instrument years ago, however with 25kHz BW and 70dB dynamic range almost any Sound Card will be a better instrument for today's jobs and much smaller.
by Audio1Man
Sat Apr 27, 2019 4:19 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 499
Views: 435998

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

Wayne

What about placing the BIG TX into a 5 Gal steel paint can? This may give you another 10-20dB reduction.
by Audio1Man
Fri Apr 26, 2019 6:01 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 499
Views: 435998

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

Hi Wayne
Is the “HUM” Electrostatic or Magnetic? What is the difference in FFT by wrapping the pickup in Alum foil vs putting it in a steel paint can and closing the lid? What is your area lighting type? Incandesce, fluorescent tube or switching fluorescent / LED type?
Duke