Search found 18 matches

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: 771510

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
by Audio1Man
Sat Apr 06, 2019 4:26 pm
Forum: The Peabody Lounge
Topic: karma
Replies: 8
Views: 7035

Re: karma

I don’t have a meter reading problem anymore, where the gate is left open. Gas, Water & Edison are all Smart Meters. Most problems I see are if it is heavier than I phone it’s too much work, even if they have an APP. One of my grandson’s was on that road until he understood and he got into a tra...
by Audio1Man
Mon Apr 01, 2019 12:28 pm
Forum: Test, Measurement and Repair
Topic: Welcome to the Test, Measurement and Repair Forum
Replies: 11
Views: 64020

Re: Welcome to the Test, Measurement and Repair Forum

I was listing to my music system this mourning and it failed. My system consist of Electro-Voice SP13.5RBXWK Rearaxial Softspeaker driven by a Crown Belchfire BF6000SUX with the Rane P1 14 Pseudoacoustic Infector preamp with the Jensen's JE-EP-ERs Multi-denomial Transpedance Informer input stage (I ...
by Audio1Man
Sat Mar 16, 2019 1:14 pm
Forum: Test, Measurement and Repair
Topic: AP System One Front End
Replies: 1
Views: 28862

Re: AP System One Front End

OK, not many persons got this. Bruce spent lots of time correcting several small errors that make small improvements that give the total system performance. There are others tricks and when another Mfg copied the special tricks this stopped all schematics/service information being released. The Syst...
by Audio1Man
Mon Mar 04, 2019 3:50 pm
Forum: Pro Audio Design
Topic: Preventing mic preamplifier HF oscillation
Replies: 7
Views: 9491

Re: Preventing mic preamplifier HF oscillation

A small resistor in each BASE will DQ the circuit and will add some noise. You can also add a ferrite bead to each BASE this will also DQ the circuit. C1 & C2 could be smaller. With SMD layouts the BW always is much higher and amplifiers have a better chance of becoming an oscillator. When the p...
by Audio1Man
Fri Feb 08, 2019 1:28 pm
Forum: Test, Measurement and Repair
Topic: HP400F Meter Wet Slug Tantalum Capacitor Reforming
Replies: 21
Views: 70739

Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

By changing the 0.01uf cap to about 0.064uf the BW would be about 15.7 kHz, however it should only be used as a ref not a true calibrated standard.
My 2.2uf cap is about 400Hz and it is a debug tool for HUM FINDING. it is much lighter & smaller than the AP & computer.
Duke
by Audio1Man
Thu Feb 07, 2019 7:16 pm
Forum: Test, Measurement and Repair
Topic: HP400F Meter Wet Slug Tantalum Capacitor Reforming
Replies: 21
Views: 70739

Re: HP400F Meter Wet Slug Tantalum Capacitor Reforming

My old 400FL has had 2 mods I added many years ago, and it is a great tool. First I added a unity buffer to the Range Switch Output (before the meter circuit) to a BNC to be a full range linear output signal. This signal connects to the scope or spectrum analyzer. This mod removed the distortion fro...
by Audio1Man
Tue Feb 05, 2019 6:16 pm
Forum: Test, Measurement and Repair
Topic: Welcome to the Test, Measurement and Repair Forum
Replies: 11
Views: 64020

Re: Welcome to the Test, Measurement and Repair Forum

Hi All
I worked for Audio Precision for many years as and Analog Engineer, now semi-retired. I service /older AP’s and have been to answer some questions. I have a web “sound-logic-la.com”.
Duke