List your favorite(cheap) test tools for audio systems

[dave_gerecke]

I can't disagree with Star882's assessment about losing female engineers; losing a pretty one is a major loss. If we are to assume that that is Star882 in the avatar, and I have no reason not to, she's definitely a rare specimen in the species!

Peace,

Dave

[Wavebourn]

I use this record that I made once to test my equipment, since neighbors don't pay attention on it, but complain about any nice music.

http://wavebourn.com/rain_helicopter.mp3

[Geek]

My favorite three cheap toos:

Finger - look for hot parts that shouldn't be.

Nose - For finding hot parts around HV or things too hot for finger (or for when finger is out-of-order with a bandage from finding said hot part).

Brain - "Wha ain'ts it werkin' nao?"


After that, a multimeter can't be beat



Cheers!

[unclejed613]

at work i usually use Robin Trower's "Too Rollin Stoned" to test speakers. since it's done by a 3 piece band, there are 3 distinct instruments for bass, midrange and treble, so if a driver in a speaker is blown, there's little doubt which one it is. plus, since i've been using it as test music for a very long time, i know the sound well enough to detect more subtle problems with speakers and amps. other 3-piece rock bands i like to use are Mahogany Rush, Grand Funk Railroad, and Jimi Hendrix Experience.......... i guess there isn't much doubt where my musical tastes lie.......

[kzim229]

I haven't seen this mentioned yet.
P3 P4400 125VAC Kill A Watt Electricity Usage Monitor - eBay (item 390227722320 end time Sep-18-10 01:34:11 PDT)

woops! Measuring ac amperage with multimeter

[Rob11966]

This one hasn't been mentioned and I use it all the time -

A fluke hand held IR thermometer. About AUS 120 (or US 119.9 )

I use it all the time to measure temperatures of resistors, heatsinks and tubes.

Rob

[davygrvy]

It isn't really cheap, but this is working-out for me. I've gotten into collecting Tektronix 5000-series plugins. I'm about a year into my collecting "bug" and think these two units are a must for any serious audio nutt:

AA5001 - distortion analyzer
SG5010 - low distortion generator
and a TM5006A mainframe as well

Both those units can be automated over GPIB

The extra slot you can use for a little monitor scope like the SC502 on the agc'd function output from the AA5001

Grab another mainframe and collect some more cool plugins like a PS5010 lab supply, or maybe a DC5009 frequency counter. Don't consider a DC503A; not good for audio.

And it just keeps going all nice and compact, too.

[davygrvy]

Originally Posted by Rob11966

This one hasn't been mentioned and I use it all the time -

A fluke hand held IR thermometer. About AUS 120 (or US 119.9 )

I use it all the time to measure temperatures of resistors, heatsinks and tubes.

Rob

I got one similar from RadShack last week for $20

[gray5596]

I like ENZO's description of an AC test cord, a death cord.

I still use a "death cord" but after getting bit a few times, I decided to power my bench with a 20 amp line isolation transformer (electronics surplus store for $25) fed by a GFCI outlet. With this arrangement neither side of the isolated AC is tied to earth ground, so I have a degree of safety in case I accidentally touch the wrong wire.

On the bench, a favorite "cheap tool" is a B&K LCR meter. (It was purchased dirt cheap because it was non working, easy fix) It measures ESR at up to 100KHz which is sometimes critical for testing switching power supply capacitors.

Another favorite is a DPM milliohmmeter (bought used and repaired for under $50) which is conveniently battery powered. It can measure speaker wires with an accuracy to .00001 ohm. It can also inject up to 2 amps so the wires or circuit is tested under a real load condition. This meter has found its share of bad switches, crushed cords and loose connectors.

I also enjoy my AEMC megohmmeter because it too is battery powered and applies either 500 or 1,000 volts while testing. (These can still be purchased for $50 to $100) Some components test fine with a low voltage ohmmeter, but when you apply 500 volts or more, it shows how they change value under real world conditions. If I need lower voltage, I simply put the appropriate resistor in series with the resister under test to get the voltage needed.

Even though I have newer and "better"meters, I still use my 20+ year old Fluke 8050A meter on a regular basis. It is a 4.5 digit meter that measures conductance up to 100,000 Meg ohm, voltage measurements can be made in decibels with 16 different impedance settings, AC and DC current with a resolution of 0.01 uA. This was my 1st Fluke meter and it has been a favorite for years. I bought it used for $50 from a large company that decided it was cheaper to buy new meters every 3 years rather than having them calibrated. Hey, sometimes corporate decisions can benefit the DIYer.

[unclejed613]

i have a test setup to measure the beta of output transistors. it consists of a 100uA current source to feed the base and a 30V power supply with 2A current limiting and an ammeter in the collector circuit. since the base current is known, the collector current divided by 100uA=beta. the current source doesn't care if the transistor is a regular bipolar or a darlington. i have been able to detect counterfeit Sanken darlington (2SD2390/B1560) devices with this test, since the fakes have very low beta and the real ones saturate at 100ua base current. the transistor is clamped to a heatsink with a squishy "gap-filler" sil-pad to conduct the heat.