Equipment for bench testing

Raccoon1400

Super Member
My bench has been swamped with power amps and I need a few more things to bench test them.

I have:
signal generator
tektronix 2215A scope 60MHz
2 8ohm dummy loads from digikey: FVE300-8.0-ND
fluke 115 RMS meter

I still need a proper set of scope probes. They need to have the 10x switch.
I'm looking at ones on digikey, but am not quite sure what I need, any suggestions?

I am going to get another pair of dummy loads.

Is there anything else I need?
 
How about:

Frequency counter

4 ohm dummy loads

Simpson 390-2 watt meter

Variac

As for the scope probe, you can check and see what Tektronics recommends and then look for a less expensive equivalent

I assume you have a soldering station etc. You should also get a Hakko 808 desoldering tool, it's the very best money you will ever spend for repair work
 
You need a THD analyzer and a low-distortion oscillator (unless it's included in the analyzer), and you'll need a big stinkin' variac to set line voltage on the nose for spec checks.
 
How about:

Frequency counter

4 ohm dummy loads

Simpson 390-2 watt meter

Variac

As for the scope probe, you can check and see what Tektronics recommends and then look for a less expensive equivalent

I assume you have a soldering station etc. You should also get a Hakko 808 desoldering tool, it's the very best money you will ever spend for repair work

My other multimeter measures frequency.
for the 4 ohm loads, I will use two pairs of 8ohm.

What is a variac?
I have a DBT


You need a THD analyzer and a low-distortion oscillator (unless it's included in the analyzer)
I have a function generator, HP3311A, or is this something else?
Where do I get a THD analyzer?
 
variac is a variable transformer ..it will go from o v if your lucky to maybe 20 or 30 percent more than your line voltage . well handy to have on your bench
 
Function generators have much more distortion than good audio amps. To measure amplifier distortion accurately, you need a sinewave source and an analyzer with THD residual roughly one order of magnitude below that of the best amp you're going to test. Look for older HP, Tek, and Sound Technology models.
 
You may want to test components-especially cap.'s. Maybe an LCR meter-I use an Elenco LCR-1810.
As for scope probes-try to match the input impedance of your scopes vertical amplifiers as closely as possible., and make sure they cover at least the bandwidth of your scope.
 
What is a variac? Where do I get a THD analyzer?

I use a Powerstat model 116B variac rated at 10 Amps, I paid $82.00 on eBay

A good choice for a distortion analyzer is a HP 333A, I paid $100.00 on eBay.

Try to find one that comes from a working environment and includes the power cord. The 333A uses an unusual cord and replacements are expensive. I changed the socket on mine to accept a standard IEE cord.
 

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How about an Audio Precision One analyzer, been looking myself since bonus time.
Well yeah, if you can make the plunge.

I bought one used from my ex employer. It was clean and was a dual domain unit (analog and digital) with wow and flutter and a few filters. Now if you ask me when I'm going to use the W&F function again, I can't answer that. It relegated my Sound Technology 1701 to a closet. The oscillator on them is very clean. The residual THD is very low. It's procedure writing capabilities are awesome. It's a very great piece of test gear. You'll need a scope, computer and APIB interface to run it, but I have absolutely no regrets.

There is a gotcha though. AP is trying to push their newer products and last I heard they refuse to work on the System One's. They might let you trade it in towards a more current unit.

For Analog measurement, I don't think there's better out there.
 
Most of those electronic devices are available on an I Pad now with Studio Six software.
You'll need a break out box and a nice condenser microphone with a phantom power supply. The overall cost will be less then buying the individual parts.
You'll have more bench/wall space to actually get work done.
 
Jon,. what is an APIB interface??

An APIB interface is how the computer talks to the instrument. It stands for Audio Precision Interface Bus, I believe. It is similar to HPIB/GPIB, but I think they did something different so you have to use their computer interface card. I have two flavors. 1. is a PCMCIA card that plugs into a laptop. 2.the PCI computer card. Both of these are sold through Audio Precision. I think it was about $50 bucks for the PCMCIA interface and about $200 for the computer card.

I have a System One, which usually had the APIB interface fitted. Occasionally,
you'd see a System One or Two with a GPIB interface. AP offered it as an option. In hindsight, I wish I had one instead.

Anyway, this interface is something you have to keep in mind if purchasing used. I believe still sells the interfaces though. Their newer stuff is more likely controlled through an ethernet or USB interface.
 
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