[sdiy] Audio test generator and mesurement tool - can anyone suggest a good set?

[Neil Johnson]

On 22/04/2013 18:07, cheater00 . wrote:
> Hi guys,
> I'm slowly building up my workbench, and after getting a Tek 7704 I
> now need a good sinewave generator. I thought to myself, why buy just
> a sinewave generator, when I could get a distortion meter? Those have
> sinewave and square built in, are of variable frequency, and it's
> better to have one large box than two large boxes.

My thoughts on various test equipment:

http://www.milton.arachsys.com/nj71/index.php?menu=2&submenu=8

The signal generator in a distortion analyzer is unlikely to generate 
square waves, only very low distortion sine waves.  Depending on the 
type of distortion you want you want to measure you might need two 
signal generators.

> Could someone suggest a good distortion analyzer that can be had
> relatively inexpensively? I'm probably looking at vintage equipment at
> this point because it can be had fairly cheaply. Something around 100
> Euro would be a good start, but it's only a very roughly estimated
> price range.. maybe those things can be had for much less -- or only
> for much more?

Good distortion analysers still command good prices, so I think you need 
to review your budget.

> Also: are distortion analyzers usually limited to 20 Hz - 20 kHz, or
> are there ones that go below 1Hz and high above?

Unlikely to go down to 1Hz, but certainly above 20kHz.

> What is the 'workhorse' distortion analyzer? Is there one or a few
> that were very good and very popular? It's important to me not to buy
> something relatively unknown, so that when it breaks I can find
> replacements, schematics, and people who know how to repair them.

The HP 8903 (A or B) is a good machine.  Tektronix and Boonton are two 
other names to look out for.
Although it really depends what you want to measure.  The lower in 
distortion the higher the price.

> What other tools - other than a distortion analyzer - could I see
> myself using when building filters, mixers, amplifiers, etc? In the
> future I'd also like to work a bit on tube circuits, but this is not
> currently a major focus.

See link above for some ideas.

> My plan is to get a distortion analyser (with integrated square and
> sine wave oscillators), and I already have a frequency counter for the
> Tek 7000 coming in. I'd probably get a curve tracer at some point too,
> and maybe a precision current and voltage source or precision
> amplifier. Still need an esr/LC meter, I saw some boxes online. To
> round  this off I'd probably get an isolation transformer and possibly
> variac (or both in one box). Am I missing something as far as the most
> basic measurement equipment goes?

It really depends on what you want to build ("filters" is a very broad 
subject), how much investigation and development as opposed to 
build-n-test someone else's design, and how detailed you want to get in 
terms of measurement accuracy and precision.

Neil
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