Sound Generator ?

[Zerotolerance]

I am looking to purchase one of these.

**broken link removed**

or

https://www.google.com/products/cat...sa=X&ei=frV8Tob4HrKMsAL_lM1A&ved=0CJcBEPMCMAM

Any suggestions before I pull the trigger on one or the other?

 

[Sceadwian]

It's kind of hard to comment if you don't say what you're going to be using it for.

 

[carbonzit]

I am looking to purchase one of these.

**broken link removed**

Heh; that name ("Sinometer") could be interpreted one of two ways: either something having to do with sine waves, or a meter made in China. (Just guess where that thing is made.)

And "one of the world's largest manufacturers of test equipment"? Sorry, I don't think so. (At least not test equipment recognized for its quality.)

 

[ronsimpson]

One of the signal generators is "DDS (Direct Digital Synthesized)" That is a good system. But this generator has no data. Try to find more data.

 

[Sceadwian]

If this is for sound the Instek unit looks good, it's a DDS synth with a TTL input, the other one is a pure sine/triangle/square and is more of a basic signal generator. The Instek unit is a 3mhz DDS that can be used for signals up to 200khz (Read up on DDS to understand why this is) but again if you don't state what you want to use this for (sound generator is a very broad term) You could use a PC sound card as a sound generator, for virtually no cost.

 

[Zerotolerance]

I will be using it to repair audio equipment or anything audio related. Main reason i am thinking about purchasing it is to fine tune audio equipment.

 

[Sceadwian]

If all you want is a basic function generator, just use an audio player, heck you can used an old CD player if you wanted to. Generate the waveforms on a computer burn them to a CD and there you go, you can even use complex waveforms then, I've done this before for basic testing purposes, lab quality equipment like that is not required nor needed to fine tune.

Of the two you listed the Instek is the only possible choice, the other one is for low end RF range (don't look at the 3mhz spec for the DDS generator it's output frequency only goes up to 200khz)

By the way there are AVR and PIC based DDS signal generators that are usable for the audio range.

 

[squishy36]

I'd go with the Instek. I've seen some of your other posts and threads elsewhere Zerotolerance and I think the DDS generator would be fine for your needs and I know you'd be fine with the $150 expense. Then you'd have a good basic test bench setup: scope, function generator, power supply, and some good DMMs.

Just realize that DDS generators don't have great distortion specs, so you won't be able to get high quality audio signals for testing. But that can be fixed by using a CD with pure waveforms if that kind of thing is important to you. I've got a couple of DDS generators that are loaners; I use them quite a bit and am happy with them.

A couple of comments. First, make sure you have some good probes to use with your scope. Also make sure you know how to use them properly and compensate them correctly. Second, you're going to want to have some methods of making interconnections between the things you test and your test equipment. I long ago standardized on using RG-58 cable with BNC connectors, mainly because most test gear uses BNC connectors. I also use 4 mm banana cables and BNC to banana adapters. Two suppliers' equipment I've used are Pomona Electronics and Cal Test Electronics. You may be a bit taken aback by the cost of some of the items, but with care, they'll last a long time. I'm still using some Pomona banana patch cords I got over 40 years ago and some HP coax cables I got 30 years ago.

I haven't looked up the specs for the Instek, but the typical DDS generators I've used (a few different models of HP and B&K) typically have their sine waves go up to the rated frequency of the generator. More modern ones also have the same spec for their square waves or sometimes about half the sine wave frequency. Then the other waveforms like pulse, triangle, sawtooth, etc. are typically at substantially lower frequencies. For example, an older B&K model would put out sine waves at 80 MHz, square waves at half that, and triangle waves at 100 kHz. Newer equipment does better.

 

[Sceadwian]

squishy, the DDS he listed his rated to 200khz, it should be low distortion in the audio range.

 

[squishy36]

Here's some **broken link removed**; looks like a typical DDS generator with sine wave to 3 MHz. Personally, I'd want the model that also could display the output voltage. Note the sine wave distortion spec goes up quite a bit for frequencies above 200 kHz. Overall, it looks like a reasonable generator for the money. The manual is pretty good for a Chinese-made instrument; I like that they've given some typical applications and had a native English speaker proofread it. It appears they've plagiarized some diagrams from an old B&K function generator app note though. At least their pictures look remarkably similar (see page 31 in the manual) -- I noticed this because I used those figures in a document I wrote (I had B&K's permission).