What signal generator for audio work?
Chris Tansit
I want to get into solid state and tube/valve amp repair.
Feel free to suggest a brands/models etc.
What other gear is handy to have?
I have a scope and a DC PSU.
Any good resources on the web? Books etc I should be reading?
Thanks
CT
Phil Allison
"Chris Tansit"
> Can someone please recommend a signal gen for audio work?
> I want to get into solid state and tube/valve amp repair.
> Feel free to suggest a brands/models etc.
** Ebay is your friend here:
Something like this will do everything and more for audio bench service
work.
> What other gear is handy to have?
** High power dummy loads for 4, 8 and 16 ohms - make your own with tubular
resistors and a bucket of water.
A " Variac " is a must to adjust the AC voltage PLUS an AC current meter
( moving iron) to see what is being drawn by the unit under repair.
Bute most important of all is a good stock of tubes, transistors, ICs, and
passives of all kinds - especially lots of electros.
... Phil
Mark Zacharias
news:4bc9538e$0$32007$c3e...@news.astraweb.com...
For general work I think any decent sine-square generator in good working
order would do.
Use sine waves for a general troubleshooting signal source, use square
waves, usually around 1 kHz as a good overall (quick) check for linearity.
One thing I've noticed for example, a square wave signal viewed on a 'scope
will quickly tell you if a loudness or filter switch is malfunctioning. One
channel may remain boosted or attenuated when the control is back in the
"neutral" position.
Also, square waves seem to show more easily the effects of dirty controls,
relays, etc as you are manipulating or tapping on them (when viewed on a
'scope of course).
I use a Leader solid state model at work (don't remember the model) but for
many years used an Eico 377 tube model. They can be found all over eBay for
under 50.00.
A new solid state model will run 179.00 and up.
I think most distortion analyzers sine wave generators built in - my Sound
Technology 1700B does. They can be had used for maybe around 400.00 or so.
Mark Z.
Tim Schwartz
different color as the IG-18, which is a bit older) This unit has
stepped frequency selection and an output meter. Really easy to work on
if it needs it. Likely available on e-bay or at hamfests for under $50.
I've seen filthy ones as low as $10. Of course the build quality of
the kit is a factor.
There are also lots of mods possible to make them lower distortion, but
some of the mods reduce the stability and make the settling time when
changing frequencies annoying at best, and damaging at worst. Also, the
unit is low enough in distortion for general use as is. If you don't
have or need a distortion analyzer, they are pointless.
That said, there a lots of good choices.
Regards,
Tim Schwartz
Bristol Electronics
P.S. Here's one on e-bay now:
190389304471
N_Cook
A calibrated , well at least consistently marked between ranges , attenuator
on the o/p is useful
William Sommerwerck
sell.
I don't remember the model number. About 35 years ago, "Audio Amateur"
published an article on modifying this generator for ultra-low distortion.
The "catch" is that when you change frequency, you have to wait a second or
two for the generator to settle.
I'd sell it for the original price of the kit. If you're interested, please
get in touch with me.
Jeffrey D Angus
> http://cgi.ebay.com/RAG101-Audio-Generator-Function-Signal-10-to-1Mhz_W0QQitemZ300417949135QQcmdZViewItemQQptZBI_Oscilloscopes?hash=item45f24e1dcf
But these are so much nicer to keep the shop warm with. ;-)
http://cgi.ebay.com/HP-205AG-Audio-Signal-Generator_W0QQitemZ320501528958QQcmdZViewItemQQptZBI_Signal_Sources?hash=item4a9f61397e
http://cgi.ebay.com/HP-Agilent-5245L-Frequency-Counter_W0QQitemZ390114618652QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item5ad4a4ad1c
http://cgi.ebay.com/HP-5245L-counter-parts-frequency-converter_W0QQitemZ190388895634QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item2c540fff92
Jeff
--
�Egotism is the anesthetic that dulls the pain of stupidity.�
Frank Leahy, Head coach, Notre Dame 1941-1954
Baron
Knock up a multivibrator circuit ! Four resistors, three caps, two
transistors & 9V battery.
--
Best Regards:
Baron.
Jeff Liebermann
>Can someone please recommend a signal gen for audio work?
A computah, of course. Get a 96KHz 24 bit sound card and some
software:
<http://www.sillanumsoft.org/prod01.htm> (see sig gen feature)
There are plenty of others, including some that I use on my iPod
Touch. (I need 2 tones, with very low intermod products, for testing
SSB and ACSSB radios). The nice thing about the laptop or iPod Touch
approach is that it's portable and can be used in the field.
More money but also more versatile are various USB
oscilloscope/generator conglomerations. For example:
<http://www.syscompdesign.com>
>I want to get into solid state and tube/valve amp repair.
You're a bit late. Xsistors happened in the late 1960's.
>Feel free to suggest a brands/models etc.
Price limit? Any specification limits? Need anything besides a
signal generator (pulse, sweep, white noise, portable, etc)? It's
difficult to be specific when your requirements are a bit vague.
>What other gear is handy to have?
Sweep generator, white noise generator, pink noise generator, audio
spectrum analyzer, distortion analyzer, power supply, DVM, dummy
loads, soldering iron, sanity tester, coffee maker, billing software,
etc.
>I have a scope and a DC PSU.
Ok, that's a start. Add a tube caddy to the above list. It really
impresses customers over 60 years old. (Yes, I have one).
>Any good resources on the web? Books etc I should be reading?
Dunno. I never RTFM or Google for info until after I get into
trouble.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Robert Macy
There are battery powered versions.
There are dedicated instrument packages.
I started using my PC's Sound Card. It was free. Gave me total
control of what was produced and produced the lowest distrotion I've
ever seen.
Then I started using the sound card as a 'scope' and then as a
spectrum analyzer.
So now I have a two channel input high quality spectrum analyzer with
two channel tracking generator outputs!
You want to test the quality of your amplifier? Best system for it.
Jeffrey D Angus
> Then I started using the sound card as a 'scope' and then as a
> spectrum analyzer.
>
> So now I have a two channel input high quality spectrum analyzer with
> two channel tracking generator outputs!
Ya wanna give us a hint as to who's software you're using?
Jeff
--
“Egotism is the anesthetic that dulls the pain of stupidity.”
Phil Allison
"Jeffrey D. Asshole"
> But these are so much nicer to keep the shop warm with. ;-)
>
> http://cgi.ebay.com/HP-205AG-Audio-Signal-Generator_W0QQitemZ320501528958QQcmdZViewItemQQptZBI_Signal_Sources?hash=item4a9f61397e
** Antique, overpriced junk.
** Wrong category entirely.
** Not even on the same planet.
Why don't you go drop dead- asshole ??
... Phil
Jeffrey D Angus
> "Jeffrey D. Asshole"
>
>> But these are so much nicer to keep the shop warm with. ;-)
>
Come back when your meds kick it.
"Flame all you want, I'll make more"
Robert Macy
Much software came on CD with the soundcard, but did not do exactly
what I wanted
I think everything you need is free and available at sourceforge under
gnu license.
There may be other free, or low cost, utility software out there,
don't know
Basically, you need software to talk to the soundcard and software to
manipulate what you want to do.
To talk to the soundcard, I used the soundcard's 'built-in' ASIO
drivers and used ASIO SDK from Steinberg. To write custom C programs,
I used free MS command line C compiler. For FFT, I used the free
'fastest FFT in the west' called fftw
http://www.steinberg.net
asiosdk2.2.zip
Jeffrey D Angus
> Basically, you need software to talk to the soundcard and software to
> manipulate what you want to do.
Thanks Robert