Re: 1KHz 0dBu pocket generator
« Reply #20 on: December 06, 2020, 09:16:44 AM »
Need to engrave fader faceplates soon, among other calibrations.
Embarrassed to say I threw money at this problem by purchasing a NTi Minirator.

Timley thread! Thanks everyone.

How do you like it?


Whoops

Re: 1KHz 0dBu pocket generator
« Reply #21 on: December 06, 2020, 12:36:25 PM »
There are numerous function generator apps for the iPhone, and probably for Android. Other than needing an external adapter to connect the phone, is there a reason why you wouldn’t go the simple route of finding the right app? What am I missing?

Hi Ian, I also think I'm missing something here...

I do the 1KHz at 0dBu easilly with my function generator, I just measure the AC output with the multimeter and set it to the correct voltage.
I do the same also if the Signal generator is my computer, phone or tablet.
We all have a Phone or computer and a DMM, so whats the need for this?

thank you, sorry if I forgot something and please fill me in if thats the case

thanks

ruffrecords

Re: 1KHz 0dBu pocket generator
« Reply #22 on: December 06, 2020, 04:01:31 PM »
We all have a Phone or computer and a DMM, so whats the need for this?
Many of us have these but lots of people asking questions about their new mic pre builds clearly and their connection to their interface do not, nor do they have the skills to to use them.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Whoops

Re: 1KHz 0dBu pocket generator
« Reply #23 on: December 06, 2020, 04:52:30 PM »
Many of us have these but lots of people asking questions about their new mic pre builds clearly and their connection to their interface do not, nor do they have the skills to to use them.

Cheers

Ian

Wouldn't someone that is not able to measure or has problems in measuring 0.775 VAV with their multimeter, also have problems in using an "1KHz pocket generator"?

I'm really sorry Ian, I'm really still missing the point...

EmRR

Re: 1KHz 0dBu pocket generator
« Reply #24 on: December 06, 2020, 04:58:30 PM »
I still don't understand, from a practical sense, what point this information will serve.    0dBm/0dBFS relationship doesn't appear to present anything of practical value, no matter how I slice that it only seems useful in comparing apples to apples metering standards, which seldom exist, it's always apples to oranges.   

They do need to understand preamp max output (different with every preamp type) and interface max input, and how those relate to one another, along with preamp max input in regards to input pad applications. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

boji

Re: 1KHz 0dBu pocket generator
« Reply #25 on: December 06, 2020, 05:07:11 PM »
Quote
also have problems in using an "1KHz pocket generator"?

I may.  ;)

True, a voltmeter is sufficient, but didn't want to have to check daw outputs every time in order to trust the gui. It'll be nice to have a small, portable reference that does other functions like cable and impedance testing.

Edit: Also nice for fieldwork.
« Last Edit: December 06, 2020, 05:12:48 PM by boji »

Re: 1KHz 0dBu pocket generator
« Reply #26 on: December 06, 2020, 05:23:24 PM »
I thought about this in app form once. Just a one button app, on/off 1k 0db tone. Would need to select your specific phone from a drop down menu for calibration, but pretty simple besides that. Anyone that wants to build it, just send me a check when your rich.

boji

Re: 1KHz 0dBu pocket generator
« Reply #27 on: December 06, 2020, 05:50:23 PM »
Quote
Would need to select your specific phone from a drop down menu for cal

Or how's about a bluetooth jack/adapter passthru that reads phone output and adjusts software accordingly. Takes all phones, soft, and chip consistencies out of the loop. Please split checks, c/o pinebox.  ;D

ruffrecords

Re: 1KHz 0dBu pocket generator
« Reply #28 on: December 06, 2020, 06:17:06 PM »
@whoops and Emrr

I have lost count of the number of times I have seen a post, on a variety of groups where someone has built or bought a mic pre, or a compressor or whatever, plugged it into their DAW and said it is noisy. "It reads -XXdB on my DAW,  why is it so noisy?"

There is no way to answer this question without knowing what -XXdB on the DAW means in dBu. A 0dBu 1KHz oscillator would allow them to at least convert their DAW reading into dBu.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruffrecords

Re: 1KHz 0dBu pocket generator
« Reply #29 on: December 06, 2020, 06:22:12 PM »
This evening a breadboarded a much simplified version of the schematic given in post  #6 using half  a TL072. I gives an output voltage very close to 2Vpp and the frequency is remarkably close to 1KHz. The second op amp can be used as a buffer and level calibrate stage. Output voltage and frequency are very stable from a power supply voltage of 6V and up.

I might knock up a little PCB for this.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


EmRR

Re: 1KHz 0dBu pocket generator
« Reply #30 on: December 06, 2020, 06:48:53 PM »
There is the Shure A15TG, -40dBv test generator for mic inputs. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

Whoops

Re: 1KHz 0dBu pocket generator
« Reply #31 on: December 06, 2020, 06:56:31 PM »
@whoops and Emrr

I have lost count of the number of times I have seen a post, on a variety of groups where someone has built or bought a mic pre, or a compressor or whatever, plugged it into their DAW and said it is noisy. "It reads -XXdB on my DAW,  why is it so noisy?"

There is no way to answer this question without knowing what -XXdB on the DAW means in dBu. A 0dBu 1KHz oscillator would allow them to at least convert their DAW reading into dBu.

Cheers

Ian

Hi Ian,
in those situations the user will already have a Multimeter.

Isn't easier to tell them,
 "you should plug you MIC pre output into the Line inputs of your Interface and not into the Mic inputs" ?
Or as they already have a multimeter/Phone/Computer to tell them to have a 1K tone out of their phone and set the outputs when they measure 0.775 VAV in the DMM?
Instead of telling them to they have to buy or build a "1KHz 0dBu pocket generator"?

They already have the tools at their disposal can can easily be used.
I guess just letting people know they have to use line inputs on the soundcard than the Mic inputs, would already solve half of the situations you describe.

Whoops

Re: 1KHz 0dBu pocket generator
« Reply #32 on: December 06, 2020, 06:59:18 PM »
True, a voltmeter is sufficient, but didn't want to have to check daw outputs every time in order to trust the gui.

Well it takes me 20 seconds to do that.


It'll be nice to have a small, portable reference that does other functions like cable and impedance testing.

If there's other functions I might consider it more useful, but I dont think that has been discussed here.

ruffrecords

Re: 1KHz 0dBu pocket generator
« Reply #33 on: December 06, 2020, 07:17:37 PM »
Hi Ian,
in those situations the user will already have a Multimeter.

The point is a lot of them do not have a multimeter.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Whoops

Re: 1KHz 0dBu pocket generator
« Reply #34 on: December 06, 2020, 07:21:48 PM »
The point is a lot of them do not have a multimeter.

Cheers

Ian

So wouldn't the best first advice for them be "you should get a multimeter"?
That's quite a usefull tool for a lot of things

This is one is capable enough:




I really don't see the usage for the pocket tool that's why I was asking, but I really don't want to ruin the party.
Wish all good fun

Cheers

Heikki

Re: 1KHz 0dBu pocket generator
« Reply #35 on: December 07, 2020, 01:31:53 AM »
...and if people can't read the manual to see the 0dBFS rating of their interface, they're kinda hopelessly lost already...
When I loan my analog pro audio gear to professional audio engineers I used to always ask to what level are their converters calibrated, what level in dBu equals 0dBFS. I would often just get blank stares and they would have no idea what I'm talkin about. I don't ask anymore and just hope for the best. Only old guys seem to know the basics of analog signal processing and the young ones are hopelessly lost.

abbey road d enfer

Re: 1KHz 0dBu pocket generator
« Reply #36 on: December 07, 2020, 02:21:04 AM »
if people can't read the manual to see the 0dBFS rating of their interface, they're kinda hopelessly lost already,
Many pieces of gear do not have this information available.
The manual for the soundcard I use for measurement does not have this info, neither for input nor outputs, only vague "maximum level". And it's not a $10 piece.
No wonder users are unaware, when manufacturers don't care.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: 1KHz 0dBu pocket generator
« Reply #37 on: December 07, 2020, 02:59:46 AM »
So wouldn't the best first advice for them be "you should get a multimeter"?
That's quite a usefull tool for a lot of things

This is one is capable enough:




I really don't see the usage for the pocket tool that's why I was asking, but I really don't want to ruin the party.
Wish all good fun

Cheers

Don't you need a true RMS meter for such measurements?

gyraf

Re: 1KHz 0dBu pocket generator
« Reply #38 on: December 07, 2020, 03:10:31 AM »
..no problem, as I mention above, if you use a 100Hz 0dBfs tone, these cheap multimeters are fine for giving you a reference point of system levels..

The imprecision of the cheap multimeters is usually on the reading of 1)higher frequencies and 2)complex waveforms

/Jakob E.
..note to self: don't let Harman run your company..

Rob Flinn

Re: 1KHz 0dBu pocket generator
« Reply #39 on: December 07, 2020, 03:35:15 AM »
There is the Shure A15TG, -40dBv test generator for mic inputs.

Yes, at a mere £209 in the UK ....
regards Rob


 

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