Recommend me a signal generator

[Harry Klippton]

For several years, I've been using the Keuwlsoft function generator on an old phone that has a headphone jack, but now I have a need for a 400hz -10dBv signal for calibration purposes. Based on what I measured, I can't quite get -10dBv out of the phone, and it's not a calibrated signal.

This is something I have a regular need for, not a one-off. If there's something cheap that'll do the job appropriately, I'm all for it. But I don't need to cheap out just to be cheap. "It's just for DIY" doesn't apply cuz it's not.

I've never used an actual signal generator before, so I don't know what I don't know or what to look for exactly.

 

[Robert]

I have an Siglent SDG1032X. I wouldn't call it cheap, but it's far from the most expensive either.

It might be overkill, or maybe not. It'll definitely do what you need.

 

[Guardians of the analog]

 

[jwin615]

So that's -7.782 dBu/~316mV(check my math)
Pretty much any modern audio interface can output that and then some.
Load up a sine wave generator, pan it to one side and bust out you DMM.
That's a cheap and easy way until you get a bench utility anyway.
Oh. I'd use the line/main output, not the headphone out.
An idea anyway...

 

[Robert]

I'm curious, what are we calibrating?

 

[Harry Klippton]

I'm curious, what are we calibrating?

Tape machines

 

[Harry Klippton]

@jwin615 suggestion probably makes the most sense for me for now. I think I saw that there's a js tone generator in reaper so I'll look into that

 

[RetiredUnit1]

In my own defense, I'd like to point out that I wanted something nice for my birthday 2024 and I had just paid off the Credit Card which got clobbered with medical/funeral expenses when my wife kicked the bucket in 2021. I started by looking at kits, then assembled kits, then really old RED LED display units, then new units and before I knew it this was on the porch....

OWON AG1012F Function generator Signal Waveform 10MHz AM FM PM FSK PWM Sweep | eBay

AG1012F:Dual-channel Arbitrary Waveform Generator. Model AG1012F Channel dual Frequency Output 10MHz Sample Rate 125MS/s, Vertical Resolution 14 bits Waveform Standard Waveform Sine, Square, Pulse, Ramp, and Noise Arbitrary Waveform Exponential Rise, Exponential Fall, Sin(x)/x, Step Wave, and...

www.ebay.com

 

[jwin615]

Doh! -10dBv is consumer line level out. Got an old component CD player laying around(aren't they all?)? Or an ADAT?
Burn a CD of your test tone at full volume(or maybe -0.5db, pop it in and take the line level out of the CD player.
As long as the CD player just converting and spitting out line level(no volume control, EQ curves) it should be close enough for tape calibration. Again, check with your DMM or scope.
Again. Not a pretty solution but should be doable with little more investment than some time.

Oh. Could also work with a unbalanced out on a audio interface.

 

[Harry Klippton]

I got it configured with js: tone generator with no issue

 

[fontoponto]

EDITR: dang it I was to late


There is also a great tone generator included https://www.roomeqwizard.com/

 

[Chuck D. Bones]

...then really old RED LED display units, then new units and before I knew it this was on the porch....

OWON AG1012F Function generator Signal Waveform 10MHz AM FM PM FSK PWM Sweep | eBay

AG1012F:Dual-channel Arbitrary Waveform Generator. Model AG1012F Channel dual Frequency Output 10MHz Sample Rate 125MS/s, Vertical Resolution 14 bits Waveform Standard Waveform Sine, Square, Pulse, Ramp, and Noise Arbitrary Waveform Exponential Rise, Exponential Fall, Sin(x)/x, Step Wave, and...

www.ebay.com

View attachment 79629

How do you like it and what kind of scope do you have?

 

[RetiredUnit1]

How do you like it and what kind of scope do you have?

It works well, and looks slick. Trouble shooting tube amps all I use is the 100mv/1000hz tho. Total overkill but I wanted something nice for my birthday, lol. And it IS nice!

Got my Oscilloscope OWON SDS7102V from this guy, but it was a lot less at $248.06, I did get the bag, but no battery.... I don't anticipate needing one.

OWON 100Mhz Oscilloscope SDS7102V 1G/s large 8" LCD LAN+VGA+battery+bag 3yrs war | eBay

(New Ultra thin 100Mhz OWON Digital Storage Oscilloscope SDS7102-V. 3) Newest Software/firmware can be download from OWON website;. 7) Orginal OWON portable bag;. 1) 2 units of 100Mhz probes;. VGA+ LAN + battery+ Orginal Portable Bag 1G/s Sample rate, Large 8" LCD, 10M points Record length, FFT.

www.ebay.com

 

[jwin615]

Got my Oscilloscope OWON SDS7102V from this guy, but it was a lot less at $248.06, I did get the bag, but no battery.... I don't anticipate needing one.

Looks like an unloaded 18650 battery pack is around $12-15 on Ali if you decide you want one...

 

[RetiredUnit1]

Looks like an unloaded 18650 battery pack is around $12-15 on Ali if you decide you want one...

I have a squat load of 18650's, battery sleds, BMS and Buck down/up chips that I've used to make power packs for various equipment.

But really, I don't go anywhere.... lol.... 68 and happily retired.