Stereo Amp build based on Hammond organ circuit

my ebay $40 emu0404 gets to 90khz, and allows a cheap 10:1 scope probe as input, and an acceptably high level output to drive an amp. With REW its noise floor exceeds any valve amp, and provides all the distortion and noise measuring capabilities.
It may not be the path to take for many, but a lot of online threads on a lot of forums to do some due diligence as to how easy/hard this may be.
 
Will that do frequency sweeps and spit out a response and THD graph? I'd like a more convenient way of doing that vs manually adjusting the generator and logging the results frequency by frequency in a spreadsheet to get that done. Not having to spend a pile of money or eat a load of desk space would be a right nice bonus.
 
The diyaudo 'equipment and tools' section has many threads.

The following groupdiy has a current thread on REW:
https://groupdiy.com/index.php?board=37.0

Like all tools, it can span from using a very simple soundcard to doing a group buy on an exotic custom one, to discussing nuances and mods on specific commercial devices. And there are a few software applications in regular use. And there is always a learning curve with any new tool.
 
A basic soundcard test setup will cover guitar style amps. I lucked on an EMU0404, and it has very good unmodified frequency response, and allowed me to have a good look at a Williamson response at both low and frequency, but it wasn't the only tool I had a need to use. Even that soundcard needed a fair bit of checking/modifying probes and getting adaptors ready and confirming achievable bandwidth and appreciating how hum was sneeking in and how to alleviate it, and arranging a battery power supply and a USB isolator.

And although I find REW is pretty straightforward to use now, it took a fair effort to grow the experience, as I needed to use an ASIO driver for high bandwidth, but was also swapping to cheap $1 soundcard for other amp testing and that changes the driver, and there are so many tweakable parameters to gain confidence with. Luckily, REW is a living product, and is getting better and easier to use. But yes it doesn't have a normal scope display, which can be a hurdle for some.

As the tool has to connect to high signal levels, due care is needed to make sure the amp has effectively a common ground for input and output signals, and that large signal levels are properly attenuated (ie. 10:1 or 100:1 cheap ebay probes can be fine), and that DC levels aren't probed without having additional capacitor coupling protection. It can be easy to fry electronics from accidental probing - but no different really from doing the same with vintage hardware test equipment.
 
I got my BK 4017A this week and just wanted to to ask opinion on sine wave.
It comes to a point on the top and the bottom. It may actually be beneficial to see clipping easier. I haven’t had a chance to read manual, just hooked up to scope to make sure it’s not DOA.
Image below.
 

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the compensation only really matters with a 10x probe. usually there is a square wave output on the scope, the basic idea is you hook the probe to that and adjust the trimmer so the square is square. If its tuned wrong you get a distinct slope to the top of the waveform. I doubt either would cause a "pip" at the peak of the sine wave though. That looks almost like a generator that converts triangles to sines with diodes, and one of the diodes is switching a little oddly.
 
This question really does not belong in this thread but I couldn't find place on the forum for it.
I just looked in the manual and there is no calibration or any adjustments. No SM on the web either.
My scope probes are compensated. Have anyone seen this before out of signal generator?
 

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