Audio Analyzer & Dummy Load Using Analog Discovery 2 - 2019 Version 

Hi Mark, I really like the series, I was all set to start ordering the parts for a similar build, when you reported the software was no longer available. I do wish to point out one problem with your design, it will work perfectly for about 90% of the amplifiers. How ever any amplifier that uses a bridge design where the minus speaker terminal is not grounded but goes opposite the positive terminal . will be shorted out. Almost all the new Class D amplifiers work this way along with high powered, and car amplifiers. I speak from experience on this, we were trying to measure the output current, (voltage across a small resistor) which caused a floating ground loop through the scope ground to the input ground of the signal generator. We burned up several sets of output transistors, which would only happen at high power, before we realized what was happening. Keep the videos comming

I’ve got about $120 in this whole setup. I’m just now getting to use it. I will update here on your channel. Thanks for your time and knowledge God Bless.

Thank you for the great video Mark. It is an excellent piece of software.

Thanks Mark. I've been waiting for this and can't wait to modify my hub with the updates.

The most comprehensive video on the subject.

It looks like between the scope outputs and possibly the BNC Adapter for the Analog Discovery, the black speaker connector is connected together between the two channels. Which is fine for most amps, but you'd have to verify each amp before connecting it up. Most home equipment is ok, but it's a big issue for automotive amps since many have bridged outputs.

Thank you VERY much. I've got all the stuff mostly rounded up. Was just waiting on the final version. I am working on a 50W stereo amp from a vintage Rowe/AMI MM4 Jukebox and I hope to put it through it's paces with this setup. If all goes well, I may sell my working ST1700b. This setup does most everything I can imagine I will ever need. thanks again to you and The Stuff Made for all the effort. doc

Hi M ark, awesome video, easy to follow around on thediagram, and this is what i have been waiting for, alot of the test equipment used normally is not just expensive, but here in ontario canada is relatively hard to find. this will be the direction i will go with as i have expanded my knowledge in audio electronics, it will be interesting to see as the future unfolds how much your videos will feature this versus the individual pieces of test equipment.... cheers and thanks for this

Thanks Mark for the update. Just finished putting my audio analyzer together, good timing! I added the ability to do IMD in mine, just a DPDT switch as you mentioned in a previous video. By the way, I found that laminating a color laser printout was a good way to make a faceplate for mine, in case you were deciding on putting some markings on your design... Cheers, - Eddy

Thanks Mark - I am very intrigued by this as I am looking to get test equipment but I do not have a lot of space for my bench..

Nice setup.

Most excellent !

Thanks mark I ordered one and it looks like a great hobby scope for what I’m using it for, can you suggest the best way to check and build crossovers with this? Maybe check a speaker system? Thanks for another great show

Much appreciated, Mark. The way you have your distribution box configured suggests that you will not be using the source in the HP8903, which means you probably won't be running Pete's software anymore. I would like to build a similar unit with the additional ability to switch between sources. So if I needed a very low distortion source (SG-505), I could switch that in. Thanks! Edit: Watched through again and I see what you are doing to use the HP8903; I missed that the first time through.

Great video. Is the variac on the far left of the bench with the built in dim bulb home made? Love to see how you made it. If not, what model is it? Thanks

The AD2 does not give specs for its Spectrum Analyzer. It appears to have a much higher (60 - 80 db higher) noise floor than a HP35665A or HP35670A. Also its signal gen is not as clean as a Tek SG505. So you still get some benefit from the older standalone equipment. Still, it is pretty good for a $300 all in one device.

Building the KT88 ,, started building yesterday... does anyone know how to put the smoke back in??

Hi Mark could I ask a silly question. How does one calibrate Audio Analyser in the settings? How do we connect input to output to run the calibration?

Hi Mark, thanks for the video. Somebody mentioned correctly that most Class D amp uses a floating ground on the output therefore it would be a good idea to isolate the input signal from its source. I am thinking of using a transformer that wouldn't be too costly and hopefully works within the limited audio frequency range. Do you have any suggestions in this regard perhaps on a product to try ? Bjoern

Do you know if there is any advantage to having the analog discover 2 over the 1 using the audio amplifier test software? I can get the 1 for half the price of the 2 in the UK. Thanks

That amp looks beautiful a question for you I see people demoing powering up tube ams with no load on it I have always made shaw the speakers are connected because of the damage that’s caused to the tubs and ore the output transformer when there’s no load on it am I right in thinkingThis, and why is there so much confusion every time this subject is brought up yours Ian 🔊🔊🤔

Do a IMD setup video :)

Great video and information, but, umm, given your usual attention to detail, why did you allow the power resistors to be mounted crookedly?

The switch that controls speaker or dummy load, is that a make before break type or does it not matter because it happens so quickly??

I'm not sure about that analog discovery software. I'm getting 0.99% thd+n at 3Wrms (the other channel shows 0.78%). I'm using a Keithley 2015 and a software of mine..

Thanks for the detailed walk-through. I could use this as a way of capturing before and after measurements for repair of pro audio gear. I prefer lab-grade instruments for any critical work but getting a display capture is not so easy. I would need 1000 watt loads and full balanced line so an unbalanced to balanced transformer would be needed or better a differential amp front end to output unbalanced version of the signal for single-ended input so common ground can be used. Few of the digital amps used in pa, home entertainment or modern SS guitar amps have a ground-referenced output so common unbalanced test instruments do not work. If the two inputs could be used in 1 channel differential mode with no ground that would work.

If anyone is out there: doesn't the Analog Discovery 2 come with its own software? If "yes," why use the software from TheStuffMade instead?

Will the software allow use of dual screens ?

It would be interesting to see the system used to analyse a solid state amp

Dude you just killed my ears, I am using head phones ! LOL