Excellent information to used analog discovery in audio application, testing. Especially about the grounds, being connected and making your own board . This is the information I’ve been looking for .

Thanks for mention about TheTuffMade software!Can you show us how to measure intermodulation and other Audio Analyzer Suite functions?

Off topic. I wonder how many good audio amplifiers are let down by their power supply. It is an issue in amateur radio transmitters too as the signal goes from almost nothing to full power with audio. It is possible to dynamically test a power supply with a programmable DC load and an oscilloscope measuring current and voltage. The DC load can be programmed for a low frequency, say 100 Hz and a 10 to 90 per cent duty cycle square wave. This stresses the supply and allows its response to be measured.

The Stuff Made wrote that software for the Discovery 1(last I saw he was still using it), we really need to send him a 3 for his efforts.

@Gabster1

10 ай бұрын

For sure of all people he contributed the most to this platform.

I noticed the GPO header box you showed contained 2x20 pin headers, but the header on your breadboard is 2x15 which matches the pins on the discovery. I am having trouble locating a 2x15 right angle connector, did you cut yours or will a 2x20 fit.

@Gabster1

6 ай бұрын

Yes just cut it I would cut at 16 then sand it to 15 for better finish

Thank you for a great video

Great video.

Hello, excellent video, thank you very much for the information.

@Gabster1

10 ай бұрын

Glad it was helpful!

Very interesting and useful

Another great and usefull video for audio diy. Thanks a lot Gabster, this is priceless. I have a quick question concerning the 100 ohms load connected to your amplifiers. I understand that it reduces a lot the current compared to an 8 ohms resistor. But do you think this has negligible effect on THD mesurements (and others important parameters) compared to a mesurement with 8 ohms ..? Thanks a lot

@Gabster1

10 ай бұрын

These are 8 ohms 100watts I did make a mistake and said 100 ohms I put a correction in the description. You are correct

Gaby, Would you be willing to hook up an Android cell phone on airplane mode running out of its USB connection to see how clean that is? Reason I'm asking is I use such a phone with USB Audio Pro Player to a USB dongle DAC amps or a chord mojo 2 (which are running off of battery or taking power from the phone). I think it sounds pretty good ! I'm wondering if I'm inherently avoiding some of the pitfalls in not having to use a switching power supply (or buy a expensive linear...) etc ... etc .. as everything is running off of battery ? Do you think a USB cleaner of some kind should be in the chain between the phone and the DAC in my scenario. The only downside to this is there are cables to deal with and you're dealing with the battery charge of the phone which is usually only a few hours but so far it's been working great in my opinion. I have 5 DACs And I run a different one every night which is a lot of fun

@Gabster1

9 ай бұрын

Your phone on battery will beat any computer Much lower noise so you are doing a good thing. But you still have some computing noise The better your dongle Dac is the better the sound

Thanks G, great stuff. What wattage 15k resistors would you use in the jig, if you were to add attenuation? I also noticed that only yourself and @TheStuffMade are using the jig. Other KZreadrs are just using the unrecommended bnc adapter. What’s up with that?

@Gabster1

7 ай бұрын

You can get away without a jig on simple Tube amps But I had a lot of issues with some amps so best is to follow The Stuffmade recommendations he knows his stuff :) So far I had not used any attenuation with Ver3 up to 90W. I would ask Jake about Wattage I am guessing 1W may be more then enough.

Hi thank you for the very valuable video Lately i have been a little shocked by reviews of amps judged quite good and sometimes very good for sound and then performing quite badly at the Lab bench I am talking about differences between channels bad square wave response and pretty high distortion even at low power Speaking of vintage i guess this means the need of maintenance But this fact that even bad measuring amps sound leaves me puzzled But what scares me is when amps with impeccable measurements sound bad How is this possible? Or said better Is this really possible? Thanks again and kind regards Gino

@Gabster1

5 ай бұрын

Generally, amplifiers that measure well tend to sound good, but since our ears and tastes vary, a bit of distortion in tube amps, typically less than 1%, is often appreciated. A completely flat response can sometimes be unexciting. When dealing with poorly measuring amps, it's wise to steer clear. They usually don't sound good, especially when the measurements are particularly bad. However, some people enjoy exaggerated bass, for instance. Additionally, not all reviewed units sound as good as the average sold unit, and some reviewers avoid being overly critical. I believe that if an amp measures really poorly, it will likely sound bad, at least to a well-trained ear.

@gino3286

5 ай бұрын

@@Gabster1 hi thank you very much for your very kind and valuable reply There is one aspect in measurements that it could be overlooked Usually to perform distortion measurements a purely resistive load is used You're very right Tubes can sound so musical I don't like them for bass but for mid and high range could be a great option Congratulations for your speakers I like the concept very much indeed and I believe the sound must be excellent Kind regards Gino

This is a great step by step - thank you. I assume you connect the Discovery 3 to a laptop running on battery. Or maybe you use a 1:1 isolation transformer. I wonder if the Discovery has the same issue as standard scopes having a grounded neutral. Thanks again for sharing.

@Gabster1

10 ай бұрын

Yes a laptop on batteries is ideal but surprisingly works well on a regular grid connected Computers

Hello, iI have not been able to find the (pdf) or schematic for the bnc board referred to. Can someone please help.

@Gabster1

8 ай бұрын

The Stuff made Video is in my description. Just go to the Video then the Description of The Stuff made video you will find a drobox link to the software and PDF. Leave him a nice comment for his efforts and contributions to the DIY community.

I don't understand the need for the extra board. As mentioned, when plugged in, all 'ground' connections from the i/o connectors are connected together. That would not change with the new board, would it?

@Gabster1

8 ай бұрын

Hi Jan I was away I had to double check When plugged in, all 'ground' connections from the i/o connectors are actually NOT connected together. they are all independent. Unless you use the I/O board that comes with it that connects all grounds together. So the extra board is critical for certain amps like Class D amps and certain Tube Amps, where you want the grounds separate

@jandidden8170

8 ай бұрын

OK, thans for clarifying.

Hi Gaby, did you use any resistors in the input channels? Not the attenuators, just the ones in line

@Gabster1

9 ай бұрын

No resistors at all in the input or anywhere

well done!

Any concerns about the voltage input to the AD with a higher powered amp? Have you used a voltage divider in that situation?

@Gabster1

8 ай бұрын

I only used it up to 90 watts But you can put your probe on 10x as a quick way or create a simple resistor devider or add one to the board

@markashley5074

8 ай бұрын

@@Gabster1 Thank you again!

When testing the Marantz or Sansui, where did you set the volume knob while doing these tests .. thanks!

@Gabster1

8 ай бұрын

About 3/4 of the way up

@markashley5074

8 ай бұрын

​@@Gabster1 Thank you for your prompt reply. I appreciate your videos.

Thanks great stuff! Can I assume this will work with balanced preamps?

@Gabster1

10 ай бұрын

Yes it will

@sandglass8888

10 ай бұрын

Is it possible to get a balanced output from analog discovery? Do you use an adapter? I can't find the setting in the software.

So is there equipment I can get to use this free software and not have to pay the 375?

@Gabster1

9 ай бұрын

Sadly no the software needs this particular hardware

@markashley5074

8 ай бұрын

Analog Discovery 2 has shown up on eBay for about $200 US. The Analog Discovery 1 is less .. either will work fine.

@gregoryjwellls

5 ай бұрын

There is a student discount available for approved universities. My cost for an Analog Discovery 3 (with free shipping) was $249 a month ago.