So, my old Tektronix died. Don't need 100Mhz for audio, but storage would be handy. Bought a Hantek 6022 20 Mhz USB interface.
NO AC MODE! Unbelievable. I see there are hacks to convert to AC only, and one could stuff a big cap in the probe, but this is just plain stupid. I knew it did not have a separate external trigger.
Glad it was Amazon, as it goes right back.
Short of buying another real scope, do any on these USB boxes have AC and DC modes? I would never have dreamed no AC mode.
NO AC MODE! Unbelievable. I see there are hacks to convert to AC only, and one could stuff a big cap in the probe, but this is just plain stupid. I knew it did not have a separate external trigger.
Glad it was Amazon, as it goes right back.
Short of buying another real scope, do any on these USB boxes have AC and DC modes? I would never have dreamed no AC mode.
The nail in the usb coffin for me was isolation and screen for purpose.
You could look at Diligent Analogue Discovery but off the top of my head I don’t know if it has AC. It sure on the actual sample rate.
You could look at Diligent Analogue Discovery but off the top of my head I don’t know if it has AC. It sure on the actual sample rate.
I was looking at a bunch of the newer digital scopes. Stand alone. Rigol etc. NONE have AC input mode. That is insane in my book. OK I can see if you had an option for an AC coupled probe but I don't see they exist. I am totally baffled. Do these folks assume the world only exists at logic levels?
That precisely the target market for these scopes - logic and line level. Breadboards and batteries. Some of the 24bit acquisition dev boards only support DC natively to improve the noise stats for example.
I ended up going down the 1104x-e route for the HV flexibility for tube amps.
Digging deeper, as you move up the line, they have it, but you have to go through a menu to set it. Pretty darn stupid if you ask me.
Don't think I'll buy another full size. Trust my old Fluke. Just don't have that many projects left. I guess I am obsolete.
Don't think I'll buy another full size. Trust my old Fluke. Just don't have that many projects left. I guess I am obsolete.
There’s something to be said for convenient size.
As long as the software is available (a real problem with Mac) given the operating system updates - another reason for going Normal DSO.
On my way to drop-off, I decided it is so cheap, I should just hack it. I'll test by making a little in-line block. If that works, I'll put it inside with a good micro relay and switch for each channel. It may be hard getting the isolation and low enough parasitics. 200V at least I think. ( I don't do tubes any more) Cap not too hard, relay maybe harder.
Success. I made a little adapter BNC to BNC. Put a .22u x7r in it. It works beautifully. Calibration square wave is square. It is only a 50V, so to make a pair of good ones, I'll order some 100V. So this thing is useable for audio work. I can look at noise and ripple.
Why the heck don't they make either nice molded adapters, or a probe with the cab built in? Seems obvious to me if they are too cheap to put the cap and relay inside.
Why the heck don't they make either nice molded adapters, or a probe with the cab built in? Seems obvious to me if they are too cheap to put the cap and relay inside.
?? My Siglent has AC where you expect on a DSO in the probe/channel menu. Similar for the Picoscopes and the Tek THS720's.
for a USB scope my first choice has been a Picoscope. Their software has always been better and they keep updating it. no reason not to get an older used one either. I have recommended a few very inexpensive USB/battery scopes that have been useful as well.
for a USB scope my first choice has been a Picoscope. Their software has always been better and they keep updating it. no reason not to get an older used one either. I have recommended a few very inexpensive USB/battery scopes that have been useful as well.
Most high voltage (tube amp) situations you'll be using a fully isolated differential probe. DSOs go up to 400V on the probe front ends and the probes are up to 300V for the entry level although I still wouldn't trust the front ends and transients so a HV capable probe is a must.
You can make your own 10:1 or 100:1 test point as part of the design of the amp. So it's not a massive restriction but HV probes are a safer option.
You can make your own 10:1 or 100:1 test point as part of the design of the amp. So it's not a massive restriction but HV probes are a safer option.
https://www.ebay.com/itm/114856470441?hash=item1abdfaa7a9:g:GYUAAOSwi8ZgzNnm&LH_ItemCondition=4
40 bucks (assuming that you are based in the USA) buys you a perfectly serviceable analogue 'scope.
Get one in addition to a USB 'scope perhaps?
40 bucks (assuming that you are based in the USA) buys you a perfectly serviceable analogue 'scope.
Get one in addition to a USB 'scope perhaps?
Turns out, to get the 2mV or better input and 12 bits so it is actually useful for audio work, it costs way too much money.
I am paring down my projects and will do without for now.
20mV, 8 bit, with two bits of jitter makes the cheap ones pretty useless unless you are just doing strait digital work, or I guess they are popular for automotive. I'm spoiled as I spent my first career with 465's and 7800 mainframes.
I wish they made one with .2mV, 14 bits and only 500Khz.
I should actually just sell all the rest of my stuff. I don't think I'll be building another amp or even any more speakers. Too many projects. I need to get my Stag back on the road, and several cabinet works on the list. If I was going to do a MegaSquirt on the Stag, I would need one, but I think it will stay carbs. These last couple of years shut in for COVID have changed some of our priorities.
I am paring down my projects and will do without for now.
20mV, 8 bit, with two bits of jitter makes the cheap ones pretty useless unless you are just doing strait digital work, or I guess they are popular for automotive. I'm spoiled as I spent my first career with 465's and 7800 mainframes.
I wish they made one with .2mV, 14 bits and only 500Khz.
I should actually just sell all the rest of my stuff. I don't think I'll be building another amp or even any more speakers. Too many projects. I need to get my Stag back on the road, and several cabinet works on the list. If I was going to do a MegaSquirt on the Stag, I would need one, but I think it will stay carbs. These last couple of years shut in for COVID have changed some of our priorities.
Its not difficult to add AC mode to a scope, its just a switch and capacitor.
I designed my own PC USB scope for audio work.
Just works upto a meg or so and is fine for audio and has storage and a spectrum analyser.
I designed my own PC USB scope for audio work.
Just works upto a meg or so and is fine for audio and has storage and a spectrum analyser.
Yes, I made a little inline one, but the scope still had such excessive limitations, I sent it back.
As you say, easy, so why the heck don't they include it! Well, a couple of relays and caps does cost money.
I figured I needed at least a 12 bit with 2mV/div scale. Too much money. I only have a couple projects left, so probably will just sell off al the rest of my lab. If I can't do it with my Fluke, I probably don't to be doing it any more.
As you say, easy, so why the heck don't they include it! Well, a couple of relays and caps does cost money.
I figured I needed at least a 12 bit with 2mV/div scale. Too much money. I only have a couple projects left, so probably will just sell off al the rest of my lab. If I can't do it with my Fluke, I probably don't to be doing it any more.
I suggested a relay as their software and controller was already set up to control one. Moot point now.
Maybe I found one I can live with.
https://www.amazon.com/dp/B09FJGQWT7?psc=1&ref=ppx_yo2_dt_b_product_details
AC/DC, 5mV. Came with a 1/10X and a 100X probe. Instructions were terrible but I got it working. Sure, no match for a "real" scope, but for basic troubleshooting it should do. UI is not the best, but I guess it works. As I troubleshoot a few projects I will see. I want to see how it works with my old Old Colony "pulser" for driver offset measurements or if just using amplitude at crossover center is better.
If you have more money, they have some that spec pretty nice, like 12 bit .2mV
I still would like to build a buffer for standard probes to feed my Focusrite so I can use RightMark and the like for measurements. Need that 1M input buffer.
https://www.amazon.com/dp/B09FJGQWT7?psc=1&ref=ppx_yo2_dt_b_product_details
AC/DC, 5mV. Came with a 1/10X and a 100X probe. Instructions were terrible but I got it working. Sure, no match for a "real" scope, but for basic troubleshooting it should do. UI is not the best, but I guess it works. As I troubleshoot a few projects I will see. I want to see how it works with my old Old Colony "pulser" for driver offset measurements or if just using amplitude at crossover center is better.
If you have more money, they have some that spec pretty nice, like 12 bit .2mV
I still would like to build a buffer for standard probes to feed my Focusrite so I can use RightMark and the like for measurements. Need that 1M input buffer.
Am not certain exactly which model is discussed here as only "6022" was mentioned, but on Hantek EU homepage there's a "DSO 6022BE" and according to their info it has AC coupling, so not sure in what regards there is no AC coupling unless there are other similar models without.
https://www.hantek.eu/dso-6022be.html
With regards to the AC coupling cap 16nF, or closest standard value, should be ok as that corresponds to 10 Hz LF cut-off in conjunction with 1 MOhm input impedance, 10 Hz is a typical value seen on Siglent, Tektronix etc..
https://www.hantek.eu/dso-6022be.html
With regards to the AC coupling cap 16nF, or closest standard value, should be ok as that corresponds to 10 Hz LF cut-off in conjunction with 1 MOhm input impedance, 10 Hz is a typical value seen on Siglent, Tektronix etc..
I don't know where you're looking, but almost all scopes have AC/DC coupling - 'toys' like your USB may not, just because of the issue of switching it. But certainly my Rigol scopes at home and at work both have AC/DC inputs.
Perhaps you're confused because it's normally done via the menu system?, if you're looking for a physical switch on the front labelled AC/DC you'll be looking for a long time.
The specs on the 6022 clearly specify AC/DC/GND coupling as is normal, presumably done on the computer screen?.
Edit: Just googled for a schematic, which clearly shows no capacitor for AC coupling (assuming it's the correct schematic of course).
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