Please be gentle.
I am a newbie in the tube world - two months ago I built my first ever stereo tube amp from a kit; ST120 from tubes for hifi.
I am quite pleased with the amp but a few things bother me - no built in bias meters, tubes closely spaced, tubes close to transformers, does not like voltage in excess of 122v, etc - and I would like to build a new one. While doing so I would like to probe, prod, poke, and measure so I can learn as I go.
I assume - remember I am new at this - an oscilloscope would very beneficial in this and future projects.
I have the other typical tools such as voltmeter, soldering irons, variac, and decent health insurance.
I imagine I do not need loads of bells and whistles when working with tube gear.
Ideally I would like to spend less than $300 on a scope but could do $400. Beyond that I would need to look at used analog scopes.
Please be kind.
Thanks
I am a newbie in the tube world - two months ago I built my first ever stereo tube amp from a kit; ST120 from tubes for hifi.
I am quite pleased with the amp but a few things bother me - no built in bias meters, tubes closely spaced, tubes close to transformers, does not like voltage in excess of 122v, etc - and I would like to build a new one. While doing so I would like to probe, prod, poke, and measure so I can learn as I go.
I assume - remember I am new at this - an oscilloscope would very beneficial in this and future projects.
I have the other typical tools such as voltmeter, soldering irons, variac, and decent health insurance.
I imagine I do not need loads of bells and whistles when working with tube gear.
Ideally I would like to spend less than $300 on a scope but could do $400. Beyond that I would need to look at used analog scopes.
Please be kind.
Thanks
Welcome to the addiction ;-)
An oscilloscope is definitely helpful for following audio signal around a circuit but you must make sure you know how to use it safely. There are many good YouTube videos and tutorials that will help you get the best out of it.
For occasional use, you don't need anything too flash. I personally use a 20-30 year old Goldstar CRT oscilloscope that I found on eBay many many years ago. It is only 20MHz but has dual trace and trigger functions. This is all I need for construction and fault finding.
There are oscilloscope modules that plug into a PC / laptop that can be pretty good around your price range if you want new and compact, otherwise a decent old used 'scope or a basic new cheap unit will do.
An oscilloscope is definitely helpful for following audio signal around a circuit but you must make sure you know how to use it safely. There are many good YouTube videos and tutorials that will help you get the best out of it.
For occasional use, you don't need anything too flash. I personally use a 20-30 year old Goldstar CRT oscilloscope that I found on eBay many many years ago. It is only 20MHz but has dual trace and trigger functions. This is all I need for construction and fault finding.
There are oscilloscope modules that plug into a PC / laptop that can be pretty good around your price range if you want new and compact, otherwise a decent old used 'scope or a basic new cheap unit will do.
Consider purchasing high voltage probes if you purchase an oscilloscope.
Most scope probes are good to about 350V, some PC scope probes much less!
Anode voltage on the output tubes can swing twice the B+ to the transformer. So, if you have a B+ of 250V, the peaks on the anodes can hit near 500V. This can break down most 1X / 10X scope probes that are rated at 350V.
Most scope probes are good to about 350V, some PC scope probes much less!
Anode voltage on the output tubes can swing twice the B+ to the transformer. So, if you have a B+ of 250V, the peaks on the anodes can hit near 500V. This can break down most 1X / 10X scope probes that are rated at 350V.
Instead, x100 probes should be ok. Make sure they (or any probes you choose)
will be compatible with your scope.
Hantek 120MHz High Voltage Probe 100MΩ Oscilloscope Clip Passive Probe Max.2.5KV DC X100: Amazon.com: Industrial & Scientific
This works well enough for me: Hantek PC Based USB Digital Storage Oscilloscope 6022BE, 20Mhz Bandwidth: Amazon.ca: Tools & Home Improvement
I would personally recommend a used analogue scope such as a Tek 2245 or something of that ilk.
Digital scopes are great for timing measurement and display but show artefacts that can be confusing. An event that happens infrequently will show as boldly as a constant repetitious event. An analogue scope will show these at different brightnesses.
Not sure if I would go to the expense of HV probes. I've used a resistive divider when such a reading is necessary.
Digital scopes are great for timing measurement and display but show artefacts that can be confusing. An event that happens infrequently will show as boldly as a constant repetitious event. An analogue scope will show these at different brightnesses.
Not sure if I would go to the expense of HV probes. I've used a resistive divider when such a reading is necessary.
I got one of those cheap oscilloscopes
It was junk with win 8 and win10
The software is for windows vista and you have to change tons of code lines. I just sent mine back. Tech was a joke. As in no tech from the company that makes them
I would also push for a good HV probe for safety reasons. A resistive divider can work but 250V to 400V on open wires is pretty dangerous. It the life insurance you need to keep current. . .
The Hantek probe looks OK except its input capacitance is quite high for X100. Usually the probe input C is divided from the scope input C- a 25 pF scope input and X100 probe would be more like 1-2 pF + strays. The two Tek probes I just checked are 2 pF on the input. This is useful for looking at high impedance (tube) circuits without the probe affecting them. The Hantek is 14-17 pF. Still it would be much safer than something not rated for the voltage.
The Hantek probe looks OK except its input capacitance is quite high for X100. Usually the probe input C is divided from the scope input C- a 25 pF scope input and X100 probe would be more like 1-2 pF + strays. The two Tek probes I just checked are 2 pF on the input. This is useful for looking at high impedance (tube) circuits without the probe affecting them. The Hantek is 14-17 pF. Still it would be much safer than something not rated for the voltage.
Thanks for all the feedback.
If I understand correctly; there really is no major benefit to digital over analog scopes when it comes to tube amp troubleshooting, and, I could do very well for very little money looking in the used market for an analog scope?
Primary reasons for wanting a digital scope are:
1. Size - while I do own a house I also have a TON OF TOOLS and a small footprint would be much easier to store when not in use.
2. Knowledge - I am completely out of my element when it comes to selecting a scope and fear I could get seriously ripped off in the used market.
My knowledge of scopes and scope use are from youtube channels such as EEVBlog, Mr Carlsons Lab, AVE, and Electroboom.
What really clued me in is when Mr Carlsons Lab was tracing the noise in a tube amp and found it was the choke. He then was able to relocate the choke and thus eliminate the noise that I realized how one could benefit me.
I want to rebuild mt ST120 in a new cabinet with a few bells and whistles and those "features" could be a source of noise, thus wanting a scope to trace and troubleshoot this foolish endeavor.
If I understand correctly; there really is no major benefit to digital over analog scopes when it comes to tube amp troubleshooting, and, I could do very well for very little money looking in the used market for an analog scope?
Primary reasons for wanting a digital scope are:
1. Size - while I do own a house I also have a TON OF TOOLS and a small footprint would be much easier to store when not in use.
2. Knowledge - I am completely out of my element when it comes to selecting a scope and fear I could get seriously ripped off in the used market.
My knowledge of scopes and scope use are from youtube channels such as EEVBlog, Mr Carlsons Lab, AVE, and Electroboom.
What really clued me in is when Mr Carlsons Lab was tracing the noise in a tube amp and found it was the choke. He then was able to relocate the choke and thus eliminate the noise that I realized how one could benefit me.
I want to rebuild mt ST120 in a new cabinet with a few bells and whistles and those "features" could be a source of noise, thus wanting a scope to trace and troubleshoot this foolish endeavor.
Technically a good analogue scope will fit your requiremants. But I agree that used scopes often are bulky, power consuming and in case of trouble without any guarantee you are on your own. I used analogue scopes for several decades but now decided to swap to a Rigol DSO - lightweight with a small footprint.
When it comes to troubleschooting a scope is indispensible. For measurements of small noise voltage its resolution is too restricted. This is the domain of an USB-soundcard connected to a PC running ARTA or similar.
When it comes to troubleschooting a scope is indispensible. For measurements of small noise voltage its resolution is too restricted. This is the domain of an USB-soundcard connected to a PC running ARTA or similar.
Scroll down and there are many scope brands in your price range shown.
Rigol DS1102E 100MHz Digital Oscilloscope, Dual Analog Channels, 1 GSa/s Sampling, USB Storage: Amazon.com: Industrial & Scientific
-RNM
Rigol DS1102E 100MHz Digital Oscilloscope, Dual Analog Channels, 1 GSa/s Sampling, USB Storage: Amazon.com: Industrial & Scientific
-RNM
If you buy a used scope, only get one you can go check out and take home yourself.
You don't want any shipping damage problems. Old scopes are heavy.
However, all you really need for casual use (if you have a PC) are these.
The PC scope also includes a basic (but adequate for casual use) function generator.
Hantek 120MHz High Voltage Probe 100MΩ Oscilloscope Clip Passive Probe Max.2.5KV DC X100: Amazon.com: Industrial & Scientific
PicoScope 2204A-D2 10MHz 2-Ch Oscilloscope w/out Probes (PP917) ($115.00) : Saelig Online Store
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Hi,
as others told before a analog scope suffices. You could get a really good one for very low cost and You'd be sure that You have a decent, reliable, repairable and durable device.
I'm almost sure that my nearly 35years old shock and rattle proofed(sic!) Philips will outlast my new DSO. For component testing and curve tracing the XY mode of an analog scope is still far better than that of DSOs.
With regard to those very cheap USB scopes I'd be very cautious. Those have been reduced hardwarewise to a level I wouldn't trust it ensures consistent and reliable results.
As with benchtop DSOs Rigol's DS1000 series has been named a couple of times, but I think that they have had their time and the newer entry level Siglent SDS1000 series offers more.
The SDS1102CML+ as direct competitor to the Rigol DS1102E features a larger and better display with more resolution. If all else equalled that alone would make a decisive difference.
Besides these 'normal' scopes I'd like to point You at the Digilent Analog Discovery 2, a tiny 2-channel 14Bit USB device.
Though it may cost a bit more at first, it could save on later investions as it is a multifunctional device, including a 2-channel signal generator, 15MHz Spectrum, Impedance and Network analyzer, curve tracer and some more.
Due to its breakout connector You can add periphery suiting Your measurement requirements. Handling isn't as easy as with an benchtop device, but it still might be a interesting alternative. Visit nifty's blog to see what You can do with that little thingie
jauu
Calvin
as others told before a analog scope suffices. You could get a really good one for very low cost and You'd be sure that You have a decent, reliable, repairable and durable device.
I'm almost sure that my nearly 35years old shock and rattle proofed(sic!) Philips will outlast my new DSO. For component testing and curve tracing the XY mode of an analog scope is still far better than that of DSOs.
With regard to those very cheap USB scopes I'd be very cautious. Those have been reduced hardwarewise to a level I wouldn't trust it ensures consistent and reliable results.
As with benchtop DSOs Rigol's DS1000 series has been named a couple of times, but I think that they have had their time and the newer entry level Siglent SDS1000 series offers more.
The SDS1102CML+ as direct competitor to the Rigol DS1102E features a larger and better display with more resolution. If all else equalled that alone would make a decisive difference.
Besides these 'normal' scopes I'd like to point You at the Digilent Analog Discovery 2, a tiny 2-channel 14Bit USB device.
Though it may cost a bit more at first, it could save on later investions as it is a multifunctional device, including a 2-channel signal generator, 15MHz Spectrum, Impedance and Network analyzer, curve tracer and some more.
Due to its breakout connector You can add periphery suiting Your measurement requirements. Handling isn't as easy as with an benchtop device, but it still might be a interesting alternative. Visit nifty's blog to see what You can do with that little thingie
jauu
Calvin
My old Tektronix 454 gave up its breath a few days ago. I begun looking for second hand oscilloscopes for sale. However, since then I have been pondering the possibility of buying a new digital oscilloscope. When I have been reading the specifications of the scopes, I have noticed that most are only rated for 300 V. Since I build tube amplifiers, I often work with higher voltages than that. Obviously, I need test probes that are properly rated for high voltage, but does the scope also need to be rated for the voltage in the circuits that I am measuring?
Remember that the input impedance of modern scopes is 1MegOhm and this will load the tube circuit. You can make an attenuating adapter with a 2.2Meg series resistor, just remember that the voltage is now multiplied by 0.3125
I have been using a Tek TDS3012B and a Tek 2465B for more than 15 years.
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