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synthiaks

Re: Oscilloscope… need one.
« Reply #20 on: December 05, 2016, 10:12:03 AM »
I would buy an old dubble beam scope at "blocket" or eBay. Don't pay to much (1000sek max) and start to mess around with it. Soon you will know what/if you need something else.

If you are working on stuff connected to the Mains (you say tubes..) make sure you know what you are doing when connecting scope test leads. 

If you don't have a transformer for the DUT this might be a good time to stop and read up on safety issues when working with high voltage.

There are people on this forum who know about these things a million times better than me though :-)
« Last Edit: December 05, 2016, 10:18:42 AM by synthiaks »
"ex observer in silence"


joaquins

Re: Oscilloscope… need one.
« Reply #21 on: December 08, 2016, 12:29:23 AM »
  Look for "how not to blow your osciloscope" or something like that, and you'll find some useful info in that. EEVblog has a video which could help a lot on that regard.

  I personally wouldn't go for an analog scope unless it's dirty cheap just to mess around and you wouldn't care much if you blow it. Depending on the budget there are a ton of DSO to choose from and they also tend to be easier to work with, at least for really starters, usually an auto setup which gives you an starting point for all the triggering configurations making a readable acquisition. Both digital and analog have traps all over the place and you need to get to know what you are doing so you get reliable measurements, usually when you say I need an scope you are ready to learn that kind of stuff so isn't the end of the world.

  I guess analog can be good for spotting troubles and just fix them but when you start to get something do something in a better way, not just to work, having actual and repeatable numbers is a really good thing.

JS
If I don't know how it works, I prefer don't turn it on.

johnheath

Re: Oscilloscope… need one.
« Reply #22 on: December 08, 2016, 08:07:57 AM »
Thank you sir

As you say I will take some serious time yo read and study how to work with a scope and what I can do with it.

DSO's are all over the place but so are the prices.

I will have a second look.


Best regard

/John
Nothing is impossible - It just takes some more time

mrclunk

Re: Oscilloscope… need one.
« Reply #23 on: December 08, 2016, 09:15:14 AM »
I've been thinking about getting a Bitscope DSO, might be worth checking out?

http://www.bitscope.com/product/BS05/
http://cpc.farnell.com/bitscope/bs05u/oscilloscope-logic-analyzer-2/dp/IN06959

The software looks good and you can build a self contained one with a raspberry Pi.

Matador

Re: Oscilloscope… need one.
« Reply #24 on: December 08, 2016, 11:35:04 AM »
I've not been a fan of USB scope for analog work:  their sampling rate is limited (and unpredictable), and the input range is limited as well (typically a volt below ground, and perhaps 7-9V above ground).  For digital work they are really awesome.  USB was never designed to provide time-accurate sampling to an endpoint, so all kinds of compromises have to be made.

You can get a Rigol 4-channel DSO for not a whole lot more, and you get up to 20x the sampling rate for comparable analog bandwidth.  You also get 1mV input resolution (compared to 20mV for most USB scopes), which can be key for seeing small high-frequency oscillations in audio gear.

Andy Peters

Re: Oscilloscope… need one.
« Reply #25 on: December 08, 2016, 11:55:35 AM »
USB was never designed to provide time-accurate sampling to an endpoint, so all kinds of compromises have to be made.

I'm not sure how this matters, as USB is used as a transport to get the data from the hardware part of the 'scope to the display (which is the computer). All of the triggering and time-sensitive stuff is in the hardware.

-a
"On the Internet, nobody can hear you mix a band"

Matador

Re: Oscilloscope… need one.
« Reply #26 on: December 08, 2016, 02:25:52 PM »
I'm not sure how this matters, as USB is used as a transport to get the data from the hardware part of the 'scope to the display (which is the computer). All of the triggering and time-sensitive stuff is in the hardware.

-a

Not always:  quite a few of the less expensive USB DSO's don't buffer the samples in hardware, they just rely on the round-trip time of the bulk transfer across the bus to define the sampling rate.  So sometimes its fine, and other times the OS decides to do a broadcast endpoint enumeration and your capture gets interrupted. :)

For the cost of the better USB-based scopes (like the PICO's) you can get a real standalone unit, unless you are focusing on digital comm's debugging (like I2C or SPI).

mrclunk

Re: Oscilloscope… need one.
« Reply #27 on: December 08, 2016, 06:03:22 PM »
Listen to those two John. They are far more knowledgeable than i.

Bluzzi

Re: Oscilloscope… need one.
« Reply #28 on: December 09, 2016, 12:11:06 AM »
By coincidence I am also looking for a scope. Rygol and Siglent models seem to be in the price range I am looking at with also enough specs.

I have access to a Leader analog one but it's a behemoth and takes up a huge chunk of my workbench. I just got a gift card for Amazon which almost pays for one so hence telling my gear addiction "I need it".

There are so many varying opinions on all these DSO's but they are all from guys working on much higher bandwidths than audio. I figure a 50Mhz is fine even for some logic circuits etc..

I have never used 2 channels yet and so 2 is enough for me. Any reason for wanting more in the analog audio world?

Curious to see what was picked by John Heath.

Cheers

Jim

Gus

Re: Oscilloscope… need one.
« Reply #29 on: December 09, 2016, 04:01:52 PM »
Bluzzi
I researched DSOs mostly web searches and youtube reviews
Rigol , Siglent , Hantek, Owon , used older Tek DSOs. etc.
I ended up with a GW Instek 2204E 200mHz 4 channel 1Gs got it on sale at a good price, it uses two zynq processors so you have 1Gs with two channels and 500mHz with 3 and 4 channels not 1 ch 1Gs, 2 ch 500Ms, 3 and 4 ch 250Ms
Each channel has it own controls
Biggest issue I have with it is it is so light you can move it pushing the buttons.
I found the EEV blog youtube videos and forum to be helpful there are other you tube scope reviews that were helpful
You might like something else

You can sometimes find under $400 on sale 4 channel 50 mhz DSOs in the USA

You might want a 4 channel that decodes 

You can even find 200 mHz two channel for a low price https://www.circuitspecialists.com/hantek-200mhz-digital-storage-oscilloscope-dso5202p.html I did not like the time base 2, 4, 8? I have not tried one. There are youtube videos with reviews

It can be confusing looking for a new scope on a budget I think I got good value for my dollar with the DSO I bought.

Make sure you check prices at other  places than Amazon
« Last Edit: December 09, 2016, 04:08:59 PM by Gus »


Bluzzi

Re: Oscilloscope… need one.
« Reply #30 on: December 09, 2016, 05:16:03 PM »
Thanks Gus. Yes it is confusing because there are so many models and combinations and some are same models rebranded.

I need to get from Amazon as I am getting $300.00 as gift. So anything above that I pay. So for a $400.00 scope I will only pay 100.00 out of my pocket. I don't want to spend more than $200.00 so max is a $430.00 or so scope (need to leave a bit for taxes and shipping to Canada).

So far I only plan on using it for audio and mostly solid state with some tube circuits in there. A 50MHz scope would be more than adequate for me. What I really need is a nice bright and clean display as well as large fonts on the menus and numbers displayed (frequencies, volts etc.). The Hantek models have larger fonts displaying those results, so I am leaning towards those. I find all the chinese brands have their fans and also their naysayers.

I will probably take a chance on this one: https://www.amazon.com/gp/product/B01EYHRGWO/ref=ox_sc_sfl_title_4?ie=UTF8&psc=1&smid=A3UJMHM53HHUF7

I wish I was in the states as prices are way cheaper. I have an address to ship near border that I may look at.

Cheers

Jim

johnheath

Re: Oscilloscope… need one.
« Reply #31 on: December 10, 2016, 02:20:12 PM »
Got my scope yesterday… an analog GwInstek GOS-630FC and I've been riffling with it since.

I just wonder if someone could guide me in a direction to find a good source to learn how to measure gain in a circuit? I have tried the scope with a function generator to add a signal at the input and read the signal at the output but I must do something wrong since the signal is weaker at the output???

I must admit that I only have two probes at the moment and therefore one for the function generator and one for the scope if that could be the issue?

Best regards

/John
Nothing is impossible - It just takes some more time

ruffrecords

Re: Oscilloscope… need one.
« Reply #32 on: December 10, 2016, 03:19:08 PM »
I must admit that I only have two probes at the moment and therefore one for the function generator and one for the scope if that could be the issue?

Best regards

/John
The function generator probably should not be fed through the probe. They often have aX10 attenuator inside. You probably need to make up a lead with a BNC at one end and a pair of clips at the other to use for the function generator.

Cheers

ian

johnheath

Re: Oscilloscope… need one.
« Reply #33 on: December 10, 2016, 04:29:43 PM »
Yes, I know… I switched the generator probe attenuator to "1X" and kept the scope probe on "10x" but the readings stayed the same… BUT, during the evening I have made two XLR-connectors with very short leads to hook up the probes and I have made new readings and there is of course amplification but now I have to understand the readings :)

Best regards

/John
Nothing is impossible - It just takes some more time

synthiaks

Re: Oscilloscope… need one.
« Reply #34 on: December 13, 2016, 04:56:18 AM »
Scopes are v/cm so its all about the right scale, with a 2 Channel you can compare Input and Output p/p and count the difference on screen like a normal ruler. From there you just do the math for the result you are looking for (dB, Neper or whatever)
"ex observer in silence"

Andy Peters

Re: Oscilloscope… need one.
« Reply #35 on: December 13, 2016, 10:51:00 AM »
Got my scope yesterday… an analog GwInstek GOS-630FC and I've been riffling with it since.

I just wonder if someone could guide me in a direction to find a good source to learn how to measure gain in a circuit? I have tried the scope with a function generator to add a signal at the input and read the signal at the output but I must do something wrong since the signal is weaker at the output???

I must admit that I only have two probes at the moment and therefore one for the function generator and one for the scope if that could be the issue?

I read the manual for your oscilloscope and one thing that stands out is that there is no way for the 'scope to know that the probe is a 10X (attenuating) or 1X type. Generally, though, you set the probe to 10X. Your 'scope as a calibration output on the front panel, which outputs a 1 kHz sine wave at 2V pk-pk. Connect a probe to that output, and see if the 'scope indeed displays what you expect.

-a
"On the Internet, nobody can hear you mix a band"

johnheath

Re: Oscilloscope… need one.
« Reply #36 on: December 14, 2016, 08:23:13 AM »
Yes, I have checked it and I am aware of the situation to keep it in mind for calculations.

I guess that I am missing something when hooking the function generator up together with the scope.


Best regards

/John
Nothing is impossible - It just takes some more time

Whoops

Re: Oscilloscope… need one.
« Reply #37 on: December 14, 2016, 03:56:11 PM »
Hello John,
I gathered some info sometime ago when I was also looking for a scope.
here are my tips:

1) Buy an used Analog scope from a good brand Tektronix or HP.
Build quality will be better than other unknown brands, Service manuals and user community available in case you need repair, those brands really thought on the engineering side and serviceability.
Buy an unkown brand and if you need to repair it you are in No mans land.

2) Jakobs Tips:
For most audio work, you should get a two-channel scope.
5mHz or more.
Vertical sensitivity at 5mV/div or better.

 You'll find that relatively low-MHz-scopes often has better vertical sensitivity than faster ones.

 You'll probably most often need sensitivity more than speed - that is, for audio work.


johnheath

Re: Oscilloscope… need one.
« Reply #38 on: December 15, 2016, 06:51:45 AM »
Hello Whoops

I bought a new...an analog GwInstek GOS-630FC

It is a 3MHz and time is down to 0,2µS/DIV, and voltage down to 1mV/DIV.

As being a beginner with scopes I am still learning a lot but this one seems just fine for my analog testing. It is easy to use, but this scope doesn't have automatic reading of voltages and such so you have to consider probe attenuation and do the math on your own. But that tends to teach me more and perhaps later on I will get a digital scope with more features but that will be when my wallet contains more gold :)

Thanks for the advise.

Best regards

/John

Nothing is impossible - It just takes some more time

Whoops

Re: Oscilloscope… need one.
« Reply #39 on: December 15, 2016, 07:37:46 AM »
Hello Whoops

I bought a new...an analog GwInstek GOS-630FC

It is a 3MHz and time is down to 0,2µS/DIV, and voltage down to 1mV/DIV.

As being a beginner with scopes I am still learning a lot but this one seems just fine for my analog testing. It is easy to use, but this scope doesn't have automatic reading of voltages and such so you have to consider probe attenuation and do the math on your own. But that tends to teach me more and perhaps later on I will get a digital scope with more features but that will be when my wallet contains more gold :)

Thanks for the advise.

Best regards

/John

For most audio related work you don't need a Digital one.
Analog Scopes are great for our uses