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Need educated model/feature advice for oscilloscope for doing high-quality audio

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Franki:
hi folks. I'm new here.

I used to use an old Hameg 20MHz from the early 80s for years, but I need something better now.

I want to start building audio devices with much better quality: headphone amps(for headphones like Beyer DT770, AKG K701), power amps(active ones for home, studio monitors or multichannel for home theaters), active filters, mixer consoles etc... for audio sources like cd-audio/aac/vorbis up to uncompressed 32bit 192kHz uncompressed PCM that is supposed to sound like that.

AFAIAAO I need a DSO/DPO scope with at least 2 channels, indep, +, -, x, / operations, fft spectrum analyzer(at least 1024 band), continuous waveform and single shot mode. This scope should have a very low noise floor(I don't like most DSOs because of their noisy bucket brigade memory), very low distortions and have a high dynamic resolution(8bit won't be enough, if that's the actual sample dynamic resolution) so as to easily identify different small noises and their profiles(designing audio equipment of that grade requires minimizing very small noises and other non-linearities). Should be real-time sampling only. Important: To minimize noise, this scope should support hi-res multisampling in various modes. Of course a good HF-shielded box and connectors are valuable too. Also, it should be able to compute average and effective/rms values(per full view and single cycle). It should have a storage of at least some 100kSa. USB/RS232 connectivity is a must.

AFAIK I don't need excessively high bandwidth, 20MHz is more that I need. Input capacity, either of 10pF or 100pF is not an issue with audio circuits.

And it should be available for purchase in Germany. Absolute budget limit is 1000€ (~ US$ 1350).

I'm still undecided as to whether use a DSO or DPO(if there is such a thing whithin my price range) scope, as my experience is limited to analog scopes.

THX in advance

EEVblog:
Check out the 12 bit Picoscope's:
http://www.picotech.com/oscilloscope-specifications.html

Dave.

alm:
High resolution and measuring low distortion aren't typically strengths of a DSO, almost all of them have an 8-bit ADC, although some can get more resolution by averaging. No idea about the Picoscope, usually I think their products are overpriced and under performing, but this may be an exception. An analog scope with a fine trace and differential inputs is the usual suggestion in this case, but you won't find them new. Something like a dedicated audio spectrum analyzer or distortion meter may be a better tool for the job, I'm not sure if any DSO will satisfy your requirements. A scope typically has about 1-3% tolerance (not sure if they publish any distortion specs), so I'm not sure how useful this is for measuring .01% distortion. A differential high-gain pre-amplifier (like the Tek AM502) may be helpful for measuring noise, but it's not available new either. I think Lecroy and Preamble has/had something similar, but it's probably expensive.

EEVblog:
Pretty much only a PC based DSO will get you the performance you need, one that sacrifices bandwidht for resolution and noise performance.
This Picoscope is just in the budget and is specced for low level signal measurement:
http://www.picotech.com/precision-oscilloscopes.html
1% accuracy, but no noise spec.

Dave.

Franki:

--- Quote from: EEVblog on February 15, 2011, 10:24:08 am ---Pretty much only a PC based DSO will get you the performance you need, one that sacrifices bandwidht for resolution and noise performance.

--- End quote ---
Why do you think that only a PC-based DSO may reach such requirements? Is there a technical reason for that, or are non-PC based ones not demanded enough for being considered to be built?

On the other hand, I would have no problem with a PC-based scope, really, any kind of interface/connector from RS-232, RS-485, USB up to version 2.0, ethernet up to gigabit would work, as long as it doesn't exercise poor signal quality and is usable under non-Windows OSes, like FreeBSD, Linux, L4...

I forgot some more requirements: It must be at least partially-portable, meaning it should be small enough to be carried in a small back-pack or regular suit-case, but it's okay if it always needs power connection, though having a rechargeable battery or 12V connector are nice-to-have. And it must have an externally triggerable.


The thing with PC-based scope is this: They don't just work alone, so I would have to carry my laptop besides the scope. Laptop weights 5kg by itself. Possible, but ugly.

I just had a glance on the PicoScope 4224 you suggested. Good specs, fulfills all requirements, except that it only runs on Windows and doesn't work on its own...FAIL :(

Here's another one with promising specs: AEMC OX7102-C unfortunately, I have no clue how reliable and trustworthy that company AEMC is...haven't heard of them yet, anyone an idea? And I don't know whether they ship to Germany, and besides, that device is a little too much overpriced :(

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