oscilloscope

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oblioblioblio
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oscilloscope

Post by oblioblioblio »

got an analogue scope w/ digital brain yesterday.

Did my research and watched ebay like a hawk for a while... Tektronix 2445... little brother/sister of 2465 which many cite as the best analogue scope of all time... with probes and in very very good condition (one weird thing I'm trying to suss)... with set of probes (good ones can set you back a lot) £130

Probably not useful for everyone... there's not loads of info you can get from watching a waveform... more useful for probing circuits and whathaveyou, but fucking hell, such incredible technology. I got it to calibrate my reel to reel, and will also come in handy for repairing and maintaining my other machines.

Lots of the Tektronix family can be found cheaply on Ebay, mine was cited as not working but really the person I collected it from didn't really understand it... they are very complex devices.

Google comes up with lots of info... Tektronix are like the Studer of the scope world... serious engineering... they all seem to have some strong points and weak points. Mine is newer and thus the CRT is less likely to die, but there are some specialist digital ICs that are hard/impossible to source.

older models like 265 are all transistors but much older, and I heard about some weird diode being equally unobtanium.

Really good time to go all analogue... Ive got a load of equipment now that would cost more than the house I live in when bought new, all at like 5% or even less of the original price.
steevio
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Re: oscilloscope

Post by steevio »

i've got two analogue oscilloscopes, and i'm going to give away one, (havent decided which yet but watch this space)
because i'd much rather use a digital oscilloscope
oblioblioblio
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Re: oscilloscope

Post by oblioblioblio »

care to say why?

FFT? that's much more musically useful than waveform display.
steevio
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Re: oscilloscope

Post by steevio »

mostly because i can put it on a big screen and spread the range along the axis so i can accurately view the individual harmonics in a waveform mostly in the mid range where it matters, i use a logarithmic scale from 20 to 10K hz and can easily see which harmonics are being doubled, tripled and quadrupled up, so i can remove them using the pulse widths of the individual oscillators for a clearer sound with definition in the mids.
my analogue oscilloscopes on the other hand are just pretty pictures in comparison. but pretty pictures are cool too :)

sorry what i mean is i like to run a spectrum analyser along side the oscilloscope on the same screen so i know what the waveforms actually mean
oblioblioblio
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Re: oscilloscope

Post by oblioblioblio »

yeah with spectrum analyser that's what I meant by FFT... which I think you can only do in digital.

i'm quite relaxed about the harmonic spectrum... I actually did all my last recording which is coming out on double cassette on the crappiest home hi fi system possible... only a few steps up from laptop speakers. hmm.

Yeah the CRT waveforms are like a work of art... really love these tools for understanding sound and circuitry... really amazing instruments.
steevio
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Re: oscilloscope

Post by steevio »

yeah its really interesting (in a full-blown nerdy way) to relate what the waveforms are doing to the spectrum. Virtual Analyser is what i use, you can clearly see what is creating the shape of the wave from the harmonics in the spectrum, for me now the two are interchangeable, if i look at the spectrum, i can pretty much predict what the waveform will look like and vice and versa.
Phurniture
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Re: oscilloscope

Post by Phurniture »

AK
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Re: oscilloscope

Post by AK »

steevio wrote:mostly because i can put it on a big screen and spread the range along the axis so i can accurately view the individual harmonics in a waveform mostly in the mid range where it matters, i use a logarithmic scale from 20 to 10K hz and can easily see which harmonics are being doubled, tripled and quadrupled up, so i can remove them using the pulse widths of the individual oscillators for a clearer sound with definition in the mids.
my analogue oscilloscopes on the other hand are just pretty pictures in comparison. but pretty pictures are cool too :)

sorry what i mean is i like to run a spectrum analyser along side the oscilloscope on the same screen so i know what the waveforms actually mean
I gave up on this because when you change a note, it all goes to pot. In other words, if I'm aware of any harmonics in a given sound, once I change to a different note, a whole new set of harmonics come into play. Too much to be aware of
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