Hello! i'm an Electrical and Electronic Engineering student at Cardiff University, travel plans for this summer have been postponed for obvious reasons so i'm looking into some audio projects to occupy myself during the periods of inevitably rubbish weather here in south England/Wales.
I've done some reading of D. Self and B. Cordell's books, along with two years of uni work including analogue circuit design, control engineering, power systems and FPGA embedded design. I think it's time to actually build something that i'm interested in.
TLDR;
My aim is to 'design' and build a class A/B power amp, preamp with volume control, and maybe even an FPGA based DAC as i'm fairly familiar with Verilog already. So, as far as purchasing some gear;
Scope: Siglent SDS1202X-E, i've been offered 20% off a new unit.
DC bench power supply: Any cheap eBay linear supply? do I need to worry about output ripple too much? anything I should avoid?
Signal generation/measurement: this I am quite stuck on, I see people using soundcards like the "Behringer UMC 202HD" to make low distortion measurements, is it possible/advisable to use the same soundcard to generate and measure the same waveform?
FPGA dev board: anyone attempted something similar to this before?
I already have two multimetres/soldering iron/breadboards etc..
Any advice/insight/problems I will face would be greatly appreciated, i'm not trying to invent anything new here, just build upon my understanding, and who knows, maybe even power two bookshelf speakers with some half decent sound quality!
Thanks!
I've done some reading of D. Self and B. Cordell's books, along with two years of uni work including analogue circuit design, control engineering, power systems and FPGA embedded design. I think it's time to actually build something that i'm interested in.
TLDR;
My aim is to 'design' and build a class A/B power amp, preamp with volume control, and maybe even an FPGA based DAC as i'm fairly familiar with Verilog already. So, as far as purchasing some gear;
Scope: Siglent SDS1202X-E, i've been offered 20% off a new unit.
DC bench power supply: Any cheap eBay linear supply? do I need to worry about output ripple too much? anything I should avoid?
Signal generation/measurement: this I am quite stuck on, I see people using soundcards like the "Behringer UMC 202HD" to make low distortion measurements, is it possible/advisable to use the same soundcard to generate and measure the same waveform?
FPGA dev board: anyone attempted something similar to this before?
I already have two multimetres/soldering iron/breadboards etc..
Any advice/insight/problems I will face would be greatly appreciated, i'm not trying to invent anything new here, just build upon my understanding, and who knows, maybe even power two bookshelf speakers with some half decent sound quality!
Thanks!
You can generate a signal and measure it with a sound card, but I've never been impressed with the results. Better off to build a good generator and there are some excellent circuits right here. If you don't have it, download a copy of Visual Analyser Others will have additional suggestions for analysis.
I don't think supplies are a big deal, since most power amps use primitive supplies anyway.
I don't think supplies are a big deal, since most power amps use primitive supplies anyway.
There are loads of TTI power supplies on Ebay and they are virtually bomb-proof. Search for Thurlby or TTI. I have several and use them daily. The later switch mode units tend to have lower mains ripple. Prices vary, but you can get them cheaply if you are patient as they are common.
NB - as a rule, an older TTI PSU will have less hash / ripple and junk than a cheap, new PSU.
NB - as a rule, an older TTI PSU will have less hash / ripple and junk than a cheap, new PSU.
Cool thankyou, but you still suggest a soundcard for measurement? is there a particular card/setup you recommend? am I right in saying that most require modification? sorry for all the questions I just normally overwhelm myself with information when trying to decide upon a particular method.
I'd disagree and say definitely go for a modern 'scope. The accuracy needed for distortion measurement and good FFT analysis isn't going to be present in any 'scope, the scope is for visualization and simple measurements. BTW the Siglent has upto 11 bit ENOB if you set the acquire mode to extended resolution, which for audio isn't problematical.
Modern scopes are small and convenient, old analog ones weigh 10--20kg or so and take up the whole bench. You can easily screen capture a modern scope too.
I've had a little play with Visual Analyser, thanks for the hint.
I've also spent quite a bit of time reading around oscillator circuits but there are so many! do you know of a single design that is generally regarded as the go to diy/beginner friendly?
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