Abraxalito,
just because you dont have to worry about the standards it dosn't mean that you'll have no noise. The noise your system creates will affect not only its self, signal integrity, but other equipement you have connected or are using.
I think it is a short sighted view of design especially if you are aiming for the best.
EMC and signal integrity are two sides of the same coin and both are critical to achieving the best design, to shun one is stupid.
You can get excellent books on the subject, often costing far less than an exotic capacitor!
just because you dont have to worry about the standards it dosn't mean that you'll have no noise. The noise your system creates will affect not only its self, signal integrity, but other equipement you have connected or are using.
I think it is a short sighted view of design especially if you are aiming for the best.
EMC and signal integrity are two sides of the same coin and both are critical to achieving the best design, to shun one is stupid.
You can get excellent books on the subject, often costing far less than an exotic capacitor!
I have an eval board from a GSM radio mfg and can force continuous transmit at +33 dBm in the 850/900 bands. Most audio gear does not handle it very well if I place the antenna close, to put it mildly.
Does all audio gear have to be hardened to cellular phone levels? Probably not, but Bluetooth, WiFi, and cellular signals are everywhere in most buildings and residences today.
The effect may be much more subtle than direct buzz. Measure and minimize output noise/interference content, both LF and HF.
I enjoyed the IC discussion, very interesting.
Maybe we should do a Group Design for our own dedicated audio IC, pretty cheap apparently:
Integration Nation on Planet Analog - Scott Elder - Design a Custom Analog IC in Your Garage
jan
Maybe we should do a Group Design for our own dedicated audio IC, pretty cheap apparently:
Integration Nation on Planet Analog - Scott Elder - Design a Custom Analog IC in Your Garage
jan
OT tinnitus Help
HI I need a dac for my tinnitus commercial or diy .... suggestion ?
PS
I and a lot around world don't have problem with vinyl.....
is dsd better for tinnits ?
for pcm is better r2r dac , or something like no pre ring digital filter ie the problem is in the band or outband ie 18k analog filter ?
thanks for helps....big problem this !!!!
HI I need a dac for my tinnitus commercial or diy .... suggestion ?
PS
I and a lot around world don't have problem with vinyl.....
is dsd better for tinnits ?
for pcm is better r2r dac , or something like no pre ring digital filter ie the problem is in the band or outband ie 18k analog filter ?
thanks for helps....big problem this !!!!
Not that we have to pass any measurement limits to get an approval, but we do want best possible sound, so we need to think about EMI and grounding issues.
I guess we also want to ahve a safe amplifier (I have had a bit too many electric shocks!), so some safety thinking is good to include.
Then, I at least want to have an amplifier that does not get too hot, and the limits in the CE demands are pretty useful.
I guess we also want to ahve a safe amplifier (I have had a bit too many electric shocks!), so some safety thinking is good to include.
Then, I at least want to have an amplifier that does not get too hot, and the limits in the CE demands are pretty useful.
Sigh..the yute of today..😀
Not outta me ya won't..
Agreed, but I believe what was meant was having to meet specs for production/selling.
Agreed.
But not a flux capacitor.
Absolutely. It's why power cords and IC's can make system changes beyond simple noise and hum. I still laugh when some posters claim PC's and IC's cannot affect the system sound because of "science".
And many times the safety bonding is what's causing a problem.
jn
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SY, PMA, you're a party poopers!
I thought we'll be discussing topology, but all you both do is pick on errors in drawing. John posted the same schematic, but later Rev. a while ago, didn't you downloaded it?
Ok, I'll ask: John, in contrast to your previous preamps, you're using LEDs to bias output Mosfets. Any special reason for that, except the largish voltage drop? P/LD-1100 has two bipolars in that place..
I thought we'll be discussing topology, but all you both do is pick on errors in drawing. John posted the same schematic, but later Rev. a while ago, didn't you downloaded it?
Ok, I'll ask: John, in contrast to your previous preamps, you're using LEDs to bias output Mosfets. Any special reason for that, except the largish voltage drop? P/LD-1100 has two bipolars in that place..
I was waiting for PMA's input. I just put up what I had on my computer, and since then, PMA has helped Parasound fix the schematic. Thanks PMA.
This schematic was put up ONLY for demonstration, but it is essentially OK, in principle.
This schematic was put up ONLY for demonstration, but it is essentially OK, in principle.
Thanks for your reply, it is good that Parasound fixed the circuit. JC-2 is a very nice design.
Agreed - I wasn't implying that not having to worry about standards meant that EMC/RFI was of no concern at all.
Sure.
What's a 'short sighted view' ?
Yep, no disagreement.
Indeed so, yet owning books is far from having an intuitive grasp of the issues.
@chris719 - I had a little experience of susceptibility under EN55022 when I was in the business. Its up to the manufacturer to state what degree of impairment is to be expected (I seem to recall there were 3 levels, broadly) and then the test house compares the claims with the actuality.
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We are using X-FAB at the university (including the BiCMOS 0.6um process) for mixed signal IC prototyping. Implementing anything that would follow the common audio wish list (like differential complementary jfets, class A output stage, etc...) would either be impossible (due to the process limitations) or extremely expensive (due to large area required by the high current output stage and power dissipation limitations). To add insult to injury, the only high voltage devices are n channel mosfets, lateral bipolars are limited to some 7V, high performance vertical bipolars with Ft=15GHz are limited to 5V.
What the audio wish list requires is not a new design, but a new process. Good luck finding or funding that.
Makes me wonder, how does the cost-quantity curve of an IC look like ?
(did the vispannetje in a semi-Rococo diner booth of the Corsendonks Hof yet, Jan with capitol J ?
)Yes. If you say it's o.k. for noise to come out of the powered speaker for example when subjected to EM radiation, that will be tested. At Harman one particular guy who worked a lot with European branches was, on the other hand, a stickler for things being dead quiet. He made life a good deal more difficult, especially as cell phones proliferated.
Gee, Waly, now you know why I stick to discrete audio gain stages, for the most part. Of course, I have to do IC based designs as well, but they will never be as good as my discrete designs, AND all else being equal, I believe that my open loop designs are better than my high global negative feedback designs. Perhaps it starts making sense to those who care about the difference.
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