Ok, While we talk of snubbers and things, all those with snu bberized ps supplies, try removing the (-) rail snubbers completely just leaving the 1000uf caps. The (+) side snubbers should remain. I think this gives the best compromise. It seems like the (+) side rails are drawing the power and not so much (-). I haven't measured that just a hunch.
sam9 said:
It depends on how the capacitors are connected. If you connect them with very short and thick wires or PCB traces, where the inductance dominates over the resistance, ringing is more likely to happen. On the other hand, if the capacitors are in different places and connected by long not-so-thick twisted wires or closely spaced PCB traces, where the resistance dominates, ringing is not likely to happen (purely ohmic resistance is the most lovely thing in electronics, it damps and cures everything). In the latter case, the additional capacitors are useful to compensate for wiring inductance. Also, when different capacitors are literally soldered one over the other, with negligible wiring inductance, ringing is less likely to happen.
Anyway, since each type and size of capacitor shows slightly different HF behaviour, the best way to ensure the absence of resonances is to build some circuit capable of drawing sharp 1us to 10us current pulses periodically, hook it to various PSU stages and have some fun watching with your oscilloscope these things that everybody argues about but very little people has actually ever seen. It's worth the effort. I strongly recommend it, because repeatability is a wonderful thing.
Also, I think that the usual decoupling scheme employed in most class-AB amplifiers, where everything is capacitively coupled to an idealized power ground, is not optimum at all and is the product of probably dozens of misconceptions. I'm working into an amplifier circuit without any power ground in order to show that alternative PSU arrangements are possible.
janneman said:
I'll do soon. Anyway, it's a very simple principle, it consists on using ground only as a voltage reference for the differential input stage and decoupling and powering everything from the rails wihout an auxiliary midpoint. For example, the output zobel has one 47nF capacitor to each rail instead of 100nF to ground, and there is a single supply decoupling capacitor from +V to -V.
P.D. wrote:
''It's not a surprise to me. I avoid adding small bypasses (in that matter, any bapasses) as it never sounds right to me.
Actually, the biggest improvement I did to my ML37 transprt was removing all those double bypasses (ceramics, tantalums or polyp.) and leaving only single electrolytics in each location (of course, much smaller capacitance).''
Is there something I missed ?
P.D. and ''The ultimate TDA1543 DAC layout'':
''In some other thread, there was a discussion about ceramic bypass caps. Well, that DAC was initially built without them, as I wanted to check out their influence. Comparing what I remembered from the sound of my other DACs (having those caps) the sound seemed to be dry and not liquid enough, lacking a bit of sparkle. After adding ceramic bypasses, it improved. I don't know what other guys are using, but the caps I favour are 15n X7R 0612 and 330n X7R 0612 from DK. They are pretty expensive and have soldering tabs on longer side, being even more suitable for bypass purposes. I solder tham directly to the chip pins, stack on each other, the smaller one being closer to the chip.
Here's the link to excellent article by Pete Goudreu discussing triplets bypassing http://groups.google.com/groups?sel...u&output=gplain''
Don't want to insult, attack, be rude or anything.
Probably I just didn't get it right.
Regards
''It's not a surprise to me. I avoid adding small bypasses (in that matter, any bapasses) as it never sounds right to me.
Actually, the biggest improvement I did to my ML37 transprt was removing all those double bypasses (ceramics, tantalums or polyp.) and leaving only single electrolytics in each location (of course, much smaller capacitance).''
Is there something I missed ?
P.D. and ''The ultimate TDA1543 DAC layout'':
''In some other thread, there was a discussion about ceramic bypass caps. Well, that DAC was initially built without them, as I wanted to check out their influence. Comparing what I remembered from the sound of my other DACs (having those caps) the sound seemed to be dry and not liquid enough, lacking a bit of sparkle. After adding ceramic bypasses, it improved. I don't know what other guys are using, but the caps I favour are 15n X7R 0612 and 330n X7R 0612 from DK. They are pretty expensive and have soldering tabs on longer side, being even more suitable for bypass purposes. I solder tham directly to the chip pins, stack on each other, the smaller one being closer to the chip.
Here's the link to excellent article by Pete Goudreu discussing triplets bypassing http://groups.google.com/groups?sel...u&output=gplain''
Don't want to insult, attack, be rude or anything.
Probably I just didn't get it right.
Regards
my intent was not to be rude, it was to give my side of the snubber story.
if you consider me voicing my findings to be rude, or impolite, then thats to bad.
i presented the conclution from my facts as seen from my point of view.
oh, and i'v come to the conclutions that cables have no decernable impact on sound, that subjectivism is the death of facts, and that psudo science is to be feared like the black plauge.
guess i'm not really welcome in your threads from now on.
-Marius
if you consider me voicing my findings to be rude, or impolite, then thats to bad.
i presented the conclution from my facts as seen from my point of view.
oh, and i'v come to the conclutions that cables have no decernable impact on sound, that subjectivism is the death of facts, and that psudo science is to be feared like the black plauge.
guess i'm not really welcome in your threads from now on.
-Marius
just saw the post that got sendt to texas, dunno if charls post were meant for me, so i wont reply, but yours carlos:
"I'm impressed."
"You don't say what you tested, how you tested, the components used, nothing. And then you talk about voodoo...
Something is deeply wrong with your 'tests'."
is it actually needed? i never meant to post more than my conclution. not how came to it. it would be a two year story containg a whole lot more than the electronics itself, although my realisation of the snubbers can be linked to a much bigger personal process, for what ever you knowing that's worth.
i tested the snubber on a large assortment of chipamp solutions, both mine and two friends of mine's. including the 3886, 1875, 4700, 4780 ect. tested it on opa549 and 541 as well.
PSU's differed, but all were good quality ones. i used my ears for testing, as i'm pretty short on any other kind of equipment. mid quality components. no fancy stuff.
"Keep your ignorance and deafness for yourself and don't call all the others psychos.
OK?"
i really am sorry you see it that way.
"I'm impressed."
"You don't say what you tested, how you tested, the components used, nothing. And then you talk about voodoo...
Something is deeply wrong with your 'tests'."
is it actually needed? i never meant to post more than my conclution. not how came to it. it would be a two year story containg a whole lot more than the electronics itself, although my realisation of the snubbers can be linked to a much bigger personal process, for what ever you knowing that's worth.
i tested the snubber on a large assortment of chipamp solutions, both mine and two friends of mine's. including the 3886, 1875, 4700, 4780 ect. tested it on opa549 and 541 as well.
PSU's differed, but all were good quality ones. i used my ears for testing, as i'm pretty short on any other kind of equipment. mid quality components. no fancy stuff.
"Keep your ignorance and deafness for yourself and don't call all the others psychos.
OK?"
i really am sorry you see it that way.
Igla said:
You should add dates to both quotes. I simply changed my opinion based on subsequent experimenting and changes made to main bypass caps, that's all.
That opinion was formed more than a year ago, and presently I'm not using ANY additional bypasses, even in digital circuits, and my position is very strong on a subject now:
http://www.diyaudio.com/forums/showthread.php?postid=525605#post525605
http://www.diyaudio.com/forums/showthread.php?postid=741511#post741511
Hi,
Eva I appreciate your stance on measuring instead of blindly throwing caps/snubbers at a circuit because everyone else does. They're compensation networks and should be used accordingly which requires measurement.
In my case this mandated the use of bridge FRED rectifiers to benefit from the soft recovery with no further snubbing, as I haven't the means to measure with.
Apart from that I think the post to mrfeedback which was linked to here has the right idea on how the cap snubbers are best implemented for full effect, and those who would bypass instead with a smaller electrolytic are basically using the higher ESR (over film) as a combined RC snubber, cheaper/simpler method.
Regards,
Chris
Eva I appreciate your stance on measuring instead of blindly throwing caps/snubbers at a circuit because everyone else does. They're compensation networks and should be used accordingly which requires measurement.
In my case this mandated the use of bridge FRED rectifiers to benefit from the soft recovery with no further snubbing, as I haven't the means to measure with.
Apart from that I think the post to mrfeedback which was linked to here has the right idea on how the cap snubbers are best implemented for full effect, and those who would bypass instead with a smaller electrolytic are basically using the higher ESR (over film) as a combined RC snubber, cheaper/simpler method.
Regards,
Chris
classd4sure:
I appreciate your support, but there are a lot of people here that want neither to understand nor to discuss electronics. They have far more fun throwing random components at their circuits and letting their imagination fly. Then again, I understand that point of view because I used to play that game a lot when I was a child.
A snubber is a frequency compensation network. The best way to learn snubber techniques is developing SMPS, as here they are required to reduce EMI and to prevent components from blowing. A SMPS with the wrong snubber component values may radiate like hell, may no longer work or may even self destruct.
On the other hand, I have still to find somebody capable of telling by ear (or even by measurement) whether some piece of audio gear has C or RC networks across its power diodes. Actually it may be measured, but they are not likely to know how.
Analog audio is a wonderful thing, because most circuits (particularly the simpler ones) will still produce sound even when component values are wrong by an order of magnitude (even by two orders sometimes). Indeed, this fact has a lot to do with people leaving their imagination fly rather than understanding electronics (or acoustics), and with the amount of poorly designed audio stuff being sold with great success everywhere under esoteric claims.
This can only happen in audio electronics, as there is no room for imagination overriding science in any other electronics field.
I appreciate your support, but there are a lot of people here that want neither to understand nor to discuss electronics. They have far more fun throwing random components at their circuits and letting their imagination fly. Then again, I understand that point of view because I used to play that game a lot when I was a child.
A snubber is a frequency compensation network. The best way to learn snubber techniques is developing SMPS, as here they are required to reduce EMI and to prevent components from blowing. A SMPS with the wrong snubber component values may radiate like hell, may no longer work or may even self destruct.
On the other hand, I have still to find somebody capable of telling by ear (or even by measurement) whether some piece of audio gear has C or RC networks across its power diodes. Actually it may be measured, but they are not likely to know how.
Analog audio is a wonderful thing, because most circuits (particularly the simpler ones) will still produce sound even when component values are wrong by an order of magnitude (even by two orders sometimes). Indeed, this fact has a lot to do with people leaving their imagination fly rather than understanding electronics (or acoustics), and with the amount of poorly designed audio stuff being sold with great success everywhere under esoteric claims.
This can only happen in audio electronics, as there is no room for imagination overriding science in any other electronics field.
Eva said:
I agree -- to a point -- if you are powering a measurement device (rather than an audio device) the radiation can causy pesky adc LSB errors. So if you are using a logarithmic amplifier, or an ADC with 12+ bits of resolution these issues have to be dealt with beforehand. Of course, that's why we use instrumentation amplifiers... For listening, it may make a difference if you are powering a preamp for a moving coil cartridge, probably not a whit of difference if you are listening to a CD, and is ridiculous if you are trying to make listening sense of FM radio ( at least here in the States).
If someone is totally immersed in his theoretical (emphasis on theoretical) world (and good on that) and cannot see the wider picture, in German, we call such a person "ein Fachidiot".carlosfm said:Than you!
Some people think that a pair of passive components only serves one purpose.
I can't translate it word by word, they would send me to Texas….maybe it's called "nerd" in English.
Perhaps too much of SMPS work will lead to the described intellectual state?
It's a pity this thread degenerated this way...
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