Re: Just want to clarify and not jack the thread
Yes I can if you supply me the band of interest
best regards
purplepeople said:
Yes I can if you supply me the band of interest
best regards
Glad I found this thread. I was going to post a new one about this topic; so here goes:
I've also been wondering about the importance of power supplies in CD and DVD players. Being that just about every DVD/CD player that is on the market today uses "Switchmode" power supplies; I guess this raises the question:
Which is better for Digital; Linear or Switchmode? Or does it really matter?
I've also been wondering about the importance of power supplies in CD and DVD players. Being that just about every DVD/CD player that is on the market today uses "Switchmode" power supplies; I guess this raises the question:
Which is better for Digital; Linear or Switchmode? Or does it really matter?
I think the only advantage of the switchmode supplies are theyr efficiency (and the head issues that comes with it)
Linear supplies dissipate more heat, but don't produce HF garbage
but I have no idea about the regulation of a switchmode supply, I'd like to know it. (performance of the line and load regulation, impulse response...)
Linear supplies dissipate more heat, but don't produce HF garbage
but I have no idea about the regulation of a switchmode supply, I'd like to know it. (performance of the line and load regulation, impulse response...)
Tom D said:
Bricolo said:
dear all
SMPS have only disadvantages sonically. They produce RF and that can be filtered current or voltage wise, but it still contains RF....
Cute example is Philips SCAD1000: Setup a completely different audio system, and only connect the SCD to the mains - be surprised.....
They meet EMC regulation limits, but they do not meet serious audio criteria.
I have been into EMC for 6 years (Philips) and spend 2 years on filtering and all related to SMPS's and converters - been there and done that.
regards
Bricolo said:
I own a Denon 2800 and recently removed the switchmode supply and am now using separate Acopian modules (linear, regulated, shielded). I use two 5V 1A supplies, one 12V 1.2A supply, and one 3.3V 3A supply (for the video chip). I have an external dac that runs on 12V lead-acid batteries. Let me say that the video is MUCH clearer, and the digital output going to the dac is VERY clean. I also put in a LC Audio X02 clock and removed the old hex inverters that were in the clock circuit, as they are crap.
I also took the SPDIF out of the decoder chip directly to the input of the dac (I mounted it internally) using a 5" piece of 75-ohm mini coax. I have no desire to get rid of this player, it sounds heavenly.
All I can say is that clean power supplies make a very big difference! Using a scope, you can see all the nasties that a switchmode supply makes. Using your ears, you can hear
how much better clean supplies can sound, and with dvd, you can see cleaner, crisper, less blurred picture, especially when you get within inches to the TV.
-Vinnie
till said:
the cost of a used HP/TEK/Anritsu analyzer will set you back about $3 to $7 grand, and a new one over $20,000
At this level even moving the cables has an effect on measurements (this is true even at tens of microvolts). You will also have to control the relative humidity, and it would be nice if you could conduct the measurements in a shielded room.
Regulated linear supplies do produce garbage -- when you produce heat you produce garbage -- true throughout the universe -- but you can take care of it -- see the threads which site the Wenzel Associates solution (among others).
jackinnj said:
Hi
I measure nV in the freq domain (untill 50 kHz) , using an HP3580A (2nd hand 500 euro) and a home made 50 dB preamp using AD797 (20 euro of bits and pieces.
That way I save some money for other nice tech stuff.....
regards
Tom D said:
potentially Yes, but again, all depends on implementation. I can make a decent SMPS and a lousy linear supply.....
regards
Guido Tent said:
At this level of measurement, a change in temperature of the AD797 will also change the measurements.
I have to go way back to my UHF Ham radio days (back when I had a full head of hair), but when you measure a signal which has been elevated by a preamplifier the threshold noise AND distortion caused by the amplifier have to be added into the numerator when you calculate the noise figure. Of course, we are talking about many things here, I worry more about the noise figure of a ham receiver than I do for playing LP's.
Problematic noise pops right out at you in LM317/337 regulator circuits. You don't have to finesse it, it's measurable in the millivolts.
btw, I have a 5L4N spec analyzer which is mounted in a D13 mainframe -- pretty sensitive -- 20 nV/div . This is now my only analog scope.
Guido Tent said:
I agree, but; most DIYers will immediately modify these DVD/CD/DVD-Audio/SACD Players mainly because of the switchmode power supplies that most of these players now have.
Such as; the budget SACD players from Sony and Philips. Without modifications to these players, most audiophiles or DIYers would say they suck(such as the numerous posts at AudioAsylum.com).
I don`t won`t to be overly pedantic and I know that a mistake is quickly made with all that zeros but as You`re talking Volts here and not Power: 1nV converts to -180dB not -90dB (when 0dB = 1V) .
0,00003V (=30µV/ mikrovolt) = -90dBV
The -90dB calculation would be correct for 1nW (where 0dB = 1W)
0,00003V (=30µV/ mikrovolt) = -90dB
Here a Link where is explained how to calculate voltage & power relationships in dB (take care not to confuse VdB with PdB):The diaBolical dB
I guess my biggest question about all this is:
Are switchmode power supplies really "OK" as far as using them in these latest DVD/CD/SACD players?
Another words; Does the switchmode supply really degrade the audio quality?
Are switchmode power supplies really "OK" as far as using them in these latest DVD/CD/SACD players?
Another words; Does the switchmode supply really degrade the audio quality?
Doesn't necessarily have to be so -- if you use a SG3524 switching chip or an NE555 timer and a pair of transistors you will have beaucoup de noise. If you use an LT3439 or an LT1533 you will have a little noise. The latter chips are good enough to be finding applications in medical apparatus.Tom D said:
I changed the SMPS caps in a cheap DVD player to nice quality Hitano low-esr types and the sound improved markedly.
I did not bother to measure any power rail noise however.
Eric.
I did not bother to measure any power rail noise however.
Eric.
I'm in the process of modding my Philips 963sa. The first thing I did was to replace a few caps in the switching and it made a difference. I also changed the fast diode 1n4004 to some schottky and it bring another slight improvement. I have not change all the caps in the smps yet and make the stupid mistake of changing the coupling caps to blackgate too early. Now if I change anything, I can not tell if the change is due to the mod or the change due to long break in time of Blackgate.
Speaking of SMPS, there is a thread in head-hifi that the 963sa measure rather good and changing to linear supply only brings marginal improvement.
I think there are currently some hi-end gear out there that actually use SMPS, anybody know any info on this?
Speaking of SMPS, there is a thread in head-hifi that the 963sa measure rather good and changing to linear supply only brings marginal improvement.
I think there are currently some hi-end gear out there that actually use SMPS, anybody know any info on this?
cocolino said:
I thought that line level signals voltage is directly related to power as P=VI. So a change in power could be measured the same as dBV and is roughly doubled at +3dB and halved at -3dB. The conversion I used is: 1 nanovolt = 1E-09 V = 2^-30 = -90dB when compared to 1.0 Volt.
🙂ensen
Changing the caps in an SMPS supply is NOT a good idea -- when you use a different ESR or capacitance value you also need to see what's going on in the compensation/feedback loop of the supply. If it's overdamped the supply won't react quickly enough to changes in load or input voltage, if it's under-damped it will oscillate or ring.mrfeedback said:
Good advice, but probably not a big problem in practice.
The caps I changed with the same values were smps 105* type but of unknown origin - they looked like the cheapest Chinese available.
The ones that went in are easily and cheaply available to me, and many past experiments have shown them to sound good as coupling or decoupling caps, and in this case the sound was markedly improved.
I have not heard BG's but I find I like the sound of these Hitano EXR low esr caps, and they are only 10% more expensive than standard 105* types.
Eric.
The caps I changed with the same values were smps 105* type but of unknown origin - they looked like the cheapest Chinese available.
The ones that went in are easily and cheaply available to me, and many past experiments have shown them to sound good as coupling or decoupling caps, and in this case the sound was markedly improved.
I have not heard BG's but I find I like the sound of these Hitano EXR low esr caps, and they are only 10% more expensive than standard 105* types.
Eric.
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