Re-clocking supply
Question:
I am going to implement a re-clocker using 74VHC74 flip-flops. a dual set for the 3 signal/clock lines.
should I use a seperate supply on each line?
implemented using 3 LM431's?
And should these supplies just be taken off the main digital supply for the CS8412?
Thanks!
Question:
I am going to implement a re-clocker using 74VHC74 flip-flops. a dual set for the 3 signal/clock lines.
should I use a seperate supply on each line?
implemented using 3 LM431's?
And should these supplies just be taken off the main digital supply for the CS8412?
Thanks!
Help please I am loosing it
I have just more or less finished my TDA 1543 (4x) DAC. As output coupler capacitors I have used 2 pieces BG-N 4,7uF (non-polar) anti-parallel (per channel).
To my "surprise" I measure on the output of the circuit approx. 4,5 VDC this is behind the capacitors!
When I measure the DC resistance of the BG-N caps they seem to be oke. I do not measure any AC on the output so I assume it is not oscillation.
How is this possible?
Peter
BTW: I will use the DAC with I2S only, during the measurement the I2S input was not connected.
I have just more or less finished my TDA 1543 (4x) DAC. As output coupler capacitors I have used 2 pieces BG-N 4,7uF (non-polar) anti-parallel (per channel).
To my "surprise" I measure on the output of the circuit approx. 4,5 VDC this is behind the capacitors!
When I measure the DC resistance of the BG-N caps they seem to be oke. I do not measure any AC on the output so I assume it is not oscillation.
How is this possible?
Peter
BTW: I will use the DAC with I2S only, during the measurement the I2S input was not connected.
DC-offset
Hi Peter K,
When you don't connect a resistor or pot to Vref of the TDA1543 the chip will output some 6.5 to 6.8V DC even when you connenct Vref to the non-inverting input of the opamp as in the datasheet. (currentoutput of the DAC to inverting input). For this reason I did not dare to try the Blackgates here I got from Jean-Paul as these are rated 6.3V.
You can trim the DC voltage down to about 50mV with a pot at Vref but I found the sound less good this way.
I did not try the passive conversion scheme so I don't know the offset in that configuration. Anyway make sure your caps can handle the DC voltage.
Hi Peter K,
When you don't connect a resistor or pot to Vref of the TDA1543 the chip will output some 6.5 to 6.8V DC even when you connenct Vref to the non-inverting input of the opamp as in the datasheet. (currentoutput of the DAC to inverting input). For this reason I did not dare to try the Blackgates here I got from Jean-Paul as these are rated 6.3V.
You can trim the DC voltage down to about 50mV with a pot at Vref but I found the sound less good this way.
I did not try the passive conversion scheme so I don't know the offset in that configuration. Anyway make sure your caps can handle the DC voltage.
Hi Elso,
Thanks for your input.
I have used the TNT Convertus diagram. http://www.tnt-audio.com/clinica/convertus3_e.html
At the Vref I have used 330 Ohm, I measure 2,2VDC on this pin. On the outputs of the TDA1543 I have 4,7VDC.
The BG-N type that I used are 50 V types. I suppose this gives me enough margin. The strange thing is that the capacitors seems to be oke (as far as I can test them) but act as sort of shortcut. I loose only approx. 0,7 VDC from in to output.
Is it possible that I have burned them during soldering. Or might it be the anti-parallel connection?
Peter
Thanks for your input.
I have used the TNT Convertus diagram. http://www.tnt-audio.com/clinica/convertus3_e.html
At the Vref I have used 330 Ohm, I measure 2,2VDC on this pin. On the outputs of the TDA1543 I have 4,7VDC.
The BG-N type that I used are 50 V types. I suppose this gives me enough margin. The strange thing is that the capacitors seems to be oke (as far as I can test them) but act as sort of shortcut. I loose only approx. 0,7 VDC from in to output.
Is it possible that I have burned them during soldering. Or might it be the anti-parallel connection?
Peter
Re: Re-clocking supply
Hi Richard,
Of course you can use a separate regulator for every supply pin of each IC. This approach was used by Pieter Treurniet in his DAC (CS8412/PCM63K/silverwire trannies)
If you use TL431's or 780x's or LM317's in TO-92 case this is quite do-able.
In my ASR I only separated the supply of the flip-fliops from the oscillator by a ferrite bead. Currently I am using a dedicated supply for the ASR simply because the CS8412 is no longer used and not connected to the supply. I noticed a slight detoration in sound when I used the +5V from the players supply. I do not hear much difference between a supply composed of LT1086 with bypassed adjustment pin or a supply composed of TL431 and series pass transistor, BC550C (similar to Cuno's Snoeren circuit.)
RichardJones said:
Hi Richard,
Of course you can use a separate regulator for every supply pin of each IC. This approach was used by Pieter Treurniet in his DAC (CS8412/PCM63K/silverwire trannies)
If you use TL431's or 780x's or LM317's in TO-92 case this is quite do-able.
In my ASR I only separated the supply of the flip-fliops from the oscillator by a ferrite bead. Currently I am using a dedicated supply for the ASR simply because the CS8412 is no longer used and not connected to the supply. I noticed a slight detoration in sound when I used the +5V from the players supply. I do not hear much difference between a supply composed of LT1086 with bypassed adjustment pin or a supply composed of TL431 and series pass transistor, BC550C (similar to Cuno's Snoeren circuit.)
lm431
Ok... so looking at the datasheets for the LM431 there is a resistor in series before the shunt regulator. There are no values on this resistor... looking at other schematics... looks like anywhere from 150-300 ohms.
What value should it really be?
For all the bypass caps on the power and ground pins on all the IC's.
Is there a recommended source and values? 33uf/0.33/0.03?
Thanks!
Ok... so looking at the datasheets for the LM431 there is a resistor in series before the shunt regulator. There are no values on this resistor... looking at other schematics... looks like anywhere from 150-300 ohms.
What value should it really be?
For all the bypass caps on the power and ground pins on all the IC's.
Is there a recommended source and values? 33uf/0.33/0.03?
Thanks!
Knowing Your Cap...
Hi,
Any cap, when left open ended will develop a voltage at the output given time...
One should always test a circuit under load, not just float it open ended...
So use a load, a resistor or a bulb, doesn't matter what but any measurement taken without a load is meaningless.
Cheers,
Jean-Paul,
Still a big fan of the Black Garbage?
Trouble with the BGs is that they can't sing unless they're run in for ages...
Not that the Beegees could sing...
Hi,
Any cap, when left open ended will develop a voltage at the output given time...
One should always test a circuit under load, not just float it open ended...
So use a load, a resistor or a bulb, doesn't matter what but any measurement taken without a load is meaningless.
Cheers,
Jean-Paul,
Still a big fan of the Black Garbage?
Trouble with the BGs is that they can't sing unless they're run in for ages...
Not that the Beegees could sing...
IIRC I said in my mail to you they were meant for decoupling the supply lines as they are rated 6.3 V and I understood you run your DAC at 5V too. For output purposes I use N series rated 50 V or MKT.
Sorry Frank but I really think that only trying them gives right to an opinion. The run in period can be shortened by putting them on a power supply for some weeks as I said before. The qualification "garbage" is more suitable for PIO. Never said BG was sent from heaven but BG N + NX HiQ really is very good but hey it is easier to criticise than to try out isn't it ? You'll never hear me about the other BG series as I did not find them that special soundwise.
BTW I use all brands and types of older and newer caps including OSCON, Silmic, Elna RJH, Panasonic FA/FC,Rubycon, Nippon Chemicon, Wima MKP, ERO MKC ( a favorite ), Siemens MKT, EMZ/NSF Styroflex,Philips KS, Kemet SMD ceramics, BCcomponents electrolytics, LCC film caps, ICEL film caps and Jahre Silver Mica since some time to name a few. So it is not only BG NX that's on my list but I do use them with great satisfaction. Using/trying all available caps broadens ones horizon.
LOL...
Hi,
I did do that recently and from a manufacturing point they're errrr, impossible to use.
Think Peter Daniel will agree...moreover I think the better filmcaps still are the best caps for coupling.
Hey, I was just yanking your chain...
Oh, those proclaiming SE amps and PIO caps you mean?
Sorry for those, I've been laughing for ten years already...nice amps can be made but let them stop claiming they found audio nirvana...
Oil cans? Nice way to filter out CD nasties...not really my cupper...
Try using ICEL caps as an affordable alternative and the MIT RTX series for the Nec Plus Ultra coupling cap...if you hear anything wrong, I tell you it will be something else...not the caps.
No offense and NO, I've got nothing against the Beegees...but what takes 'em sooo long to sing?
Hi,
I did do that recently and from a manufacturing point they're errrr, impossible to use.
Think Peter Daniel will agree...moreover I think the better filmcaps still are the best caps for coupling.
Hey, I was just yanking your chain...
Oh, those proclaiming SE amps and PIO caps you mean?
Sorry for those, I've been laughing for ten years already...nice amps can be made but let them stop claiming they found audio nirvana...
Oil cans? Nice way to filter out CD nasties...not really my cupper...
Try using ICEL caps as an affordable alternative and the MIT RTX series for the Nec Plus Ultra coupling cap...if you hear anything wrong, I tell you it will be something else...not the caps.
No offense and NO, I've got nothing against the Beegees...but what takes 'em sooo long to sing?
Please explain that one ! Availability ? Price ? Technical merits ? I do have a Rotel preamp that's full of them so it can't be that impossible.
You think that film caps are better but if you tried them I would expect a more detailed story...
ICEL stock is locked in a safe place and only used in gear that it deserves. MIT RTX is a bit too expensive for me and even if I would have the money I wouldn't spend so much on caps. I prefer a weekend in Brussels for that money
You'll have to advise me about the NEC part. Never even heard of it but I am curious as always.BTW there are more caps that need a firm break in period, even film types.
I also think that 4.7 BG N is a very good choice for a coupling cap. It is only when compared to much bigger and more expensive film alternatives, one can hear a difference. I will still use it in my amps as from their design POV, there is simply no other alternative, (keyword: simplicity)
For my personal projects, I will either try not to use caps at all, or use bigger and better ones. Since most of the good stuff can be bought second hand now, the price is not an issue here
For my personal projects, I will either try not to use caps at all, or use bigger and better ones. Since most of the good stuff can be bought second hand now, the price is not an issue here
Oh dear...
Hi,
Burn in time and the wildly varying results in between.
Yes, and it sounds exactly as Jonathan Carr described it in another thread...
It reminds me of the the Lowther speaker colouration... and I ain't laughing here.
Hey, com'on mate, it's not as if they're all that costly...probably 1/10th of the MITs...and available upto 1200VDC...
Oh dear... comes in here: Nec plus ultra...ring a bell?
Fair enough, but nothing as wild as the BGs I'd say?
Cheers and let's all have a drink in Brussels,
Hi,
Burn in time and the wildly varying results in between.
Yes, and it sounds exactly as Jonathan Carr described it in another thread...
It reminds me of the the Lowther speaker colouration... and I ain't laughing here.
Hey, com'on mate, it's not as if they're all that costly...probably 1/10th of the MITs...and available upto 1200VDC...
Oh dear... comes in here: Nec plus ultra...ring a bell?
Fair enough, but nothing as wild as the BGs I'd say?
Cheers and let's all have a drink in Brussels,
Koinichiwa,
We are at last in full agreement. I shall try to nick some of the new Silver & Mylar ANUK Caps (interestingly the ANJ Caps in stuff like the Ongaku, M7/M10 Pre ets are also Silverfoil/Mylar) of Peter Q, if he lets me. So far PIO's generally suck big time.
The BG-NX or NX-HiQ I like very much too (except cost). but most of the times I need Capacitors with a voltage rating way past anything these ones do. And the NH or WK/WKZ BG types for high voltage have yet to convinvce as better than good quality Mylar caps (which are arguably as bad a filmcap you can get).
Like you I figure "Horses for Courses".
Sayonara.
jean-paul said:
We are at last in full agreement. I shall try to nick some of the new Silver & Mylar ANUK Caps (interestingly the ANJ Caps in stuff like the Ongaku, M7/M10 Pre ets are also Silverfoil/Mylar) of Peter Q, if he lets me. So far PIO's generally suck big time.
jean-paul said:
The BG-NX or NX-HiQ I like very much too (except cost). but most of the times I need Capacitors with a voltage rating way past anything these ones do. And the NH or WK/WKZ BG types for high voltage have yet to convinvce as better than good quality Mylar caps (which are arguably as bad a filmcap you can get).
Like you I figure "Horses for Courses".
Sayonara.
Re: Rc Constant Degoutants...
I agree that a cap may be better than servo and I would usually go for a cap. But other alternative is choosing circuits that don't need coupling caps or just accept few mV of DC offset.
By saying bigger, I had 4.7u BG N cap in mind, which is 5mm x 12mm. Everything that replaces it, IS bigger and I think I preferred it to Hovland which is not bad by audiophile standards and quite much bigger. And here the size plays big role IMO, and sometimes for simplicity and purity of a circuit one might choose a cap which even sonically inferior in some small ways, fits perfectly between other small parts. There is one other thing I didn't try, I still have to skin those red jackets off the caps
fdegrove said:Hi,
Somewhere, somehow you'll end up needing a coupling cap...servos are usually even worse of than caps...if that's what you had in mind.
Oh...and bigger doesn't equate better...seems you Canadians are getting Americanised?
Ciao,
I agree that a cap may be better than servo and I would usually go for a cap. But other alternative is choosing circuits that don't need coupling caps or just accept few mV of DC offset.
By saying bigger, I had 4.7u BG N cap in mind, which is 5mm x 12mm. Everything that replaces it, IS bigger and I think I preferred it to Hovland which is not bad by audiophile standards and quite much bigger. And here the size plays big role IMO, and sometimes for simplicity and purity of a circuit one might choose a cap which even sonically inferior in some small ways, fits perfectly between other small parts. There is one other thing I didn't try, I still have to skin those red jackets off the caps
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