Re: Re: Re: Re: Re: Re: Re: Vishay LED
For the resistors, you spec a 0.6W part, is this an absolute necessity? Digikey doesn't carry any in that value, but they have lots in 0.25W.
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I am using 0.1W RN55Cs - no problem.
For the resistors, you spec a 0.6W part, is this an absolute necessity? Digikey doesn't carry any in that value, but they have lots in 0.25W.
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I am using 0.1W RN55Cs - no problem.
At last ....
packages of the members of European and Asian region have been delivered at he post-office today. All packages (except 2) are send priority mail as I planned, so they should arrive within 1-5 days depending on the destination.SLet me know when you get your package. Sorry for the longer wait than I had planned and thanks for your patience.
I'll make sure the other two packages are send on before friday.
When I had to pay for the postage I was at the one hand happily surprised because the postage-tariffs were lower (much lower)than I have looked up in the the TPG-tariffs book. The difference is on the average Eur 3,- for the European destinations and Eur 6,- for the Asian area. I feel sorry for this for those that cancelled their orders due to the high tariffs and thankfull for those that didn't. I will refund the Irwin and Andrea by sending it with their order, as they are the ones I haven't send yet.
I would like to hear from the others what to do with the money I haven't spend on their postage. I can refund it or fund it to the Diyaudio-forum.
Henk
packages of the members of European and Asian region have been delivered at he post-office today. All packages (except 2) are send priority mail as I planned, so they should arrive within 1-5 days depending on the destination.SLet me know when you get your package. Sorry for the longer wait than I had planned and thanks for your patience.
I'll make sure the other two packages are send on before friday.
When I had to pay for the postage I was at the one hand happily surprised because the postage-tariffs were lower (much lower)than I have looked up in the the TPG-tariffs book. The difference is on the average Eur 3,- for the European destinations and Eur 6,- for the Asian area. I feel sorry for this for those that cancelled their orders due to the high tariffs and thankfull for those that didn't. I will refund the Irwin and Andrea by sending it with their order, as they are the ones I haven't send yet.
I would like to hear from the others what to do with the money I haven't spend on their postage. I can refund it or fund it to the Diyaudio-forum.
Henk
The junction to ambient thermal resistance of the pass device is nominally 75 deg C / W. I use a pair of 15V reg's, without heatsinks and with a similar load and they don't get this hot.
The temp rise above ambient is nominally 0.25 x 75 = approx 19 deg.
If ambient is around 25 deg C then I'd expect a figure closer to 25 + 19 = 44 deg. Even with the large margins of error here that's a world away from 90 deg C.
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Actually, the 45 C value applies when the pass transistor is heat sinked. The pass transistor is for me too hot to handle without one. All voltages are normal.
As someone with a background in heat transfer, I have never trusted calculations in electronics and most failures in electronics equipment are due to heatv dissipation and contact probvlems!
I am lokking for another 2 to 4 boards + and -. Can anyone spare them please?
The temp rise above ambient is nominally 0.25 x 75 = approx 19 deg.
If ambient is around 25 deg C then I'd expect a figure closer to 25 + 19 = 44 deg. Even with the large margins of error here that's a world away from 90 deg C.
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Actually, the 45 C value applies when the pass transistor is heat sinked. The pass transistor is for me too hot to handle without one. All voltages are normal.
As someone with a background in heat transfer, I have never trusted calculations in electronics and most failures in electronics equipment are due to heatv dissipation and contact probvlems!
I am lokking for another 2 to 4 boards + and -. Can anyone spare them please?
Ahhhmmm,
I see I've come too late....
If there's other people who might join, how about a 2nd edition?
Or maybe someone wants to give a board away? I would need at least one pos. and one neg. rail board.
Rüdiger
I see I've come too late....
If there's other people who might join, how about a 2nd edition?
Or maybe someone wants to give a board away? I would need at least one pos. and one neg. rail board.
Rüdiger
I want to make these boards myself, so I downloaded the zip files with the Gerber files in. Now, I wonder how I can see the drill holes? I'm using ViewMate, the only program that allowed me to open these files.
The Gerber files at the beginning of this thread are NOT the same as the boards that everyone has purchased.
Please read Post #54.
Andy.
Hm, well, I am talking about the Gerber files in post #56 & #57. Are they the good ones? If if so, have you got any idea how I could make the drill holes visible?
Devil_H@ck said:
The Drill Holes are not in those gerber files and hance cannot be made visible as far as I remember. There are errors in the PCB layout as well, a complete working set of files was never posted on this thread. Andrew has never given his designs over to the public domain, again as far as I know. He was approached by a few members to provide a group buy which he graciously agreed to do. I beleive this was a one time offer and any subsequent orders for boards were to go through him directly.
Andrew is not supporting a DIY effort to produce his boards outside of his purvey for reasons already covered in this thread. Please read the thread in its entirety.
Regards
Anthony
I tried, but I gave up when I saw that there are over 300 posts in this thread. Anyway, I'll contact Andy personally and see if I can get my hands on those designs.
Hi,
I need to build a 12v supply using the boards, just wondering if the values of r2/r3 for pre regulator are critical, as andy states 249r for each in the manual, or do these need to be adjusted regarding the input voltage, anyone???
Thanks
Raja
I need to build a 12v supply using the boards, just wondering if the values of r2/r3 for pre regulator are critical, as andy states 249r for each in the manual, or do these need to be adjusted regarding the input voltage, anyone???
Thanks
Raja
Raja
No, they're not crtical. In fact the manual states 1K now (249R was the original value) as per Walt's revised article.
The pre-reg is always set to 2.5V, as it maintains this voltage across the super-reg part of the circuit, it's configured as a tracking pre-reg, not as a ground-referenced pre-reg.
The advantage of this approach is it does not require setting differently for different output voltages and it works dramatically better, since it sees some of the performance benefits of the super reg.
A larger value for R2/3 improves the effectiveness of C8 (or C_Kelvin - oops more manual inconsistencies!). The trade off is a minimum load requirement for regulation in the pre-reg - low value R's can provide this min load, high ones require a minimum load at the output for regulation. Whilst this won't affect output voltage, it will affect performance and will increase power dissipation in the super-reg, as the pre-reg o/p may rise with no load.
If you look at the LM317 data sheet, for example, there is a graph of Minimum Operating current showing quiescent current against input - output differential. Essentially, even under extreme conditions, if you maintain a 3-4mA min load on the reg o/p you'll be fine. You can always pre-load the reg with a resistor of suitable rating, if your circuit load does not meet this requirement.
To go back to the original question, as long as both resistors are equal, the pre-reg will maintain 2.5v across the super reg, providing the min load requirements are met.
Andy.
No, they're not crtical. In fact the manual states 1K now (249R was the original value) as per Walt's revised article.
The pre-reg is always set to 2.5V, as it maintains this voltage across the super-reg part of the circuit, it's configured as a tracking pre-reg, not as a ground-referenced pre-reg.
The advantage of this approach is it does not require setting differently for different output voltages and it works dramatically better, since it sees some of the performance benefits of the super reg.
A larger value for R2/3 improves the effectiveness of C8 (or C_Kelvin - oops more manual inconsistencies!). The trade off is a minimum load requirement for regulation in the pre-reg - low value R's can provide this min load, high ones require a minimum load at the output for regulation. Whilst this won't affect output voltage, it will affect performance and will increase power dissipation in the super-reg, as the pre-reg o/p may rise with no load.
If you look at the LM317 data sheet, for example, there is a graph of Minimum Operating current showing quiescent current against input - output differential. Essentially, even under extreme conditions, if you maintain a 3-4mA min load on the reg o/p you'll be fine. You can always pre-load the reg with a resistor of suitable rating, if your circuit load does not meet this requirement.
To go back to the original question, as long as both resistors are equal, the pre-reg will maintain 2.5v across the super reg, providing the min load requirements are met.
Andy.
Thanks Andy, I have a number of uses in mind for these regulators. The 12 volt supply in this case is for a tube heater supply, the total output per reg is less than 1 amp. I have used a 317 circuit to good effect in this position before, and tweaks to the circuit affected sound quality noticably.
Thanks
Raja
Thanks
Raja
I think that may be the first thermionic application of these reg's I'm aware of 🙂
I'll be very interested in the results from this!
Andy.
Hi,
I have used a 317 regulator for DHT's before, in which case the quality of the supply definatley affects sound quality, in my new project however the tubes are IDHT, so perhaps it may be a waste.........
By the way is a regulated supply of 2.73 volts possible with these regulators, if so what sort of reference would be required in the circuit or even opamp (I know that zetex have a range of low power opamps..?
Thanks
Raja
I have used a 317 regulator for DHT's before, in which case the quality of the supply definatley affects sound quality, in my new project however the tubes are IDHT, so perhaps it may be a waste.........
By the way is a regulated supply of 2.73 volts possible with these regulators, if so what sort of reference would be required in the circuit or even opamp (I know that zetex have a range of low power opamps..?
Thanks
Raja
By the way is a regulated supply of 2.73 volts possible with these regulators, if so what sort of reference would be required in the circuit or even opamp (I know that zetex have a range of low power opamps..?
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yes, just ; us e the AD8561 opamp which works down to 2.7V single rail. It's fast and works perfectly in a 5V version. Quieter than the AD817.
I am finally powering my Valpey Fisher 11.284 XO with the unit, instead of a Tent PS. First impression is good sound with better definition but a less abrasive treble. On a modifoied Sony XE670, SACD definitely sounds better and more refined than CD. Interaction of the PS, XO and Digital Processor is substantial and the combination gives about 50mV pk-pk hf noise seemingly related to the clock frequency and it's harmonics when viewed on a 400 MHz tek scope.
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yes, just ; us e the AD8561 opamp which works down to 2.7V single rail. It's fast and works perfectly in a 5V version. Quieter than the AD817.
I am finally powering my Valpey Fisher 11.284 XO with the unit, instead of a Tent PS. First impression is good sound with better definition but a less abrasive treble. On a modifoied Sony XE670, SACD definitely sounds better and more refined than CD. Interaction of the PS, XO and Digital Processor is substantial and the combination gives about 50mV pk-pk hf noise seemingly related to the clock frequency and it's harmonics when viewed on a 400 MHz tek scope.
fmak said:By the way is a regulated supply of 2.73 volts possible with these regulators, if so what sort of reference would be required in the circuit or even opamp (I know that zetex have a range of low power opamps..?
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yes, just ; us e the AD8561 opamp which works down to 2.7V single rail. It's fast and works perfectly in a 5V version. Quieter than the AD817.
I am finally powering my Valpey Fisher 11.284 XO with the unit, instead of a Tent PS. First impression is good sound with better definition but a less abrasive treble. On a modifoied Sony XE670, SACD definitely sounds better and more refined than CD. Interaction of the PS, XO and Digital Processor is substantial and the combination gives about 50mV pk-pk hf noise seemingly related to the clock frequency and it's harmonics when viewed on a 400 MHz tek scope.
Hello fmak, I have a Sony SCD XE670 I would like to modify, do you have any schematics or drawings for some mods?
Regards
Anthony
Hello fmak, I have a Sony SCD XE670 I would like to modify, do you have any schematics or drawings for some mods?
Regards
Anthony [/B][/QUOTE]
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No drawings. Get the manual from Sony which is cheap. Start from the I/V and analog side. Change the opamps and coupling caps. Also the clock.
Regards
Anthony [/B][/QUOTE]
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No drawings. Get the manual from Sony which is cheap. Start from the I/V and analog side. Change the opamps and coupling caps. Also the clock.
Nice to hear
fmak,
It's good to hear some listening reports back from you guys, anyone else got to the stage where they have them installed yet?
Andy.
fmak,
It's good to hear some listening reports back from you guys, anyone else got to the stage where they have them installed yet?
Andy.
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