With 15V transformer and LDO regulator you have more than 2V. The device itself will have internal regulators too so going in extremes may not be necessary.
Just suppose that the device has internal 7805 regulators 🙂
Just suppose that the device has internal 7805 regulators 🙂
This is what is written in the product description:
I don't know why there is that +8 in the calculation...
But with 18VAC input I should have about 17.5 output (which still seem adjustable).
I don't know why there is that +8 in the calculation...
But with 18VAC input I should have about 17.5 output (which still seem adjustable).
Maybe it is wise to investigate what is in the DAC. What regulators? What voltage is really needed? I have seen devices that had 12V PSUs and 5 and 3.3V regulators.
All that is too much will end up in waste of energy so heat.
That +8 is because that PSU is the opposite of an LDO. That was it, you have enough information. Good luck!
All that is too much will end up in waste of energy so heat.
That +8 is because that PSU is the opposite of an LDO. That was it, you have enough information. Good luck!
My DAC has 21dBu output, so 15VDC of power supply is suited.
However, I got 12VAC r-core transformer and a rectification board from china.
Strangely after the rectification board (and 20000uF filter) I measure about 15VDC (instead of 12 X 1.41 = 17).
The transformer supplies 12VAC correctly.
I assume the rectifier is not working properly... or am I doing something wrong?
However, I got 12VAC r-core transformer and a rectification board from china.
Strangely after the rectification board (and 20000uF filter) I measure about 15VDC (instead of 12 X 1.41 = 17).
The transformer supplies 12VAC correctly.
I assume the rectifier is not working properly... or am I doing something wrong?
Hi. 12 x 1.41 = 16.92V
16.92 - (2 x worst case Uf of diodes) = 15V
The math on the transformer is about right. You just forgot the Uf of the diodes.
The output voltage of your DAC is ridiculous or does it drive loudspeakers directly?!
Otherwise such high output voltages will not be acceptable for the average amplifier adhering to the (more or less/generally accepted) standards. You will have the need to “marry” such a device to another non standard device like the tube world likes to do (and then complain no other device performs right in their system 😉). Two ugly ducklings may be a happy couple but they will also have no other choice.
16.92 - (2 x worst case Uf of diodes) = 15V
The math on the transformer is about right. You just forgot the Uf of the diodes.
The output voltage of your DAC is ridiculous or does it drive loudspeakers directly?!
Otherwise such high output voltages will not be acceptable for the average amplifier adhering to the (more or less/generally accepted) standards. You will have the need to “marry” such a device to another non standard device like the tube world likes to do (and then complain no other device performs right in their system 😉). Two ugly ducklings may be a happy couple but they will also have no other choice.
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No. The power supply and LPS seem good. An R-core transformer is even excellent.
You could try to reduce the output level of that DAC or create an equally deviating amplifier to go with it.
Normal line level for sources is 2Vrms for calculation (so on the high side) and 1Vrms input sensitivity for amplifiers.
You could try to reduce the output level of that DAC or create an equally deviating amplifier to go with it.
Normal line level for sources is 2Vrms for calculation (so on the high side) and 1Vrms input sensitivity for amplifiers.
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I bypassed the buffer in my nCore amp, so 21dBu from DAC is also a bit low to get full power. But it is enough in my case.
Anyway... what is Uf of diodes? Micro farad?
How do I calc the final DC output after rectifier and filter?
Anyway... what is Uf of diodes? Micro farad?
How do I calc the final DC output after rectifier and filter?
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Re diodes, it's not "Uf" it is "Vf" - forward voltage (drop), the amount of voltage dropped over the diode at the specified current. Typically 600mV to 1V or so for standard rectifiers - it will be prominently stated in the datasheet.
Here it is Uforward. U is expressed in Volts. It is like that for a very long time 🙂 V was already taken for velocity. U is also the official SI symbol so no discussion there.
For instance power is P = U x I
Probably those that already have issues with other generally accepted international standards like to use other letters and unit names.
For instance power is P = U x I
Probably those that already have issues with other generally accepted international standards like to use other letters and unit names.
It is not my transformer. The R-core principle is superior to other types. The ones I have used have approvals (or the devices they were used in) or they are recycled Sony transformers. Till this day I never bought the ones as seen on ebay etc.
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Okay I realize that but point me to even one mfg that sell R-core transformers with regulatory approvals cause I do not know of any and I have done some looking with no success
Sorry for the off topic request
Wouldn't it be good to have a transformer that is OK without any visual approvals compared to mediocre stuff that has no place left without approvals? Just a question 🙂 Some manufacturers know how how to make stuff and don't need any organization to tell them how to do it. In my world the organizations have meanwhile become more important than the material itself. A bit like parasites really. Just a thought.
I would think Kitamura Kiden has the approvals. AFAIK they invented R-core and make them for Sony etc. I have never seen a faulty one and reuse these with confidence as they are simply excellent.
http://kitamura-kiden.co.jp/
I would think Kitamura Kiden has the approvals. AFAIK they invented R-core and make them for Sony etc. I have never seen a faulty one and reuse these with confidence as they are simply excellent.
http://kitamura-kiden.co.jp/
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Really going off topic on this one, sorry again, we probably should have taken this off line or split into a new thread.
FYI, I’ve performed ULc regulatory approval on HID lamp ballasts before, had the UL EE watch me perform these tests, it’s a lot of paper work and testing to determine core temperature rises, insulation breakdowns etc.
How do you determine what’s good and safe vs what’s mediocre and a potential problem?
Sure it’s possible that these unknown to me mfr’s are capable of doing it properly but they are also capable of cutting corners and using lower grade materials as well. Safety with connection to high line voltages that are potential shock hazards, that can cause damage such as fires is to be taken seriously imo, thats why i point these regulatory issues out, so folks are aware of what they are playing with. I myself would not be using them without regulatory approvals.
Hard to determine if that mfr has any approvals and what they are since it’s all Japanese 🙂 .
Show me or give me the ULc or CSA approval label on one of your excellent transformers. Each approval can be verified on the UL web site. how about showing me something written in English too 🙂
FYI, I’ve performed ULc regulatory approval on HID lamp ballasts before, had the UL EE watch me perform these tests, it’s a lot of paper work and testing to determine core temperature rises, insulation breakdowns etc.
How do you determine what’s good and safe vs what’s mediocre and a potential problem?
Sure it’s possible that these unknown to me mfr’s are capable of doing it properly but they are also capable of cutting corners and using lower grade materials as well. Safety with connection to high line voltages that are potential shock hazards, that can cause damage such as fires is to be taken seriously imo, thats why i point these regulatory issues out, so folks are aware of what they are playing with. I myself would not be using them without regulatory approvals.
Hard to determine if that mfr has any approvals and what they are since it’s all Japanese 🙂 .
Show me or give me the ULc or CSA approval label on one of your excellent transformers. Each approval can be verified on the UL web site. how about showing me something written in English too 🙂
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