The question is can i use a RCore transfo 230v~ 2x12v~ ( 30VA) for the regulators 3.3v and 5v.
One 12v~ for the 3.3v and the other 12v~ for the 5v ?
Serge
If we multiply by AC output of your transformer by 1.4 we get the approx voltage DC your regulator will have to deal with, which is 16.8V. So we need to convert 16.8 to 3.3 and 5v so depending on the regulator type that will cause heat generation as it brings down the voltage. It is quite possible but would be more efficient if you brought the transformer voltage down. You need to include some voltage off for the diode bridge and allow some voltage headroom to operate the voltage regulator.
Chris
Backbones is quite new to this and already he has identified an area that has not been considered in the brief.
How can anyone think that 12Vac and 5Vdc is sufficient to start a design analysis?
The guide can not be an essay on thermal sinking, its already too big and complex for many to follow. Gives caution about need for proper sinking, power dissipation calculation for the reg's Mosfets, also an example. For those needing more on the subject, this one link seems simple enough to follow Heat sinks for transistors
Backbones did already about the voltage. Can work, but why not smaller VAC trafo? You don't need useless headroom, its just heat, is the resume to answering his original VAC question. What is more is he needs state current. About trafos, sinking, and ventilation, you know very well, have seen you calculating in power amps threads to the last iota of power and thermal detail, I will have nothing more to add that I know better my self. If he will tell you his power needs and sinking config you can answer.
IMO, bigger VA trafos provide some "ease" in the stage representation.
I have one small PSU made with a small toroid ( 2 x 25VA) and another one (bigger) with two 120VA R-cores.
Both produce 2 x 40V to power my double mono Riaa builds.
Both PSU have separated windings and double rectifying + smoothing circuits with idential components.
The only difference between them is the trafos type and VA.
There is no way one can not agree with the difference produced in almost every part of the stereo presentaion.
The big PSU sounds much more detailed, with greater image sizes and principally with greater sense of dynamics.
The small PSU is more compact sounding... there is some congestion in the upper registors so bass seems tighter and more present.
Big PSU sounds spatious and non tyring
Small PSU sounds less spatious with proeminence in bass "punch"
You must bear in mind that these are subjective impressions based on my system ... but I keep hearing about the idea that using bigger than needed TX specs serves no purpose.
There must be a reason for these discrepand ideas.... When does a TX size (VA) stop from making a difference and just signify lost energy ?
PS: I know this question is not directly connected with what has been discussed here (Having more or less Voltage headroom for the shunt) but I would like to have your opinion on this also.
I have one small PSU made with a small toroid ( 2 x 25VA) and another one (bigger) with two 120VA R-cores.
Both produce 2 x 40V to power my double mono Riaa builds.
Both PSU have separated windings and double rectifying + smoothing circuits with idential components.
The only difference between them is the trafos type and VA.
There is no way one can not agree with the difference produced in almost every part of the stereo presentaion.
The big PSU sounds much more detailed, with greater image sizes and principally with greater sense of dynamics.
The small PSU is more compact sounding... there is some congestion in the upper registors so bass seems tighter and more present.
Big PSU sounds spatious and non tyring
Small PSU sounds less spatious with proeminence in bass "punch"
You must bear in mind that these are subjective impressions based on my system ... but I keep hearing about the idea that using bigger than needed TX specs serves no purpose.
There must be a reason for these discrepand ideas.... When does a TX size (VA) stop from making a difference and just signify lost energy ?
PS: I know this question is not directly connected with what has been discussed here (Having more or less Voltage headroom for the shunt) but I would like to have your opinion on this also.
A 6.3VAC Tx will be enough for a 3V3 out Bib and 9VAC for a 5V out one. As for over sized Tx power, there are many anecdotal experiences supporting your own above, but even if we will say OK, what the heck, oversize! It will still depend much on the circuit you supply. A linear power amp or phono is different to a DAC for instance. Big main PSU means less source impedance. Beyond min requirements of volts, mA, for everything to work alright and no more than 45-50C temp for Tx, tech analysis can't provide a certainty towards oversize.
Transformers like components can alter the sound we hear. It is not just down to the paper specifications. With transformers it will be their design (R-Core, toroid etc) type and quality of the core material, static shields and the like. At the end of the day it does come down to how they sound when plugged in. The ears are very sensitive and can shortcut a lot of discussion about specifications (the latter are of course important when getting the basics such as safety sorted) but AB testing of components is very time consuming and expensive and therefore not everyone's cup of tea.
I think also that as one matures in life it is possible to compromise over sound. When I was younger it was always a case of spending on the 'best' equipment for the best sound. But what is the best sound? It turns out that when I was younger and spending all that money I didn't know what good music sounded like. Now I do and I have one of the cheapest things I have ever invested in (in terms of hardware not time and effort you understand) in the shape of the Nelson Pass BA-2. Music is a personal journey. With experience, certainly for me, it is a case of producing a product which I find enjoyable, not necessarily something that contains the most expensive components.
Chris
I think also that as one matures in life it is possible to compromise over sound. When I was younger it was always a case of spending on the 'best' equipment for the best sound. But what is the best sound? It turns out that when I was younger and spending all that money I didn't know what good music sounded like. Now I do and I have one of the cheapest things I have ever invested in (in terms of hardware not time and effort you understand) in the shape of the Nelson Pass BA-2. Music is a personal journey. With experience, certainly for me, it is a case of producing a product which I find enjoyable, not necessarily something that contains the most expensive components.
Chris
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Hi Chris
I agree with you, the quality of the equipments does not directly relate with their prices. In the High End market, people pay for pride of ownership. The more exclusive and expensive the better. Sometimes this is confused with high effectiveness.
I know that from personal experience. In my Country, the majority of audiophiles measure items performance with their "flashing" effect , brand and cost.
One Friend that is making and selling High End equipment told me that luxury is implicit in a HE system for most buyers.
Imagine what people would say if JC´s Blowtorch would sell for 1000€.....
I agree with you, the quality of the equipments does not directly relate with their prices. In the High End market, people pay for pride of ownership. The more exclusive and expensive the better. Sometimes this is confused with high effectiveness.
I know that from personal experience. In my Country, the majority of audiophiles measure items performance with their "flashing" effect , brand and cost.
One Friend that is making and selling High End equipment told me that luxury is implicit in a HE system for most buyers.
Imagine what people would say if JC´s Blowtorch would sell for 1000€.....
Very true, Ricardo.
I don't see any way round this because it is an essentially human problem, which is with us from birth. We grow up being told by our parents and society, essentially authority figures, what is right and what is wrong, what is good and what is bad. Then about middle age it suddenly seems to strike us that no, that's not how it is. Same with the hifi experience. We listen to so called authority figures to begin with and then those of us who are in it for the long haul begin to use our own experiences to separate the hype from the reality. Knowledge plus experience is wisdom.
Chris
I don't see any way round this because it is an essentially human problem, which is with us from birth. We grow up being told by our parents and society, essentially authority figures, what is right and what is wrong, what is good and what is bad. Then about middle age it suddenly seems to strike us that no, that's not how it is. Same with the hifi experience. We listen to so called authority figures to begin with and then those of us who are in it for the long haul begin to use our own experiences to separate the hype from the reality. Knowledge plus experience is wisdom.
Chris
Hi,
I am not really good in electronic. I am not too sure of Rx01 and red LEDs to use.
I want to build 3 kinds of output with this BiB board, and here I list out the red LEDs and Rx01 setting.
1. Input is 6.3Vac, output is 3.3Vdc with 100mA (BII Trident)- Rx01=20ohm 1W, red LED=0
2. Input is 9Vac, output is 5.0V with 400mA (Philips CD player 5V regulator supply)- Rx01=2ohm 5W, red LED=1
3. Input is 12.6Vac, output is 12.0V with 1500mA (tripath 2024 amp)- Rx01=0.5ohm 5W, red LED=4.
Am I correct? Anything I miss out?
Thanks.
I am not really good in electronic. I am not too sure of Rx01 and red LEDs to use.
I want to build 3 kinds of output with this BiB board, and here I list out the red LEDs and Rx01 setting.
1. Input is 6.3Vac, output is 3.3Vdc with 100mA (BII Trident)- Rx01=20ohm 1W, red LED=0
2. Input is 9Vac, output is 5.0V with 400mA (Philips CD player 5V regulator supply)- Rx01=2ohm 5W, red LED=1
3. Input is 12.6Vac, output is 12.0V with 1500mA (tripath 2024 amp)- Rx01=0.5ohm 5W, red LED=4.
Am I correct? Anything I miss out?
Thanks.
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Need to know the voltage drop on your red leds at ~3mA current. Use 9V battery, 2k2 resistor, and light up 2 or 3 led for a test. Measure the voltage on them when on. Tell us the average. Also clarify, if those currents you mention are just the load demand in each case. Are you having the newer boards that can take up to 4 leds or the ones that can take up to 3? Then you will get your answers.