Do I really need voltage regulation on such a small current?

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Sunsun22

Sunsun22

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Joined 2004
I am building a DIY DAC kit using 1541 and 6DJ8. Yet, considering the plate current is only somewhere around 6 to 7 mA on each channel (voltage drop on R105), is the regulated power supply overkilling? Would it be better using CLCRC directly?

For such a small current, will non-regulated power supply sound better?
 

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Regulated means only that voltage is alot more constant then with CLCRC directly.Since this is anolog and not digital I would recomened the use of 78Lxx, where xx is your needed voltage.
You could make it with tranzistor in CV

You ask why use regulation?
Well there is no poin of making good amp if there is noting constant like supply voltage.
 
A voltage will become unstable if the drawing current various or the current is too large that the PSU become unstable.

In the captioned circuit, the current is more or less stable (as observed) at 7 mA per channel. The total drawing is 14 mA. It is so small that any transformer can provide sufficient current for it. In the kit, it uses a 120mA transformer that the current is only 12% of it.

My question is why regulation because of such a small current. Is this PSU circuit an overkill?
 
Sunsun22 said:
A voltage will become unstable if the drawing current various or the current is too large that the PSU become unstable.

In the captioned circuit, the current is more or less stable (as observed) at 7 mA per channel. The total drawing is 14 mA. It is so small that any transformer can provide sufficient current for it. In the kit, it uses a 120mA transformer that the current is only 12% of it.

My question is why regulation because of such a small current. Is this PSU circuit an overkill?
Click to expand...


Even with large enough transformer the voltage will vary with current, because the supply has an internal impedance. varying current through an impedance gives varying voltage that is added or subtracted from the supply voltage with no load.
Secondly, the supply will always have ripple, noise, etc, although will small current draw and a lot of LCLC sections that may be very small already.

Bottom line: regulated voltage gives more ideal DC supply and give better performance. Is it audible? Impossible to say before you try, and even then the effect may be psycho-acoustic rather than real.
Jan Didden
 
ha!!

something i know about TUBES!! igrew up with them, who needs pesky transistors any way.😀

i agree that with the transformer giving say 120 volts at 120 ma that is 14.4 watts you are only going to use a max of 1.8 watts with that tube.

and your dc from th filter is going to be ~ 160 vdc too much for that tube. it should be around 130vdc........


no need for regulation other than a big cap. inductor and bleeder resistor

also the 6dj8 is 130vdc plate and 90 vdc plate for a class a amp.

what are you going to use this for...

although this is a neat way of doing it...........

jimbo
 
jamesrnz said:
ha!!

something i know about TUBES!! igrew up with them, who needs pesky transistors any way.😀

i agree that with the transformer giving say 120 volts at 120 ma that is 14.4 watts you are only going to use a max of 1.8 watts with that tube.

and your dc from th filter is going to be ~ 160 vdc too much for that tube. it should be around 130vdc........


no need for regulation other than a big cap. inductor and bleeder resistor

also the 6dj8 is 130vdc plate and 90 vdc plate for a class a amp.

what are you going to use this for...

although this is a neat way of doing it...........

jimbo
Click to expand...

Yes, I can see you have a lot of experience. Maybe not so much in writing, but in amps. First telling what to do, then afterwards asking what it is for.
Jeez... 🙄

Jan Didden
 
The circuit is the I/V part of TDA1541 converting current to voltage output therefore current draw is rather stable.

How do I get this funny idea? Any passive or active source will generate noise and so is regulator therefore lesser components would be better. For such a small current draw, I think using a CRCLC filter should be more than enough. I use the Duncanamp PSU designer II and have the following simulations:

160V (107 ohmes) transformer using full wave rectifier, the rectified voltage will go through the first C1 (100uF). Voltage reduction by using a 2.2k ohime resistor then go into a 47u C2. Another voltage smoothening and reduction stage by using a 20H 1.666k chock then go into a 47u C3. The final voltage will be 160V with 14 mA going into R105 of the circuit with a ripple of around 512uV after 4 seconds. One can see this CRCLC filter is only having a few passive components that I believe it should be better than a bunch of active components.
 
The circuit is the I/V part of TDA1541 converting current to voltage output therefore current draw is rather stable.

How do I get this funny idea? Any passive or active source will generate noise and so is regulator therefore lesser components would be better. For such a small current draw, I think using a CRCLC filter should be more than enough. I use the Duncanamp PSU designer II and have the following simulations:

160V (107 ohmes) transformer using full wave rectifier, the rectified voltage will go through the first C1 (100uF). Voltage reduction by using a 2.2k ohime resistor then go into a 47u C2. Another voltage smoothening and reduction stage by using a 20H 1.666k chock then go into a 47u C3. The final voltage will be 160V with 14 mA going into R105 of the circuit with a ripple of around 512uV after 4 seconds. One can see this CRCLC filter is only having a few passive components that I believe it should be better than a bunch of active components.
 
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