Clefchef
Did you actually measure that 3.3V or you just guess it must be. I am afraid that input voltage of 5V might be to low to get 3.3V. Min. recommended input voltage is 5.3V for that reg.
And how did you connect the middle leg to the ground? That spot it is soldered now is not a ground.
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The output voltage that I get from L78L33ACZ is steady 3.3V. There is a ground connection wire that runs from middle leg of the regulator underneath the board.
I also looked at the tube heater supply regulator. It is KM7806 and produces 5.8V. I am going to try and wrangle in regulated LM317 to get to 6.3V.
I also looked at the tube heater supply regulator. It is KM7806 and produces 5.8V. I am going to try and wrangle in regulated LM317 to get to 6.3V.
You can solder a diode between the middle leg of the existing reg. and the ground[conductivity to ground] and you will get 6.4V. I did this way and it works.
It's simple. You just cheat a reg. You make this way ground potential 0.6V higher , and a reg. makes output voltage accordingly higher too.
As I said - conductivity to ground.
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I was afraid that input voltage 5V is to low to get 3.3V out of that regulator . I did that mod and got 2.97V in the output. Did not destroy the dac yet but is it safe? It is risky. Have no idea how come you got 3.3V in the same circumstances.
Hi,
Having 3V instead of 3.3V is safe, it may however not provide best performance. It may be better to take the input for the 3.3V regulator from the supply voltage before the 5V regulator.
That said, if you can find any fixed voltage version of the various low dropout regulators (e.g. LM2940-3.3), they will regulate fine with only 5V in. If you can solder SMD try AMS1117-3.3.
Ciao T
Having 3V instead of 3.3V is safe, it may however not provide best performance. It may be better to take the input for the 3.3V regulator from the supply voltage before the 5V regulator.
That said, if you can find any fixed voltage version of the various low dropout regulators (e.g. LM2940-3.3), they will regulate fine with only 5V in. If you can solder SMD try AMS1117-3.3.
Ciao T
Thanks
And what about raising that 2.97V output with schottky diode [with voltage drop of 0.3V] soldered betwen ground and middle leg of the L78L33ACZ.
I did measure the output of the regulator and I see 3.22V, on the input it is 5.09V - go figure... I measured other voltages and for some reason the B+ now shows 75V instead of 100V as it did after the zener mod. The player still works.
Anyway, I finally got tired of this Chinese marvel and this player is GONE - decided to get this DAC: DAC AD1865 coupling transformer SRPP output Kit | eBay
I also put modified CS4397 lampucera board into Pioneer DV-59 - the sound is awesome, I will do the tube output as well.
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Hi,
The reason you are seeing 3V and not 3.3V is that there is not enough voltage for the regulator to actually regulate. The diode will not help that.
If you want to be adventurous, feed the 3.3V reg via a choke and/or series resistor followed by a big cap (several 1,000uF) from the raw supply. If there is enough voltage in front of the 5V regulator this one too may benefit from such extra filtering. Just check the voltages, circuit and datasheet to make sure you do not exceed the power limits (derated) for the regulator.
Or as said, get a LM2940-3.3. This will work well with only 0.5 across it. Incidentally, the LM2940/2990 fixed voltage regulators are an excellent upgrade for any of the 78XX/79XX dreck the Chinese manufacturers like to fit.
Peter Daniel's put me on these and I have since used them extensively in upgrades. For a new design, using LT1033/1085-ADJ is a better choice, but as a straight drop in for 78XX/79XX they improve things a lot if you do not want to majorly hack up the PCB.
Ciao T
The reason you are seeing 3V and not 3.3V is that there is not enough voltage for the regulator to actually regulate. The diode will not help that.
If you want to be adventurous, feed the 3.3V reg via a choke and/or series resistor followed by a big cap (several 1,000uF) from the raw supply. If there is enough voltage in front of the 5V regulator this one too may benefit from such extra filtering. Just check the voltages, circuit and datasheet to make sure you do not exceed the power limits (derated) for the regulator.
Or as said, get a LM2940-3.3. This will work well with only 0.5 across it. Incidentally, the LM2940/2990 fixed voltage regulators are an excellent upgrade for any of the 78XX/79XX dreck the Chinese manufacturers like to fit.
Peter Daniel's put me on these and I have since used them extensively in upgrades. For a new design, using LT1033/1085-ADJ is a better choice, but as a straight drop in for 78XX/79XX they improve things a lot if you do not want to majorly hack up the PCB.
Ciao T
Look , but the same problem was with 7806 reg. for heating. The output from that reg. was only 5.8V , and when I soldered regular diode to the middle leg it did help to raise the output to 6,4V. We have the same case here. We just need different diode.
What you have done is simply turn a DV-59avi into a DV-47A(different from 47ai), except inferior by adding an unnecessary spdif interface, and I can tell you from upgrading all of these that the 59avi(& 47ai, 45a & 79avi)'s PCM1738 is capable of sounding smoother & more musical than than the CS4397, if you upgrade the analog stages & esp the power supply support. These models do, however, use the most reliable dvd/sacd transport ever made, as yet, so good choice in that respect. The next generation, e.g., DV-46/48/58, went cheap on the transport mech, and have one of the worst reliability records of any dvd player.
Hi,
Congratulations, you just cut the lifespan of your tubes to a quarter...
Past that, 5.8V seems low for a 7806, but not as low as 2.9V for 3.3V Regulator.
I rather doubt it.
Ciao T
Congratulations, you just cut the lifespan of your tubes to a quarter...
Past that, 5.8V seems low for a 7806, but not as low as 2.9V for 3.3V Regulator.
I rather doubt it.
Ciao T
LM2940-3.3 is hard to get , but I can have
LM1117T-3,3 . What you think about that.
