Hello,
In my opinion, a conventional power supply is not worth it. Neither in terms of sound nor about the structural and financial effort
Not to mention the size and weight.
Best regards
Attachments
Hello
try it here.
https://de.aliexpress.com/i/1005001983485605.html
But in my experience these Chinese-SMPS have not been available for over a year.
That's why I switched to the Hypex SMPS400A400 (for 8 ohm speakers) or the Hypex SMPS400A180 (for 4 ohm speakers). Unfortunately the Hypex SMPS are twice as expensive as the Chinese- SMPS.
The Hypex- SMPS work very well despite their small size.
Best regards
Michael
try it here.
https://de.aliexpress.com/i/1005001983485605.html
But in my experience these Chinese-SMPS have not been available for over a year.
That's why I switched to the Hypex SMPS400A400 (for 8 ohm speakers) or the Hypex SMPS400A180 (for 4 ohm speakers). Unfortunately the Hypex SMPS are twice as expensive as the Chinese- SMPS.
The Hypex- SMPS work very well despite their small size.
Best regards
Michael
Attachments
For those who stuff their board with other transistors, please be aware LJM like to use NCC 5551 , which is used on my L20.5 board and has different pin out as the other 2n5551 type. NCC5551 pin ECB，2N5551 pin EBC.
The 2n5401 used on this board seems to be the normal one however.
The 2n5401 used on this board seems to be the normal one however.
Yes it is.
When using the 2N5551, the legs of the transistor must be twisted.
See pictures.
Described here: https://www.diy-hifi-forum.eu/forum...-LJM-L20-5-Amp&p=324927&viewfull=1#post324927
But I would keep both the 2N5401 and the 5551 (kit or board). This gives the best distortion.
Best regards
Michael
When using the 2N5551, the legs of the transistor must be twisted.
See pictures.
Described here: https://www.diy-hifi-forum.eu/forum...-LJM-L20-5-Amp&p=324927&viewfull=1#post324927
But I would keep both the 2N5401 and the 5551 (kit or board). This gives the best distortion.
Best regards
Michael
Attachments
Beware of the brand of D669 transistor used. I have changed the D669 to an original Hitachi D669 with similar HFE 130 to old one on board and it blew all power transistor and kill a 100R resistor. The type of D669 will change the bias current, in my case, the original Hitachi really up the bias current and burnt the 100R resistor after D669 and the rest of npn transistors. Make sure to change the bias resistor to higher value to more than 1K (the 1k resistor above 5551) , the one LJM used is actually 1050R and not 1k. Best is replace the 1K with a 2k pot and start around 1.5k .
Hi Michael,
i see a little difference between your board and the boards i got on my table a few days ago. The feedback capacitor on your board got 680 µf. On the other boards the value was 470 µf 16 Volt. I would take, to make something better, a non polar capacitor (green Muse) and a 100 nf Wima parallel (on the backside). 470uf is enough. I cant see the imprint on your board.
In the past the 100 nf parallel was on the board, not really necessarary, but better.
i see a little difference between your board and the boards i got on my table a few days ago. The feedback capacitor on your board got 680 µf. On the other boards the value was 470 µf 16 Volt. I would take, to make something better, a non polar capacitor (green Muse) and a 100 nf Wima parallel (on the backside). 470uf is enough. I cant see the imprint on your board.
In the past the 100 nf parallel was on the board, not really necessarary, but better.
Attachments
Hello Peter
https://www.we-online.com/components/media/o127145v410 AppNotes_ANP071_Aluminium-Elektrolyticvs.AluminiumPolymerCapacitor_EN.pdf
https://www.we-online.com/components/media/o127146v410 AppNotes_ANP071_Aluminium-Elektrolyt-vs.Aluminium-Polymer-Kondensatoren_DE.pdf
Polymer elkos are the technical best product, I wanted to try it out.
Muse would be too big with 470/16 volts and diameter1m mm to fit on the board.
With 680µF I achieved the best sound results.
The most important thing in terms of sound is the power supply anyway.
Therefore, this double mono structure receives two Hypex SMPS400A180 again
Incidentally, by far the best end transistor is the on MJL4302/4281. The Kombi 2SA1943 / 2SC5200 is too imprecise and soft.
greeting
Michael
https://www.we-online.com/components/media/o127145v410 AppNotes_ANP071_Aluminium-Elektrolyticvs.AluminiumPolymerCapacitor_EN.pdf
https://www.we-online.com/components/media/o127146v410 AppNotes_ANP071_Aluminium-Elektrolyt-vs.Aluminium-Polymer-Kondensatoren_DE.pdf
Polymer elkos are the technical best product, I wanted to try it out.
Muse would be too big with 470/16 volts and diameter1m mm to fit on the board.
With 680µF I achieved the best sound results.
The most important thing in terms of sound is the power supply anyway.
Therefore, this double mono structure receives two Hypex SMPS400A180 again
Incidentally, by far the best end transistor is the on MJL4302/4281. The Kombi 2SA1943 / 2SC5200 is too imprecise and soft.
greeting
Michael
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Hi Michael,
I know about the polymer capacitors. I will choose some for a phono stage. Panasonic has 470 uf 16 non polar with 12,5 mm diameter. If you are happy with the sound no need to change.
SMPS...i like Connex SMPS more, but i think the sound would be identical.
Greets
Peter
I know about the polymer capacitors. I will choose some for a phono stage. Panasonic has 470 uf 16 non polar with 12,5 mm diameter. If you are happy with the sound no need to change.
SMPS...i like Connex SMPS more, but i think the sound would be identical.
Greets
Peter
