LJM Audio

[ekremy18]

hi, i use my mx 50se kit with the gain of 12kohm/220ohm=55x, i wonder, is there any disadvantage with this configuration? i have not observed any issue and "hiss" due to high gain yet.

 

[umut1001]

Hi.I am using this amp in bridged mode.There is a temperature difference (1. tip transistor 45celcius and 2. Tip transistor which on the right 60 celcius degree) Is it normal in bridged mode? Amp is singing fine.

 

[umut1001]

Please consider picture 180 degree clockwise

 

[tupoi33]

Is it really LJM?

 

[AlexScan]

Pictures and measures.

L20.5 AP SYS Test data My design

and my post:

LJM Audio

Not trace of schematic, the only one i found is a "piece of schematic":

 

[AlexScan]

So I have two questions for ljm, what resistor is on the signal path and ca I replace all the 150µF Nippon KY by better one with bigger capacity ? (like 180/220µF)

 

[ivanlukic]

No need to replace Nippon caps. They are good.

 

[AlexScan]

No need to replace Nippon caps. They are good.

Yes it's not only for improvement is for the height.

I need to lowering the height of the module for make a seven channel amp un one enclosure and the area is "short" ... i need to place them in staggered position and the capacitor of 25mm height block me.

I see Panasonic FR for good competitor, but 150µF/63V (16mm) or 180µF/63V (20mm) (the ESR is lower on the big one) for 60V supply ?

 

[jvhb]

I wouldn't use 63V caps with 60V rails - that is too close. Leave at least 10% safety margin (many will say 20%) for voltage fluctuations. So eg. 56V rails would be better, and the small reduction in 8 ohm power will not be noticed. 4 ohm power will be almost the same.

Also, there isn't room on the board for ø16 or 20mm caps. 12mm diameter is the absolute maximum you can fit.

 

[AlexScan]

I wouldn't use 63V caps with 60V rails - that is too close. Leave at least 10% safety margin (many will say 20%) for voltage fluctuations. So eg. 56V rails would be better, and the small reduction in 8 ohm power will not be noticed. 4 ohm power will be almost the same.

Also, there isn't room on the board for ø16 or 20mm caps. 12mm diameter is the absolute maximum you can fit.

You right my futur SMPS must be +-58V max, with 5V of margin I will be safe.

 

[Erlend Sæterdal]

If you buy Capacitors from overseas they can be fake. 63 Vdc but maybee only 50 inside.

 

[AlexScan]

If you buy Capacitors from overseas they can be fake. 63 Vdc but maybee only 50 inside.

I buy Caps only on Mouser ...

 

[Astaro]

LJM! Hello, tell me, please, which amplifier of your development plays better than the others (i know L6, L7..L20 etс), I want to buy (probably on aliexpress) for three-band acoustic with a pair of eight-inch speakers on the bass

 

[dak20]

You can show the measurement?????

Douk аудио CM6631A + AKM4490 USB ЦАП 32BIT 384 К HiFi аудио декодер доска собранный купить на AliExpress

 

[verde57]

Can someone make a summary of all LJM amps available, by date of design, new, old, etc.

 

[augustoriodosul]

LJM audio

I hope to help with this:

??-ljm ?????????-???

 

[Erlend Sæterdal]

LJM! Hello, tell me, please, which amplifier of your development plays better than the others (i know L6, L7..L20 etс), I want to buy (probably on aliexpress) for three-band acoustic with a pair of eight-inch speakers on the bass

,L 7 for midrange and treble. Something more powerfull for bass.

 

[Astaro]

,L 7 for midrange and treble. Something more powerfull for bass.

why L7 ? Can you explain in more detail why it's so good? I bought (but still not listened to) L12-2,, too, praised people in appropriate topic forum

 

[Erlend Sæterdal]

I know the L 7 and L 20 nothing more. I really do not like the 20 in any way.

 

[Peterma]

I have just received the stereo unsoldered l-20D kit from along on ebay and noticed that the 2 suface mount capactors are not soldered on th track side of the board Does anybody know what they are? theres nothing on the pcb, vers 4 pcbs