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LJM Audio

Hello. I purchased your amplifier L7.Tested it with +_ 60 v.Sound good.But there is a question.Test whether it is in dual-channel variant powered by a single transformer?When I connect the two modules to the source, there is a significant noise in the speakers.And another question. Quiescent current 120mA the norm for your amplifier? Transistors apparently you used the "CC5551" and not "2N5551"?With respect!CC5551 datasheet, CC5551 datasheets, CC5551 datenblatt, CC5551 manual, CC5551 data sheets, CC5551 pdf - ALLDATASHEET.COM
 
Hello Ljm_ Ljm! Bought your amplifier. Tested with power +-60v. The sound is good! But there is a question. Test whether the amplifier in the dual-channel variant powered by a single transformer? I if you connect a second channel to the sound source, there is a significant noise in the speakers.And more! In your amplifier so I figured used transistors "CC5551" replacing "2N5551"?With respect!
 
Hello Ljm_ Ljm! Bought your amplifier. Tested with power +-60v. The sound is good! But there is a question. Test whether the amplifier in the dual-channel variant powered by a single transformer? I if you connect a second channel to the sound source, there is a significant noise in the speakers.And more! In your amplifier so I figured used transistors "CC5551" replacing "2N5551"?With respect!

Just about to connect to other amplifier. A transformer, the use of a power board.

If it is two transformer, then use two power panel.

Must be the same number. And does not require any earthed alone.

It USES CC5551. Can not use 2 n5551
 
Pot for L15D

Hi all of you,

recently bought two L15D modules and wanted to use an already existing Connexelectronic SMPS 300R with +-45V for both of them. I want to build my amp without any preamp. Is that possible? And at what position do I put the pot in place?
Would like to keep it as simple as possible. Sorry for a newbie question…

Thanks for any advice
 
Differences between L15D and L15D-Pro

Hi ljm_ljm,

may i ask you to elaborate the differences between the L15D and the L15D-Pro boards? The obviously difference is the speaker protection of the L15D-Pro and the use of two IRF14019 instead of one IRF14019H. Are there advantages of doing so? Are both boards deliver a comparable sound quality?

Thanks
 
I finally got the L7 modules to work... by buying a new kit for my left channel. I replaced the blown transistors on the previous module, but they promptly blew again, so I suspect a bad trace in the PCB. Both channels are now functioning properly, but it was a painful experience, since QC is practically non-existent on eBay.
 

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I already build this L7 amp. using original parts quiescent current is about 6mA. when I changed RE (original 10k) for 14K I`ve got ~150mA (using multi turn pot.)
When I wanted used 2SK175 and 2SJ55 output transistors (orgiginal Hitachi VMOS) and back to original value RE 10K the quiescent current is over 2A !! I had to reduce RE to 0R to get the lowest value of quiescent current but it is still too high 0.6A

What I should change to get lower quiescent current?

Or if someone have schematic please send via mail or pm
 
I bought a L15-D Pro kit and soldered it. It was working very well. Dead quiet and sound was extremely well. Then I used it to drive my subwoofer.

Accidentally I interchanged the vcc and vee connections (I think) so it didn't work. Without noticing it I unplugged the power supply and connected another power supply which had two 10,000uf caps which already had charge.

I got a spark when connecting vcc (due to the stored charge in 10000uf caps)
I didn't care about that and connected all other connections and fired the amp.

All the speaker protection transistors caught fire. Later IRS2092 burned with smoke.

Now I'm waiting for the replacement parts to arrive from china (These ICs and Mosfets are not available in my country).

Does anyone know the possible reason why this happened?
How to avoid it in the future?

Thanks in advance :)