Serj Amp 1 (LM3886) nearing completion

[srdjant]

Got my updated rear panel by UK manufacturer MeFace Ltd yesterday, and decided to solder the RCA connectors and replace the rear panel.


Getting near completion now.


Here's a few pics. Thanks to all that helped me, this has been my biggest project by far, and the most involving.


I'm debating adding a front latching push button power switch.
And I still want to get MeFace Ltd to make me a front panel which I will design.

 

[NanoFarad]

Very nice! Congratulations.

 

[tomchr]

Are you using RCA connectors for the speaker connections?

Nice panel design! I like the compact chassis as well.

Tom

 

[srdjant]

Thanks @tomchr


Yes, speaker outputs are on RCA connectors. I've been told to perhaps get banana plugs for speaker outputs, but wasn't really sure why, and RCA seemed more versatile somehow.
The speaker cables are RCA to banana plugs anyway, so should give me various options for the future.

 

[Puffin]

The rear panel looks quite thick. I have had occasions where the Phono sockets or speaker binding posts have not been fully insulated from the panel. Those Red and White washers IMO are too thin. I now wrap the thread of the socket with several winds of insulating tape before inserting them through the washers and this normally does the trick. Check them for continuity with your DMM.

 

[srdjant]

@Puffin, wow you are right. DMM says there's continuity between the RCA earth and case earth. I will check the connectors when I get a chance, probably next week. Thanks for the tip

 

[chrisb]

I’d definitely suggest using RCA plugs & jacks only for low level signal interconnects on any serious future project. You might want to model if the existing rear panel has sufficient space to accommodate Speakons or 5-way binding posts; while that might interfere with the tidy outline surrounding the existing outputs, let’s face it who spends that much time looking at the rear of the amp once the system is fully operational.

Nice compact build.

 

[Mark Tillotson]

Thanks @tomchr


Yes, speaker outputs are on RCA connectors. I've been told to perhaps get banana plugs for speaker outputs, but wasn't really sure why, and RCA seemed more versatile somehow.
The speaker cables are RCA to banana plugs anyway, so should give me various options for the future.

My worry with RCA's is that it allows accidentally connection of the source to the amp's output, risking burning out the source. And a lot of RCA hardware isn't designed for high current.

I'd favour SpeakOn connectors for speakers, no possibility of mis-connection, less fiddly than terminal posts, and no exposed live metalwork.