Finished my first LM3886 dual Mono Amp

Bernd-HH · 23rd July 2005, 05:54 PM

I have just finished my first LM3886 dual Mono Amp. It is based on the BrianGT PCB. For the PSU I use a 160 VA toroid transformer (2x22VAC) with the Carlosfm inspired snubberized design. Since I use a 9-pin Sub-D for the interconnection I have the option to power each channel with a separate PSU. There are also two 1800uF caps for each channel near the chips power pins.
(I am not so happy with the Sub-D connector. The contacts are rated with a maximum of 3A/pin. Maybe I will use the high-current-version for my next design.)

The enclosure is simply built with two heat-sinks (Fischer SK85 -160x40x50(mm)) and 4 aluminium plates The overall dimension are 50x180x160 (mm) (H-W-D) without the knob, connectors and spikes. I think that the heat-sinks are a bit oversized for this design. For the connectors (Speaker and RCAs) I,ve used types that I’ve found in the nearest store. Cardas or WBTs are not really an option for my budget.
The last think I have finished was the knob for the volume control. It is built in massive brass wit 40 mm in dia. Now I go and search for a nice enclosure for the PSU that match to the Amp-design and will – with respect -not be a copy of the great 47 Lab design.

For me the best sound impression for this Amp-design is without any cap in the signal path and the additional caps near the LM3886 power pins. Since the output offset voltage for both channels are below 30 mV I’ve removed the offset compensation cap too.

Finally:
Without the inspirations and experiences from all the great people in this forum I’d never started this Chip Amp project.
I hope I don’t boring you if I add some pictures of my finished Amp.

Thank you all.

Bernd

homer09 · 23rd July 2005, 06:17 PM

sweet amp!

let's see more pics! and the insides too...

jaudio · 23rd July 2005, 06:49 PM

It looks very good!

carlosfm · 23rd July 2005, 06:57 PM

C

L

asgorath · 23rd July 2005, 08:13 PM

That looks fantastic. Great job!

Bernd-HH · 23rd July 2005, 10:54 PM

Here are some more pictures of my 3886 Amp:

Bernd-HH · 23rd July 2005, 10:54 PM

...more pictures

Bernd-HH · 23rd July 2005, 10:54 PM

one more picture:

Bernd-HH · 23rd July 2005, 10:54 PM

picture from the top:

carlosfm · 23rd July 2005, 11:44 PM

Oooohhhh... so ssssexy.

23rd July 2005, 06:17 PM	#2
homer09 diyAudio Member Join Date: Jan 2004 Location: Montreal	sweet amp! let's see more pics! and the insides too... __________________ Most people wouldn't know good music if it came up and bit them in the ***. - Frank Zappa

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23rd July 2005, 06:49 PM	#3
jaudio diyAudio Member Join Date: Oct 2004	It looks very good!

23rd July 2005, 06:57 PM	#4
carlosfm Banned Join Date: Mar 2003 Location: Lisbon, Portugal	C L

23rd July 2005, 08:13 PM	#5
asgorath diyAudio Member Join Date: Jun 2005 Location: Seal Beach, CA	That looks fantastic. Great job!

23rd July 2005, 11:44 PM	#10
carlosfm Banned Join Date: Mar 2003 Location: Lisbon, Portugal	Oooohhhh... so ssssexy.