Chip amps

I currently use a kit with two parallel TDA7293 (with modifications suggested by a member at diyaudio called “danielwritesback” ) to drive the Dayton 15″ IB woofers in my dipoles.

To come: an LM3886 kit with speaker-protection and DC-servo. This kit comes from Douk audio. And I will review both the build experience and the sound quality.

This will power mids and highs in my dipoles. I have some experience with the LM3886 having had a true dual mono based on boards by BrianGT.

The transformer will be a 400VA 2x22VAC from toroidy

/Mayday

Update 2017/10/07

I may use a nice 500VA 0-24VAC + 0-24VAC transformer I have laying around for the LM3886 amplifier. 

I have a power supply board on the way for that amp as well. It’s an assembled 4x10000uF kit using MUR2040 rectifying diodes. It’s the same as this one.

There’s also the heatsink, I did not think any of the ones I had laying around would be good enough for two LM3886 on the same heatsink.

So one with these specs is on it’s way:

Heatsink size:

Length:300mm

Height:70mm

Thickness:40mm


Substrate thickness:7.5mm

Fin thickness: 3.3 mm 


Weight:about 1.1kg

That should be plenty to keep the LM3886’s nice and cool as I don’t play music extremely loud with a one year old daughter in the house and also a neighbour next door.

/Mayday 2017/10/07

Update

I’ve started populating the Douk audio LM3886 board.

They seem to have missed two dip8 sockets. I’ll replace the noname metalfilms (not populated) with parts that I know and trust. I’ll also replace a couple of the capacitors with ones I know to be very good. Some of the included capacitors are actually very nice.

The cost, had I bought all parts, would be about $150 plus whatever a 500VA 2*24VAC toroidal transformer cost and the enclosure material (except for the heatsink). Soo… maybe…$200-$250 with enclosure, connectors, the parts I decided to use over those included and so on.

/Mayday 2017/10/11
Update

A few more parts populated.

/Mayday 2017/10/12

Update

I populated a few more parts today. I did use ON LM3X7’s instead of the included fairchild ones.

/Mayday 2017/10/19

Update

The amp board is fully populated. I got the heatsink today. Waiting for some tools to arrive before getting started on the enclosure. Heatsink on the 3mm alu-sheet I’ll use one for bottom and one for top of the enclosure. The PSU board is there for size reference.

/Mayday 2017/11/06

Update 

I think I have more or less all parts needed to complete the Douk audio LM3886 amp at home now. I will get the CS4397 DAC/BF862 headamp done first. If time and my pain allows it, I should be able to get to where I can flip the switch on that project tomorrow. Then I can get going on the layout (in the enclosure) and wiring of the LM3886 amp. 

/Mayday 2017/11/15
Searching engine nonsence:

LM3886 LM3886TF MUR2040 TDA7293 TDA7294 chipamp gainclone power amplifier power amp heatsink poweramp chip amp powersupply capacitors supply

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