New/Old Integrated LM3886 PCB

[Arius]

Hi,

Sorry for bringing up an old thread with a new thread....

I have a couple of leftover PCB's from my old integrated LM3886 project. Specifications:

2-layer PCB measuring 5.25" X 7.30" with
1) 2 X LM3886 non-inverting designed for 20W X2 into 8ohms.
2) LM3886 circuit features local decoupling, output inductor, Zobel, RF filter.
3) Onboard PSU with snubbered Schottky diodes and 4 X 4700uF bulk capacitance.
4) Amp circuit fed by op-amp buffer (can by bypassed).
5) Onboard LM1036 tone, volume and balance control (can be bypassed).
6) Onboard RCA input sockets.
7) Tone and buffer circuit individually bypassed and supplied from regulated rails.
8) Toroidal transformer can be mounted onboard.
9) No wiring mess
10) Ground plane (with proper sectioning) - prototypes are quiet and perform well.

The design objective is not for the best possible GC implementation but rather for a compact, integrated amp that can outperform my computer gaming active speakers without costing more than what they're intended to replace.

Here's a picture..



PRICE: $21.00 plus shipping (NO PROFIT - my cost from www.pcbfabexpress.com - had to order 5pcs minimum)

Moderators: Please delete or move this post if it is inappropriate.

[head_spaz]

That's really nice. Beautimous!
Could you post the schematic?
Why only 20 watts per channel?
How are you controlling the volume with only a single pot?

Best Regards,
David

[Arius]

Why only 20 watts per channel?

That's because the goal was to make it compact. The transformer and heatsink I used allowed a realistic power of 20W per channel. You're free to size up the heatsink and transformer but a bigger transformer will have to be mounted offboard. 20W is sufficient for my needs - PC gaming & MP3 music. With my bookshelf monitors in my PC room, this amp gets so loud I get yelled at by my wife from downstairs.

How are you controlling the volume with only a single pot?

The LM1036 is a DC-controlled vol, bal, tone chip. Meaning only DC runs through the pots. This chip isn't great for sound quality but it works well in a small space and I don't have to worry about routing the input signal to the front of the PCB. I can live with the chip's nominal 0.03% THD considering the source signal comes from my Audigy soundcard.

Could you post the schematic?

Attached...

[Spasticteapot]

I'll take one.
Can I have a list of the parts that I will need, and perhaps a place where I can find them?
What is the expected financial cost for building one of these, incl. PSU?

[Arius]

Hello Mr Teapot,

Thanks for your interest. Attached is a costed BOM. The BOM has all the details that you seek. I may have some extra parts too that you can have for free.

Let's communicate offline via email.
arius (at) surewest.net

[elementx]

did you get any extra PCBs? Can you possibly order more and make them available for sale?

I'm yet to use my LM1036. If anyone is in need of one, message me, I'll have to see how many I got.

[abcheng]

you have email.

[jgrigg]

Hi,
I too would be interested in one for the very same application you built it for in the first place.

[Arius]

Hello,

Thank you for your interest. I am sorry to say that I already sold my last two remaining PCB's (with what's left of my extra parts).

However, if you are still interested, I can supply you with complete design details, i.e. schematics, layout, gerbers, etc. I can send you the exact same gerber package I sent to the PCB fab shop. Don't think I can do a group buy though, too much hassle. Might be cheaper to go to the PCB shop direct too - then you don't have to pay for shipping twice.

The design is free for DIY use.

[rajudp]

you have mail