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-   -   My version of GC, a LM3886 based (http://www.diyaudio.com/forums/chip-amps/118919-my-version-gc-lm3886-based.html)

Dino-Indo 7th March 2008 03:53 PM

My version of GC, a LM3886 based
 
Hi All,

Just wanna share my version of Gainclone using LM3886..

Dino-Indo 7th March 2008 04:57 PM

2 Attachment(s)
Oops...
Forgot the attachment!! Sorry...

Dino-Indo 7th March 2008 05:00 PM

2 Attachment(s)
Another view..

Bought in a kit mode… Toroid is 300VA, using 18V supply from it with Carlos FM’s snubber circuit design on the PS PCB (thanks for sharing Carlos!!)

Dino-Indo 7th March 2008 05:07 PM

2 Attachment(s)
PCB view...

Simple PCB layout, several Riken RM resistors , one 0.7uH inductor paralleled with 10R 1 Watt resistor (at bottom side of PCB), Nichicon Gold 47uF, Nippon Chemicon 100uF...

LM3886 supply pins (at the bottom side) decoupled to ground with 3300pF Wima FKS and ground pin connected to central grounding with 22K Resistor... reducing the DC offset from 30mV to approx. 4mV....

Dino-Indo 7th March 2008 05:09 PM

2 Attachment(s)
Another pic

Dino-Indo 7th March 2008 05:12 PM

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Last pic..

Input Buffer BU-2 from Audio-GD…

Really improves the sound performance ;)

Overall... really satisfied with this new toy...:D :D

Puffin 7th March 2008 07:09 PM

The pictures are difficult to follow. Did you have your own PCB's made ? if so show us the schematic. I have not used an inductor. where have you put it ?

Dino-Indo 8th March 2008 10:39 AM

2 Attachment(s)
Hi Puffin,

Thanks for your respond..
Enclosed please find the schematic....

The PCB was purchased (together with the components, toroids, etc) in a kit form from a local electronic supplier in Jakarta, Indonesia (Mr. Alex MNP at www.langsungjadi.com).

I put the inductor as per schematic, parallel with R7...

Problem is... now I'm hearing very small hum...
:xeye: (shouldn't be isn't it ?)


Regards,

Puffin 8th March 2008 10:45 AM

The one thing that is different to the circuit I used is the use of the inductor. Do you know why it is there ? I understand that inductors pick up RFI.

peranders 8th March 2008 11:47 AM

The output inductor is for isolating the amp against capactive load but also to block RFI picked up from the speaker cable.


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