Mauro Penasa's INV GC/REF GC group buy.

[Russ White]

Originally posted by BrianDonegan
So, I was just perusing the 3W replacements for R1, R4, R24 and R27 to see what's out there, and noticed this note in the datasheet for the Vishay/BC resistors (currently 1W).

http://www.vishay.com/docs/28729/pr010203.pdf

The resistors should be mounted 8mm above the board (+/-2mm). Mine are about 2-3 mm. They get warm to hot, but no problems so far. Just a tip for those who haven't soldered yet.

I think the 3W version would do well as a replacement, though they cost 4 times as much. The 2W verision is only twice as much.

Did you look at the IRC thick films? I can't remember how much I paid.

[Russ White]

Also look for Sprague "BlueJacket" 2W wirewound type. I tried those, and they work great.

[awashi]

Would a heatsink with 200 X 40 X 75 MM --- 0,7 °C/W be enough for cooling the amp?

[Russ White]

Originally posted by mauropenasa
Any informations:

I have found any numerations not correct on the BOM and have corrected it ( only the serigraphy references, the quantities are correct ).I attach the corrected version to verify. I Creed that you did a good work, Brian.

LM3886 T now TF: The T version ( not iso ) has theoretically a better ability of dissipate of the heat ( internal ) toward the heatsink. In my LM3886 circuit it has to dissipate " theoretically " a lot of energy if the load is 4 ohms. This calculations however I am in " sinusoidal continues power" that doesn't exist in the ordinary music. I have done my test with the "T" type (not iso), but I believe that for an "moderate" use goes well the TF type ( iso ) for the reasons lists from Russ...

Heatsink: I Suggestion to use a type with 1-1.2 °C/W of Thermal Resistance, with vertical development ( like NS- AN1192 by BR100 mod. )

Ciao

Mauro

So anything with less than 1.2 deg C/W thermal resistance should be OK.

[Tergofante]

Because i don't speak Englis, i wrote in Spanish:
Aqui añado mi contribución, pequeña.
He modificado la alimentación para disminuir el rizado y aumentar la Irms del los condensadores de filtro de alimentación, por trabajar a 100Hz.
Añado el esquema y la PCB

[Tergofante]

And the PCB is here

[Tergofante]

The TopSilk

[Tergofante]

And last, but not the Last: The Bill Off Materials ( the BOM)