Chipamp.com is looking for Beta Testers

[littlerick]

I sent PM if this offer is still on.

 

[Rodeodave]

littlerick, if you want the selector boards I can send them to you if you want, I have been accidentally sent some...

 

[littlerick]

Hi Rodeodave.. Thats a nice offer, u have PM

 

[JL889]

Alright replied to all PM's. I only have selector boards left for Beta testers. Please contact me if you'd like to purchase the boards. I am looking forward to some cool looking amps!!

 

[BrianGT]

Sorry for the delay on the BOMs. Here is what I have from my notes:

LM3886Mono
R1 = 22.1K
R2 = 681R
R3 = 22.1K
R4 = 1K
R5 = 10K
R6 = 2.7R 2W
R7-R8 = 2.2K 2W
C1-C2,C6 = 0.1uF 63V
C3-C5 = 47uF or 100uF 50V
C7-C12 = 1000uF or 1500uF 50V
D1-D7 = MUR860


LM4780 amp board
R1 = 22.1K
R2 = 22.1K
R3 = 681R
R4 = 22.1K
R5 = 681R
R6 = 221R
R7 = 221R
R8 = 0.1R 3W
R9 = 0.1R 3W
C1 = 1500uF 50V
C2 = 1500uF 50V
Cz1 = 0.1uF 63V
Cz2 = 0.1uF 63V


LM4780 integrated (blue)
R1 = 221R
R2 = 22.1K (for Stereo, Jumper on back for Parallel)
R3 = 221R (for Stereo, Jumper on back for Parallel)
R4-R6 = 22.1K
R7-R8 = 681R
R9 = 10K
R10,R11 = 2.7R 2W
R12,R13 = 2.2K 2R
R15,R16 = 0.1R 3W (for Parallel only)
R0 = 10k
C1-C2,C7-C8 = 0.1uF
C9-C12 = 10000uF 50V

Thanks to Joe for helping get these off the shelf. The blue LM4780 and 3886mono boards have been sitting untouched on the shelf since early 2009.

 

[UrSv]

Still haven't figured out if the LM4780 Board (1) is parallel or bridged. One or the other I suppose since there is only one input. Or have I missed something?

Bump 🙂

Just one input and output so it's either bridged or parallell. Anybody know which? Just to be able to choose a suitable transformer.

 

[UrSv]

Bump 🙂

Just one input and output so it's either bridged or parallell. Anybody know which? Just to be able to choose a suitable transformer.

Actually thinking more than one second I realize that it is parallel as otherwise it would not have an output ground. Obviously.

 

[Rodeodave]

UrSv, the LM4780 board is in parallel configuration, correct.

And regarding the BOM...for the LM4780 (parallel amp, red boards) a 10k 0.5W SMD resistor (1206 package size) is needed for the mute pin, the solder pads are on the back of the pcb.
And two 2R7 2W resistors are needed for the Zobel network at the output.

For the LM4780 integrated (blue board) 8 diodes (like MUR860) are needed.

 

[BrianGT]

UrSv, the LM4780 board is in parallel configuration, correct.

And regarding the BOM...for the LM4780 (parallel amp, red boards) a 10k 0.5W SMD resistor (1206 package size) is needed for the mute pin, the solder pads are on the back of the pcb.
And two 2R7 2W resistors are needed for the Zobel network at the output.

For the LM4780 integrated (blue board) 8 diodes (like MUR860) are needed.

That is correct about the parallel config for the red board.

As for the mute resistor (10k on backside), I have used a regular small form factor resistor in the past soldered to the terminal.

--
Brian

 

[littlerick]

Got the boards today.. nice one guys... gonna price up parts and will post asap