Bil Christie's LM12 140W amp hum problem

[hydra]

Originally posted by Tottman2

PC boards: I copied Bil's artwork and ordered my PCB's from ExpressPC.

Out of curiosity how much did it cost for 2 amp pcbs and 1 power supply pcb from ExpressPC?

Also what did you use to heat sink the LM12CLK with? In the article Christie suggests an Aavid 79815 which I have been unable to locate. So the heat sink you used and a source would be appreciated.

As mentioned in a previous post the Chassis Wiring Diagram (pdf) shows the power in (earth) ground going directly to the pcb star ground. There is no (earth) ground shown connected to the chassis. How did you wire your grounding with respect to the power in (earth) ground?

---------
Don

 

[gootee]

Re: in your previous

post its mentioned PC .....

didnt really exactly understand .....

is your amplifier connected to a pc ?????

because if it is there should be absolutelly no hum while is not connected to PC

all this theory about groubd handling is academical bull sh****et in case you are connected with a pc .....

first !!!!!

nobody can guarantee you that ground is handled properly from your pc and of course there is absolutely no reason to do so since the litle green out of your pc is not a line out !!!!!!

this out is designed to drive pc speakers ( do not require exactlly line level signals ) and headphones....so ground cable of headphones could be power ground after all ....


so please make all your tests with a cd player and as about the pc i can tell you what to do exactly after that

Not to worry. I think that 'PC Board' = 'Printed Circuit Board'.

 

[east electronics]

any news ????

any progress or news ????

 

[alpine67]

Speaking of Mr. Christie's projects, has anyone noticed errors between the schematics, photos and parts list for the Hybrid Hi-Fi Power Amp in the January 08 audioXpress? Was there an errata page published in a later issue?

Thanks!

 

[hydra]

The Corrected Pars List for the LM4702 Hybrid Amp is in the June issue of Audio Xpress. A new thread for this Amp would probably be in order.

--Don

 

[Magnetar]

The Corrected Pars List for the LM4702 Hybrid Amp is in the June issue of Audio Xpress. A new thread for this Amp would probably be in order.

--Don

Hello, Bill Christie is a friend of mine. I'll let him know there is a thread here. Maybe he'll participate.

 

[alpine67]

Thanks for the info - I had looked at this issue but did not look closely enough. I agree there needs to be a new thread. As I move forward with the project I'll post updates, unless someone else beats me to it!!