Newborn F2 refuses mating, what's going on?

[DQ]

Originally Posted by Tea-Bag

With nothing connected and pot removed, does it still buzz?

Not at all.

I'm tired too. Thank you and all the others for trying to help, please keep doing that as I'm coming up with more data. Will probably experiment more tomorrow and post the findings.

A Happy New Year to everybody!

[Nelson Pass]

I probably should have looked at the pictures earlier.

I see that the input wiring and such are right over the
transformer and rectifiers. It is very possible that the
noise is coming from that.

[DQ]

Mr. Pass, thanks for chiming in again!

Actually those are output wiring, inputs are safely on the back. Anyway, I will consider this possibility too and will move this wiring and the corresponding headphones connectors to the back as well. I would have expected to have noise all the time in this case, though, regardless of the input connections, and this is not the case...

[mymindinside]

Hi
i am just finishing my my F2 build, and i think i have a problem similar to what the OP here was describing. i am using Peter Daniel's F2 boards and a PSU that follows the schematic in the F2 service manual. The boards have signal ground, output ground and the 0v rail tied together. when i first wired up the amp i had input ground, output ground and the 0v rail connected at the PCB. the grounds of the two channels were not connected anywhere. the 0v rails were going to the chassis through a thermistor. when i used the amp with only one input connected it was dead silent. As soon as i connected both inputs i got terrible, loud buzz. i was using an RCA to 1/8" mini cable and my ipod as a source for the testing.
then i rewired the grounds so that the two input grounds and the two output grounds met at a star, and there were two wires going out from this star, one to the ground of each channel's pcb. the 0v rail was connected directly to the pcb and was connected (by the pcb track) to the wire coming from the star.
i am still getting some buzz. is there anything i am doing wrong? can i improve this grounding arrangement in any way? i repeat that the amp is dead silent with no inputs connected.

EDIT: just to add that the only psu is connected to ground only by the 0v rail...Mr Pass had once posted that 'the leads going to the ground ends of your PSU(should be connected at one star)' can someone clarify what leads these are? are they the 0v AC taps from the transformer?

thanks
mymindinside

[mymindinside]

i will try and expand on my problem, and on what it is that i am unsure about.
Mr. Pass has said that the power supplies are independent for each channel. they are meant to be connected only by joining the 0v rails to each other through the chassis, with one thermistor between each rail and the chassis.

my confusion is that the 0v rail goes to the channel's board, where it is connected to the wire coming from the signal ground star (input and output, both channels). so in fact the 0v rails of the two channels are also connected through this star.

if i keep the two channel's grounds seperate (as i had initially) then they still meet at the input cable miniplug (i am using an RCA to 1/8" miniplug). maybe i am wrong in connecting the 0v rail to the board's ground? where should this be connected..

any help is really appreciated, i have searched through the grounding threads and have not figured out how to solve this.

cheers
mymindinside

[mymindinside]

okay the noise is killing me...i just pulled apart the f2 to troubleshoot it and any advice would help...

what i propose to do is to tie the input signal grounds together and bring one wire to the star which will also have the output ground and a wire each going to each channel's psu. what i am confused about is where to connect the 0v rails from the psu right now they go to their respective board (and not to the star). they are also connected together through two thermistors, with the chassis in between the thermistors. i would have connected the 0v rails to the star but Nelson specified that the only place the two supplies are connected is through the thermistors.

cheers,
mymindinside