Hot reg on headhpone amp

[pete.a]

Er having a small prob with this circuit again....Using the design of Carlos and Pavel and the gain set to 5 as per the 4.7k/1k , R3/R4.
Pos reg is giving out around 15v and running fine with just the op amps powerd up, but as soon as the buf634 chips come into play it get's very hot

Neg reg is fine doesn't get hot one bit, buf chips get warm but nothing to alarming, and it sounds ok..not much bass though, but that may be down to the headphones im using...cheap sennheisers (hd36)

Just another thing i used a small cap before and after the pos reg as per the manufactures spec .

[carlosfm]

Originally posted by pete.a
Er having a small prob with this circuit again....Using the design of Carlos and Pavel and the gain set to 5 as per the 4.7k/1k , R3/R4.

Thanks for the reference, but you have a headphone amp on the BUF634 datasheet, page 9.

About the regs...
What regs are you using?
What voltage do you have before the positive and before the negative regs?

EDIT: Oh, weak bass is the fault of your cheap Sennheisers, I know them.

[pete.a]

Hi Carlos,

Before the regs its 22v and they are the lm7815 and lm7915 fixed voltage.
I still think it's a problem caused by the vero board, i'll just have to wait for a local guy to make a pcb for it.

Carlos, was there any audiable noise on your headamp. There's a slight noise, might have something to do with the pos reg or the power on led !

Its just a shame as it's cost a fair amount to build it and i could have purchased a valve one for not much more

[carlosfm]

Originally posted by pete.a
Carlos, was there any audiable noise on your headamp. There's a slight noise, might have something to do with the pos reg or the power on led!

Mine is a line preamp.
No, no noise.
I take the volume to the max. and nothing.

You can connect the led to the primaries of the trafo (AC) with a single diode + a small cap.

Originally posted by pete.a
Its just a shame as it's cost a fair amount to build it and i could have purchased a valve one for not much more

What would be better?
Who knows?
It depends on the valve, the implementation, the components, layout, everything.

I would like to help, but I'm really at a loss with ideas.
Maby someone has more ideas?

Oh, post a pic of the board.
Top and bottom.

[sss]

test the regulato with resistive load and see if its working fine

i hate the 78/79xx regs ! one time i had 7915 regulator when the output was -18
those regulators made by many companies , u should use the ones from known manufacturer