GGG Bipolar power supply question

[Morocotopo]

Hi boys, I made the bipolar power supply that´s to be found at http://www.generalguitargadgets.com/pdf/ggg_bipolar_ps.pdf

Now, in the positive side I get 8,99V. Cool.
In the negative side I get -9,24V!! What the...?

I used a brand name 1A reg for the positive side, and the negative one is NOT the same brand, looks quite cheaper, not branded, just says "CUE" and the number. could this be the cause.
And more important, can I use it anyway to power a bipolar circuit (LHX2 Fender sim, all opamps)? Will it have any consequences, like non zero V ground (just guessing)?

Any help appreciated

Morocotopo

[Morocotopo]

Sorry, forgot to say that I made it for 9V, used a 12V 300 mA transformer and 7809 and 7909 regulators.

[axg20202]

Are those the readings when the PSU is under load i.e. powering the circuit? You may well find that when driving a load the values will tighten up. Even if they don't, I doubt this would be a problem because the values are so close to 9V.

[Morocotopo]

axg, thanks for answering. The power supply was tested without a load. Will try it with a load.

Thanks

Morocotopo

[rody82]

these regulators have a tolerance factor, like resistors, so its normal to have slight differences.
I've had the same issue with mine, i used a 120ma 12V tranny for 9V and it couldnt drive
my LXH2 marshall prototype (around 20 opamps). (which was fine with batteries)
Please report if yours works fine.

[Morocotopo]

rody, thanks. I´m testing/completing/finishing my LHX2 Fender sim and cab sim, will do a full report when i have it finished/tested to my satisfaction. I´ve been reading the thread on the LHX2 started by... hmmm ¿Guitar lord?

Morocotopo

[R.G.]

The 7909 data sheet says that its output voltage will be between -8.6 and -9.4V at between 5ma and 1A.

-9.24V is completely within spec.

[Morocotopo]

Thanks R.G. On with the testing/modding...

Morocotopo