OpAmp Rail Voltage Tolerance vs Distortion

Just fixed my pre amp and I noticed the voltage rails on the op amps are off a little.
The L7915cv has -24.2vdc going in and -14.78 coming out.
The L7815CV has +24.5vdc going in and +14.74 coming out.
As you can see there is a .04vdc difference between each rail.

Can this difference in voltage on the +/- rails cause distortion at the output of the pre amp?

I don't have a scope but when a signal is ran through and recorded into Pro Tools the wave looks good until about 7000hz then it starts to distort.
At 10khz and up the wave distorts and clips bad.
Looks like a saw wave even though a sine is going in.
Is the difference in voltage on the +/- rails causing this and how can I fix it?
Adjustable rugulator?Or a resistor on the output of L7915C to put a voltage drop of .04 accross it?
Anyone else have this problem?

That's a tiny offset. That's not going to cause the gross problem you describe. Look elsewhere.

The unit is a Minprint En-Voice.There is a 12ax7 tube in the circuit.The step up transformer,12v/250v, that feeds 300vdc to the tube burned up.
I put a 16/230 step up in it's place.A mains transformer backwards.

The voltage at the tube plate is about 100v unsaturated and about 60 saturated,or when the suturation blend is on.
I thaught the plate voltage should be higher than this.
Is this voltage normal on the tube?
Maybe this is the problem?
Thanks for your help.

Well, let's see... Simple math to the rescue again...

The original transformer, 12V:250V, has a 1:21 turns ratio.

The replacement transformer, 16V:230V, has a 1:14 turns ratio.

If you feed 12VAC to the replacement transformer, the raw rectified and filtered DC output will be around 237V instead of 353V, which is what you'd get with the original transformer. The voltage will be even lower after the usual additional stages of filtering. (Note to nitpickers: no, I'm not including the forward drop of the rectifiers because it's inconsequential in this case).

So the short answer is yes, that's a big enough difference that it could be causing a problem.

[quote author="volta"] ...
I put a 16/230 step up in it's place.A mains transformer backwards.[/quote]

when you first power these things up just beware that you could be over voltaging the secondary.

The secondary is normally the primary ( get it ?? ) and even though the is some headroom in normal operation you could be very close to trouble in the reverse mode.

Here is Australia we say we have 240Volts BUT there is movement to 235/230 volts .. I don't quite remember the paper of when it did or if it has to taken effect
:roll:
... don't know much do I ! .... :sad:

Anyway the point is that many mains trafos may in fact be 220volts.
SO the over voltage could be much closer.
Listen for the trafo in stress.


... just something to watch for when you are experimenting.