salas said:
It was probably there, but I usually don't pay attention to such things in the beginning. The scope shows a spike about 10mV/div high on the PSU output, but I didn't check the frequency. The transformer was quite far from the regulator and preamp, far enough for it's field not to affect anything, I think. I suspect the psu as the main culprit, or a ground loop/problem.
Yes, the TT ground cable was properly connected. I still tried different connections for it, but no change.
I was referring to the trafo+bridge+CLC filter as the psu, just to keep it separated logically from the regulator. Surely it's something stupid I've done, I'll check things again tonight.
What I don't understand from what you said salas, is, do you mean that even if there is ripple going into the regulator, the regulator should flatten it out? It certainly behaves so in simulation...
I was referring to the trafo+bridge+CLC filter as the psu, just to keep it separated logically from the regulator. Surely it's something stupid I've done, I'll check things again tonight.
What I don't understand from what you said salas, is, do you mean that even if there is ripple going into the regulator, the regulator should flatten it out? It certainly behaves so in simulation...
I believe I will have enough headroom
ikoflexer said:You guys are hilarious
In a good way, of course.
Why not...it is such a perfect day, listening to TTs relaxes us.
This picture explains a lot. The upper trace is what comes out of the regulator, the lower trace is taken right after the diode bridge. The two traces are scaled differently, but the main idea is that their frequency coincides. The regulator output was not connected to anything. It looks like my implementation of the regulator somehow does not flatten the ripple. I just noticed that my bjt is a BC550B, not a BC550C. Would the different hfe (330 vs 600) make such a difference? I'll look around here see if I got something like a BC550C.
