RIAA Phono Preamplifier

I still have lots of vinyl records so an RIAA equalisation preamplifier is a necessity. In the 80's I built one, put it in a pretty orange box and it worked fine, based on TL084 chips which were really new then. They were also cheap and noisy. For some reason I never upgraded them to TL074's, the low noise versions, and my next preamp was based on NE5534's which became very popular, and the preamps became very complicated. 

Eventually I went minimalist, built a valve preamp, with valve power amplifier but while the power amp was fine, the preamp still wasn't there and I resurrected my 1980 design, this time with TL074's and it was ok. Time moved on, and still not happy, I invested the time to redesign the build with new components, a dual battery/mains power supply with charger. Built, it didn't sound anywhere as good but swapping the old model back with the new battery PSU made all the difference, happy. So this is my RIAA preamp page.

This is an addition to what I've written, because having been happy, I'm now even happier. I had intended to build on a mains supply that would charge the batteries in situ, and be able to power the preamp while it did so. The downside to this is that now built, the power supply sounds better than the batteries, even though it's nothing special!!!!

First off, it isn't strictly accurate because it doesn't have the low frequency roll-off filter included. If there is rumble, I live with it.

I put a small socket in parallel with the input load resistor so that I could add an appropriate capacitor as required, that's not shown. 

There are two gain sections with the RIAA compensation in between, and an output buffer amplifier, these are all taken from the same 4 way TL074.

The two capacitors are polystyrene and bought as 1% 10n standard values, doubling up for the low level second stage. This made getting values easier as the resistors were a lot easier to calculate and make up!


It's still a hand drawing, need to use a schematic tool someday, but it works today so.......