I have an Octave preamp which actually uses 4 ECC82/12AU7 tubes. I have tried a number of NOS as well as new production tubes and prefer RT and Gold Lions in combination with Amperex/Philips tubes. Don’t get me wrong, the Horizon is a very good sounding tube, especially for its price, but it sounds a little thin in my system. If the Horizons already sound nice in your system then they should even sound better after burning in although I thought that Psvane website said that all Horizon tubes are subjected to factory burn-in after production??