I use gold lions in my Cary SLP 50A. However, the reason I am replying is that although this is an ok preamp it requires some other changes in order to open up. Some changes that I have made:
The coupling capacitors, which reside on either side should be replaced. Use Mundorf silver and oil. If you can afford it Mondorf gold and oil is even better. Hifi collective out of the UK has the best price.
The next easiest change is to update the power supply. This preamp is sensitive to power surges and dips from air conditioners, refrigerators, and washing machines. The 100 uf capacitor on the side and the 100 uf in the muddle should be switched to ruby gold 200 ufs. The 100 uf in the back by the connectors should be replaced with 47 uf film from Solen. This will make the transformer run cooler and give cleaner power. See parts express.
Finally, if you feel really ambitious update the volume control for a big change. In it's current configuration I could only use 25% of the volume control. I used an Elma switch and Takman metal film resistors. The switch needs to be make before you break, two deck, 26 position. The input signals run through a 220k 1/2 watt, then out to the tubes and the volume switch at the same time position 1 goes to ground, 2 to the lowest homage available, 3 to the next ohmage and so on. The other side of each volume control resistor goes to ground. This will allow you to use over 50% of the volume control and will greatly improve the sound. I can help you with this giving you the values and wiring if you wish. My email is ajcrock@yahoo.com.
So in summary this is an ok preamp but if you really want it to sound good a solder iron and high quality parts go a long ways and will make more improvement then any tubes you can choose.
