Fosgate Signature Phono Preamp

Hi Frank, I also own the Fosgate Signature V1 that I bought new. I don't know if you have the owners manual but the tube complement you referenced in your unit is way off.

The original tube complement would consist of, V1 and V2 being 6DJ8, then V3 and V4 being 12AX7, and V5 and V6 being 12AT7.

I am not a tube expert but if you have 12AT7 tubes in V1 and V2 that is probably where most of the noise is originating. I would suggest contacting Musical Surroundings and try to acquire at least one of the originally supplied 6DJ8 tubes. The original supplied V1 6DJ8 is very quite, I use it in the V1 position then in V2 I've substituted  a Tungsram E88CC (compatible with 6DJ8 and 6922). 

Next you need to remove the 6DJ8 from the V3 position (you could use it in V1 or V2) and replace with 12AX7 or you can substitute a 12AT7 but you will have less gain with that tube. 

The Fosgate is fun to tube roll and you can alter its sound a lot, I have been at it for years and think (maybe) I've found my preferred arrangement. 

Gary 

The original supplied 6DJ8 tubes have no markings on them except 6DJ8 printed vertically in red ink. Musical Surroundings was the distributor for the Fosgate Signature and I believe the only place you will find those tubes, I did buy one from them a number of years ago. The last time I spoke with them it seemed they still sold them, suggest you just give them a call, I always found them pleasant to deal with.

Jim Fosgate recommended not to swap out the supplied 6DJ8 tubes saying you would probably end up with to much bass energy. I have tried a number of different brands of tubes in the V1 and V2 positions and I'm happy with my current setup. I will also say that in my system I found the Mullard CV4024 (12AT7) to be to warm. I believe the Svetlana 12AX7 is the original supplied tube for V3 and V4, the Phillips JAN 12AT7WC was the original supplied tube for V5 and V6.

Gary