Tube Rolling in Doge 7 DAC
I started tube rolling in a Doge 7 DAC, which is a poor man's Lampizator. I've rolled a ton of tubes in the past in three different amps and one preamp. I'm no expert. Nonetheless, I've learned a few things about what I like and don't and where rolling pays and doesn't pay dividends.
Like most products, the Doge 7 comes stock with less than high end or, shall we say, just basic tubes. In the case of the Doge, it's Shuguang 12AX7s and 12AT7s. 4 a shot for a total of 8.
The stock tubes were just fine and nothing more. I expected them to be shrill or something, but I should've known better. Many Sino tubes are a straight 'B-" across the board. So many complain about them. I think they are not good at much but not inherently bad at stuff either.
For the 12AX7s I went reissue Gold Lion because the 12AX7 is such a popular tube in audio and guitar that the NOS prices are pretty pricey. For the 12AT7s I went with some vintage Sylvania's that tested superbly.
As for the results, well the Doge sounded great out of the box. Everything sounded complete but just a touch reserved. It was--in my mind--like a warm, subdued polished chrome. All three areas, bass, midrange, and highs were relaxed at the expense of being slightly less detailed. Again, the Shuguang's were just fine.
I suspect from my limited experience with amp kits and tweaking that the 12AX7s must be the gain stage and the AT7s must be the driver stage, but I'm not sure and there's no schematic on line or intel on this subject.
The roll made just about everything better yet not night and day. The biggest difference is definition. The bass is stronger and notes are clearer. The way up top stuff has more air...not much though. Things like bells, symbols and percussive effects sound more like a picture of the actual thing. Midrange is clearer but maybe not as seductive? I'm not sure yet.
In one way I think that "better" tubes are certainly worth it here. In another, the unit sounded great stock. I prefer it "rolled" though.
Perhaps one of my own personal takeaways was not with the Doge but with tube makes in general. I was so very impressed with the Gold Lion 12AX7s. It made me think about all my re-issue Gold Lion purchases. I don't think I've ever been let down by them. I love their 300Bs, KT88s, and others--now add the 12AX7. More experienced folks may have better knowledge here; I'm thinking that Gold Lion re-issue as a brand is pretty strong across the board.
That's it. I had to write this down somewhere because my wife doesn't want to hear it. :)