Since I really really liked my Ultradac, when I got a chance to buy another one for my parents, I pulled the trigger and sent it straight to Frank for the upgrade. (Thanks Kurt, highly recommended fellow!).
So you know what this means... a real A/B test! Yes! I got some digital switches, and after some imaginative cabling I was able to set up an actual test using different inputs into the preamp.
The result... well... the difference is subtle, nothing as obvious as when I compared it to the dacmagic some time ago. I have four tracks that I've been using lately for this kind of thing.
1. 10,000 Maniacs "Noah's Dove": neither dac gets rid of annoying bass drum thump. I suppose nothing ever will.
2. Joni Mitchell's "Carey": One of my favorite tunes. Clarity of the bass line on this one is a bit of a challenge, and I only got to learn it by listening to it through my Stax headphones some time ago. Well here there was an improvement with the upgrade, and for the first time I felt like I could hear it via my speakers without annoyance at lost information.
3. Mahler's 3rd symphony, Mehta conducting Das Bayerische Staatsorchester, first movement, first percussion solo. This is very faint, and one could be forgiven for not spotting that it is actually musical. The temptation is to turn the volume knob up high enough to spot this without making an effort, but the punishment for that will be felt later on in the movement--and in fact the speakers may have to make a trip back to the shop for massive repairs. So the proper way to do this is to get a good clear signal and leave the volume at no more than concert level. Here once again, the upgrade makes an improvement.
4. Luis Eduardo Aute, "Anda", a live version from his album with Silvio Rodriguez. This is a brilliant recording that captures a lot of crowd involvement while being very clean and musical. This gives the equipment a chance to show off those little ambience cues and here once again the upgrade makes an improvement.
Overall, the improvement is greater clarity, more air, more musical. The difference is subtle, but consistent. In a word, it is more "Frank".
A quick peek under the hood reveals a much larger pair of transistors--it looks like you could fit four of the previous ones inside one of the Exicons. I guess this is one of those instances where size matters.
Frank, thanks for making this available at such a reasonable cost. Your effort to bring older equipment towards the level of your new offerings speaks volumes about what your work is all about.
