I had an opportunity to hear HiFlight’s topkit that includes 2 buffers, 2 LR opamps, and 1 alternate LR opamp. During this listen, I used JH13's, RS-1’s and HF-2's.
Since I know very well how the stock D12 compares to (and falls short of) the SR71 (which is my personal favorite benchmark amp), I spent time not only comparing the stock D12 opamps to the topkit, but also compared the opamps to the SR71 to see if the same stock D12 shortcomings were still there. It was also easy to rapidly switch back and forth between the SR71 amd D12 amp using the D12 DAC as the source for both.
With the 8532 buffers and two single opamps, the combination has a nice open sound and more separation than the stock D12. Actually, I'm pretty sure it's more than I've heard in a portable amp....even more than the SR71 which is saying something. Instruments like trumpets and cymbols sound great...better than the stock D12.
The bass is spot on (tight and impactful with better microdynamics than the stock D12) and I would not change a thing in that department. Detail level is also spot on....all of my test track detail ques were hit by this combination with no problem.
I've always had a personal preference to a slightly darker and fuller sound. The topkit is a little brighter and more aggressive than stock...and though it sounds good, I'm wondering if this combination will lead me to listening fatigue over extended listening sessions. However, so far….no problems.
In summary, I believe this “half” of the topkit definitely sounds better than the stock D12, and brings it very close to my historical benchmark amp.
I also spent some time with the alternate dual opamp. While I can note some differences between the alternate dual opamp and the original LR opamps...in truth, the overall quality on both seems to be to the point in which my ears struggle to discern which I like better.
The alternate opamp seems very slightly fuller/warmer and more upfront. Detail and bass level/quality seem very similar to the other LR opamps. The alternate also seems to present a slight reduction of instrument separation and openness.
To my ears, the alternate opamp moves the sound back in the direction of the D12's stock opamps. As far as which one I like better, they are close enough (and enjoyable enough) that it would take me an extended period of listening to pick a favorite.
Both combinations sound very strong to me and appear to be good options to tweak the D12's sound. Thanks HiFlight for pushing the D12 (and its little brother the D10) forward!
