I finally got around to hooking it all up today, and was able to do back-to-back auditions with my 2 preamps: the AD815 and Starfish.
The setup:
Ergo IX speakers, 2x NAP-based monoblock power amplifiers, Squeezebox3 streaming audio player. I used the same PSU for the trials: a 25-0-25 Avondale EI core transformer, hexfred rectifier diodes,10,000uF smoothing. The Starfish is powered by +26V from a TeddyReg, the AD815 by local ALWSRs @ +/-15V.
The AD815 has the SRs just a couple of inches from the circuits, uses Rubycon ZLs for decoupling on-board, and has only one cap in the signal path: a 2.5uF polypropylene.
The Starfish is symmetric and uses 2x 12V Tracos, giving +/-24V rails. These are locally regulated by the 14 on-board regs to +/-12V. All coupling caps are bog-standard tants. Feedback caps are 47u MMKs. The 1K resistor in the feedback network has been swapped for a 2K, halving the gain of the Starfish to 6x. It has an ERT, not a NERT.
I approached the listening with as little bias as I could, although I must confess to having preconceptions of the AD815 being smaller, tighter, fewer components, and - most importantly - having only 1 cap per channel in the signal path. That was countered by my feelings about the regenerated 0V of the Starfish, coupled with the carefully laid out 0V routing scheme, the clever application of local regulation, and decoupling in all the right spots. My main bias was that the AD815 was already hooked up to my remote-controlled input selector and attenuator.
Playing a variety of music ranging from metal, prog rock, acoustic female and male, jazz, and electronic was a very enjoyable experience
The first thing I noticed was that there's more bass from the AD815. It's deeper and more enveloping. The Starfish is leaner, but tighter. After much swapping and reflection it seems that the AD815 has a slightly bloated feel to it, like the bass is a little too big and just slightly muffled compared to the Starfish. The 'fish does not want for bass, and it is more accurate, easier to follow, and more controlled than the AD815.
The presentation of the Starfish was subjectively larger than the AD815 and I felt myself more immersed in the performance when listening to it. The AD815 just squished the instruments together a little more, compressing the sound ever-so-slightly in comparison.
The midrange of the Starfish is clearly superior. Sharper, more attack, more realism, just better in all respects. Female vocals are expressed with more finesse and clarity, and there's a texture to voices that's missing from that AD815, covered as it is by the slightly thicker lower-end.
I think a lot of the difference between the two preamps stems from the thicker bass, the more rounded, bloated feel to it. The upper registers from the AD815 are amazing, probably slightly better than the Starfish - sounds like large cymbals, hi-hats, tambourines, etc are more clearly expressed and seem to have the edge on detail. The thing is... it's just not as musical as the Starfish!
All of these conclusions come from a slightly compromised Starfish, too. It doesn't have the NERT, isn't to the latest BOM, has an old Alps pot, and crappy 10p tants doing coupling duty. Still, it's definitely my favourite of the two - it's simply more pleasurable to listen to, expresses the music more accurately (I feel), and makes my toes tap more. There's a very good chance I'll be stripping my preamp out and replacing the AD815 board with the Starfish.... hah, who am I kidding? Of course I'll be stripping it out!
Carl
The setup:
Ergo IX speakers, 2x NAP-based monoblock power amplifiers, Squeezebox3 streaming audio player. I used the same PSU for the trials: a 25-0-25 Avondale EI core transformer, hexfred rectifier diodes,10,000uF smoothing. The Starfish is powered by +26V from a TeddyReg, the AD815 by local ALWSRs @ +/-15V.
The AD815 has the SRs just a couple of inches from the circuits, uses Rubycon ZLs for decoupling on-board, and has only one cap in the signal path: a 2.5uF polypropylene.
The Starfish is symmetric and uses 2x 12V Tracos, giving +/-24V rails. These are locally regulated by the 14 on-board regs to +/-12V. All coupling caps are bog-standard tants. Feedback caps are 47u MMKs. The 1K resistor in the feedback network has been swapped for a 2K, halving the gain of the Starfish to 6x. It has an ERT, not a NERT.
I approached the listening with as little bias as I could, although I must confess to having preconceptions of the AD815 being smaller, tighter, fewer components, and - most importantly - having only 1 cap per channel in the signal path. That was countered by my feelings about the regenerated 0V of the Starfish, coupled with the carefully laid out 0V routing scheme, the clever application of local regulation, and decoupling in all the right spots. My main bias was that the AD815 was already hooked up to my remote-controlled input selector and attenuator.
Playing a variety of music ranging from metal, prog rock, acoustic female and male, jazz, and electronic was a very enjoyable experience
The first thing I noticed was that there's more bass from the AD815. It's deeper and more enveloping. The Starfish is leaner, but tighter. After much swapping and reflection it seems that the AD815 has a slightly bloated feel to it, like the bass is a little too big and just slightly muffled compared to the Starfish. The 'fish does not want for bass, and it is more accurate, easier to follow, and more controlled than the AD815.
The presentation of the Starfish was subjectively larger than the AD815 and I felt myself more immersed in the performance when listening to it. The AD815 just squished the instruments together a little more, compressing the sound ever-so-slightly in comparison.
The midrange of the Starfish is clearly superior. Sharper, more attack, more realism, just better in all respects. Female vocals are expressed with more finesse and clarity, and there's a texture to voices that's missing from that AD815, covered as it is by the slightly thicker lower-end.
I think a lot of the difference between the two preamps stems from the thicker bass, the more rounded, bloated feel to it. The upper registers from the AD815 are amazing, probably slightly better than the Starfish - sounds like large cymbals, hi-hats, tambourines, etc are more clearly expressed and seem to have the edge on detail. The thing is... it's just not as musical as the Starfish!
All of these conclusions come from a slightly compromised Starfish, too. It doesn't have the NERT, isn't to the latest BOM, has an old Alps pot, and crappy 10p tants doing coupling duty. Still, it's definitely my favourite of the two - it's simply more pleasurable to listen to, expresses the music more accurately (I feel), and makes my toes tap more. There's a very good chance I'll be stripping my preamp out and replacing the AD815 board with the Starfish.... hah, who am I kidding? Of course I'll be stripping it out!
Carl
