Thanks for the contribution, sfmatt.
post #121 of 126
3/10/09 at 1:04pm
Got some opamps this morning (2xLM6172, 2xLM4562), spent the day switching them around with the stock opamps as well.
Headphones: HD600, DT250/250 and SR80 (just a bit, they're way too bright to my ears).
Music: wav for Classical, Blues and Reggae, 192K for electronica (di.fm minimal, psytrance)
Player: Foobar, application and PC volume 100%
The tests were done with the Viper both used through USB and as an amp only fed by the headphone DAC of my RME 9632.
I've become quite an expert at switching opamps in 2-3 secs... In the end my 2 preferred combos:
Larry's LM4562/LM6172 is pretty surprising coming from stock. Much more in your face but warmer with more body/fullness to the sound. Better soundstage too.
Bass: more and deeper than stock, not as dry though, slightly rounder.
Mids: the most striking change, mids jump at you, they're rich and velvety at the same time. Very enjoyable.
Treble: more extension than stock but a tad harsh at times.
2xLM4562 is more analytical, not as cold as stock but colder than LM4562/LM6172. Soundstage is better than LM4562/LM6172, there's more separation. It's more airy but not thin at all, just not as "meaty" as LM4562/LM6172. Slightly less forward too (but more than stock).
Bass: more bass than LM4562/LM6172, it's dryer but more impactful on electronica. Unsure if it's deeper, both go low.
Mids: they're good, not recessed at all but nothing special either. They blend well with the rest of the spectrum so you don't notice them one way or another, which is good i guess but somewhat of a letdown compared to LM4562/LM6172.
Treble: slightly better extension than LM4562/LM6172 but smoother. No hint of harshness at any time.
In the end, both combos are a marked improvement over stock. It comes down to your personal taste and your headphones match.
I've settled on 2xLM4562 for now, I'll try LM4562/LM6172 again on a longer run later. Unsure about he battery life, LM4562s draw more than LM6172s so we shall see.
Many thanks to everyone on this thread for all their hard work.
I did not measure the battery life accurately but it seems on par with stock.
One big drawback with 2xLM4562 is periodic RFI with my cell phone. I didn't have it in my pocket at the time of my initial test so didn't notice but it's pretty annoying actually. I never had such issues with the stock opamps. Not worth reinstalling them but it will definitively be a consideration in my future rolling sessions.
greenarrow: I don't know for your DAC specifically but connecting the D2 to the headphone output of a RME9632 sound card yields a very noticeable improvement compared to the USB dac of the D2. If my laptop had a SPDIF output I would be very tempted by the D10 which I assume has better DAC performance through SPDIF than through USB.
It's too bad there don't seem to be any high-quality dacs that take USB inputs directly.