A friend of mine was seeking a good sounding cheap solution to computer audio...Firestone recently decided to update their 24/96 Spitfire S/PDIF DAC w/ a 16/48 USB input and a swappable opamp.
I've received it today, as he wants me to pick a matching opamp for him.
Let's hope it'll sing "Jingle Bells" when you shake it
So we have a USB cable, a RCA cable, the wallwart, the manual, a wrench to open Pandora's box and a warranty card:
Gold plated USB baby :
The stock opamp(used as PCM1793 LPF) is the highly praised LM4562NA:
The old Spitfire w/ the dragon on its front panel was also running PCM1793 and also had a swappable DIP8, but it was running the now obsolete CS8414...the new one was running DIR9001 but had a soldered LM4562MA, so no more rolling possible
Now the Spitfire MKII runs PCM1793, 24/96 DIR9001, 16/48 PCM2704 and the swappable DIP8 socket opamp is back w/ a vengeance...using some nice WIMA caps(to minimize oscillation I would guess). the WIMA's are famous for their "energic" sound, compared to the "laid back" signature of the Mundorf's I believe(but don't quote me on that).
Anyway, doing A/B comparisons against the old Spitfire is a clear knock out...everything's you've read about the CS841x/DIR9001 difference is very real. Tighter sound is the motto.
I've already rolled the opamps of course (), and I will compare the wallwart/Supplier PSU and the coax input against the PCM2704 USB input later on.
So far w/ the Supplier > Bravo+Supplier > ADuM4160 and opamps more to my taste, it sounds extremely good...I shall try a dual LT1028ACN8 module within a few days.
Just like all the Firestone DAC's, it's fully able to drive headphones via its RCA out...my Fostex ortho sounds really good...of course I've only tried easy to drive headphones, You can't really expect a dual opamp to drive a K701 on its own. The nice thing is that there's no volume pot, which either ruin the SQ when they're cheap or cost a lot of money to sound good. What could possibly sound better than 64bit digital volume attenuation anyway?
It's sold at a discount until the end of the year, and so far it's a great DAC...after going through a lot of DOA and crappy sounding ebay DAC's, finally my friend will be delighted
PCM1793 is known for its chirurgical and uncompriming sound, and I can only agree...the old Spitfire did good in RMAA, when using its Supplier linear regulated PSU: http://www.firestone-audio.com/rmaa/SPITFIRE.htm
It's easy to understand why Firestone sold so many of those Spitfire's, it's small and highly efficient...this is a great sounding solution for the members of Team "shortest signal path". The opamps are fed w/ ±12V, and it's recommended to stick to "unity gain stable" chips whenever possible.
More impressions later.
Edited by leeperry - 12/22/10 at 9:33am