Thanks abvolt - really appreciate that.
Congrats -those are two very well regarded DACs you have - I haven't had the pleasure of hearing either of them, unfortunately. PureDac is on my shortlist though. As you say, the WA7 can definitely benefit from something of this quality - and it speaks to the high level that the WA7 amp sits at.
Relatively speaking, the on-board WA7 DAC is really no slouch, though. It has a small issue with some thinness in the sound that unfortunately t ends up detracting from all the other things that it does really really well. Once you roll in the JANs or the Mullards, that adds a solidity to the amp's sound that helps smooth over the grain imparted by the DAC. This can allow the listenter to appreciate all of the WA7 DAC's good qualities: which for me would be its dynamics, agility and overall musicality. In my experiments The WA7 DAC was equally as far ahead of the Schiit Modi as the Rega DAC was, in turn, ahead of the WA7 DAC. The WA7 DAC even did a good job through the Asgard II, which was a nice surprise.
For size of gains I would do it in this order:
1. replace stock 12AU7s in the power supply - $30 JANs or $100 CV4003 (both offer
big improvement)
2. Dac Upgrade - anywhere from $500+ (
big improvement)
3. Electro Harmonix Gold Pin tubes $100 (
small improvement)
Of course, many people will want to do all three, but if I was pushed for money and space then I would be more than happy with just no.1 or no.1+3. If you do 1 + 2, then doing no.3 would be even less critical and would be the final 5-10% to the top.
If you do all three, then that's at least $700. Does it sound $700 better? For me, yes. 40-50% improvement if I had to quantify, and the stock units are already superb! So it's a great journey to take at whatever pace your budget allows.
The EH tubes were quite an interesting journey for me: when I compared them right at the beginning I struggled to hear a difference. However, after spending a good few days with them, when I rolled the Sovteks back in, I wanted the EH's back immediately - I had taken for granted everything that the EH Golds were contributing, even if the improvements were relatively small in comparison to the 12AU7 rolls. Subsequent comparisons convinced me I wouldn't want to give them up. I know many people don't hear a difference, though. We're all different and maybe I'm deluded.