DAC suggestion to pair with MC275 & Usher Spk

Certainly the speakers you have aren't easily 'digestable' by tube amp, but integrating them with sub can give you a possibility to keep tubes. If you aiming for more control, than certainly getting MC252 or MC352 will justify your goals(if we speak in terms of Mac)
Financially and logically adding 2x2Wq is a lot cheaper. Having MC275 is more like investment that will never lose the value just like gold so I would think forever before I would decide to sell this unit.

I have been greatly enjoying my system, which includes a tubed DAC. I run a late 2009 Mac Mini to a Lenehan Audio PDX Level 2 DAC to an MC 275 MKV out to Totem Acoustic Forest speakers. I have swapped out all of the stock tubes on the MC275 (12ax7s = late 1950s Bugle Boys, 12at7s = early 1960s military spec Mazdas and KT88 = Shuguang Treasure Tubes). I have not yet upgraded the tubes in the DAC (currently Gold Lion 6DJ8s), but understand that dropping in Amperex 7308s will make yet another big difference. The detail is tremendous, with female vocals and acoustic instruments, in particular, really shining. Very, very involving and emotional system. I'd strongly recommend trying out the PDX if you can find a way to do so. Good luck!

Rbw,

I understand Lenehan is a boutique shop out of Australia, with very limited distribution. Do you know if they distribute elsewhere? There was a forum member whose userid escapes me now, who has a PDX and kept speaking highly of it, but also mentioned the PDX was more like a work in progress than a finished product, so being close to the manufacturer was a big benefit (he was down the road from Lenehan).

BTW, I wasn't aware the PDX was meant to directly drive an amp.

It's true that Mike Lenehan has very limited (no?) distribution in the States. He has told me that his preference is to engage directly with audiophiles and rely on word of mouth rather than sink money into marketing. I have very much enjoyed the conversations on the phone and via email that I've had with Mike. He is very, very accessible and completely committed to helping you get the most out of his DAC.

If you happen to be in the Bay Area, I would be more than happy to work out a listening session.

Mike has designed the PDX to be an upgradeable platform, so in that sense, yes, it is a work in progress. I found this to be a plus, but perhaps others won't see it that way.

The PDX can drive an amp directly; that was a key requirement for me. The analog volume control is optional, so buyer's choice on whether or not you'd like to employ it as a pre-amp. I'm using unbalanced Harmonic Technology Pro Silway MKIIs, at the moment. I've tried Mike's RibbonTek interconnects, but could not discern a difference between them and the Pro Silways.

Let me know if you have any other questions!

Here is a short update and summary in regards to DAC question and More Base Question:

1. I have learned a lot about the content and variation of the recording quality since I original posted and have to say with the right quality recording the base of the MD2"s is very nice. But I would agree more power would bring more out.

2. Since posting i have had a chance to listen to newer versions of the MC275 and there is as expected a big difference in performance when compared to the vintage MC275 so much that the new MC275 is not acceptable in my opinion and not an option for vertical bi-amp pairing with the vintage MC275. The new MC275 was bright, fast response, but missing detail and in fact in some content specific instruments just dropped off especially in the mid range.

3. Since posting I have added a vintage McIntosh C22 Preamp with Telefunken tubes. The pairing of the MC275 with the C22 is nice; more warmth, more base, more detail and extension of the sound stage.

4. Since posting I demoed an Antelope DAC...more on this later. Seemed flat, way to bright which could have been the SS amp running it and no I don’t remember the amp or system but I did not prefer it. I will have to run the Antelope on my system.

5. Vertical bi-amping with SS on the low end will cause problems with the response time/ rise and fall mismatch between amps. I have not tried it but can tell it will be a problem so that is out

6. Added a Music Hall MMF 5.1 turntable but looking for a vintage Thorens. Again learning about the quality of the recording and the many variations. Leonard Cohen is a kick.

7. Ultimately I believe I will add a second vintage MC275 for the additional power, a back up system and more base even though I am starting to be happy with what I have now; C22 made a nice impact, content getting better, and speakers starting to break in. In fact they system is down right impressive.

8. Purchased 4 match KT88 Genelex Gold Lion Tubes mfg in Russia. The mfg states they are mfg to the exact design of the original Genelex tubes and that they are licensed to do so. The tubes look identical to the originals and the electrical tests were spot on. I am not however able to check the materials; I have to think there is a variation based on environment regulations. As for the sound quality they only have 50 hours on them and they sound brighter than the originals and maybe not as clear or detailed. At a cost of $50 a tube vs. $350 its worth further exploration; I think they could use a 1000hr burn in then see how they sound.

9. Cables are next to review but I am hearing I should be moving to silver coated copper cables for the turntable and the pre-amp to amp.

10. I apologize for the variation in information that is furthermore not related to the original post. I will see about breaking it up to more appropriate sections of the forum. Thanks for all the input.