DAC advice

I currently have an arcam cd36, matched to a mcintosh ma6900 integrated amp, and focal electra be speakers. I feel the arcam is the weak link in my line up and would like to get better digital performance. Is buying a new (or used) DAC at approx $2000 to pair with my arcam the best rout? If so, what DACs should I consider? Furthermore, I've been reading how important the transport is to digital playback and am wondering if purchasing a whole new player might serve me better. In this case I can sell my arcam and put the proceeds towards a new player in roughly the $2800 range. Would this be a better option? If so what players should I consider?
If you choose the second option, I can strongly recommend the Northstar CD 192 (MK 1 or II) with Philips CDPro2 transport (one of the best in the world) and DAC 192 MK II. This DAC is very good to begin with (even more so if you have a server that can output to I2S). With the CD 192 and the included I2S cable, this is really a killer 2-piece combo with the added benefit of additional digital inputs to the DAC. Additionally, since the DAC has balanced outputs, it will be excellent with an existing balanced system. The 2 piece system will run $2500-2600 or about half that for each piece.

A second good option would be the Resolution Audio Opus 21 with the reference GNSC mods. You are looking right at the $2800 price tag (used). This is a very good CD player that also offers the added benefit of digital inputs (again for secondary sources).

$2,000 can get you a pretty darn good (used) DAC. But to go to state of the art DACs, you are probably about half way there with this budget (used prices).

FWIW: I have owned the following digital as reference to these comments: Resolution Audio Opus 21 w/GNSC, Esoteric X-03SE, EMM Labs CDSA/DAC6 combo, Wadia 800 Series, Northstar CD/DAC 192 (currently own) and a DCS stack (currently own), among other lesser digital components.
I have a Bryston BDA-1 after trying many others (Berkley, BelCanto, MHDT Labs (v good), Tube Audio Design PreDac, Benchmark USB.....) and it has been the best by far.
If you really believe it's the front end then seriously look at the Audio Sector/Audio Zone or Scott Nixon DACs. I believe it's your Mac. I've listened to most of their integrateds and well....... I like the Arcam a lot and your choice of speakers. Call me crazy, but I would try a different integrated.
There is listed (I think yesterday) a Cal Audio Labs Alpha tubed DAC for pretty good price. I would buy this and listen, I think you will like this DAC a lot and it will only put you out $500, which you could sell in 6 months without a loss. That is a very good move for a very small amount of money upfront and no loss if you want to upgrade again. (FWIW: I have absolutely nothing to do with the sale of the Cal Alpha DAC).
Just curious how long you listened to the Tad Predac for as it has only been out a few months now if that. From what I'm hearing it's supposed to be A giant killer and easily bests it's predescessor the Tadac which was no slouch. The reason I'm askng is that you really need to experiment with the tubyness control over the course of several weeks for optimum results
I like the Arcam as well,call me crazy..Ive demoed other dacs with it and heard nothing worth spend $$$ on.. You will have to spend more than 3 grand on a player to hear an upgrade IMO...I have to agree w/above poster ..dump the Mac