Esoteric K-03X Runin RCA & XLR Outputs Separately?

I have a relatively new unit which I have run in one of the settings (no upsampling and no filters) using the RCA outputs. I wanted to compare my RCA cable with a different type of XLR cable. I am finding that there is some glare and harshness listening with the XLR cable. I am wondering would some of the differnce be due to significantly less time playing using the XLR output circuitry?

My Esoteric KO3x is fully broken in. i started with RCAs and moved to a higher XLRs and i am not going back
Yes, definitely. You should break-in the XLR output circuitry using the same combination of upsampling and filters (or none to your example) to ensure the XLR circuitry has the same amount of time on it as the single-ended you wish to A/B. Esoteric gear sounds its best (IMHO) with its fully balanced circuitry in use; the break-in is vital to hearing this unit at its best. Also, no-up/no-filter may not be the best you can do with this unit. See many comments on other threads by many of us who own the upper Eso units (P/D and K); I think you'll find that after you break-in the unit with XLR, you'll also want to check out S_DLY2+176 upsampling and several other combinations.
I am finding that there is some glare and harshness listening with the XLR cable.
If by any chance you have performed the comparison with the RCA and the XLR cables both connected at the same time, I would re-do it with only one of the two pairs of cables connected at a time. While I suspect that in this particular unit the RCA and XLR outputs are driven from separate and independent output stages (which is often not the case with lesser designs), it is still conceivable that things like ground loop effects could occur with both cables connected simultaneously that could affect the sonics of whichever is being listened to.

Also, of course, be sure that the equipment returns to a full state of warmup after being turned off when the cables are changed.

Finally, keep in mind that the comparison you are making involves not only differences between the cables, but also differences between the balanced and unbalanced receiver circuits in the preamp or other component the K-03X is driving, and between the balanced and unbalanced driver circuits in the K-03X.

-- Al
The XLR is the way to go.
Turn on 4X upsampling and S_dly2 filter... Give the player 500 hours of further break-in. You should experience the hardness to disappear, while sound will gain stage, solidity, imaging, frequency extension, and musicality.

If this setting were not warm enough for you, switch to S_dly1.

Guido's feedback is dead-on, those are the best filter settings. More warmth, try S_dly1...
Many thanks to you all for your helpful advice. Guidocorona & Zephyr24069, I have moved to S_ldy2 and 8x upsampling, and using the balanced cable I will run this setting in. Guidocorona I read your very helpful thread on the settings for the K-01 reommending S_ldy2 and 4x upsampling. Do you have any experience with the additional 8x upsampling option offerred on the K-03X?

Thanks again,
Hi Bluewolf.... Unfortunately, I have no experience at all with 8X upsampling options... If the progressive pattern of smoothing and opening up found on 0X, 2X, and 4X holds true on 8X, you might find the setting preferable to 4X. On the other hand, if 8X had been added purely for marketing rather than musical reasons, it might introduce some artifacts of peakiness in the treble region... The only way to find out is to try it, and break it in. Please let me know your 8X vs 4X comparative opinions.

Best, Guido
Having heard the results of all available modes, I prefer 4X Upconversion and S_DLY2. 8X (8Fs) is quite good but for overall natural, musical presentation, imaging, etc...I prefer 4Fs (4X).
Hy Zephyr, what does 8X do that is not completely of your liking?

I do like it but for some reason the imaging is not as precise as with 4X.....will give it another try though. Same with upconversion to DSD (meaning giving it another try).
As I mentioned above, I do like the overall sound quality when the transport is set to output to an ESL3-capable DAC using Dual AES/EBU cables with UPCONV=>8Fs (352.8) (also, NoFilter on the P-02 and S_DLY2 on the D-02, Master CLK sync "MCK-IN" at 22.576 Mhaz between the two units), however, I just tested a few key tracks again using both UPCONV=>4Fs (176.4) as well as 8Fs (352.8) and found that again, I prefer the 4Fs due to my hearing alot more ambient information and the overall depth and 'thickness' of the soundstage being very real and very much "better" in every way at least to my ears.

There is a very tell-tale thing that happens when switching from 4Fs to 8Fs UPCONV, at least on the P-02/D-02, namely that on the face of hte D-02 you see it switch from "ESL3 176.4" to "DUAL 352.8". This is the DAC's way of saying the communication channel bit-depth dropped from 48-BIT(!) to the legacy 24-BIT depth AND it is no longer an ESL-linked communicaton channel. I believe the additional bit-depth is what is causing the increase in ambient information, soundstage depth, palpable thickness, etc...that I definitely prefer.