Rockadanny, I'm happy you are satisfied with the Reference CD2.2 I would guess you have the original version, prior to the Linear and MKII, correct? A good number of these original version units were modified. The original version can be identified by the volume control knob on the rear of the player, the RCA outs in the middle of the rear panel, and the Philips CD transport/laser head assembly instead of the Sony.
One caution I would like to throw out there is that the lion's share of vacuum tubes are designed for operation in the normal vertical mounting position ONLY. Some of the 6V tubes (6DJ8/6922/ECC88/7308, 6CG7, and the 6H30 used by Consonance) are suitable for mounting in any position, as they were designed for the USA/NATO and Soviet/Warsaw Pact missile and rockets they were used in. These 6V tubes are able to cool themselves (via the typical convection means of vacuum tubes) in any position which a rocket would find itself in; the 12V tubes are not (they also cool themselves via convection - but using the chimney effect, hence the required vertical positioning).
It has previously been fashionable to replace the 6H30 tube inside some of the Consonance components with 12V (ECC99, 12AU7, or 12AX7); moreso to allow folks to tube roll than anything else. The Consonance owner/designer assures me there is a sonic degradation, in addition to reliability questions. Otherwise, he would have used the lower cost and more ubiquitous 12V tubes in the first place. I cannot say with 100% confidence whether the statement regarding the sonics is true, as I have never A/B'd the swap on its own in a CD player. Normally, the tube swap is a part of a larger and more extensive mod, which gets us into more of an apples and oranges type of deal. I will say that in my experience, it does seem to not improve the hybrid integrated amplifiers it was done to (not that that product was my favorite anyway), though I do try to keep an open ear/mind in any situation. We have encountered some in for repair due to volume stability (during warmup and cooldown) and overall reliability issues related to the swap. So, this mod is obviously something I recommend against, even if we do encourage people seeking to max out their components in a sensible manner.
One caution I would like to throw out there is that the lion's share of vacuum tubes are designed for operation in the normal vertical mounting position ONLY. Some of the 6V tubes (6DJ8/6922/ECC88/7308, 6CG7, and the 6H30 used by Consonance) are suitable for mounting in any position, as they were designed for the USA/NATO and Soviet/Warsaw Pact missile and rockets they were used in. These 6V tubes are able to cool themselves (via the typical convection means of vacuum tubes) in any position which a rocket would find itself in; the 12V tubes are not (they also cool themselves via convection - but using the chimney effect, hence the required vertical positioning).
It has previously been fashionable to replace the 6H30 tube inside some of the Consonance components with 12V (ECC99, 12AU7, or 12AX7); moreso to allow folks to tube roll than anything else. The Consonance owner/designer assures me there is a sonic degradation, in addition to reliability questions. Otherwise, he would have used the lower cost and more ubiquitous 12V tubes in the first place. I cannot say with 100% confidence whether the statement regarding the sonics is true, as I have never A/B'd the swap on its own in a CD player. Normally, the tube swap is a part of a larger and more extensive mod, which gets us into more of an apples and oranges type of deal. I will say that in my experience, it does seem to not improve the hybrid integrated amplifiers it was done to (not that that product was my favorite anyway), though I do try to keep an open ear/mind in any situation. We have encountered some in for repair due to volume stability (during warmup and cooldown) and overall reliability issues related to the swap. So, this mod is obviously something I recommend against, even if we do encourage people seeking to max out their components in a sensible manner.