Raysonic 168


Thanx for the responses on the 128. I see now the 168 has been released. I saw what Underwood Audio has done to the 128 as far as mods go, it looks like some things done in the mods have been incorporated in the 168.
Has anyone yet heard the 168? I am hedging my bet between the two for an upcoming purchase.
hockeydad

Showing 4 responses by reb1208

Which two tubes are used for the RCA outputs in the CD168. Is it the pair in the center? I understand the circuit is configured in matched pairs and a identical matched quad is not needed (for tube rolling purposes) Only a specific matched pair for either the RCA or XLR outputs.

Thanks
Thanks, for the info. I believe what happened in your unit is that when one tube failed, the filament voltage increased in the remaining tubes due to lower current draw. Resulting in a percieved change in sound. I still need to known which pair is for the RCA outputs and which for the xlr.
Undertow, its quite easy and economical to change the two .22uf film caps to whatever type you prefer. The XLR outputs are capacitor free, so you can compare your "experimenting". Although, there are probably some extra op-amps in the XLR signal path that may scew the results.
I have experimented with tube rolling the CD168. The two center tubes are reported to affect the RCA outputs and the outer two the XLR. However, my findings are the same as that repoted by Newbee on his CD128. Changing either the inner or outer pair will affect the sound from both the RCA and XLR outputs. I have settled for now on a pair of Siemens CCA 6922 in the center and a pair of Amperex White label 6DJ8 "D" getters for the outer positions. Seams to meld the Siemens and Amperex sound into one cohesive sonic signature.