Unfamiliar tubes for a preamp

I hope some of that info helps you enjoy your music.

One other question comes to mind on the rectifier tube. It looks like a GZ30 tube is the same as the 5Z4. Could someone verify this. Thanks in advance.

Thanks Rodman99999 for the info. I knew about the Ecc88 but was in a fog about the others. The 1 in front of the 5Z4P tube was probably given by mistake. I'll check on the RCA OD3 once the pre arrives. Thanks for the link.

The EC88 is a European designation for the 6DJ8/6922/E188CC/7308 family, and is a dual triode. The Holy Grail of the family being the Siemens CCa. The WY4P is a chinese voltage regulator tube like the RCA OD3 (http://cgi.ebay.com/NOS-0d3-VR150-JAN-RCA-MADE-IN-USA-TUBES-OD3_W0QQitemZ330230807107QQcmdZViewItem) Change yours for an RCA, and you should realize quite a sonic improvement. There is a 5Z4/5Z4P full wave rectifier tube, but I've never heard of a 15Z4P.