Try the Siemens 7308 (E188CC) on the two output tubes, you may like it, very extended top end, the Siemens CCa has better bass but not as extended. The Telefunken E88CC is also excelent but, less dramatic than the first two.
This are just my observation on my own system, of course different vintage of the given tubes will sound different also.
Goodluck Hunting.
This are just my observation on my own system, of course different vintage of the given tubes will sound different also.
Goodluck Hunting.