Upgrading my Sovtek 6922 vacuum tubes

Hi,
a note for putting an ecc88 where the circuit requires e88cc. They will not last long as their anode voltage is considerably lower compared to the one in e88c/e188cc. Check your amp for this. If your amp is made for running an E88cc then you know why ecc88 is getting noisy after a while, even if some of them sound better in the mids compared to their expensive cousins.
Russian 6n23p and 6n23p-ev have even higher anode voltage figures than a E88CC/E188CC and can take a lot of punishment in a circuit.
Mullards dimple discs appeared in 1969, Mitcham factory only, as E88CC/CV2492, CV2493 (equivalent to Cca) and E188CC.

Hi,
@dekay, Blackburn did make ecc88 a frames with ddg and indeed sounded warmer with better mids than both versions of Holland made ones. I was refering to Mitcham factory only for the ddg E88CC variants. I own SF and i know that an ecc88 will not have a chance in these units and some others too, that's why i believe the e88cc is the better bet valve for audio use from this family.

Hi,
for better bass response try Amperex 7308, Siemens E88CC or any Holland E88CC. All from early to mid 1960 production.
If you want to keep the same character of what you are having now but with everything way better try Voskhods 6N23P from 1976-1978 period.
If you want new production ones try Gold Lion E88cc. Bear in mind that most advertised as NOS tubes are used, the few true NOS left are way too expensive. That does not preclude trying a little used tube from the golden era. Find a good vendor who can supply tested tubes. Still you may find that you do not have to spend your budget.