All tubes are not created equally and most depend on production period.
Best is to get them from same vendor who can provide tighter matching and same working parameters by your request and could have stock from same batch.
Winged C6550 could be the top tube of its kind but KT88 may work better in your amp, you have to try to find out.
Best is to get them from same vendor who can provide tighter matching and same working parameters by your request and could have stock from same batch.
Winged C6550 could be the top tube of its kind but KT88 may work better in your amp, you have to try to find out.