Marshall SV20C tube test: 12ax7 vs 5751 in V1

12ax7: stock Marshall ECC83
5751: GE 5-Star*****
Tube position: V1 (preamp)
Normal: 4 | High: 2
00:00 12ax7 4|2
00:25 5751 4|2
Normal: 6 | High: 4
00:50 12ax7 6|4
01:15 5751 6|4
Normal: 8 | High: 5
01:40 12ax7 8|5
02:05 5751 8|5
Normal: 10 | High: 10
02:30 12ax7 10|10
02:55 5751 10|10

[@digitalchris6681]

Try the 5751 in V2. I prefer it. I hope to try swapping out both V1 and V2.

[@oficinadomarcheto]

Subtle diferent

[@goodboy65]

With 5751 the distortion is less farty in the low frequencies