5751 tubes to replace 12AX7's

[Dflip]

I have checked numerous sites and some individuals state a preference for 5751 tubes over the 12AX7's.

The comments seem to question the musicality of the 12AX7's in comparison. Does anyone have experience with this tube?

"The 5751 tube draws another 20-50 mA on the heater, has less gain, and lower plate dissipation. However, plate voltages are the same and it appears to be designed to reduce microphonics."

I have a newly restored Scott LK-72 amp with GE 12 AX7's in it already. Craig suggests replacing the preamp and phono tubes for the most bang for the

buck in improvements if I want to roll tubes. Any past experiences or suggestions?

Don

[mobile homeless]

I really like certain 5751 tubes a lot. They can actually sound much better depending on circuit and the tube choice. Please see the last two examples. CIRCUIT and tube. IT is really true that they have less gain. They have worked great for me in the past in input/driver stages of various amps. I liked them in the HF-81. BUT, you have to TRY THEM out. Sometimes they dont do the best things for a circuit. I have found they dont work well in most phono stages I have had on hand, despite some better qualities, this due to the loss of gain. Again, it depends on the use. Certain vintage RCA 5751 can be VERY nice, indeed. But again, you have to try it out and see. I am not sure how they will float in the Scott circuit. But good NOS in these vintage amps before the output stage can really do some great things for the sonics. I am still in favor of the NOS EL-84 over the modern selections too but you are talking some serious bux to get all NOS for these beasts. 7189 and 7591 NOS options need a bank roll! heh...slightly overstating but you get idea.

kh