MC275 Change 12AU7 to 6CG7- Is It Sacrelidge?

[AA6U]

Unfortunately, I don't have the means to test something like that accurately. Then again "rolling" tubes the same type also produces a change in the spectral balance and sound quality. I guess the best way I can describe the change I perceived with the 6CG7 is that everything sounded clearer and more precise, almost like a veil was lifted. Remember, I did this doing an A/B test where one channel was 12AU7 and one was 6CG7. I would not have made the full changeover unless I thought it offered significant improvement.

 

[apachef1]

No problems with it on other models. I've also done it to a McIntosh MC-30 and MC-225 as well as a Heathkit W5M with no problems. It made the least difference on the MC-225 and the biggest improvement on the MC-30. I'm just starting to rebuild an MC-240 and plan to do it to that too.

Thx for the reply, I will keep my mc225 stock and continue to roll a few tubes. Ed

 

[audiobliss]

Unfortunately, I don't have the means to test something like that accurately. Then again "rolling" tubes the same type also produces a change in the spectral balance and sound quality. I guess the best way I can describe the change I perceived with the 6CG7 is that everything sounded clearer and more precise, almost like a veil was lifted. Remember, I did this doing an A/B test where one channel was 12AU7 and one was 6CG7. I would not have made the full changeover unless I thought it offered significant improvement.

What is the specs of the 6CG7 ? Is the gain the same as the 12AU7 ?
I have a pair of DIY mono blocs that use 12AU7s.

 

[AA6U]

The 6CG7 has a GM of 2600 and the 12AU7 has a GM of 2200, so the gain is a little more with a 6CG7.