I have a tube preamplifier for my turntable that has no markings so I don't know anything. I also am extremely new to the use of tubes but want to upgrade the tubes in the preamp to potentially get a fuller and cleaner sound. The preamp has 2 of 819 6Z4 tubes. 4 of 6N2-J tubes and 2 of 12AX78 tubes. They all appear to be Chinese made and the preamp has a tag that is in either Japanese or Chinese. Can anyone help me find upgraded tubes?
Some had the option of running either 6N2P or 12AX7 tubes for the phono stage. Could be a Little Bear. Post up some pics, otherwise it's anyone's guess.
jeff
![20240518_185351[1].jpg](/community/data/attachments/1219/1219712-4fcbfb5ed64c24a605caee6ad602e1a0.jpg)
![20240518_185413[1].jpg](/community/data/attachments/1219/1219713-0e97b039a53c4b9390abf818ac3e250c.jpg)
It may well be that tube rolling will change the sound but to get a clear,more transparent and fuller sound from other tube types is anybody guess and opion.tubes dont opperate in isolation.there is the supporting circutry thats contributes. And thats another story.keep learning,keep exploring,diy rules.
Is this thread the same amp?
https://www.diyaudio.com/community/...-shigeru-wada-japan-circuit-need-help.331702/
https://www.diyaudio.com/community/...-shigeru-wada-japan-circuit-need-help.331702/
6N2P-EV soviet tubes might be a good sub for the 6N2-J tubes.
12AX78 I would look at good quality 12AX7s, either NOS or modern made.
Tube rolling almost always results in degraded distortion and possibly bandwidth, unless you are willing to change resistor values as well. In which case you are redesigning the amp, not tube rolling.
12AX78 I would look at good quality 12AX7s, either NOS or modern made.
Tube rolling almost always results in degraded distortion and possibly bandwidth, unless you are willing to change resistor values as well. In which case you are redesigning the amp, not tube rolling.
