How about this schematic

[cloneforlife]

I got it from internet.
How about conventional of them 12ax7/12au7 and if I want to modify/improve this schematic, How can I do.(I interested Conrad Johnson PV12 schematic but it 12au7/12au7)

thanks
CFL

 

[ErikdeBest]

Some questions

First: How much gain do you need? What kind op power amp you are going to drive? What is the lenght of the cables between the preamp and power amp?

From what I see it is a very straightforwarded preamp, with lots of gain (probably way too high for what you need) and a buffered output (for a low output impedance) so you can use it to drive SS and/or long cables. If you need the gain I would go for the Aikido stage, using the ECC83 at the first stage. If you don't need gain I would go with the heretycal line stage from SY. Both designs will probably perform 'better' (that is, on paper) than your schematic.

 

[cloneforlife]

I used several system

I want to build perfectly 12ax7+12au7 such as my uploaded file but I like direct coupling from 12ax7 to 12au7.

Could anybody suggest me how to calculate or compare with brandname schematic.

Happy for quick reply

CFL