[JayB]

I went ahead and purchased a Clarinet board. My question is, which of the 1uf film caps are filter bypass and which are filtering DC? I assume that C301 is bypassing the 47uf caps and C303 is filtering DC, but want to make sure before I proceed.

Also, I have read where some have deleted the .1uf cap, which is related to DC offset. I don't understand what that means, nor do I know if my sources are a problem, but if this cap was needed and I delete it, am I creating a  sound quality problem or can the preamp be damaged?

[hagtech]

Using a jumper instead of the 0.1uF input caps is recommended.  You remove a part from the signal path.  It is only needed if you have a source component with a dc offset (more than about 0.1V).

jh

[tubesforever]

Jayb, to check your sources for DC simply take a multi meter set for voltage DC and put one test probe to the positive RCA and the other to the negative.  Test both right and left channels.  If your meter reads more than 0.10 vdc then you will want that 0.10uf signal cap. 

In my Clarinet, I tried using the 0.10uf incoming signal cap because I take my gear out and show it off in a lot of different systems.   I want it to be safe.  However whatever cap I tried, it mucked up the sonics.  I don't have gear with dc issues so I am bypassing mine with some silver wire. 

My Clarinet sounds superb thanks to Jim's recent revisions of 4 resistors that keep my tubes happier!

Thanks Jim!  You are the best! 

[JayB]

Thanks for your responses. Now, can anyone answer my first question?

[tubesforever]

Well I suppose the final coupling cap is partly there to eliminate DC from reaching the next stage, but the value of the cap is selected to tune the frequency response of the circuit.  303 is the final signal cap.

The other pair of 1.0uf film caps are there to bypass the 47uf electrolytic B+ power supply feeding into the circuit.  I highly recommend Mundorf Silver in Oil at both spots for the Clarinet line stage.   

Try the Russian FT-3 0.10uf 600v Teflons as a bypass for the Mundorfs if you want incredible dynamics and overall clarity in the midrange.

Yes I am bypassing the bypass caps!  Call this over the top, but that's what it takes if you want world class sonics.

Cheers!
 

[JayB]

Thanks. I am really looking forward to this build. I will let you know how it comes out.

[david62]

Jay,

   I have my Clarinet 99% built,and when the last component comes off of back order, any day now, it will be 100%.The people here have been very kind and helpful to me.I can't wait to hear it...Good luck with your build.
David