Seduction.....need more gain w/ Foreplay and Dynaco 70

[Paul Joppa]

Put in that 20K resistor. It will reduce the level 10dB, and 3 clicks is 9dB, so the CD and LP should be about equal.

[choff]

ok.....do i need to also need to change out the .47uF to 1uF caps on the seduction?

[Grainger49]

Carl,

If you have moved the resistor away from being the jumper between the selector switch and the SW, and added no other resistor you might have lost some bottom end from the Seduction since it isn't designed to work into a 20k load.  That could be the reason it "sounds very different."  But most of us can't hear anything below 50 or 40 Hz in our rooms anyway.   That takes a big room to get flat response down there.

Also the lowering of the noise floor that resulted from that change might also be the reason.

[Paul Joppa]

ok.....do i need to also need to change out the .47uF to 1uF caps on the seduction?

Into a 10K load (what you have without the 20K resistor), the extra bass rolloff is -3dB at 34Hz. Since most records already roll off at 50Hz, that is not usually very audible - and you said you did not hear a loss of bass. So, I do not see a need to change the capacitor.

Adding the 20K resistor would move the rolloff to 11Hz, where you will be much less likely to hear it. In that case there is absolutely no need to change the capacitor.

In both cases you can of course change the capacitor just to hear for yourself if it makes any difference, and whether you like the change if it is audible. I'm just saying that I see no technical or theoretical need to do so.

[choff]

I added the 20k resistors and I am in a very happy place now.  I have plenty of gain with the records and they are very nearly matched to any cd's I may toggle to during a listening session.   Most importantly,  I feel like i am finally able to hear all that my vinyl has to offer.   I'm looking forward to revisiting many titles that were simply too quiet with my prior arrangement.

Thank you PJ and Grainger for your invaluable assistance!!

[Grainger49]

Carl,

I didn't have the calculator close to figure the roll off and PJ did.  I would expect if you rolled the capacitors you would hear the difference in capacitors more than anything else.

I'm still looking for that 20 Hz note that isn't a pipe organ!