Tube DIY Asylum: Re: Best Driver Stage for a 10/10Y by JLH

1.) Agreed, the 6SL7 would not be my first choice either.

2.) Agreed, low mu, low Rp tube is required to get into A2 territory.

3.) Trading one cap for another, Yes. I find it easier and less expensive to change the one ultra-path cap than two or three caps in the power supply. Four or six caps if it has two supplies! In addition, I have found that if you donâ€™t like what you are hearing from a Monkey amp, change or bypass the ultra-path cap with something else. We are all taught in school that caps are AC shorts, well they are not completely. What ever is left or ineffectively bypassed is what you hear in the Monkey amp. The AC has a choice; it can go through the ultra-path cap or go through the cathode resistor. Obviously, most goes through the cap, but bypassing it makes a tremendous improvement. The Monkey amp is not the last word in amps, but its economic performance ratio sure is impressive.

4.) I have never liked the 6C45pi. The original ones I was given were microphonic as hell and poorly matched. Later on, I borrowed a new pair from a friend that bought them from New Sensor. They were better, but the whole deal of keeping the grid resistance low and dealing with the tubeâ€™s gross input capacitance was more trouble than what it was worth to me. I gave up on the 6C45pi and went back to what I knew would work reasonable well. I would love to hear this tube in a circuit that was done right, it might change my opinion of.

5.) I chose the operating point of the 10Y to accommodate my circuit. If I changed the operating point, I probably wouldnâ€™t be able to eliminate the first cathode resistor as I did. Believe me, eliminating the first cathode resistor makes a difference on how the amp sounds. Iâ€™m guessing when you say hotter, you mean more voltage? Or both? What is your favorite operating point for the 10Y? I am willing to try some different things if you want to throw out some suggestions. Thanks.

JLH