So I was really bored tonight and figured what the hek I'll do some tinkering while drinkering.
I will start with a little background details.
The last band I was in the music we played was all over the place so I needed a versatile amp that will not break my back lugging to gigs and practices. I used a lot of effects in that outfit so the amp needed to take pedals well. I also wanted good clean headroom but still sound warm. I don't need an overdrive channel because I dig the sound of my Ibanez tube screamer. I settled on the Deluxe Reverb with an upgraded speaker. The speaker I went with was an Eminence Cannabis Rex which sports a cool 103db sensitivity giving me more clean headroom.
Ok so now I don't play in that band any more. The group I play with now is just for fun and we pretty much play 50's 60's rock n roll. So I find myself only using my Tweed Deluxe, it really is a super amp and love it. I can go from warm cleans to dirty with the roll of my guitars volume knob, something about an amp pushed into distortion sounds so good compared to pedals IMHO. Well now I never use my poor Deluxe Reverb and it has been sitting collection dust.
Ok Ok I will stop blabbering sorry I will get to my point.
I have a bunch of 6K6's laying around and thought to myself what can I do with these and it hit me, I will put them in my Deluxe Reverb (or even better just one in my Deluxe Reverb).
First thing to do was remove the B+ from the center tap of OPT. Next I took one plate lead off of one output tube socket and hooked it up to B+ using the whole primary winding.
Now I need to lower the B+ so I substituted the 5AR4 with a NOS 5Y3GT. I already have diodes in series with the plates of my rectifier tube to help them last longer so I wasn't too worried about the extra input capacitance of the reservoir cap being higher than 5Y3GT datasheet.
Conclusion:
With the 6K6 pulling 22mA I get a plate voltage of 375 giving me about 8 watts plate dissipation.
How does it sound? It sounds great let me tell you! In Hi-Fi you don't want core saturation so you will hear a lot of talk about not using PP OPT with single ended designs due to core saturation. This amp is killer, I can set the volume on 6-7 and use my volume on guitar to go from clean to dirty just like my 5E3 but now I have tube reverb and Vibrato and the classic AB763 preamp. With the Cannabis Rex's High sensitivity (103db) this amp is just as loud as my 5E3 and only has an output power of about 4 watts. Full on amp distortion without bleeding ears is what it's all about.
Maybe the 6K6 will have an early death but I have a bunch and don't really care. The one I settled on was a black glass NOS Tung-Sol and man it screams.
Thanks for reading
I will start with a little background details.
The last band I was in the music we played was all over the place so I needed a versatile amp that will not break my back lugging to gigs and practices. I used a lot of effects in that outfit so the amp needed to take pedals well. I also wanted good clean headroom but still sound warm. I don't need an overdrive channel because I dig the sound of my Ibanez tube screamer. I settled on the Deluxe Reverb with an upgraded speaker. The speaker I went with was an Eminence Cannabis Rex which sports a cool 103db sensitivity giving me more clean headroom.
Ok so now I don't play in that band any more. The group I play with now is just for fun and we pretty much play 50's 60's rock n roll. So I find myself only using my Tweed Deluxe, it really is a super amp and love it. I can go from warm cleans to dirty with the roll of my guitars volume knob, something about an amp pushed into distortion sounds so good compared to pedals IMHO. Well now I never use my poor Deluxe Reverb and it has been sitting collection dust.
Ok Ok I will stop blabbering sorry I will get to my point.
I have a bunch of 6K6's laying around and thought to myself what can I do with these and it hit me, I will put them in my Deluxe Reverb (or even better just one in my Deluxe Reverb).
First thing to do was remove the B+ from the center tap of OPT. Next I took one plate lead off of one output tube socket and hooked it up to B+ using the whole primary winding.
Now I need to lower the B+ so I substituted the 5AR4 with a NOS 5Y3GT. I already have diodes in series with the plates of my rectifier tube to help them last longer so I wasn't too worried about the extra input capacitance of the reservoir cap being higher than 5Y3GT datasheet.
Conclusion:
With the 6K6 pulling 22mA I get a plate voltage of 375 giving me about 8 watts plate dissipation.
How does it sound? It sounds great let me tell you! In Hi-Fi you don't want core saturation so you will hear a lot of talk about not using PP OPT with single ended designs due to core saturation. This amp is killer, I can set the volume on 6-7 and use my volume on guitar to go from clean to dirty just like my 5E3 but now I have tube reverb and Vibrato and the classic AB763 preamp. With the Cannabis Rex's High sensitivity (103db) this amp is just as loud as my 5E3 and only has an output power of about 4 watts. Full on amp distortion without bleeding ears is what it's all about.
Maybe the 6K6 will have an early death but I have a bunch and don't really care. The one I settled on was a black glass NOS Tung-Sol and man it screams.
Thanks for reading
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So you turned a P-P into a single ended? With the PI still working wouldn't you then have only one side of the signal being amplified? Your plate voltage is still pretty high (Oh yeah you have a bunch of 6K6s LOL).....What are you biasing the cathode with? I played around with 6K6s and also some 6Y6s (200v plate max) on my Deluxe breadboard, got them all to work P-P with the cathodyne PI, but went back to 6V6s for my final build design. Interesting project!
So you turned a P-P into a single ended? Yes
With the PI still working wouldn't you then have only one side of the signal being amplified?
No, the PI doesn't separate the two halves it just makes the signal 180 degrees out from one another. Think about the cathodyne PI, it pulls the signal from the plate which is 180 off from the input. It also pulls the signal from the cathode which is in phase with the input. Each signal gets sent to a different power tube in PP designs.
Your plate voltage is still pretty high. Yes but datasheet says 315 plate volts max for a 6V6 (same as 6K6) and they run fine in Deluxe Reverbs running over 400v. If you look at "typical operating characteristics" you will see that they recommend 315v at plate and 225v at screen for 6V6. With a 6K6 they recommend 315v at plate and 280v at screen. If anything the screen is going to fail but I think it will be ok NOS tubes are rugged.
What are you biasing the cathode with?
Nothing the amp is fixed bias. Remember most single ended amps are cathode bias but they don't have to be.
With the PI still working wouldn't you then have only one side of the signal being amplified?
No, the PI doesn't separate the two halves it just makes the signal 180 degrees out from one another. Think about the cathodyne PI, it pulls the signal from the plate which is 180 off from the input. It also pulls the signal from the cathode which is in phase with the input. Each signal gets sent to a different power tube in PP designs.
Your plate voltage is still pretty high. Yes but datasheet says 315 plate volts max for a 6V6 (same as 6K6) and they run fine in Deluxe Reverbs running over 400v. If you look at "typical operating characteristics" you will see that they recommend 315v at plate and 225v at screen for 6V6. With a 6K6 they recommend 315v at plate and 280v at screen. If anything the screen is going to fail but I think it will be ok NOS tubes are rugged.
What are you biasing the cathode with?
Nothing the amp is fixed bias. Remember most single ended amps are cathode bias but they don't have to be.
Thant's pretty cool! Have you thought of making it switchable? Swap a tube, flip a switch.... or run both tubes (6V6 and 6K6) with a fat resistor to lower the B+, and have both running with their different personalities.
I don't think I will make it switchable and in all honestly I will probably put it back to stock. It was more or less just an experiment. We will see how it holds up with a band situation though.
I have though about mixing different power tubes like 6V6/6K6 or 6V6/6l6 but I will have to change the bias scheme to be able and run different bias voltages to each tube. Some Mesa amps do this with 6L6/El34's. Maybe this will be my next project for the deluxe?
I followed your experiment with the princeton/5E3 circuit and I think it is fun to do things like this for the sake of humanity and fun.
I have though about mixing different power tubes like 6V6/6K6 or 6V6/6l6 but I will have to change the bias scheme to be able and run different bias voltages to each tube. Some Mesa amps do this with 6L6/El34's. Maybe this will be my next project for the deluxe?
I followed your experiment with the princeton/5E3 circuit and I think it is fun to do things like this for the sake of humanity and fun.
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