You're still taking your DAC output and adding distortion while increasing the output impedance. You're also taking a pretty useful 2V of signal and making it uselessly high.
What exactly is the goal here?
What exactly is the goal here?
Sorry if I haven’t mentioned it before.
I would like it to act as a pre amp with 4 switchable inputs and a volume control driving a solid state power amp.
I would like it to act as a pre amp with 4 switchable inputs and a volume control driving a solid state power amp.
OK, well you're not doing a good job with that. A 10K pot would be a better functioning preamp between your DAC and a solid state power amp than what you've made.
Thanks for your patience.
So basically you’re telling me to ditch the tube?
Kindly help me understand how branded tube preamps works differently as almost any source that I know output about 2V? What am I missing?
So basically you’re telling me to ditch the tube?
Kindly help me understand how branded tube preamps works differently as almost any source that I know output about 2V? What am I missing?
Tube preamps will use a cathode follower or an output transformer to be able to drive low impedance loads. It's reasonable to assume that someone would use a preamp with a solid state amplifier and perhaps even in conjunction with a subwoofer plate amp, so you really should design to drive a 5K load.
Your circuit will not perform well into a 5K load. It will perform far worse than most DACs would on their own.
I drew out a proper linestage for you with a voltage amp and a cathode follower. You could also just use a self biasing cathode follower if you wanted to. You could also use a 15K:600 output transformer with a tweaked version of what you have now.
What you have now will have an output impedance that's many thousands of ohms, and a lot of distortion because the load line is so steep.
Your circuit will not perform well into a 5K load. It will perform far worse than most DACs would on their own.
I drew out a proper linestage for you with a voltage amp and a cathode follower. You could also just use a self biasing cathode follower if you wanted to. You could also use a 15K:600 output transformer with a tweaked version of what you have now.
What you have now will have an output impedance that's many thousands of ohms, and a lot of distortion because the load line is so steep.
Why not use the 5670 tube as a follower instead of a gain stage? Then it can drive the SS amp with ease and has a lot of headroom.
Thanks for everyone here, I've learned a lot from your comments.
I decided to use the 5670 tube as a tube output gain stage for my Diy AD1862 based DAC using passive I/U converssion with 100ohm resistor.
How can I calculate the output impedance of the tube circuit?
I decided to use the 5670 tube as a tube output gain stage for my Diy AD1862 based DAC using passive I/U converssion with 100ohm resistor.
How can I calculate the output impedance of the tube circuit?