• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Millett NuHybrid Headphone Amp

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I finished the NuHybrid last night. I made no modifications at all, just made it the way Pete specified. I should note my soldering skills are average at best and I struggle to understand and read a schematic. So I approach any project like this with a certain amount of trepidation. Pete though, made this project as easy as possible. You can just link to the project on Mouser and add the parts listed to the cart. He was quick to send the PCB and Nutube.

It went together with no trouble at all. So following his directions I powered it up. The Nutube lit up with a cool light blue glow and the green led lit up. I adjust the bias to the 11 volts recommended by Pete. Plugged in my headphones, turned up the volume, started the CD player and...silence?? So check everything again and discovered I had not soldered two pins of the K1 relay. Okay, solder those and try again.

This time music. How does it sound? Well I think it sounds very good. I use a pair of Sony MDR-V6 headphones I have owned since they first came out in the early 90's. I played Boston, the Berlin Philharmonic, "The Planets" Alison Krauss and The Dave Brubeck Quartet. The NuHybrid handled them all easily and made listening enjoyable. It is also quiet, no hiss evident. I also plugged it into the amp section of an old Sanyo receiver. It did well there also. The Dave Brubeck Quartet was suddenly in my room through the ADS L9E speakers. A worthy and fun project.
 

Attachments

  • Nutube 001.jpg
    Nutube 001.jpg
    474.9 KB · Views: 525
  • nutube 002.jpg
    nutube 002.jpg
    569.3 KB · Views: 536
  • nutube 004.jpg
    nutube 004.jpg
    434.6 KB · Views: 511
Hi all,

I was looking at this too as I was thinking of adding a 'tuby' feel (harmonics and distortion hehehe) to a Pi/DAC I have.
Even though it says it can be used as a PRE... Im thinking that if the PI/DAC outputs linelvel signal and I pass it through the full amp I might be clipping on the input of my Denon AVR.

Will this work?

Thanks
 
Even though it says it can be used as a PRE... Im thinking that if the PI/DAC outputs linelvel signal and I pass it through the full amp I might be clipping on the input of my Denon AVR.

Will this work?
You can always turn down the volume knob on the preamp if the gain is too much. Fortunately, the amplification factor on this tube is low so I doubt you have much to worry about!
 
Here is what Pete Millett says about it "The Korg Nutube 6P1 is a newly developed, low-power directly heated dual triode vacuum tube.

It was developed by Korg, the musical instrument maker, and Noritake, a manufacturer of vacuum fluorescent displays, in Japan." You can read more about it at NuTube
 
You can always turn down the volume knob on the preamp if the gain is too much. Fortunately, the amplification factor on this tube is low so I doubt you have much to worry about!
Thanks a lot.

I have the (uneducated) worry that by turning the volume close to the lowest Im getting more of the noise floor or static/hum etc. Does this technically makes sense or im wrong?
 
It does make sense and if you are that far down the volume knob you can always attenuate after the preamp. Keep the input pot and add a 1K or so audio taper after the preamp which you can use to increase or reduce the input to the amplifier. It's always easier to get rid of too much gain than it is to get more when you don't have it.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.