• 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.

6n3p buffer?

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Hi,
I hope asking this question doesn't violate any rules here. I'm interested in building a tube buffer to put in my headphone setup to change the sound an give it some tube color.
Unfortunately I don't know much about how to make a circuit like this. I have in my possession 8 6n3p-ev tubes from Russia, so I would like to use those if it is possible. I bought these to replace the chinese 6n3 tubes that come in this. This device is what I am using right now, and with the Russian tubes I really like how it sounds, with the Chinese tubes I couldn't hear a difference but the Russian ones sound noticeably different. I don't like this device though, the design is questionable at best and I think it's not a real buffer as it ins't unity gain.

My question is where can go to learn how I would go about designing a circuit like I am describing? Are there any well known schematics I could look at? I've seen many good looking schematics around the web that use all manor of different tubes, but I don't want to just copy someone's design without thoroughly understanding how it works.
Thank you!
 
Tube 6N3 Buffer Audio Preamplifier Pre AMP Kit For DIY
Maybe you can study the schematic and ask some questions. If you're happy with you can order one to see how it really sounds like or DIY.

In case OP was looking for a bit of reading on the subject:

Valve Technology - A Practical Guide

I was curious as to what was all going on in the topology and the split resistor for bias and load drive...etc etc. I hadn't seen anything on this particular topology until doing some research and found that link and was a pretty decent read.
 
In case OP was looking for a bit of reading on the subject:

Valve Technology - A Practical Guide

I was curious as to what was all going on in the topology and the split resistor for bias and load drive...etc etc. I hadn't seen anything on this particular topology until doing some research and found that link and was a pretty decent read.

That link is great, thank you I'll definitely spend some time reading there. Koonw, thank you for the suggestion, though I have already reverse engineered the schematic of the tube preamp that I already have. I think I will attempt to reverse engineer the design of that one first.
 
The article doesn't mention that the grid leak resistor R1 is "bootstrapped" by the signal voltage being applied to both sides of the resistor (attenuated in this case on the cathode side by a factor of ~0.83). This makes the resistor seem higher in impedance to the input signal. In this case about 5.88M (1M/0.17). This information is needed to calculate the turnover frequency of the high pass filter formed by the input cap and grid leak resistor. In this case it's calculated to be 0.27Hz. One could probably get away with a smaller value cap. ;~)

Also of note: since the output swing equals 0.83 x the input swing and the grid bias is -0.6V this circuit will run into trouble with any signal larger than 1.1-1.2V peak to peak. And with a load of only 1K the load line will be pretty steep, so you will be relying on the 100% feedback of a CF to quash the resulting distortion.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.