Hello to all forum members. I am looking for a 300B amp design that will go into the so-called euphonic distortion early (but non-destructive)
I am also looking for a circuit to pick up the 300B speaker output and produce 2 channels of biampable line level signals to further amplify the result into class d
The 300B amp will be hooked up to a pair of pioneer coaxial that are very inefficient but go very low for night mode for monitoring and the class d stage for daytime when I can let it rip. I will also be occasionally stereo mic-ing the pioneer speakers when recording, but 90 percent of the use of this system will be the front channels of a smallish nighttime general music and video playback
I don't really care for purity all the time, I enjoy "effected music" and love the overdriven 300b sound
Thanks and regards
Randy
I am also looking for a circuit to pick up the 300B speaker output and produce 2 channels of biampable line level signals to further amplify the result into class d
The 300B amp will be hooked up to a pair of pioneer coaxial that are very inefficient but go very low for night mode for monitoring and the class d stage for daytime when I can let it rip. I will also be occasionally stereo mic-ing the pioneer speakers when recording, but 90 percent of the use of this system will be the front channels of a smallish nighttime general music and video playback
I don't really care for purity all the time, I enjoy "effected music" and love the overdriven 300b sound
Thanks and regards
Randy
Are you sure it is the distortion you're looking for? If so, you could just emulate it digitally from the source.
Randy, to get the overdrive sound earlier, you may not need a different circuit. Instead, experiment with lower plate voltage. Maybe start with 300V plate to cathode, and adjust the value of cathode resistor to get the sound you like best.
You can do this with most of the 300B SE amp designs found here or elsewhere; the ones with a pentode driver (EL84, SV83 etc) are easy to make, and allow the possibility of adding some overdrive sound in the driver circuit, by using VG2 at 200V or even a little lower.
Randy Bassinga,
If by any chance 2nd harmonic distortion is the cause of the euphonic sound that you are talking about, then try this:
For Single Ended amplifiers that do not have negative feedback, and that also do not have significant 2nd harmonic distortion cancelation caused by the opposite phase of the driver and output tube, many of those amplifiers will have significant 2nd harmonic distortion.
And many loudspeakers have significant 2nd harmonic distortion.
So, for the amplifier and speaker connected "in-phase", versus for the amplifier and speaker connected "out-of-phase", the resulting system 2nd harmonic distortion will either be the addition of the amp's and speaker's 2nd harmonic distortion (more system 2nd harmonic distortion), or will be partially cancelled (amp and loudspeaker total) and the system will have less 2nd harmonic distortion.
Try swapping the speaker cord's leads either at the amplifier, or at the speaker (but not at both).
Euphonic does not mean the same thing to all listeners.
As posted earlier, overdrive can be the input, driver, output stage, or a combination of two or three of those.
All generalizations have exceptions
Oh . . . welcome to the Tubes / Valves threads (usually Hi Fi / Stereo amplifiers)
FYI, there are also an Instruments and Amps threads (usually Guitar amplifiers).
Amazing! Those Tubes / Valves experts!
If by any chance 2nd harmonic distortion is the cause of the euphonic sound that you are talking about, then try this:
For Single Ended amplifiers that do not have negative feedback, and that also do not have significant 2nd harmonic distortion cancelation caused by the opposite phase of the driver and output tube, many of those amplifiers will have significant 2nd harmonic distortion.
And many loudspeakers have significant 2nd harmonic distortion.
So, for the amplifier and speaker connected "in-phase", versus for the amplifier and speaker connected "out-of-phase", the resulting system 2nd harmonic distortion will either be the addition of the amp's and speaker's 2nd harmonic distortion (more system 2nd harmonic distortion), or will be partially cancelled (amp and loudspeaker total) and the system will have less 2nd harmonic distortion.
Try swapping the speaker cord's leads either at the amplifier, or at the speaker (but not at both).
Euphonic does not mean the same thing to all listeners.
As posted earlier, overdrive can be the input, driver, output stage, or a combination of two or three of those.
All generalizations have exceptions
Oh . . . welcome to the Tubes / Valves threads (usually Hi Fi / Stereo amplifiers)
FYI, there are also an Instruments and Amps threads (usually Guitar amplifiers).
Amazing! Those Tubes / Valves experts!
Last edited:
It is very simple to design a high distortion 300B SE amp. Run it at high voltage with low idle current. Also, use 2K OPT for high power and large distortion. Great. Use very linear driver tube like d3A or C3g so that there's no cancellation between driver and power tube.
Hi all, thanks for the replies and suggestions. I am taking a step back from the 300b but will keep it as an option. First I would like to see if I can get the desired effect from small signal tubes in the pre stages
If you don't mind solid state, Nelson Pass' H2 Harmonic Generator may work for you if you are looking to add "good" distortion:
H2 Harmonic Generator
H2 Harmonic Generator
A very interesting read and looks promising. Thank you for pointing this out. I am still going through it all and absorbing it
At the moment, I have been leaning towards a tube headphone single ended design and trying to figure out if output transformers on that can be chosen to output a signal for further amplification. I find the glowing tube aesthetically pleasing too and fitting in well with the glowing sound. For this project I have purchased a 3 axis CNC with a laser head too. I may be able to execute a visually appealing enclosure displaying the tube stuff
The H2 does look promising, and I will have a go at that too
Even better, check out Korg Nutube. There is a kit in diyaudio store. And reading on Mr. Nelson's web page First Watt.
Just ordered a H2 kit. Looking forward to playing with this. Also trying to pick a headphone amp that may suit this purpose, any suggestions?
The nutube looks awesome but glowing things sticking out looks so appealing for similar cost and results
The nutube looks awesome but glowing things sticking out looks so appealing for similar cost and results
I am leaving the 300B idea alone for now. I think I have found a better option
Anyway, my process so far has been a jumble of ideas and thots. I am clearer now on the results that I am after and the approach to take. Let's scrap all the above, I'll try to organise my approach again
Thanks to all for contributing, and I hope I can look towards you folks for future interaction
Randy
Anyway, my process so far has been a jumble of ideas and thots. I am clearer now on the results that I am after and the approach to take. Let's scrap all the above, I'll try to organise my approach again
Thanks to all for contributing, and I hope I can look towards you folks for future interaction
Randy