Please forgive my ignorance, GNFB is also against my religion, but could you please explain how to achieve such amazingly low distortion without it?
Almost an hour searching for a precise meaning of "euphonic" without results.
Anyway, with .000000000225% of theoretical distortion, how can you distinguish between "euphonic" and "ultra realistic"?
Topology is not my strong point, so be patient with my dumbness, and my Tarzan-English.
NFB isn't the only method of linearization. There's endless schemes for feedforward, error correction, etc. It just depends on how you want to skin your cat. There's also just designing the circuit to operate as linearly as possible, the NP aleph current source is an example of a circuit that attempts to do this. Tubes themselves don't need extra NFB to be linear unless you want them to provide a lower output impedance but there are ways around that too.Please forgive my ignorance, GNFB is also against my religion, but could you please explain how to achieve such amazingly low distortion without it?
Euphony causes dopamine in the brain, that's pretty much the definition of the word, it's based off of the word euphoric but only applies to a condition caused by audio as far as I know.
It's caused by some form of distortion in the sound.
Realism is just realism.
My SS amp may have .000000000225% distortion or whatever but it will still sound like whatever is feeding it. I designed it as a power buffer but I can also configure it to have gain, technically making it an amplifier. I'm currently using it as a unity gain power buffer for my dac/line stage designs.
Ah, now I can understand, typical audiofool chatter, no offence intended.
A unity gain power buffer... that explains all!
I still do not understand the relation with a SET amp, with a transformer!
If you are looking for a "distortionless wire" with tubes/valves, search for SY's "Heretical Unity gain line stage"
It's a good one though.Ah, now I can understand, typical audiofool chatter, no offence intended.
Which tubes for colored sound?
I'm disappointed with my "wire with gain" 4P1L line stage. If I wanted an amplified version of my source with nothing added I would have just used a solid state gain stage.
Any recommendations for tubes that add some "magic" to the sound?
I've heard 10Y and 01a have something special in their sound. 10Y is like impossible to get though. I've considered the 300B but I've heard it's way overrated. 2a3 or 45 is another consideration.
I know circuit matters just as much or more than tube choice but hopefully someone here has experience with audible trends using certain tubes.
I'm disappointed with my "wire with gain" 4P1L line stage. If I wanted an amplified version of my source with nothing added I would have just used a solid state gain stage.
Any recommendations for tubes that add some "magic" to the sound?
I've heard 10Y and 01a have something special in their sound. 10Y is like impossible to get though. I've considered the 300B but I've heard it's way overrated. 2a3 or 45 is another consideration.
I know circuit matters just as much or more than tube choice but hopefully someone here has experience with audible trends using certain tubes.
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Look at lower voltage designs using less linear tubes like the 12AU7 if you want "that tube sound" thing, I personally think that all the tubes you listed are pretty linear when implemented correctly, and won't really give what you want.
Are you still wanting to do a simple line stage, or would you be open to a small SE amp? You could do an SE amp with a dummy load that has been tweaked to give the output you want, that will be a good way to get some tube bend to the signal too. Sort of a higher power line stage that could even double as a headphone amp really, but with the right load would do a great job as a line stage, with all the coloration of the circuit and operating points tweaked to give you what you want.
Are you still wanting to do a simple line stage, or would you be open to a small SE amp? You could do an SE amp with a dummy load that has been tweaked to give the output you want, that will be a good way to get some tube bend to the signal too. Sort of a higher power line stage that could even double as a headphone amp really, but with the right load would do a great job as a line stage, with all the coloration of the circuit and operating points tweaked to give you what you want.
Your point is still confusing, some people (including me) use valve amplification because of its linearity, not to obtain a "sound" or a kind of "magic"
Old valves that you mention are mostly pre-GNFB, i.e. very linear (see Ale Moglia's blog Benchmark)
If for any reason you want to build an effects box, you must try more pedestrian ones, even so, to obtain more distortion you must work out of the linear region.
For any reason, electrons prefer vacuum, and many times SS, even at very low distortion sounds horrible.
Each one have his own reasons/theories about this, you can see some here
Intriguing measures on tube amp
With all due respect, you have not a clue about to make ECC82/12AU7 sing, as I said before on another thread, in SRPP the sound is transparent, and REAL measurements made by member DualTriode are amazing.
Obviously you did not see them.
Just in case
http://www.diyaudio.com/forums/tube...ply-design-input-6sn7-srpp-2.html#post5408462
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The only experience I've ever had with tubes has been using OCL/OTL tube amps. The original reason I got into amp design was because of the "magic" I heard in the sound, it wasn't undetailed either like some vintage amp designs.
I've mostly used 6sn7 and 6080 triodes, the first tube of higher quality that I've used is the 4P1L and soon the 6c33c. I think some of you have a point about taking the bias out of the linear range.
What about the 01a tube though? I've seen a zillion people claim it has some "special" sound. I'm assuming this still applies in the linear range? I guess I kind of always thought that tubes inherently added something to the sound even in their linear range.
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A well designed valve circuit adds almost nothing to the sound, maybe a little 2nd order distortion, which is innocuous because human hear is almost deaf to even order distortion. So the "special" sound and "magic" is just listen to the music, instead to listen to the amplifier system.
If you want add something to the sound, i.e. an effects box, try a very low transconductance valve and build a cathode follower, working on the non-linear region of valve curves.
Right... I think what you need is a little more 2nd order harmonic distortion.
Many of the valves/tubes listed above are actually very linear. However designing a circuit to increase harmonic distortion is not too hard.
Post your circuit and maybe you will get some advice.
Ha. Popilin posted quicker than me! Guess we both have the same idea.
I wouldn't go for cathode follower though (I don't like that sound - perhaps too familiar to me?) I would get rid of global feedback and try to bias the input valve/tube differently. Is the amplifier single ended or push-pull?
Many of the valves/tubes listed above are actually very linear. However designing a circuit to increase harmonic distortion is not too hard.
Post your circuit and maybe you will get some advice.
Ha. Popilin posted quicker than me! Guess we both have the same idea.
I wouldn't go for cathode follower though (I don't like that sound - perhaps too familiar to me?) I would get rid of global feedback and try to bias the input valve/tube differently. Is the amplifier single ended or push-pull?
- for an easy sound, think I like an anode follower (12au7) with low gain better than CF - if its input Z can be driven. Perhaps avoid B+ regulators and use reasonably small filtering and de-coupling caps in the PS. - there's always starved operation - dunno if that's good but did like the INDEED headphone amp.
Tubes has no "sound", they are a voltage-controlled resistor that might be more
or less non-linear. A fine amplifier has no sound of it's own, a less perfect amp
might alter the sound, if that is preferred well, your luck is made! But tubes
themself has no sound.
As I've said, even with -30db 2nd harmonic I could not tell the difference between an equivalent circuit with 2nd harmonic well below -100db.
2.5 years and $15,000+ worth of R&D, I'm not giving away anything sorry
My designs are my way out of poverty, as much as I'd like to share. Getting third party feedback on potential optimizations would be godly.Currently I'm using a two stage design, SE line stage into power buffer. Planning on making a WCF out of 6c33cs soon, hopefully they will add something to the sound, at least I hope they do.
Why would anybody bother with tubes in their linear range if they have no unique sound? So much more expensive and bulky than SS parts. Yes I know most SS amps on the market sound terrible but that is a design issue.
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Nope, on an SET thread, you shouldn't say that. SETs are definitely not low (none) distortion and noise amps, but quite the contrary, I'll repeat: SETs are a high distortion amps. People buy or build them exactly for their distortion and noise patterns. If you want an absolutely transparent amp, Class D is unbeatable - it is a perfectly transparent amplifying wire (regardless of what others might think about this).
Good luck playing low quality MP3s through a class D amp though. Perhaps you know, one way the MP3s get so small is by erasing as much of the naturally occuring harmonics as they can get away with, presuming that people can't hear them. That's why solo cellos sound so bad in 128kbps MP3s. Playing the same MP3 through an SET, and you'll get back at least some these harmonics and overtones, and that distortion WILL make it sound better, warmer, sexier, etc..
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