I feel I’m polluting this thread with digital emulation shiiit, so this is my last post about it.
After listening to this digital H2 plugin (HoRNetHarmonics inserted in Auridvana) with two different audio systems for several days, I think I can conclude that adding certain amount of H2 have a positive effect for wide variety of sources (tracks), with some exceptions.
I don’t have a real H2 board, and this is my personal preference in my own environment, but I believe it’s worth to try H2 effect in your system. You may not like it at the end, but it’s fun, for sure.
After listening to this digital H2 plugin (HoRNetHarmonics inserted in Auridvana) with two different audio systems for several days, I think I can conclude that adding certain amount of H2 have a positive effect for wide variety of sources (tracks), with some exceptions.
I don’t have a real H2 board, and this is my personal preference in my own environment, but I believe it’s worth to try H2 effect in your system. You may not like it at the end, but it’s fun, for sure.
I'm afraid if my post is causing some kind of misunderstanding, so I just want make clear that I have never said this cheap emulation and real H2 board are the same.
I have 20+ years experience with digital plugins, and I know plugins can't be exactly the same as its analog counterpart, even if the developer claims his emu is the exact same behavior / sounding as a specific analog equipment.
I have 20+ years experience with digital plugins, and I know plugins can't be exactly the same as its analog counterpart, even if the developer claims his emu is the exact same behavior / sounding as a specific analog equipment.
Hi Plasnu,
This may not be the place, but I'm interested in your experiments with plugins. Let me know if you open a dedicated thread. You could also extend some discussions started there one month ago: DSP - Triode response.
By the way, will there be H2 kits on the DIY store ? I have skill tyo build one without kits except that I don't have a distortion analyser to trim the device :-(
JMF
If you have an oscilloscope, you only need to build a twin T notch filter, or you can build a sound card interface and use sound card distortion software like DiAna.
Have Fun.
If you have an oscilloscope, you only need to build a twin T notch filter, or you can build a sound card interface and use sound card distortion software like DiAna.
Have Fun.
Thanks Indra for the hints and opening the possibilities
JMF
Hi again
First thanks to Nelson for such a nice article on H2. I feel better after reading it, since it proved what I was subjectively "feeling" a long time ago, and all the time with audio amps. The first such "feeling" happened around 2005 when, out of curiosity, I built a Gainclone. I first tried a Joe Rasmussen tube-buffered gaonclone, where a 6922 tube was a buffer and itvwas driving an LM chip via inverting output. It sounded really nice, with a tube-like sound. But, it had a low level hum and since I was not motivated enough to solve it, I just removed the tube and built the GC withoutbit, with non-inverting input, almost like in a datasheet. It worked flawlessly, no hum, nice and clean, but...something was missing. The magic was gone, just like when you go out of a smokey bar to inhale fresh air, it is cleaner, but you probably enjoyed the smoke
So I started wondering, was it an inverting input of the chip that made the difference, or the tube, or both. Yet,the question remained-why?
The more recent occasion of a similar phenomena was the case of a cheap D-clasa amp (TPA 3116), whicj by itself was just that, a cheap amp which sound was nothing to write home about, and I found it to be a bit edgy and harsh.
Then, I had a chance to listen to this amp with a tube buffer in front. It sort of transformed it, into an amp that one could live with. Now, I felt even more perplexed. I could understand that tube buffer is needed in front of an amp with lowish input impedance, but what the heck can the tube buffer do in front of an amp with high input impwdance, beside adding one more unnecesary stage, thus "polluting" the signal and adding more distortion. But, I heard it, and it sounded better with the tube!
In my main system, I am using a midified Jfet BoZ (j310, 220 ohm degeneration resistor, 680 ohms drain resistor, 24v clean supply-thanks to Juma for the tips). I found that it very nicely complements my F2-lite (like an F2, but with the lightbulb as a CCS). Although on paper F2 has the worst distortion numbers, when paired with this preamp, it outperformed my F3!
My logic again said that it can't be right, but my ears just enjoy it, so it remained.
I knew that the whole thing has to do with H2, but I didn't know why is it so.
Now, I realize that both a jfet BoZ and an F2 must be generating a fairly high amounts of H2 in positive phase. But, since they are both inverting, these distortion partially cancel each out each other, leaving the "just right" amount of H2 at the amp output...
P.s. just for info, speakers are Visaton B200's on Open Baffle...
First thanks to Nelson for such a nice article on H2. I feel better after reading it, since it proved what I was subjectively "feeling" a long time ago, and all the time with audio amps. The first such "feeling" happened around 2005 when, out of curiosity, I built a Gainclone. I first tried a Joe Rasmussen tube-buffered gaonclone, where a 6922 tube was a buffer and itvwas driving an LM chip via inverting output. It sounded really nice, with a tube-like sound. But, it had a low level hum and since I was not motivated enough to solve it, I just removed the tube and built the GC withoutbit, with non-inverting input, almost like in a datasheet. It worked flawlessly, no hum, nice and clean, but...something was missing. The magic was gone, just like when you go out of a smokey bar to inhale fresh air, it is cleaner, but you probably enjoyed the smoke
So I started wondering, was it an inverting input of the chip that made the difference, or the tube, or both. Yet,the question remained-why?
The more recent occasion of a similar phenomena was the case of a cheap D-clasa amp (TPA 3116), whicj by itself was just that, a cheap amp which sound was nothing to write home about, and I found it to be a bit edgy and harsh.
Then, I had a chance to listen to this amp with a tube buffer in front. It sort of transformed it, into an amp that one could live with. Now, I felt even more perplexed. I could understand that tube buffer is needed in front of an amp with lowish input impedance, but what the heck can the tube buffer do in front of an amp with high input impwdance, beside adding one more unnecesary stage, thus "polluting" the signal and adding more distortion. But, I heard it, and it sounded better with the tube!
In my main system, I am using a midified Jfet BoZ (j310, 220 ohm degeneration resistor, 680 ohms drain resistor, 24v clean supply-thanks to Juma for the tips). I found that it very nicely complements my F2-lite (like an F2, but with the lightbulb as a CCS). Although on paper F2 has the worst distortion numbers, when paired with this preamp, it outperformed my F3!
My logic again said that it can't be right, but my ears just enjoy it, so it remained.
I knew that the whole thing has to do with H2, but I didn't know why is it so.
Now, I realize that both a jfet BoZ and an F2 must be generating a fairly high amounts of H2 in positive phase. But, since they are both inverting, these distortion partially cancel each out each other, leaving the "just right" amount of H2 at the amp output...
P.s. just for info, speakers are Visaton B200's on Open Baffle...
Listening to a H2 inspired circuit ... and I really like it.
I think it brings more spark and room to the music. Only tried it on my small (but quite ok) "PC speakers" .... close range listening.
Have tried to sim all kind of modifications but the simplest is the best of producing the wanted mainly H2 distortion.
Would like to add a second stage to make it into a non inverting unity gain stage ... but keeping the distortion quialities ... any suggestions?
I think it brings more spark and room to the music. Only tried it on my small (but quite ok) "PC speakers" .... close range listening.
Have tried to sim all kind of modifications but the simplest is the best of producing the wanted mainly H2 distortion.
Would like to add a second stage to make it into a non inverting unity gain stage ... but keeping the distortion quialities ... any suggestions?
Thinking about making it variable ... see picture.
I need it to front my input circuit of my class d amps of -3x
Guess I could just take the output at the source instead to have a 1x circuit ... with the same properties ...
Attachments
Sounds like a nice way to avoid switching cables at the speaker.
For those like myself with limited electronics design skills, is there a way to do this with the existing H2 board?
The posted schematic is not enough "Betty Crocker" for me.
Not really. You'll need to add one or two DPDT relays, a switch, two or four transistors, a handful of coupling capacitors, and 1.5 handsfull of resitors to set the gain and to bias the caps.
Using ICs won't reduce parts count dramatically since you still need the relay(s), you still need the coupling caps, and you still need the gain setting resistors.
Using ICs won't reduce parts count dramatically since you still need the relay(s), you still need the coupling caps, and you still need the gain setting resistors.
I was also thinking about this. "The normal mode of operation" as I would call this H2 generator, is the assumption that you have an "ordinary" amplifier, ie not SE, an amp that does not enhance second harmonic and that does not invert phase (most commercial amps). In that case, by adding H2 circuit, you would introduce a small amount of positively-phased second harmonic, but since it is inverting, you would have to invert speaker connections at the output of am amp, in order to "bring back the overall phase". But, by doing this, you would invert the phase of the second harmonic, which would now become nagative, as is the intention of the circuit.
The problem arises if your amplifier already inverts the phase (Zen amp for example). By adding H2 circuit, you make one more inversion at the input, so now you have to reverse your speaker connection, in order to get "the right phase". But, in this case, you will get positive second harmonic, both from H2 and the Zen amp, and your result may not be as expected.
Hence, for such cases, it is necessary to "invert the phase once again". That also applies if you don't want to invert speaker connections in case of an "ordinary amp".
So, the simplest thingvwould be to build an opamp based phase reverser, which is basically an opamp which input goes to - input, with 100% feedback. It't easy to do, I've seen such circuit on some "subwoofer phase switches". On the other side, I don't know what (negative) efect can an additional opamp with 100% feedback have on the sound, so maybe we want a different solution.
Sorry if all of this sounds confusing, but it is actually very simple. Remember, the aim is to get the right overall phase at the speaker, while adding a small amount of negatively-phased second harmonic.
I am saying this because I have seen the tube buffers added on front of amps that do not invert phase. The result of this is the addition of positively-phased second order harmonic, but we want it negative.
Now if what I said is confusing enough, maybe Nelson can draw a simple schematic
P.s. Just had an idea :lightbulb: What about using a 1:1 transformer at the input as phase reverser?
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