From some of the systems I have heard, maybe they shouldn't! I've visited homes with $100,000 systems that sound horrible.
Maybe I just try to have a buck each way - anything built has to make some sort of engineering sense. However. The original musical performance exists once, I go for reproducing it in a manner I find plausible and enjoyable, and with one (SE) amp in particular, it's got a bit of 2H distortion, but I like it.
Until I get bored and swap amps.
At the moment a modified Tubelab SPP is playing, it's fun, and not burning up any rare tubes, it just bounces along with some John Coltrane on a pair of mk1 Heresys. An imperfect but fun speaker.
Context is everything, and personally, if I am not having fun because I'm agonising over one dud note, I'm doing it wrong.
Respect to Andy for his pursuit of the magic that interests, and Anatech for an interesting counterpoint. We play on. Great thread 🙂
Until I get bored and swap amps.
At the moment a modified Tubelab SPP is playing, it's fun, and not burning up any rare tubes, it just bounces along with some John Coltrane on a pair of mk1 Heresys. An imperfect but fun speaker.
Context is everything, and personally, if I am not having fun because I'm agonising over one dud note, I'm doing it wrong.
Respect to Andy for his pursuit of the magic that interests, and Anatech for an interesting counterpoint. We play on. Great thread 🙂
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Although it will sound as if came from a mental health hospital, I have a different hypothesis of why different tubes have a specific sound, including mesh plate ones.
Some years ago, I began testing, although subjectively, the influence of different materials (woods, metals, liquids) when placed on inherently vibrating surfaces, such as speaker baffles, walls and speaker basket itself. I also believe our audio components, such as amplifier chassis do resonate mechanically together with music, by direct airwave excitation, or mechanically coupled by the ground floor and cables.
I also tested tubes. Smaller ones, big ones, mesh plate ones, triodes, pentodes, heptodes, thyratrons. It seems that, when the tube bulb and vacuum are intact, the tube when mounted/glued to a resonating surface, reduces harshness and gives midrange depth/richness in a strikingly similar way as if employed in an electric circuit. However, a broken tube with a lost vacuum has no more midrange "magic".
Honestly said, after discovering this, I ditched all DIY tube project and began building solid state stuff by adding passive tubes. I think they work as a vibration dampener, because of their vacuum, where atmospheric pressure is applied to the bulb. Pressure on a surface dampens vibrations. As for mesh construction, the mesh itself has a lower mechanical resonance Q, compared to a thin solid surface. Nowadays, I just add copper braid/mesh, oil, sand, bitumen, copper mass to vibrating surfaces instead of using tubes.
If one of you has some time on his hand, it might be useful to test this hypothesis by adding tubes to different devices/surfaces and then take measurements using an accelerometer to the surface or microphone.
As for a subjective test, one can also try connecting a passive tube to speaker basket and do some A/B tests. Especially a mesh vs non mesh tube.
Some years ago, I began testing, although subjectively, the influence of different materials (woods, metals, liquids) when placed on inherently vibrating surfaces, such as speaker baffles, walls and speaker basket itself. I also believe our audio components, such as amplifier chassis do resonate mechanically together with music, by direct airwave excitation, or mechanically coupled by the ground floor and cables.
I also tested tubes. Smaller ones, big ones, mesh plate ones, triodes, pentodes, heptodes, thyratrons. It seems that, when the tube bulb and vacuum are intact, the tube when mounted/glued to a resonating surface, reduces harshness and gives midrange depth/richness in a strikingly similar way as if employed in an electric circuit. However, a broken tube with a lost vacuum has no more midrange "magic".
Honestly said, after discovering this, I ditched all DIY tube project and began building solid state stuff by adding passive tubes. I think they work as a vibration dampener, because of their vacuum, where atmospheric pressure is applied to the bulb. Pressure on a surface dampens vibrations. As for mesh construction, the mesh itself has a lower mechanical resonance Q, compared to a thin solid surface. Nowadays, I just add copper braid/mesh, oil, sand, bitumen, copper mass to vibrating surfaces instead of using tubes.
If one of you has some time on his hand, it might be useful to test this hypothesis by adding tubes to different devices/surfaces and then take measurements using an accelerometer to the surface or microphone.
As for a subjective test, one can also try connecting a passive tube to speaker basket and do some A/B tests. Especially a mesh vs non mesh tube.
As I can see the problem is that not everybody knows the real timbre of not amplified musical instruments.
Other important thing is: when you listen at home you don't have the same room acoustics like for example you listen in a church, studio, concert hall, etc. So it's very very difficult to recreate the same sound....
Other important thing is: when you listen at home you don't have the same room acoustics like for example you listen in a church, studio, concert hall, etc. So it's very very difficult to recreate the same sound....
Heater power is not irrelevant.
The temperature of the grid will reach a level determined by the inflow of heating power multiplied by the effective thermal resistance of the grid structure (⁰C/W).
Comparing EF184 to PL802, the heater power is more than 2.5x greater. All the physical dimensions are closely matched (bar a little extra height), so the PL802 cathode can only grow width-wise. Extra width increases the cathode radiative area, but improves the grid's thermal resistance very little.
The cooling of the grid relies on a similar pair of support rods In both, but even these to will receive more radiative power.
This is offset by the addition of a top radiator.
The burden of anode and Grid.2 power dissipation is also far greater for the PL802: 9W vs. 3.4W (design maxima).
Reflected radiation from here can't simply be ignored.
Conclusion: the design-level of thermal dissipation within the anode radius increased from ca. 5.5W to 14W looking from EF184 to PL802. This naturally requires drastic redesign, considering the small size of anode structure in both.
The EF184 already required the thermal expedient of a mesh anode, so it is no surprise to find something more radical in the PL802.