See subject. I don’t get it. Speakers I can see.
The only advantage I cansee with the amp thing is they look boss.
the shielding of grills and enclosures can be useful and important.
he’s an audiophool.
When you are grilling, the sound of meat cooking will interfere with your music.
So, turn the grill off for maximum fidelity.
The front grill cloth won’t alter the sound at all. The guy who sold it to you sounds like hipster dip shit. Like posted above, it might save yourself spilling a beer or sticking something through a speaker when you put it back in trailer going to the next show.
I’m really asking only about the tube amp.
I just read somewhere that the external grill can cause resonance sometimes. I don’t know what that means.
Second question:
Does it keep the amp hotter or cooler? It’s in a tight fit already…
ETA: I am a music listener. It’s not a guitar amp, etc.
I think you need to experiment with it both ways, and report back. Of course, the music will sound better when you can clearly see how cool your amp looks, so you’ll have wear a blindfold.
The part about the resonance is believable. If it’s vibrating or buzzing on loud music, removing it would make sense.
you will read lots of stuff concerning audio everywhere. it’s a religious war.
it could keep things cooler. it could be engineered to get more cooling air past hot components because the air flow is ducted.
I, and I suspect some others here, thought you were referring to guitar amp with a speaker grill. Rereading the OP, I see you differentiated between the amp and speakers.
Now I’m thinking you’re talking about about an amp sans speaker, with a grill along the lines of this (shown installed and removed), this, or this. For this type of amp, I’m wondering how resonance could be a factor, since there’s no sound at the amp. Perhaps he means if the sound is turned up really loud in the room, it could make the grill vibrate, but I still question that said vibration will be picked up the circuitry in the amp.
I expect a slotted grill would retain some heat, but I also expect the engineers who designed it know that and don’t see it as a problem. Obviously the grill is there to prevent the tubes from getting hit by something (or some little critter), which certainly could be a problem. Seems to me there’s a tangible risk in removing the grill.
This is not my field of expertise, but I find the claim that you’ll get better sound with the grill removed to be highly dubious. I think you’re right to question it.
Resonance can be a severe problem. It often ends up in a feedback loop with major spillover steps. These can wreak havoc on your equipment and beyond. His advice was sound, though a bit roundabout. He was probably thinking that to get the grill off you’d use a crow bar, something very handy to have when working around resonance cascades.
It is probably audiophool silliness. However - and this can be important - tube amps are all microphonic to a greater or lesser degree. Vibrating the tube will vibrate the grids, and mechanical displacement of the grid wires will modulate the current through the tube. In guitar combo amps this can be a noticeable influence on sound - but here the tubes are hanging a few inches away from the speaker. However there is some suggestion that for audiophile tube amps the inherent microphonic nature of the tubes adds some of the “tube flavour” to the sound. A mechanically resonant grill attached to the amp chassis could conceivably affect the sound in a noticeable way. So whilst I suspect it is the usual rubbish, there could be a germ of truth.
Here are jpegs of the amp i have, from the company’s web site. Of course I should have done this from the first.
Look at how sexy I am as I strip to my tubes; take a look at my exposed backside; do I make you hot?(My wife has been teasing me today about the damn amp.)
Comments on approve replies:
Microphonic. Huh. That means the little suckers themselves are vibrating?
My living room is very small, and the speaker tweeter is horizontal with the amp less than a foot away.
I agree that the manufacturers factored in the thermal limits. But as I say, the box is placed into a barely acceptable cubby hole, and I can feel the heat quite clearly on the top of the enclosure. It is not ducted as far as I can tell.
(And no, I can’t organize my room any other way without moving into another apartment… 
)
And that last shot is bottomless, from below. Yowza.
Microphonic means that acoustic sounds from the room can enter the electric audio signal path. That can’t happen in transistors, but in tubes, the parts that work like a transistor are coils of wire, much like an incandescent light bulb filament, and other mechanically mounted parts. These can vibrate, and that can affect the properties of the tube, by an amount that varies at the frequency of the sound. That effect gets amplified, and can make an audio difference.
Sound waves coming from the room through the air aren’t going to be affected a lot by whether the cover is there or not, so removing the cover might not make much difference. If the cover is buzzing right near the tubes, though, that buzzing could make it into the electric audio path. Buzzing could be more annoying than just a (slightly delayed) copy of the music.
Looking at the close-ups with the cover off, there are raised bits where the cover attaches. Are those hard, or something soft like rubber? If they’re soft, that would probably damp out any cover buzzing, and it wouldn’t hurt to leave it on (thermal issues aside).
Oh yes. The grid wires are quite fine and will cheerfully vibrate. The 12AX7 is the worst offender - to get the gain up the grid wires are placed closer to the cathode. This closeness means the vibrations have a greater effect on the gain, and so modulate the signal. Good quality tubes have very good control of these tolerances, but there are limits, and audiophile tubes are not always “good quality” in the quantitative measures, but may be “good quality” in the aural sense, which can simply mean a particular combination of distortion and other effects that sound better. In the end, if you have bought in to tube amps it is all about the sound, don’t let anyone try to tell you that there is some inherent magic accuracy in tubes. Heck the specs of amp suggest 1%THD at full power (which is actually pretty good) but orders of magnitude worse than even basic modern designs. When you add in the significant frequency response anomalies inherent in attaching a reactive load to the output transformer, you are well into a sculpted sound. Lovely, but sculpted.
The internal pics of the amp look nice, very nicely made, and for the money pretty amazing.
Probably the most important aspect of the sound improving when you remove the grill is the lovely warm glow from that quad of EL43s. Turn down the lights and enjoy.