Turning the tubes upside down will cause all the electrons to fall out. You'll have a real mess on the floor. You'll have to get out your molecular tweezers to get some of those electrons out of the carpet.
As for the real answer, it seems to be no problem. I've got and amp in-house using 6550 outputs upside down and had zero problems with tube life. Haven't done it with a PCL86, but that's got a structure which looks symmetric. The one caution would be to ensure that air flow around the tube is not impeded by the chassis- warmed air rises.
As for the real answer, it seems to be no problem. I've got and amp in-house using 6550 outputs upside down and had zero problems with tube life. Haven't done it with a PCL86, but that's got a structure which looks symmetric. The one caution would be to ensure that air flow around the tube is not impeded by the chassis- warmed air rises.
Hi,
............And used retainer clips to keep'em seated.
IMHO, it not such a great idea to have tubes mounted tip facing downwards.
Unless there's no other way I just wouldn't do it. It's just plain asking for trouble.
Current production sockets are nowhere near as tight a fit as they should be for this kind of operation, especially not those dreaded Chinese clo(w)nes...
Besides, how are you going to replace them? By dismantling half of the amp while you could have just pulled them out from atop?
Cheers,
............And used retainer clips to keep'em seated.
IMHO, it not such a great idea to have tubes mounted tip facing downwards.
Unless there's no other way I just wouldn't do it. It's just plain asking for trouble.
Current production sockets are nowhere near as tight a fit as they should be for this kind of operation, especially not those dreaded Chinese clo(w)nes...
Besides, how are you going to replace them? By dismantling half of the amp while you could have just pulled them out from atop?
Cheers,
Speaking of those tube amps like Fenders, etc. that all mounted the tubes hanging downwards, I think this is an especially bad idea because heat naturally rises and this bakes the snot out of the chassis components, or in the case of newer amps bakes the circuit boards causing heat related failures also in solder connections and traces.
One case where mounting the tubes upside down is in tube amps manufactured in China and exported to North America. Once on our shores the tubes are all right side up!
Some directly heated tubes including the 5U4, 5Y3 type rectifiers as well as power triodes must be mounted either vertically, or with special attention given to pin orientation if Horizontal so that filament sag will not cause an internal short. If a tube can be mounted sideways, or upside down the good tube manuals say so, and say how.
The english language is weird. "Upside down" could be interpreted to mean that there is an upside to mounting it pointing down no?
One case where mounting the tubes upside down is in tube amps manufactured in China and exported to North America. Once on our shores the tubes are all right side up!
Some directly heated tubes including the 5U4, 5Y3 type rectifiers as well as power triodes must be mounted either vertically, or with special attention given to pin orientation if Horizontal so that filament sag will not cause an internal short. If a tube can be mounted sideways, or upside down the good tube manuals say so, and say how.
The english language is weird. "Upside down" could be interpreted to mean that there is an upside to mounting it pointing down no?
Tube pins
I think RCA alluded to heat rising, solder connections etc. Another sinister problem is the heat around the tube base, the pins.
Heat is transferred through these pins, especially the filament pins. I prefer to keep the tube upright so the cool air surrounds the tube socket, helping to cool the socket and therefore pins.
Otherwise, harder to keep the tube pins cool.
Hope this helps.
Steve
I think RCA alluded to heat rising, solder connections etc. Another sinister problem is the heat around the tube base, the pins.
Heat is transferred through these pins, especially the filament pins. I prefer to keep the tube upright so the cool air surrounds the tube socket, helping to cool the socket and therefore pins.
Otherwise, harder to keep the tube pins cool.
Hope this helps.
Steve
the only reason a lot of guitar amps use their tubes upside down is because its easier and cheaper to make the chassis,and keep all the controls at the top of the amp, eg, messa boogies, marshalls etc,[i have them in for repair all the time] it is not a paticularly good idea to run any output tube upside down, some of the more serious reasons being, they cook the tube bases and cause hairline fractures,which lead to high voltage shorting, as other people have allready stated, they cook the hell out of the components on the top of the chassis,especially the power supply electrolytics. in some circumstances,in the case of octal based valves, eg, EL34, 6L6, KT88 6550, etc, i have known the solder to melt on the tubes bases!!!also, if they use printed circuit boards, [as most of the new amps do] the heat warps the printed circuit boards, again leading to cracks, and track failier. there are more reasons but i think you get the picture by now,if you want convenience, then go ahead,but if you want long term reliability, put some thought into the design, and do it right.
Hi to all ,
take a look at the german studioamps like V 72 , V 73 , V 76 , V 81 and so on . The tubes in this legendary amps are mounted horizontal and upside down in extremly small cases and they worked for years and years without problems .
Many of my amps are older than 50 years and I only changed the electrolytics in the power supplies .
Regards , AlexK.
take a look at the german studioamps like V 72 , V 73 , V 76 , V 81 and so on . The tubes in this legendary amps are mounted horizontal and upside down in extremly small cases and they worked for years and years without problems .
Many of my amps are older than 50 years and I only changed the electrolytics in the power supplies .
Regards , AlexK.
Hi,
O.K...but those are mic preamps running at low currents and mostly horizontally mounted tubes, alligned in such a way as to avoid microphony at all cost.
All little engineering masterpieces, I must add.
The PCL86 however is a little powerhouse that's good for about 12W of plate dissipation alone....
Besides, what's to be gained in the case of upside down mounted powertubes for domestic use?
Cheers,
O.K...but those are mic preamps running at low currents and mostly horizontally mounted tubes, alligned in such a way as to avoid microphony at all cost.
All little engineering masterpieces, I must add.
The PCL86 however is a little powerhouse that's good for about 12W of plate dissipation alone....
Besides, what's to be gained in the case of upside down mounted powertubes for domestic use?
Cheers,
Hi Frank ,
you are right , most of this amps are mic preamps , but the V 73 is a 4 watt PP - amp with two EF 804 s and two EL 42 and the V 81 is 10 watt PP with E88 CC , two 5654 and two E 84 L . OK , they are mounted horizontal but believe me , this little power - amps runs very hot and the racks with further amps were above and below . I would have no problem , if a 50 cent tube ( PCL 86 ) failed after a few years ;-)
My Valvo and TFK handbooks says for this small tubes , including E 84 L : "Mounting position any" .
But it says also : "Special precautions must be taken to prevent the tube from becoming dislodged".
Regards , AlexK .
you are right , most of this amps are mic preamps , but the V 73 is a 4 watt PP - amp with two EF 804 s and two EL 42 and the V 81 is 10 watt PP with E88 CC , two 5654 and two E 84 L . OK , they are mounted horizontal but believe me , this little power - amps runs very hot and the racks with further amps were above and below . I would have no problem , if a 50 cent tube ( PCL 86 ) failed after a few years ;-)
My Valvo and TFK handbooks says for this small tubes , including E 84 L : "Mounting position any" .
But it says also : "Special precautions must be taken to prevent the tube from becoming dislodged".
Regards , AlexK .
li_gangyi said:
Yes, you are. Mercury vapour rectifiers have strict instructions about their operating orientation, warm-up time before applying anode voltage, and ambient temperature.
Regarding Octal sockets, there's not much point in spending lots of money on beautifully low leakage sockets when the valve that will be plugged into them comes complete with a leaky phenolic base. A cheap ceramic base will do just fine.
ok guys, now i have come to some conclusions, rectifier tubes and power tubes standing up-right will live longest and will not detoriate other components as PSU capacitors and others as they would if mounted up-side-down, but that assumes that the psu caps are placed nearby, which they aren't in my particular amp. (separate psu)
lowlevel tubes mounting is of less importance if they does not exceed...say 4W..
..then i will mount my tubes sideways instead
lowlevel tubes mounting is of less importance if they does not exceed...say 4W..
..then i will mount my tubes sideways instead
Hi,
Not so weird, really....
That must be their "export" version for all those guitarplaying customers from "Down Under"...
Kidding aside, Groove Tubes caters mainly to guitarshops and repairshops and those tubes with the "upside down" logo are probably intended to go in those Fender (?) amps that have their tubes heads down.
Probably the Russian ones. They can be recognized by a cube-like logo on the side rim of the octal sockets.
Reinhofer in Germany has connections with a plant in China where they can make just about any type of socket and topcap to order.
From what I've seen so far quality is on a par with NOS Johnson sockets, which are reputedly among the best ever as far sockets for powertubes go.
Of course there's also the lunatic fringe Yamamoto sockets for those with deep pockets and an inclination to empty them in a hurry...
Cheers,
Not so weird, really....
That must be their "export" version for all those guitarplaying customers from "Down Under"...
Kidding aside, Groove Tubes caters mainly to guitarshops and repairshops and those tubes with the "upside down" logo are probably intended to go in those Fender (?) amps that have their tubes heads down.
Probably the Russian ones. They can be recognized by a cube-like logo on the side rim of the octal sockets.
Reinhofer in Germany has connections with a plant in China where they can make just about any type of socket and topcap to order.
From what I've seen so far quality is on a par with NOS Johnson sockets, which are reputedly among the best ever as far sockets for powertubes go.
Of course there's also the lunatic fringe Yamamoto sockets for those with deep pockets and an inclination to empty them in a hurry...
Cheers,
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