Stratman
Guitaris Maximus
Re: Upside down tubes?
yes, but I have given up trying to teach proper English for the UK folks!
yes, but I have given up trying to teach proper English for the UK folks!
Upside down tubes?
- Thread starter Hank Grizzly
- Start date
Hank Grizzly
New member
Re: Upside down tubes?
Yeah, damn us and our language (Essex lad!)
So the general consensus is that it makes no difference to sound, and heat is probably dissipated better with the valve/tubes socket at the bottom?
Also, what was meant the Australian sound? The only Australian music I have really heard is the Easybeats, who sound damn fine. (and ACDC but not such a fan)
Yeah, damn us and our language (Essex lad!)
So the general consensus is that it makes no difference to sound, and heat is probably dissipated better with the valve/tubes socket at the bottom?
Also, what was meant the Australian sound? The only Australian music I have really heard is the Easybeats, who sound damn fine. (and ACDC but not such a fan)
Hank Grizzly
New member
Re: Upside down tubes?
Just got it... Man do I feel stupid. Too much Special Brew.
Just got it... Man do I feel stupid. Too much Special Brew.
The JEM Ghost
New member
Re: Upside down tubes?
Ah, don't worry Hank mate!!
The story you heard is (in British language ;-) plain bollocks!
Most of the tubes you find hanging upside down are in combo-amps, the reason for that is space management, and said even more, combo tube amps are more prone to feedback because the tubes are always near an operating speaker, and therefor also near a lot of vibrations, which is something tubes tend to rather not like.
Rather then that, it does not matter at all how your tubes are mounted.
Don't feel stupid mate, no need to in my opinion!!
You just asked a question, and learned something with it, so nothing stupid about it! ;-)
PS: I bet you've heard more "Aussie" music mate:
- INXS (R.I.P. M.Hutchence)
- Kylie Minogue
- Nick Cave
- The Bee Gees (bloody hell ;-)
- Midnight Oil
- And not as known, but a very gifted guitar player named Frank Gambale.
Ah, don't worry Hank mate!!
The story you heard is (in British language ;-) plain bollocks!
Most of the tubes you find hanging upside down are in combo-amps, the reason for that is space management, and said even more, combo tube amps are more prone to feedback because the tubes are always near an operating speaker, and therefor also near a lot of vibrations, which is something tubes tend to rather not like.
Rather then that, it does not matter at all how your tubes are mounted.
Don't feel stupid mate, no need to in my opinion!!
You just asked a question, and learned something with it, so nothing stupid about it! ;-)
PS: I bet you've heard more "Aussie" music mate:
- INXS (R.I.P. M.Hutchence)
- Kylie Minogue
- Nick Cave
- The Bee Gees (bloody hell ;-)
- Midnight Oil
- And not as known, but a very gifted guitar player named Frank Gambale.
Jeff Seal
New member
Re: Upside down tubes?
Umm... I really hate to tell you this, but yes it does make a difference, but not for the reasons you may think when it comes to older designs.
1. Tubes do not respond any differently regardless of being vertical/horizontal or any polar positioning.
2. DO understand heat rises and the older amps used carbon resistors which are VERY susceptible to variances with temperature changes. Since most older Fender's had the Plate and Grid resistors soldered to the tube sockets, they rarely operated at their given value under operating conditions and became even less within their specs the harder the amp was pushed. (thus spongy)
3. Unless the amp design uses Carbon composite resistors, there's no point in even worrying about where the tubes face. But I can tell you Matchless, /13 and several others only use Carbon composite resistors, as do I in my amp designs while the RI's from every company (Marshall, Fender, Vox) all use metal film resistors which is why they sound nothing like the originals.
Just fwiw
Jeff
Umm... I really hate to tell you this, but yes it does make a difference, but not for the reasons you may think when it comes to older designs.
1. Tubes do not respond any differently regardless of being vertical/horizontal or any polar positioning.
2. DO understand heat rises and the older amps used carbon resistors which are VERY susceptible to variances with temperature changes. Since most older Fender's had the Plate and Grid resistors soldered to the tube sockets, they rarely operated at their given value under operating conditions and became even less within their specs the harder the amp was pushed. (thus spongy)
3. Unless the amp design uses Carbon composite resistors, there's no point in even worrying about where the tubes face. But I can tell you Matchless, /13 and several others only use Carbon composite resistors, as do I in my amp designs while the RI's from every company (Marshall, Fender, Vox) all use metal film resistors which is why they sound nothing like the originals.
Just fwiw
Jeff
Chickenwings
Alnico 6/8
Re: Upside down tubes?
upside down is just so the amps chassis is at the top of the combo or head cabinet. upside down tubes can sometimes damage the circuit and the sockets so its better if they are up like in a regular marshall head for heat dissipation. Apart from that id have to say...whatever....
upside down is just so the amps chassis is at the top of the combo or head cabinet. upside down tubes can sometimes damage the circuit and the sockets so its better if they are up like in a regular marshall head for heat dissipation. Apart from that id have to say...whatever....
Fresh_Start
New member
Re: Upside down tubes?
That's short & to the point.
All other things being equal, it is better to have the tubes pointing up (socket at bottom) for heat management reasons. Also, it's harder on the gas seal of the tube (power tubes only) to be upside down and have the base get really hot. Doesn't help everything else inside the chassis to get cooked by the tubes either.
If you look at tube spec sheets, some have limitations on how they can be mounted. Most are fine vertically, either end up. Some can be mounted sideways - like 12AX7s - without any problem. Their insides are small, light and don't get terribly hot. Even so, 12AX7s need to be rotated to the right orientation if mounted sideways.
Jeff - with all due respect, planning on cooking carbon comp resistors at the tube socket seems like asking for trouble instead of mojo but you obviously like the end result. I'd rather have those resistors - especially the screen grid resistors - maintain a constant value over time. They're there to protect the screens and that's a good thing IMHO.
OTOH screen grid resistors have high voltage across them and large current fluctuations - exactly the conditions where carbon comps do have variable resistance and appear to add something special to tone & touch response. Good place in the circuit for carbon comps, I just wouldn't deliberately place them where they're going to get really hot too.
Cheers,
Chip
That's short & to the point.
All other things being equal, it is better to have the tubes pointing up (socket at bottom) for heat management reasons. Also, it's harder on the gas seal of the tube (power tubes only) to be upside down and have the base get really hot. Doesn't help everything else inside the chassis to get cooked by the tubes either.
If you look at tube spec sheets, some have limitations on how they can be mounted. Most are fine vertically, either end up. Some can be mounted sideways - like 12AX7s - without any problem. Their insides are small, light and don't get terribly hot. Even so, 12AX7s need to be rotated to the right orientation if mounted sideways.
Jeff - with all due respect, planning on cooking carbon comp resistors at the tube socket seems like asking for trouble instead of mojo but you obviously like the end result. I'd rather have those resistors - especially the screen grid resistors - maintain a constant value over time. They're there to protect the screens and that's a good thing IMHO.
OTOH screen grid resistors have high voltage across them and large current fluctuations - exactly the conditions where carbon comps do have variable resistance and appear to add something special to tone & touch response. Good place in the circuit for carbon comps, I just wouldn't deliberately place them where they're going to get really hot too.
Cheers,
Chip
L
Lewguitar
Guest
Re: Upside down tubes?
It's a matter of convenience: we want our amp chassis at the top of our amp's cabinet so we can adjust the control knobs more easily. We don't want to get down on your hands and knees every time we want to adjust the volume or tone. Plus it's easier to see the settings if they're at the top of a combo amp rather than down on the floor.
And it's also because if you had your chassis in the bottom of your amp you'd still throw your extra cables and maybe an effects pedal or two in the back of your amp and you'd break the tubes.
It is better to have the tubes and chassis in the bottom though because of heat. And so when Marshall amps were built as a head only they did it right and put the chassis in the bottom of the cabinet. But the back is sealed with a cover so you can't throw to much stuff in it and break the tubes.
Fender didn't go that route. They just used the same chassis they had in their combo amps and let the tubes hang upside down. Cheaper.
It's a matter of convenience: we want our amp chassis at the top of our amp's cabinet so we can adjust the control knobs more easily. We don't want to get down on your hands and knees every time we want to adjust the volume or tone. Plus it's easier to see the settings if they're at the top of a combo amp rather than down on the floor.
And it's also because if you had your chassis in the bottom of your amp you'd still throw your extra cables and maybe an effects pedal or two in the back of your amp and you'd break the tubes.
It is better to have the tubes and chassis in the bottom though because of heat. And so when Marshall amps were built as a head only they did it right and put the chassis in the bottom of the cabinet. But the back is sealed with a cover so you can't throw to much stuff in it and break the tubes.
Fender didn't go that route. They just used the same chassis they had in their combo amps and let the tubes hang upside down. Cheaper.
