So, a recent idea has resurfaced in my mind, and that is how best would one go about mounting tubes to a chassis that will be used in an automotive environment, given the technology available today? Years ago I built a four channel EL84 AB1 design, and used guitar type sockets with spring-retainers that go over the top of the glass of the tube. This setup saw mostly smooth road use, and lasted over a year without issues, but was not given all that much attention to the idea as a whole. I was young and dumb ![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
For practical purposes, lets assume that the amplifier design is able to provide sufficient SPL in the chosen automobile environment, is matched to efficient enough speakers, and has a stable, sufficient power supply. Lets say that it has safeguards built in to protect against loose tubes and/or physical damages. Power range, lets say 10-20 watts, just to give an idea of form factor, nine-pin or octal (or loktal?) tube types, for ease of maintenance.
I don't want to go off-topic into the "tubes don't go in a car, forget it" discussion, I just want to know how you would physically mount everything.
Part of me thinks that going smaller (physically) on tube selection is best, and using rubber grommets or vibration-dampening studs would be best. Something like using Russian surplus "EV" tube types as much as possible, and mounting them vertical may be the best bet, as you would have less mass flailing around during hard bumps (potholes, for instance, or large speed humps/bumps) but I'm not sure if supporting the tube at the opposite end of the socket would be a good idea. FWIW, I think small 6V6 or 6AV5GA sized octals may be a good size, and are pretty stable in good sockets.
Looking at history, we see a good bit of octal and loktal tubes used in portable equipment for the military, in both aerial and ground based vehicles, and these seem to be supporting the tube at the sockets, with no additional regard to the rest of the tube's envelope. The guitar guys and MI use situations often have retainers on their nine pin tubes, that have spring loaded mounts to retain them too their base somewhat, but these aren't meant for active use while in motion.
Any suggestions?
For practical purposes, lets assume that the amplifier design is able to provide sufficient SPL in the chosen automobile environment, is matched to efficient enough speakers, and has a stable, sufficient power supply. Lets say that it has safeguards built in to protect against loose tubes and/or physical damages. Power range, lets say 10-20 watts, just to give an idea of form factor, nine-pin or octal (or loktal?) tube types, for ease of maintenance.
I don't want to go off-topic into the "tubes don't go in a car, forget it" discussion, I just want to know how you would physically mount everything.
Part of me thinks that going smaller (physically) on tube selection is best, and using rubber grommets or vibration-dampening studs would be best. Something like using Russian surplus "EV" tube types as much as possible, and mounting them vertical may be the best bet, as you would have less mass flailing around during hard bumps (potholes, for instance, or large speed humps/bumps) but I'm not sure if supporting the tube at the opposite end of the socket would be a good idea. FWIW, I think small 6V6 or 6AV5GA sized octals may be a good size, and are pretty stable in good sockets.
Looking at history, we see a good bit of octal and loktal tubes used in portable equipment for the military, in both aerial and ground based vehicles, and these seem to be supporting the tube at the sockets, with no additional regard to the rest of the tube's envelope. The guitar guys and MI use situations often have retainers on their nine pin tubes, that have spring loaded mounts to retain them too their base somewhat, but these aren't meant for active use while in motion.
Any suggestions?
So, a recent idea has resurfaced in my mind, and that is how best would one go about mounting tubes to a chassis that will be used in an automotive environment, given the technology available today?
Monroe Mini-Matics?
Use EAR Elastomer vibration absorbing grommets on sockets and the top plate as a whole.
Standard Grommets | E-A-R Aearo Technologies LLC
In addition I’d use a healthy amount of damping sheets underneath the chassis.
Noico is a brand I’ve used. There’s many others.
Amazon.com: Noico 80 mil 36 sqft car Sound deadening mat, butyl automotive Sound Deadener, audio Noise Insulation and dampening: Automotive
Look at the car forums and see how they address rattling from subwoofers.
If not damping sheets explore spring systems.
Vibration Isolator,Spring,80 to 113 lb. MASON 5C142 - Newegg.com
There were record players in cars which I imagine would be much more precarious. Explore how they addressed those issues. Here’s a throwback from consumer reports:
Car Record Players of the 1950s and 1960s | Early Infotainment Systems- Consumer Reports News
Standard Grommets | E-A-R Aearo Technologies LLC
In addition I’d use a healthy amount of damping sheets underneath the chassis.
Noico is a brand I’ve used. There’s many others.
Amazon.com: Noico 80 mil 36 sqft car Sound deadening mat, butyl automotive Sound Deadener, audio Noise Insulation and dampening: Automotive
Look at the car forums and see how they address rattling from subwoofers.
If not damping sheets explore spring systems.
Vibration Isolator,Spring,80 to 113 lb. MASON 5C142 - Newegg.com
There were record players in cars which I imagine would be much more precarious. Explore how they addressed those issues. Here’s a throwback from consumer reports:
Car Record Players of the 1950s and 1960s | Early Infotainment Systems- Consumer Reports News
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I don't think it is a problem. You can spend far more time fooling with grommets and braces than it is worth. Car radio tubes did not die all THAT often, even minis in hard-mounted chassis. IMHO, Loctals are more pain than they are worth, in any vehicle I would drive for pleasure. (Yes, going to die for my country in a Jeep or a P-38 is different; however a B-17 is a very smooth ride until the shooting starts.)
As others have said: small tubes will typically be seated in quite ordinary sockets, maybe EL84 will need spring loaded fasterers.
But do take care of cooling issues, make sure ventilation is adequate, add a temperature controlled fan and an independent shut-down on overtemperature.
But do take care of cooling issues, make sure ventilation is adequate, add a temperature controlled fan and an independent shut-down on overtemperature.
How rugged do you want?
You can ( or could ) get seven and nine pin sockets with a matching spring loaded shroud, that fit over the tube, and bayonet lock to the base. Those tubes aren't coming out by accident.
Some ( IERC ?) have contact material inside the shroud that will sink heat from the tube to the shroud, and the tube will run cooler than it would in free air.
Bigger tubes like octals would have a piece of all thread beside the tube, and a plate that would fasten down against the tube to hold it in place.
There are ruggedized tubes for rough service applications, and tubes that have consistent heater / cathode output over the large voltage swings you would see in the vehicle charging systems of the tube era. These types are scarce nowadays.
You can ( or could ) get seven and nine pin sockets with a matching spring loaded shroud, that fit over the tube, and bayonet lock to the base. Those tubes aren't coming out by accident.
Some ( IERC ?) have contact material inside the shroud that will sink heat from the tube to the shroud, and the tube will run cooler than it would in free air.
Bigger tubes like octals would have a piece of all thread beside the tube, and a plate that would fasten down against the tube to hold it in place.
There are ruggedized tubes for rough service applications, and tubes that have consistent heater / cathode output over the large voltage swings you would see in the vehicle charging systems of the tube era. These types are scarce nowadays.
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I think you had it right the first time you did it. I've repaired old tube car radios, and have never noticed anything extreme regarding tube mounting arrangements. Some good spring clip retainers for the power output tubes, and then putting the small tubes in shields, would be the way to go. That and use good sockets, don't cheap out and use cheap China sockets which will get loose over time.
Even cooler- Milbert BaM230/235 from the 80's.
I didn't realize they were still active. Milbert, the Most Musical Amplifiers
I didn't realize they were still active. Milbert, the Most Musical Amplifiers
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I had no problem with 1625s push-pull in a 1980 Honda Civic. I used them because they have 12 volt heaters and were selling for $4.50 each from Antique Electronics.
1625s were used in WW2 radio transmitters in fighter planes. I think they will do OK in a car.
I pulled them out after about a year and a half when the car died and the tubes still matched well.
1625s were used in WW2 radio transmitters in fighter planes. I think they will do OK in a car.
I pulled them out after about a year and a half when the car died and the tubes still matched well.
rfbrw, how much power on that amp?.
2 x 13W.
I can tell you what the military did back in the Tube Era (as I was an AT-3 in the NAVY doing intermediate level maintenance in 1973), they shock mounted the equipment, not the tubes.
Isolate your chassis.
Use it's mass to your advantage.
Laws of physics are the same now as then.
Isolate your chassis.
Use it's mass to your advantage.
Laws of physics are the same now as then.
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That and use good sockets, don't cheap out and use cheap China sockets which will get loose over time.
I’m unaware of any new sockets NOT manufactured in China, besides maybe Belton which I think is Eastern Europe?
Can you enlighten me?
I’m unaware of any new sockets NOT manufactured in China, besides maybe Belton which I think is Eastern Europe?
Can you enlighten me?
Belton is Korea, they're pretty good. I'm not an expert by any means, usually I try and find old stock Amphenol or Cinch, if I am building something for myself. I haven't had good luck with the Chinese ceramic sockets
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