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Are cooling fans recommended for tube equipment ?

kappclark

kappclark

AK Subscriber
Subscriber
I have a tube receiver in the original case, on top of a chest - nothing is above it... The tubes do get hot for sure ... I have a 12V computer case fan which I was thinking of connecting to help move air --- is this necessary ? I wonder if the tubes last longer ... I could hook it up to one of the switched outlets on the back of the unit..

comments ?
 
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I'm sure there's plenty of other opinions, 4what its worth, I use a Fan on my Citation 2 amp, known to Run hot. IMHO when they were built early 60's, Line voltages were lower
115-117 Volts. Now line Voltages are around 120-122 .If I use my Variac, Now shorted out, I just set it on 115 volts. Amp runs much cooler. And the tubes will also last longer as well.
So yes a fan would help.
 
Nyjblbob said:
I'm sure there's plenty of other opinions, 4what its worth, I use a Fan on my Citation 2 amp, known to Run hot. IMHO when they were built early 60's, Line voltages were lower
115-117 Volts. Now line Voltages are around 120-122 .If I use my Variac, Now shorted out, I just set it on 115 volts. Amp runs much cooler. And the tubes will also last longer as well.
So yes a fan would help.
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So a stock 1964 Fisher receiver will run hotter in 2020 because of higher line voltages ? Amazing --- I looked at the Fisher manual, and the power consumption specs are for 117 volts...

I wonder if there are special boxes available to give "vintage voltage" (115 V) .. I don't know how much a variac cost
 
Under 100$ used I would stay away from the Chi Com units go for at least a 5- to 7 amp unit
 
kappclark said:
So a stock 1964 Fisher receiver will run hotter in 2020 because of higher line voltages ? Amazing --- I looked at the Fisher manual, and the power consumption specs are for 117 volts...

I wonder if there are special boxes available to give "vintage voltage" (115 V) .. I don't know how much a variac cost
Click to expand...

If you have a transformer with a secondary of ~10V, you can use that to knock 125V down to 115V for example. DAGS for "bucking transformer"
 
WOW - the fun never ends --- the plans for the bucking transformer look straight enough ... before going ahead, would like to measure the line voltage over time --- is there a device that will do that ?? I was going to get a 'killawatt' device --- will that show variations in line voltage ?
 
I don't think so, although I have one, I haven't played with it in a long time... I don't believe it has a logging feature. I know some modern Flukes do, although I don't have one of those either...
 
kappclark said:
WOW - the fun never ends --- the plans for the bucking transformer look straight enough ... before going ahead, would like to measure the line voltage over time --- is there a device that will do that ?? I was going to get a 'killawatt' device --- will that show variations in line voltage ?
Click to expand...

Kill-A-Watt does not store/record min/max voltage.

Far as voltage, 125V would be on the high side of normal these days. Mine runs 121, give or take a volt. A transformer with ~6V secondary is about right on average.

If you have to buy a transformer to do it, the toroids from AnTek are pretty inexpensive. A 6V, 25VA toroid from them is $11. A 6V, 25VA transformer wired in a bucking configuration will handle approximately 460W load (or up to 4A current, if you prefer). If you really needed more, you could step up to a 6V, 50VA for $17.50 and would have double the capacity of the 25VA.
 
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So, the specs of the Fisher 400 are rated at 117 Volts, according to the user manual.....although this is below what is"normal" today, the modern level of 120V represents a little more than 2.5% above the original "rated' voltage ... is this really an issue ? Maybe a bigger issue if the spec'd voltage were 110 ...
 
whoaru99 said:
Kill-A-Watt does not store/record min/max voltage.

Far as voltage, 125V would be on the high side of normal these days. Mine runs 121, give or take a volt. A transformer with ~6V secondary is about right on average.

If you have to buy a transformer to do it, the toroids from AnTek are pretty inexpensive. A 6V, 25VA toroid from them is $11. A 6V, 25VA transformer wired in a bucking configuration will handle approximately 460W load (or up to 4A current, if you prefer). If you really needed more, you could step up to a 6V, 50VA for $17.50 and would have double the capacity of the 25VA.
Click to expand...

Depends on area. For a while I had a Monster power conditioner mostly for the amp sequencing, but I let it go because it drew an insane amount of current even in standby (like 5A!) Had a display on the front, and i don't think I ever saw it below 123. Usually on the high side of 125. Occasionally it would dip to 121 when the A/C started or something.
 
Did you update the parts in your 400? For instance, if you put in a full wave bridge rectifier in place of the selenium and installed a resistor, like Dave G. Recommends, then that will regulate voltages....

However I still use bucking transformers, overbuild mine, use 8-10 amp transformers to plug in multiple devices, always shoot for 112 -117 volts but 110 will suffice....

Where I live the power has a tendency to cycle on/off and tubes hate cycling power, so a safety plug that trips and stays off is another “must have” unless one doesn’t mind replacing tubes.....

VR
Andy
 
kappclark said:
So, the specs of the Fisher 400 are rated at 117 Volts, according to the user manual.....although this is below what is"normal" today, the modern level of 120V represents a little more than 2.5% above the original "rated' voltage ... is this really an issue ? Maybe a bigger issue if the spec'd voltage were 110 ...
Click to expand...

Depends on who you ask. Here on AK it's a big deal. If there was still a Fisher engineer around my guess is not a big deal would be the answer.
 
kappclark said:
I have a tube receiver in the original case, on top of a chest - nothing is above it... The tubes do get hot for sure ... I have a 12V computer case fan which I was thinking of connecting to help move air --- is this necessary ? I wonder if the tubes last longer ... I could hook it up to one of the switched outlets on the back of the unit..

comments ?
Click to expand...

I would only be concerned if it was in an enclosed space. Sitting on top of a dresser should not be a problem.
 
The OP Really just asked is a Fan a good Idea?
While I'm setting up my new old Variac, Using my Tube amp With a big old Room fan!
My amp stays just barely warm.Any one who has ever owned a Citation 2 Knows they get really hot at current voltages.
I'm sure the EI KT-90's will last a lot longer staying much cooler.
Someone in another thread had mentioned Military grade Tube Coolers they used in WW2 and in Korea. that proved this.
So yes A Fan Does Work,
 
adnick said:
Did you update the parts in your 400? For instance, if you put in a full wave bridge rectifier in place of the selenium and installed a resistor, like Dave G. Recommends, then that will regulate voltages....

However I still use bucking transformers, overbuild mine, use 8-10 amp transformers to plug in multiple devices, always shoot for 112 -117 volts but 110 will suffice....

Where I live the power has a tendency to cycle on/off and tubes hate cycling power, so a safety plug that trips and stays off is another “must have” unless one doesn’t mind replacing tubes.....

VR
Andy
Click to expand...
Have not 'updated' the parts ... thankfully, the unit has a silicon rectifier - I am planning to get a 'killawatt' and keep an informal eye on voltages ...
 
My el-cheapo solution -- a 12V computer case fan...moves quite a bit of air... will eventually connect it to the switched outlet on the 400 ...
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