Hey there esteemed members, seems like I’m on a run with questions lately. I need to replace the 25k section of the dual value 20watt “standee” resistor in this amplifier from a Seeburg V200. My question: is each section 20watts or is it 10watts per section, for a total of 20watts? Reason I ask is that I have, on hand, 2- 5w resistors I can put in series and I’d be done but if I need a 20 watt then I have start hunting one down. Parts list/manual doesn’t help here. Thanks, Mauro
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On 2024-11-18 2:36 p.m., M De Simone via Jukebox-list wrote:
Hey there esteemed members, seems like I’m on a run with questions lately. I need to replace the 25k section of the dual value 20watt “standee” resistor in this amplifier from a Seeburg V200. My question: is each section 20watts or is it 10watts per section, for a total of 20watts? Reason I ask is that I have, on hand, 2- 5w resistors I can put in series and I’d be done but if I need a 20 watt then I have start hunting one down. Parts list/manual doesn’t help here. Thanks, Mauro
Hi Mauro,
Two 5-Ohm 5Watt resistors in series equals 10-ohms @ 5 Watts. The resistance adds in series & divides when parallel, the wattage only adds when parallel.
You need a 25K @ 20W resistor. Nothing wrong with going to 25W!
John :-#)#
On 11/18/24 16:32, John Robertson via Jukebox-list wrote:
Two 5-Ohm 5Watt resistors in series equals 10-ohms @ 5 Watts. The resistance adds in series & divides when parallel, the wattage only adds when parallel.
If they're of equal value, the wattage is additive in both series or parallel.
It gets messy when they're of unequal value, higher resistance consumes more power in series, lower resistance consumes more in parallel, but you can't just add up the wattages with unequal values.
Two 5-ohm 5-watt resistors in series = 10 ohms at 10 watts.
Two 5-ohm 5-watt resistors in parallel = 2.5 ohms at 10 watts.
On 2024-11-18 4:58 p.m., Jay Hennigan via Jukebox-list wrote:
On 11/18/24 16:32, John Robertson via Jukebox-list wrote:
Two 5-Ohm 5Watt resistors in series equals 10-ohms @ 5 Watts. The resistance adds in series & divides when parallel, the wattage only adds when parallel.
If they're of equal value, the wattage is additive in both series or parallel.
Dang, you are correct. "A string of N identical resistors in series each rated for P watts can dissipate $NP$ watts."
electronics.stackexchange.com
Wattage calculation for resistors in series <#>
I need the formula for calculating resistor wattage when the resistors are in series. For example, say I have 3 1/4 watt 10 ohm resistors in series. What is the potential power dissipation for the
🔗 https://electronics.stackexchange.com/questions/28309/wattage-calculation-fo... https://electronics.stackexchange.com/questions/28309/wattage-calculation-for-resistors-in-series
How quickly we forget our wattage laws...
Going back under my rock...
John :-#(#
It gets messy when they're of unequal value, higher resistance consumes more power in series, lower resistance consumes more in parallel, but you can't just add up the wattages with unequal values.
Two 5-ohm 5-watt resistors in series = 10 ohms at 10 watts.
Two 5-ohm 5-watt resistors in parallel = 2.5 ohms at 10 watts.
On 11/18/24 14:36, M De Simone via Jukebox-list wrote:
Hey there esteemed members, seems like I’m on a run with questions lately. I need to replace the 25k section of the dual value 20watt “standee” resistor in this amplifier from a Seeburg V200. My question: is each section 20watts or is it 10watts per section, for a total of 20watts?
The 25K section is between the 315 volt line and ground. P=E^2/R so in normal operation that section dissipates 3.969 watts. The 2500 ohm section drops 85 volts so it dissipates 2.89 watts in normal operation.
Your two 5W resistors in parallel should be just fine.
On 11/18/24 16:45, Jay Hennigan via Jukebox-list wrote:
On 11/18/24 14:36, M De Simone via Jukebox-list wrote:
Hey there esteemed members, seems like I’m on a run with questions lately. I need to replace the 25k section of the dual value 20watt “standee” resistor in this amplifier from a Seeburg V200. My question: is each section 20watts or is it 10watts per section, for a total of 20watts?
The 25K section is between the 315 volt line and ground. P=E^2/R so in normal operation that section dissipates 3.969 watts. The 2500 ohm section drops 85 volts so it dissipates 2.89 watts in normal operation.
Your two 5W resistors in parallel should be just fine.
I see you said in series, rather than parallel. Assuming that they're close in value like two 12K resistors, you'll still be fine. If they're not close in value, the higher resistance one will consume more power. If in parallel, the lower resistance one will consume more power.
Power resistors tend to run hot. Don't be surprised if they're hot to the touch even at roughly 4 watts total dissipation.
Hi John and Jay, I actually have 15K and 10K 5watt resistors I was going to use in series. After reading the replies I think this would be ok but I’d rather err on the side of caution and make a trip to my local electronic supply and get the “more correct” 25K at 10W resistor. Thanks for the replies, I always appreciate it when I learn something new! Mauro
Sent from my iPhone
On Nov 18, 2024, at 7:52 PM, Jay Hennigan via Jukebox-list jukebox-list@lists.netlojix.com wrote:
On 11/18/24 16:45, Jay Hennigan via Jukebox-list wrote:
On 11/18/24 14:36, M De Simone via Jukebox-list wrote: Hey there esteemed members, seems like I’m on a run with questions lately. I need to replace the 25k section of the dual value 20watt “standee” resistor in this amplifier from a Seeburg V200. My question: is each section 20watts or is it 10watts per section, for a total of 20watts?
The 25K section is between the 315 volt line and ground. P=E^2/R so in normal operation that section dissipates 3.969 watts. The 2500 ohm section drops 85 volts so it dissipates 2.89 watts in normal operation. Your two 5W resistors in parallel should be just fine.
I see you said in series, rather than parallel. Assuming that they're close in value like two 12K resistors, you'll still be fine. If they're not close in value, the higher resistance one will consume more power. If in parallel, the lower resistance one will consume more power.
Power resistors tend to run hot. Don't be surprised if they're hot to the touch even at roughly 4 watts total dissipation.
-- Jay Hennigan - jay@west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV
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On 11/18/24 17:14, M De Simone via Jukebox-list wrote:
Hi John and Jay, I actually have 15K and 10K 5watt resistors I was going to use in series.
Your 10K resistor will dissipate 1.59 watts. Your 15K resistor will dissipate 2.38 watts.
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