Behringer ep2500/4000 fan positioning

[Peppe007]

guys i finally got my behringer ep2500. i immediately disassembled it and cleaned it from the dust. i inverted the fan so that the air is expelled from the back and then enters from the front. did i do something right or do i have to reset everything to default? that is, that the air is sucked in from the back and exits from the front?

 

[sergeauckland]

I can think of a few reasons for the air to be taken from the back. Firstly, as the equipment will normally be in a rack, it's likely the inside of the rack will have less dust than the front.
Secondly, in a permanent installation, the racks could be actively cooled, so the air at the back will be cooler than at the front.
Thirdly, the air path (baffles, etc) through the equipment will be designed for the fan blowing one way. You could reduce the effectiveness if the cooling by reversing the airflow.

Having said that, drawing the air from the front allows for a front mounted filter, which us likely to get more attention than one at the back.

I would put the fan back to blow as intended.

S

 

[Peppe007]

Mi vengono in mente alcune ragioni per cui l'aria dovrebbe essere presa dal retro. Innanzitutto, poiché l'attrezzatura sarà normalmente in un rack, è probabile che l'interno del rack abbia meno polvere rispetto alla parte anteriore.
In secondo luogo, in un'installazione permanente, i rack potrebbero essere raffreddati attivamente, quindi l'aria nella parte posteriore sarà più fredda di quella nella parte anteriore.
In terzo luogo, il percorso dell'aria (deflettori, ecc.) attraverso l'apparecchiatura sarà progettato per la ventola che soffia in una direzione. È possibile ridurre l'efficacia del raffreddamento invertendo il flusso d'aria.

Detto questo, aspirare l'aria dalla parte anteriore consente di montare un filtro anteriore, che probabilmente riceverà più attenzione rispetto a uno posteriore.

Rimetterei il ventilatore in funzione come previsto.

S

Ok all right. I’ll do it now

 

[Peppe007]

I can think of a few reasons for the air to be taken from the back. Firstly, as the equipment will normally be in a rack, it's likely the inside of the rack will have less dust than the front.
Secondly, in a permanent installation, the racks could be actively cooled, so the air at the back will be cooler than at the front.
Thirdly, the air path (baffles, etc) through the equipment will be designed for the fan blowing one way. You could reduce the effectiveness if the cooling by reversing the airflow.

Having said that, drawing the air from the front allows for a front mounted filter, which us likely to get more attention than one at the back.

I would put the fan back to blow as intended.

S

I also wanted to tell you that during the disassembly I tightened the main bolt that holds the toroidal transformer, I tightened it because it was almost completely unscrewed. Do you think I should have put some threadlocker (glue on the thread) on the bolt?

 

[sergeauckland]

I also wanted to tell you that during the disassembly I tightened the main bolt that holds the toroidal transformer, I tightened it because it was almost completely unscrewed. Do you think I should have put some threadlocker (glue on the thread) on the bolt?

That's a good idea. The only comment I can make is that toroidal transformers usually have a rubber washer under them, and one on the top under the top metal washer to isolate the transformer windings from the cabinet metalwork. These washers also protect the windings against rubbing, so usually, the main bolt is only done up finger-tight, just enough to stop the transformer moving. If you have tightened it too much, I would undo it until the transformer is held, but not crushed, with some thread locker to stop it coming undone.

S.

 

[Peppe007]

That's a good idea. The only comment I can make is that toroidal transformers usually have a rubber washer under them, and one on the top under the top metal washer to isolate the transformer windings from the cabinet metalwork. These washers also protect the windings against rubbing, so usually, the main bolt is only done up finger-tight, just enough to stop the transformer moving. If you have tightened it too much, I would undo it until the transformer is held, but not crushed, with some thread locker to stop it coming undone.

S.

what happens if i tightened the bolt too much? i don't remember how hard i tightened it right now... i just remember that the bolt was loosened too much and the transformer was moving too much

 

[sergeauckland]

what happens if i tightened the bolt too much? i don't remember how hard i tightened it right now... i just remember that the bolt was loosened too much and the transformer was moving too much

Probably nothing, but theoretically, you could crush the transformer windings, and possibly damage them. It depends how hard is hard. I've found if I over tighten the bolt, I deform the chassis, which is a hint I've gone too far.

S.

 

[Old_School_Brad]

I'd let the fans operate as the amplifier was designed -someone at Behringer probably gave it some thought back in the day.

Now, onto more important things: where are the pictures?

 

[Peppe007]

Lascerei che le ventole funzionassero così come è stato progettato l'amplificatore: probabilmente qualcuno alla Behringer ci avrà pensato qualche tempo fa.

Passiamo ora alle cose più importanti: dove sono l

ok guys thanks for the answers. let's come to another question that is the power cable, I will use a 10 amp iec c13 plug and a 1.5 mm2 section cable is that ok?

 

[sergeauckland]

ok guys thanks for the answers. let's come to another question that is the power cable, I will use a 10 amp iec c13 plug and a 1.5 mm2 section cable is that ok?

That will be fine. 10amp is 2.2kW so unless you're going to run it flat out with sine waves, you'll never get close to that continuous power level on speech or music. The 1.5mm2 cable is rated at between 10 and 20 amps depending on the method of mounting, so fine for this application.

You'll be asking about loudspeaker cables next...

S.

 

[Peppe007]

That will be fine. 10amp is 2.2kW so unless you're going to run it flat out with sine waves, you'll never get close to that continuous power level on speech or music. The 1.5mm2 cable is rated at between 10 and 20 amps depending on the method of mounting, so fine for this application.

You'll be asking about loudspeaker cables next...

S.

Ok thank you

 

[JuergenN]

what happens if i tightened the bolt too much? i don't remember how hard i tightened it right now... i just remember that the bolt was loosened too much and the transformer was moving too much

The rubber washer are also meant for mechanical damping.
Every toroid transformer will vibrate (50Hz or 60Hz depending on your mains). The washers will de-couple that vibrations from the case.
I the worst case, you destroyed the washers or they already were crumbled due to their age.
Check and renew them if possible - and tighten the screw carefully.

Juergen

 

[Peppe007]

I noticed that as soon as I start the amplifier, the toroidal transformer emits a slight hum for a few seconds then disappears, is this normal?

 

[Old_School_Brad]

I noticed that as soon as I start the amplifier, the toroidal transformer emits a slight hum for a few seconds then disappears, is this normal?

Magnetostriction..

 

[Peppe007]

Magnetostriction..

what do you mean?

 

[Old_School_Brad]

When a transformer is first powered on, it experiences a surge of electricity known as inrush current, which occurs as the magnetic core becomes magnetized and the capacitors are charged. This surge can potentially cause the core to saturate, leading to a physical change known as magnetostriction.

During this saturation phase, the core may hum. Once the inrush current settles down and the capacitors in the circuit are charged, the current stabilizes, and the humming typically stops.

 

[Peppe007]

When a transformer is first powered on, it experiences a surge of electricity known as inrush current, which occurs as the magnetic core becomes magnetized and the capacitors are charged. This surge can potentially cause the core to saturate, leading to a physical change known as magnetostriction.

During this saturation phase, the core may hum. Once the inrush current settles down and the capacitors in the circuit are charged, the current stabilizes, and the humming typically stops.

great answer, thanks!

 

[sergeauckland]

When a transformer is first powered on, it experiences a surge of electricity known as inrush current, which occurs as the magnetic core becomes magnetized and the capacitors are charged. This surge can potentially cause the core to saturate, leading to a physical change known as magnetostriction.

During this saturation phase, the core may hum. Once the inrush current settles down and the capacitors in the circuit are charged, the current stabilizes, and the humming typically stops.

May I correct one thing. Magnetostriction happens all the time, as the mains goes through the cycle, the magnetic core of the transformer is taken through a cycle of magnetisation, demagnetisation and remagnetisation in the opposite direction 50 or 60 times a second. The laminations of the transformer core will move in response, causing a low level but audible hum. This is in addition to the switch-on surge, which typically lasts a fraction of a second. All mains transformers hum, although whether it's audible except very close up depends on the transformer construction and mounting method.

S.

 

[Peppe007]

May I correct one thing. Magnetostriction happens all the time, as the mains goes through the cycle, the magnetic core of the transformer is taken through a cycle of magnetisation, demagnetisation and remagnetisation in the opposite direction 50 or 60 times a second. The laminations of the transformer core will move in response, causing a low level but audible hum. This is in addition to the switch-on surge, which typically lasts a fraction of a second. All mains transformers hum, although whether it's audible except very close up depends on the transformer construction and mounting method.

S.

Thank you so much for giving a thorough answer! Thank you so much for giving a thorough answer!

 

[Old_School_Brad]

May I correct one thing. Magnetostriction happens all the time, as the mains goes through the cycle, the magnetic core of the transformer is taken through a cycle of magnetisation, demagnetisation and remagnetisation in the opposite direction 50 or 60 times a second. The laminations of the transformer core will move in response, causing a low level but audible hum. This is in addition to the switch-on surge, which typically lasts a fraction of a second. All mains transformers hum, although whether it's audible except very close up depends on the transformer construction and mounting method.

S.

Of course, feel free. I realize my earlier comment was a bit convoluted, and I can see how the phrasing might have caused some confusion between inrush saturation and magnetostriction. You’re absolutely correct to point out the mention of laminations -though the transformer in this amplifier is a toroid.

That said, the main point remains useful enough to understand the how and why.

----

In my experience, toroids also tend to be a bit more sensitive to dirty mains power compared to EI or R-core transformers. While EI transformers have the drawback of their laminations potentially coming loose over time, toroids have the advantage of being more low-profile for the same power output. This is why PA and professional amplifiers in 2U enclosures often used toroids before moving to SMPS.