• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Tech21 VT Bass 500 Fan Observations

Acoustic356

Acoustic356

Jul 3, 2014
3,505
6,519
56
Earth
#1
  1. The fan itself is not noisy. The airflow is. The air sucked into the unit then distributed out the 2 side vents is the primary cause of the "fan noise"
  2. The variable speed fan that doesn't seem to turn off.. does.
  3. The fan doesn't come on unless a speaker cabinet is connect and being used.
I was doing some silent practice tonight and noticed that the fan didn't come on after about 30 minutes. I connected the speaker cabinet and the fan came on... plugging headphones in the headphone jack causes the fan to slow down and shut off.

Disconnecting the cabinet doesn't seem to impact the fan... only plugging a jack into the headphone jack.

I used different speakon cables, ranging from high end Fender to Spectraflex to Neutrik branded. The results were always the same.

Plugging in the headphone defeats the power amp section, so maybe that gives it time to cool down? I plan on calling Tech21 tomorrow.
 
Last edited:
  • Like
Reactions: jwindham and wave rider
#2
I shot my infrared thermometer through the side to see what's going on. The internal temp on the left side of the amp (where the neutrik connectors are) is definitely warmer than the other side. I took gaffing tape to restrict the airflow through the opposite side to see if more airflow would keep the components cool. It does not. Once the internal temp hits about ~102-105 degrees F. internally the fan comes on low. Once it hits ~110 F, the fan switches to high.

As you're playing, I've seen the temp go as high as 120-126F. When you stop it may drop to around 110F, but it doesn't go any lower, unless you plug in the headphone jack, in which the temp drops fairly quickly.

I think the problem is that they probably need a larger heat sink in order to disperse the temperature.
 
#4
This doesn't sound abnormal to me. I'm no engineer/designer but maybe the fan on/off is based upon use. In other words, if you're recording/practicing w/o a speaker load, you want it quiet.
If you are driving speakers, the power amp will start working harder and requires cooling.
Maybe the amp is designed to work that way?
Also, the internal temps you measured under load don't sound abnormal either. Just guessing here. I'd be curious to see what Tech 21 says.
 
  • Like
Reactions: Acoustic356
#5
SJan3 said:
This doesn't sound abnormal to me. I'm no engineer/designer but maybe the fan on/off is based upon use. In other words, if you're recording/practicing w/o a speaker load, you want it quiet.
If you are driving speakers, the power amp will start working harder and requires cooling.
Maybe the amp is designed to work that way?
Also, the internal temps you measured under load don't sound abnormal either. Just guessing here. I'd be curious to see what Tech 21 says.
Click to expand...

I agree. However, in a situation where I am recording using both the DI and micing the cab, the fan is noisy enough to be picked up by the fan. So noisy in fact that I had a sound engineer ask me to move the head to a different room.
 
#7
I have a VT Bass 500 that I purchased last summer. I have wondered about the fan to. I purchased it from Sweetwater and emailed their tech support as soon as I noticed the fan. Their response was that 500 watts can make a lot of heat, and if I thought it is abnormal to bring it in and they'd take a look or replace it. I did neither, I only got to use it for 1 gig before an accident put my band on hiatus. I have just recently added a second B112 VT cabinet and have been playing sporadically the last several months with the amp. The fan comes on after about 5-10 minutes then after awhile increases speed. It seems loud when it is the only amp on in the room, especially when I'm in my home studio. I realized recently that my Hartke HA3500 that I keep at my rehearsal space has a fan that is always on, and I don't notice it when playing so maybe I'm just overly sensitive to the fan noise.
 
Last edited:
#8
Crash_BassWrex said:
I have a VT Bass 500 that I purchased last summer. I have wondered about the fan to. I purchased it from Sweetwater and emailed their tech support as soon as I noticed the fan. Their response was that 500 watts can make a lot of heat, and if I thought it is abnormal to bring it in and they'd take a look or replace it. I did neither, I only got to use it for 1 gig before an accident put my band on hiatus. I have just recently added a second B112 VT cabinet and have been playing sporadically the last several months with the amp. The fan comes on after about 5-10 minutes then after awhile increases speed. It seems loud when it is the only amp on in the room, especially when I'm in my home studio. I realized recently that my Hartke HA3500 that I keep at my rehearsal space has a fan that is always on, and I don't notice it when playing so maybe I'm just overly sensitive to the fan noise.
Click to expand...


IMHO, the fan is quiet. Airflow is loud...
 
#10
It is not unusual to put the amp in the control room and speaker in the studio.
Aside from fan noise, it is much easier to adjust based on the mix.

Be careful with infared thermometers.
They don't always work well with metal surfaces.
Try taking a measurement into a duct register where there is reflection; the numbers very and don't make sense.
Same with my motorcycle exhaust; the stainless tube offers some sort of reflection; I can angle the device at the same distance and can get a temperature swing of about 100 degrees F
 
  • Like
Reactions: Acoustic356

Latest posts

Top Bottom
Back