Dummy load for tube amp

[Wavebourn]

You don't need it to be exactly 8 Ohm. Something like 36 Ohm would be fine.

 

[chrisng]

You don't need it to be exactly 8 Ohm. Something like 36 Ohm would be fine.

Thanks for your input Wavebourn,
36 ohm is 4 times of 8 ohm, dose it mean I can go up to 4 times of the impedance tap value? what is the reason behind it and how about 4 ohm tap, can I still use 36 ohm or 18 ohm is the max.

 

[Wavebourn]

You don't need to squeeze full power from the amp right? You just need to load it reasonably, so when overdriven voltage spikes don't go too high and don't damage the transformer. Such relaxed load would result in cleaner sound before saturation. However, you would not hear the sound when loaded on the dummy load, though... ;-)

 

[chrisng]

You don't need to squeeze full power from the amp right? You just need to load it reasonably, so when overdriven voltage spikes don't go too high and don't damage the transformer. Such relaxed load would result in cleaner sound before saturation. However, you would not hear the sound when loaded on the dummy load, though... ;-)

Thanks Wavebourn,
That is very true, @ normal listening level in my room, all I need is just a few watts.

 

[chrisng]

200W 4ohm Aluminium Shell Braking Resistor Resistance Dummy Load for Audio | eBay

Tolerance +-5%, 40W without heat sink. I mount a pair back to back and the speaker plug is connected directly to wire lead, for very quick manual switching between the speaker and dummy. If your amp has gNFB, it's probably ok without a load, because gNFB has to clamp down the output when unload, but if zero feedback must have a load.

Thanks Koonw,
From your link, I also found these monsters:
1000W 8ohm Aluminium Shell Braking Resistor Resistance Dummy Load for Audio | eBay
5000W 8ohm Aluminium Shell Braking Resistor Resistance Dummy Load Audio | eBay
I going to build two switchers for my friend to compare his tube amps, I have to be very careful to make sure he won't blow his amps.