Speaker Simulator Comparison Test
Noise Levels & EMI Sensitivity
Behringer - GI100 Ultra-G
I read some comments on Harmony Central that mentioned noise problems of this device. Therefore I payed attention to noise being generated by any of the speaker simulators.
When doing some first testing I also noticed a very loud noise floor from the Ultra-G. In further testing it was not present anymore. I didn't know what the reason was for the noise to disappear until I sat down for bringing all recorded samples for each basic sample to the same loudness. I had to listen carefully to achieve that and I heard the noise again! It shows up when using the Ultra-G at the speaker output, i.e. when engaging the attenuator pads on it. You can easily compare the Ultra-G's recordings for the basic sample "Country" taken a) from the preamp's output and b) from the poweramp's output. Especially in the more silent phases of the recording it becomes quite obvious...
Hughes & Kettner - Red Box Pro
Hughes & Kettner's Red Box Pro is quite sensitive to EMI. This means that you will hear humming and buzzing in its output signal, if it is placed too close to a power supply (your amp surely has one built-in) or other emitting devices like computers and monitors. Sometimes you can find a "magic angle" and the humming decreases or goes away completely. Some people reported that they mounted a Red Box Pro into their combo amp or amp head without such problems. I just wanted to mention the possibility...
I got in contact with Hughes & Kettner and reported this problem. They simply answered that this is a known problem you cannot avoid, because of the transformer inside. The Palmer PDI-09 however also works in passive mode using a transformer. It seems to be EMI-immune due to its internal shielding with so called Mu-Metal. Mu-Metal is expensive and this might be one good reason why the Palmer PDI-09 is the most expensive speaker simulator in this test.
©2006 by Frank Nitsch