Speaker Simulator Comparison Test

Devices under Test

As mentioned earlier I was interested in buying an additional speaker simulator for not more than 100 EUR. The following table contains all I found and tested in that price range. The prices are taken from internet shops in the summer of 2006. Don't complain that they are not up-to-date when you read this article. I put them here just to give you some idea...

Tested Devices
	Price	Power
Red Box Pro Hughes & Kettner	discontinued	not required / passive
Red Box Classic Hughes & Kettner	70 EUR	power supply phantom power battery
PDI-09 Palmer	90 EUR	not required / passive
GI100 Ultra-G Behringer	50 EUR	phantom power battery
F.A.N.T.A. Tube Amp Doctor	75 EUR	not required / passive

Although the speaker simulators are pretty similar in terms of connectors and operation, there are some important differences you should notice:

Hughes & Kettner Red Box Classic
- All speaker simulators listed on this page have an output jack for connecting a poweramp in case a speaker level signal is connected to the input jack. Almost all units can also bypass line level input signals to the output jack (sometimes called "through"). All except one: the Red Box Classic does not bypass line level input signals! It has a "through" output only for the speaker level input. While the Red Box Pro has a switch for selecting, if the input signal has speaker level or line level, the Red Box Classic has separate input jacks for this purpose.
- Although not documented anywhere in the manual or in product descriptions, this unit has a ground lift switch! It is hidden in a small hole on the back of the housing. There is no label or something, but it is a ground lift switch! I asked Hughes & Kettner via e-Mail and they told me. ;-) I tested it and it works as expected. Coming from the factory the ground lift switch is engaged.
Tube Amp Doctor F.A.N.T.A.
- It is designed to work with speaker level input signals only! There are no switches or a second input jack, which would allow for line level input signals. If used with line level input, the output signal is very weak and can introduce extra noise. All other speaker simulators listed here can work with either line level or speaker level input signals.
Behringer GI100 Ultra-G
- It has no jack for connecting a power supply. You either need to feed it with phantom power through the XLR jack or with battery power. A workaround would be to connect a power supply to the battery clip. You would need to keep the battery housing open for doing so, but that's not really a big deal.
- I guess it is two times as heavy and three times as big as all the other devices listed here. On the other hand it looks extremely sturdy and elegant.

Overview — What are Speaker Simulators good for? — Devices under Test — Test Setup & Execution — Recorded Sound Samples — Frequency Response — Noise Levels & EMI Sensitivity — Summary & Next Steps — Your Contribution