Impedance!!!!!!!!!!!!!!!!

[optimo]

This is a mic pre amp with a balanced transformer output impedance of 600ohms. please see http://www.groovetubes.com/product.cfm?Product_ID=2084 From what people have said above it looks like this cannot be connected directly to my RME input which is 10kOhm impedance input. Running either a bass or mic through this pre amp which is connected to my RME gives a very poor low volume signal. When I asked for support from the manufacturer they told me that "The impedance is actually working in your favor, you should have more than enough output" This conflicts with what is said above. Now I am really confused???

[optimo]

Just to reiterate what nufflink said (which is absolutely correct), you want your output impedance to be much lower than your input impedance, so 600 ohms into 10k ohms should be fine.

The key bit from the Sound On Sound article is:

The solution to this problem is to dispense with the idea of matched impedances completely, and use what is called voltage matching instead. The idea here is to engineer the equipment to have the lowest possible output impedance and a relatively high input impedance — the difference between them must be at least a factor of ten, and is often much more. Modern equipment typically employs output impedances of around 150(omega) or below, with input impedances of at least 10k(omega) or above. With the minuscule output impedance and relatively high input impedance, (the cable impedance can be disregarded completely in comparison) the full output voltage should be developed across the input impedance.

This ties up with what the manufacturer said also. So It looks like it has a possible fault with it then.

Thanks.

[camsr]

When output is low Z (impedance) and input is high Z, this is because how ohm's law works and this gives you maximal VOLTAGE transfer. Since most audio amps and ADCs work with transistors, this is what you want.

You only want matching impedance when your trying to get maximal POWER (Volts * Amps) transfer, like in power lines and I think tubes work this way too. The voltage method with low out Z and high in Z doesn't care about amps, just voltage.

Most likely your hardware is defective.

[BertKoor]

This is a mic pre amp with a balanced transformer output impedance of 600ohms. From what people have said above it looks like this cannot be connected directly to my RME input which is 10kOhm impedance input.

You haven't read all the posts. An output impedance of 600 Ohm and input impedance of 10K Ohm are extremely normal, and the combination works excellent. Look up the spec sheets of some of your own equipment, e.g. the line inputs/outputs of your soundcard.