Output impedance preference

[oon_the_kid]

Hi,

I have been thinking about doing a little experiment for fun. I have a class D amp which I am thinking of adding a resistor in series with a high efficiency full range driver.

Increasing the output impedance by adding a resistor in seriesis one of the ways mentioned by NP in his paper to improve the sound of voltage source amplifiers with regards to high efficiency speakers.

http://www.firstwatt.com/pdf/art_cs_amps.pdf

So my question is, what resistor values would you use. 1 ohm, 3 ohm, 8 ohm?

Or if you have tried this before maybe you could share your experience.

BTW, I have already built the F2J and it sounds fantastic. But I am experimenting with class D amp for a change.

Oon

 

[drjbf1]

The F2s have an output impedance of about 15 Ohms. Why not start there if you like the sound of the F2J on your speakers? The comparison might be interesting...

 

[oon_the_kid]

Thanks but 15 ohms might be a bit too high. Would have lost 2/3 of the power of the amp to the resistor.

I guess I could always build a resistor switch box and try it out...

Oon

 

[Nelson Pass]

Get some resistors and have at it.

 

[oon_the_kid]

Dear Nelson,

You are probably the most experienced in this field of them all....

What is your favourite output impedance for high efficiency drivers, a F1 of a 100 ohm, F2 of 15 ohm or lower for the voltage source type amps F5, F6...

Oon

 

[Zen Mod]

I believe Pa already covered that , with article

lookielookie: FIRST WATT

 

[jan.didden]

Hi,

I have been thinking about doing a little experiment for fun.

Yes, fun is good.

So my question is, what resistor values would you use. 1 ohm, 3 ohm, 8 ohm?

So experiment!

Jan

 

[oon_the_kid]

I believe Pa already covered that , with article

lookielookie: FIRST WATT

I think the link went to all the articles, any particular articles you are referring to?

Oon

 

[woody]

Probably this one . PassDiy

 

[Zen Mod]

I think the link went to all the articles, any particular articles you are referring to?

Oon

nothing wrong with choosing by adequate title

same - nothing wrong with reading them all

 

[Nelson Pass]

What is your favourite output impedance for high efficiency drivers, a F1 of a 100 ohm, F2 of 15 ohm or lower for the voltage source type amps F5, F6...

There is no favorite, only an interesting range of effects.

 

[PKI]

Adding a series resistor to your driver will change its Qts and will affect its performance especially if you already have a box designed for it. How significantly will depend on the driver motor. Something to keep in mind as well.

 

[oon_the_kid]

There is no favorite, only an interesting range of effects.

Care to share your observations?

Oon

 

[analog_sa]

The problem with resistors is one may end up listening to resistors, rather than Df if they are different brands.

Perhaps the cleanest solution to hear what various Dfs sound like is tweaking an F7.

 

[Nelson Pass]

You can test that hypothesis as well.