Orphean tweak.. (Orphean)

by Bert , Tuesday, April 17, 2007, 22:34 (6215 days ago)

Hi All,

Playing with several amps lately (A, B, D, and T's) showed weird things on some of them that should not be....

We only have two amps left and those will be the Redwine Sig 30 and a dedicated BD30 amplifier not optimised for bass only. To our own surprise this BD30 (standard version optimised for bass) sounded rather well and kicked the PS-Audio "D" amplifier out of the room...(the NuForce amps were already brought back to their owner).

More about this in a few weeks after the Redwine and the BD30's are burned in properly and we have done an honest shootout between these compared to the LadyDay so that we can give a full "review" of our experiences with a selection of all type of amps on the market today.

Okay, back to the "weird" things...

Most Tube amplifiers, Class A amplifiers and Class B amplifiers act normal on speakers with impedance variations.

Class D (NuForce and PS-Audio as example) starts to show a lift in the top frequencies (above 10kHz) giving more "air" to the sound caused by this rise in amplitude. Not a real problem but not 100% honest and probably making them sound "better" to people.

Class T is the worst and most sensitive to impedance changes. I have seen this with the Sonic T and today the Redwine Sig 30's showed the same extreme sensitive behaviour... :shame:

Other T-amps like the TA10 will probably show the same...

In combination with the Orphean this is not good, very disappointing to listen to these amps in this situation. I am sure that most speakers will change their whole tonal balance in the higher frequencies too simply because of this sensitivity to impedance changes.

NOTE: There are no dynamical speakers on the market having a flat impedance like a resistor.

[img]images/uploaded/image38.gif[/img]

The shown external tweak for the Orphean cures this T-Amp problem with the shown notch though (should only be included when using a T-Amp!) at the left side of the diagram where the speaker drawn is showing the Orphean's inputs.

The parts at the right side are showing a tweak giving the Orphean a better tonal balance if you feel that they are sounding a bit too forwarded, the resistor might not be needed (try and listen yourself if you prefer this or not). This tweak can be applied no matter what type of amplifier you are using but in combination with a T amplifier this will sound worse unless you use the T-tweak (the notch) too...

Bert

--
BD-Design - Only the Best!

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