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anonymous 27 August 2005

I was reading in another proaudio forum, that some guys use there API 512's for preamps (in a lunchbox). But what they do different is attach a bigger load (resistor) to the preamp to make it sound smoother.
For instance, they said that the API 512's were made to be installed into the slots on an API console. However, the circuit load on a board that size is signifigant, when campared with the circuit load contained in a lunchbox.
Now one guy says that he read using a 600 ohm resistor was better than using it alone. His reasons were that, the load induced a more closely matched load from an API console, thus making the tails (peaks, etc.) have a different / better sound.
And another guy says that a 1200 ohm resistor is better, because it is closer to an actual API console circuit design.
Anybody else do something simular? I have an API3124+, and they are the same preamp as the 512's. Does this sound like it has any real truth to it?

Comments

Kev Sat, 08/27/2005 - 16:26

some truth to it

the output has a transformer designed to carry some load ... certainly more than is typical these days when loaded into a modern bridging input.

This load will get more energy running through the core .
AND many people believe the sound comes from the iron.

Additionally it may also need some attenuation post API. The API may have a max output of say 26 to 28dBu and the interface may be as low as -18dBu.

SO by using a load resistor of 1.2 k ohms down to 600 ohms you can load the output trafo and stop ringing etc and get a little more 2nd Harm Dist
then attenuate by 10 dB
To allow the COOL sound and still keep things under the 0dBFS on the DAW ... give or take a couple of dB

makes sense ?

I could get deeper if you like but I think that covers the basics.

anonymous Sun, 08/28/2005 - 09:59

Kev wrote:
I could get deeper if you like but I think that covers the basics.

Please do.
I went to school for 5 years for electrical school, so I should understand everything you throw at me.

I would like to connect the load to my preamp and do some tracking to hear the results. I certainly can see where this all makes sense. It is somewhat along the same idea as the THD hotplate, or the Marshall Powerbrake.

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