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Holy grail preamp: most versatile?
Old 26th February 2021 | Show parent
  #361
Lives for gear
Quote:
Originally Posted by Jim Williams ➡️
Sonic subjective opinions are as usual all over the map, but where are the hard specs one can use for objective comparisons?

I realize THD and IMD specs may be meaningless to some consumers, but the noise floor is real and should be addressed by any high end preamp manufacturer.

EIN (equivalent input noise) is a real world spec and should be listed at +60 db of gain for easy comparisons. Sounds/colors/preferences are one thing, noise is another.
Old 26th February 2021
  #362
Lives for gear
Gordon's full specs:


Old 27th February 2021 | Show parent
  #363
Here for the gear
 
API 512c with resistor trick-


Whole thread here suggesting 512c needs a resistor when in a lunchbox to give it a load similar to it being in the console.

The resulting sound is -

'cushy and 'luxurious', rounder and more colourful.'

API 512c in lunchbox with resistor
Old 28th February 2021 | Show parent
  #364
Lives for gear
 
Paul Wolff Designs's Avatar
 
🎧 15 years
In the olden days, everything had to feed 600 ohms. The output transformer of just about anything from those days needed a load if they weren't looking into one.

Now days, adding a 600 ohm resistors is the thing to do, but it does load the output some, which is why a 550A was always 1.5 dB hot. When it was feeding the 600 ohm fader, it was unity.

The load on most tube stuff from those days sounded a lot better with the load. The API gear, from the start, had a very smooth output, loaded or not, with no resonances (their was a period where the transformers were a bit brighter because of a change of winding, but that was discovered and corrected in the late 90s).

I did wire a few Lunchboxes with a 1K load (If you notice, the API lunchboxes all have a position for a LOAD R on the output) The 1K was better for the later transformers.

The sound will change some, the low end may seem calmed down a bit. The gain WILL drop, so don't be surprised when it does, but it makes for another flavor.
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