These audio files accompany my review of the Golden Age Project Pre 73 DLX mic preamps and the EQ73 equaliser that appeared in SOS March 2013. The examples are intended to highlight the differences — and the similarities! — between two versions of the Pre 73 DLX.
One preamp is the standard model, with stock transformers, whereas the other has been upgraded to include only Carnhill transformers and inductors. Bear in mind that there are a few other subtle differences in the designs which may be making a sonic contribution, such as the electrolytic capacitors in the upgraded model — but the main difference you'll hear is in the transformers.
I find that some of the more obvious differences between the sound of different transformers is in their behaviour on LF-rich sources when driven into saturation. In the examples that follow, I've taken a bass loop and run it through both preamps at a range of different settings to try and get more 'flavour' from the output transformer, going right the way from relatively clean through to silly distortion settings. In all cases, there's a healthy input level, so you'll also be hearing a little of the contribution of the input transformer. Although the preamp sounds nice at lower settings, it's much cleaner sounding, and I could discern absolutely no difference between the two, so I've provided no examples at such settings.
If you can't wait to find out which is which, then scroll down to the bottom of the page, but I'd urge you to listen to the examples first and make your own mind up which you prefer before revealing which is which. One thing I would say is that the differences are very subtle and really you'd be much better off auditioning these files within your DAW and studio monitoring environment than listening online!
Bass-nopreamp
This is the original loop, without any processing.
Bass-preampA-01
Bass-preampB-01
These files are with settings approximately as follows: Line Input -15; Output pad off; output level between 9 and 10 o'clock.
Bass-preampA-02
Bass-preampB-02
In these examples I've introduced a post-transformer output pad at -14dB and raised the output level with the knob set at approximately 1 o'clock. It's subtle, but the output transformers are beginning to lend a little more thickness/saturation to the sound. Can you hear it?
Bass-preampA-03
Bass-preampB-03
This time, the pad is set at -21dB and the output level has been raised again to compensate, this time to somewhere between the 2 and 3 o'clock positions. The clip light on the preamp is starting to blink and the effect is slightly more obvious. The differences still sound vanishingly small to me!
Bass-preampA-04
Bass-preampB-04
With the pads set to -28dB now, the level going into the transformer now has to be quite high to get a similar overall level. The clip light is now on most of the time, just blinking off occasionally and you can start to hear the saturation give way to something more recognisable as dirty distortion. Still, the differences are slight, though to my ears one breaks up slightly more gracefully than the other. Don't take my word for it, though: what do your ears tell you? Incidentally, there's still bags more output gain in reserve if it's needed (e.g. if lowering the input level).
Bass-preampA-05
Bass-preampB-05
This time, I've whacked the input and output levels to full, with the -28dB output pad engaged. It's a stupid amount of distortion which no sane person would use on a mic preamp in the real world, other than for an effect... but this does reveal the subtle differences in the character of the two output transformers more clearly.
So, which preamp is which? Scroll down to find out...
Preamp A is the Pre 73 DLX with the full Carnhill mods.
Preamp B is the standard Pre73 DLX.