Thanks for the kind words about our EP pedals
Don't want to spam, but there seems to be some confusion about the output impedance of our EP-PRE.
Early EP-PREs did have high output impedance, just like the original EP-3. We tried conventional emitter follower buffers, but found that they reduced the effect of the preamp. We have never received any reports of hum, but we found couple of delay pedals with low input impedance that could drag down the output of the EP-PRE, making it sound muddy.
In mid 2011 I designed an output driver that reduces the output impedance without affecting the tone. Since then, our EP-PRE has much lower output impedance, capable of driving almost anything.
Cheers,
Peter.