[Juan R]

I went to the ampzilla website and saw the spec of the son. I will like to biamp my rm -40 and wonder is will be a good match the son for mid and high and the ampzilla for bass. I am very happy with the mono but I will like to see if I can have better bass at low volume with the two set of amps. In the website the description of input inpedance is 33Kohms vs 70in the mono. If anyone try this or know if I can run the amps without active x-over with that inpedance difference.

[tkp]

I went to the ampzilla website and saw the spec of the son. I will like to biamp my rm -40 and wonder is will be a good match the son for mid and high and the ampzilla for bass. I am very happy with the mono but I will like to see if I can have better bass at low volume with the two set of amps. In the website the description of input inpedance is 33Kohms vs 70in the mono. If anyone try this or know if I can run the amps without active x-over with that inpedance difference.

JR,

If I remember correctly Ampzilla2000 has SE input impedance of 47 Kohms and balance input impedance of 70Kohms.  You might want to check with JB to be sure.  Any way, there are two things you need to consider when passive biamping with the SOA and Ampzilla2000.

a)  Assuming the Ampzilla2000 has an input impedance of 47Kohms and you are driving both amp from a preamp which only has one output, you need to figure out whether or not your preamp can drive the combine load.  In this case, the preamp would see a load of

(47Kohms x 33Kohms)/ (47Kohms + 33 Kohms) = 19.3Kohms.

b)  The gain of the Ampzilla2000 is 32 db and the gain of the SOA is 26 db for SE.  This means, if you drive the upper section of the RM40 with the SOA then make sure that the midrange LPAD has enough gain adjustment for the 6db different between the 2 amps.  BC should be able to tell you how much attennuation the mid and high LPAD of the RM40 provides.

[Juan R]

I have the Kora Eclipse with high output, balanced and unbalanced 600 ohm and low output with 1.5k, acording to the manual I can use  the low and the high at the same time for biamping.

[ekovalsky]

A few things:

1. I don't think the LPAD adjustment is 6db, more like 2db or so if I remember correctly.  It is designed for "fine tuning" not matching of levels differing by an order of magnitude. Brian should know for sure.

2. James B. will likely customze input impedance and sensitivity for your needs.  I had inquired about an Ampzilla with balanced gain reduced to 23db or so for use with my Elgar Plus.  Wound up going with a different amp though.

[tkp]

I have the Kora Eclipse with high output, balanced and unbalanced 600 ohm and low output with 1.5k, acording to the manual I can use  the low and the high at the same time for biamping.

JR,

I have no experience with the Kora preamp.  I went to the Kora website to read about the unit and here is my take on this particular preamp.

This is a tube preamp with a tube direct output of 1.5kohms.  This tells me that the balanced and unbalanced output of 600 ohms is basically a buffer output of the 1.5Kohms tube direct output to provide the balance output drive of 600 ohms.  You will need to experiment with different output combination with the Ampzilla200/SOA combo.    You should be able to use the high drive 600 ohms SE output to drive both amps. 1.5Kohms is a bit too high to drive into a 20 kohms load.

The above does not tell any thing about the musicality of the combo.  All it tells you is that the  Kora preamp can drive the Ampzilla2000/SOA combo with its high SE output without degrading the signal.  The only way to know for sure is to check it out for yourself.

Another option you can do is to check with Bongiorno on this one.  JB can adjust the gain and input impedance of the SOA to match the ampzilla2000.

Good Luck,
TKP

[Juan R]

Thank you for the input.