Zen Bi-amp and more
Erik Wiemann
1. My speakers have a low sensitivity (86-87 db) and I am wondering if I
can use
the Zen amplifiers if I bi-amp. I want to build two Zen amps and use
one for the
left speaker and one for the right speaker, using one channel of the
amp for the
woofer and one for the tweeter. Is the amp efficient enough or
should I buy
something else ?
2. If I build the amps I wondered if it is possible to include a
stand-by function
in order to make it "green" and save money ?
Any suggestions ?
Have fun
Erik
Yves C Vidal
>I have two questions regarding the Nelson Pass's Zen amplifier
>
>1. My speakers have a low sensitivity (86-87 db) and I am wondering if I
>can use
> the Zen amplifiers if I bi-amp. I want to build two Zen amps and use
>one for the
> left speaker and one for the right speaker, using one channel of the
>amp for the
> woofer and one for the tweeter. Is the amp efficient enough or
>should I buy
> something else ?
The ZEN is a monoaural amp, so you would have to build 4 of them
to Bi-amp a stereo system. I am not sure it is going to sound
louder even if it is biamped. In addition you may have to design
and build an active filter to put before the amps.
>2. If I build the amps I wondered if it is possible to include a
>stand-by function
> in order to make it "green" and save money ?
The greener I know is to shut them off. The ZEN is a single
device amplifier. There is nothing to stand-by. It is all or
nothing.
Yves
Hans-Willem ten Brinke
Yves C Vidal wrote:
You could make the bias-resistor switchable, so you canm switch between the normal
(0.3) and a standby resistor (47 Ohms ie). But i dont know if damage is done to the
transistors in the time you switch the resistors.
Greetinx, Hans-Willem
also take a look at my homepage http://home.student.utwente.nl/h.tenbrinke/
pref...@my-dejanews.com
Erik Wiemann <er...@hum.aau.dk> wrote:
Hi Erik,
> I have two questions regarding the Nelson Pass's Zen amplifier
>
> 1. My speakers have a low sensitivity (86-87 db) and I am wondering if I
> can use the Zen amplifiers if I bi-amp. I want to build two Zen amps and use
> one for the left speaker and one for the right speaker, using one channel of
the amp for the woofer and one for the tweeter. Is the amp efficient enough or
> should I buy something else ?
The Pass Zen Amps are nice units, mostly in the mid and highs. I'm
suspecting they are a bit lean in bass but I like the color they
privide. I've built two of them and the Bride.
Regarding your first question, I would suggest parralleling the L+R channels
for a doubling of power (20 Watts). i.e. One amp per loudspeaker. Now, are
they efficient enough to drive your speakers...well, 86-87 dB is not that
much. It all depends on your listening habits(dB-wise) and the impedance load
of your speakers on the amp. The "Return of Zen" I have made are sensible to
lower loads. They play loud enough for me (in parrallel mode) with one of my
3-way tower model (94.5 dB/1W/1M), they load 4 Ohms in bass passband. I did
not measure the sensitivity at listening point with full power with Bride,
but could do so If you want. Nelson Pass suggest that in parallel mode, the
amp will produce lower distortion and will be capable to run on 4 Ohms load.
Just to give you an idea...I gave the Zen's an extreme test. We ran one amp
in stereo mode with Apogee Stage loudspeakers. Just to remind you, these
Ribbons are 83dB/1W/1m and 3 Ohms stable. The amps played all right but
were'nt very efficient. Bass was at very least 3dB down near 30Hz. At
semi-high level the speakers tend to distort. At low level, mid-high sound
quality was comparative to my other speakers(towers).
> 2. If I build the amps I wondered if it is possible to include a
> stand-by function
> in order to make it "green" and save money ?
I'm not convinced this would be a good feature...Mosfets are supposed to be
runned hot and they are sensible to big temperature difference, like when
turning them off and on. The use of stand-by will not preserve the transistors
longer because of the temperature difference when activated.
> Any suggestions ?
What are your listening levels?
> Have fun
I am... :0)
> Erik
Here is a question for the ones who have built the Zen amps. Guys, I would
like to have your comments on the bass performance of this amp. Have any of
you measured its performance compared to M.Pass tests. If the amp is lean in
bass, how could we bring it to flat???
Thanks,
Guy
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