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Q Should a coaxial digital cable or an audio RCA cable be used to connect the AC-3 RF out on a laserdisc player to a RF demodulator? What kind of cable should be used to connect the demodulator to the preamp/processor?
A Theoretically,
75 Ohm cables should be used with both, because the first one
is a radio frequency and the second is a digital bitstream. However,
I have used regular audio cables in this situation, and they seem
to work fine. That does not mean that all audio cables would work,
since the impedance can drop as low as 25 Ohms with some of them.
With CD digital outputs from transports, though, it is very important
to use 75 Ohm cables. Otherwise, the sound can be quite harsh
and unnaceptable. This is caused by high frequencies being reflected
back into the cable.
Q I
am interested in buying a DVD player, but I have an old television
(actually not that old -- it's from 1995) which only has that
one plug. (I confess I don't even know what it's called -- it's
definitely not S-Video and it's not a yellow RCA type plug for
video. It's the kind you hook up to your VCR or cable.) Anyway,
is it even "possible" for me to hook up a DVD to this
type of TV, and if so, how? What do I need to get, where can I
get it, and what am I looking at in terms of cost? I've searched
on every possible DVD website for an answer and I've seen no discussion
of this!
A There
are adapters that will do what you want. I have seen them come
with older LD players a few years ago. You might be able to find
such a converter at Radio Shack. It has an audio and video in
and outputs the coax. You connect the coax to your TV through
the "F" connector (that's the one you didn't know the
name of). An "RF output on channel 3 or 4" is something
that was commonly used with VCRs years ago, but just about every
TV has audio and video RCA coaxial input jacks now, so RF outputs
have been deleted from DVD players. Anyway, the RF output reduces
the resolution due to limited bandwidth, and this would throw
away the advantage of DVD images. RF outputs are still present
on VCRs because VCRs don't have much resolution and the RF bandwidth
is sufficient to carry all the detail in the image from VHS tapes.
Q I
am hoping that you will be able to review the newest Definitive
Technology speakers - BP3000. I am wondering how you would rate
these compared to the Mirage bipolar speakers and other speakers
in their price range.
A We
hope to review these speakers in particular, because they use
built-in 1,000 watt amplifiers to drive the woofers. This is part
of the new trend in using power amplifiers that have the AC from
the wall connected directly to the capacitors (through rectifier
diodes), rather than stepping the voltage down with a transformer,
and they probably use a switching scheme for the output devices.
This works well for low frequencies, but the technique needs some
work before it will be commonly used with full spectrum audio.
In the meantime, however, it is sure having an effect on subwoofer
amplifier designs.
Q I
just read that DVD is not compatible with HDTV. If that is true
then why the heck are people buying it? That is very important
to me because I was going to buy a DVD player (Panasonic 310)
for Christmas..
A DVD
will work fine with HDTV, but you will not get progressive line
scan out of the player unless you have one of the newest generation
players. The 310 does not have this feature, but some of the players
being released before Christmas will have it. If you are planning
to get HDTV, then wait until these players become available.
Q I have been bitten by the tube bug and am the proud owner of a Conrad-Johnson Premier 14 preamp, which at present is mated to a Krell KAV 250a power amp. I am interested in matching the preamp with a tube amp -- CJ 11a, but I am a bit hesistant to exchange my SS amp for a tubed amp beacuse of the following concerns:
1. Will the 70W/pc CJ 11a do a good job of powering my B&W 802s ? I do not listen to very loud music. My room is 14 x 14, and the speakers are rated at 90 dB/w/m, and 8 Ohms. 2. I know that the quality of sound my system produces is going to be limited by the weakest link in my audio chain. But I have to ask, if I have x dollars to spend on getting a good preamp or a good amp, which upgrade is going to give me more bang for the buck ? 3. I have been told by my sales advisor at my local stereo store that after 100 hours, tubes start degrading and the effects are audible to "audiophiles". Is that true?
My system at the moment:
CJ Premier 14 (Preamp)
Krell KAV 250a (Amp -- still under tryout period)
CAL 10 (CD Player)
Monster 550s and MIT 4s (interconnects)
MIT 5s (speaker cables)
A 70
watts/channel will be fine with the 802s, so your choice should
be based more on the type of sound that you prefer. The CJ tube
power amplifier will give you more warmth than the solid state
amplifier, but if you like the effect you are getting from your
CJ preamp, it will be more of the same. Tubes do change over time,
but they are not expensive to replace, and the lifespan depends
on the tube type. If you like the tube sound, then get the CJ
and just replace the tubes when you notice a degradation.
Q I
recently purchased my first DVD player, the Panasonic DVD-A110,
and I love it. Currently I only have a Dolby Prologic Receiver,
but I am looking to move to Dolby Digital and DTS very soon. I
know of many excellent receivers, but I am not certain I would
like to spend even close
to $1000. I was figuring that even when I buy the best system,
in a couple years I'm always going to want something newer, and
I won't mind
doing that if I've spent under $500.
I have heard of a new Sony receiver, the
STR-DE925 that has 110 watts times 5, plus DD and DTS decoding
(this replaces the STR-DE915). I've seen where I can preorder
this for $450. My question, is this even worth this limited dollar
value or will it sound terrible for the dollar? I
don't expect to get DSP-A1 quality for the money, but I am still
looking for a good machine that won't make my ears bleed.
A The
Sony receiver should sound OK as long as you don't try to rattle
the rafters with it. At that price, asking for the power amplifiers
to output high levels for more than a millisecond is dreaming.
I found the STR-DE925 listed on Sony's website, but they did not
say anything about DTS, although it does say that the product
handles DD. So, before you buy, make sure it has the features
you want.
Q I
am trying to improve the playback resolution of taped satellite
programs over standard VHS. I only have composite signals to work
with out of the satellite receiver and must use composite to drive
the video projector. The feed from the satellite looks much better
than the
VHS tape. Would a S-VHS recorder preserve the resolution of the
composite signal?
A The
signal from your satellite, although composite, has a horizontal
resolution of about 480 lines (assuming you have a modern system).
VHS horizontal resolution is only about 240 lines. S-VHS, at 420
lines of horizontal resolution, will preserve the signal much
closer to what you are seeing in the satellite-to-TV image. Even
conventional NTSC broadcast TV has 330 lines, so S-VHS would give
an improvement of recording this format over VHS too.
Q As part of my (at present, anyway) modest home theater, I have an inexpensive Harman Kardon AVR20/II Pro Logic receiver. It has left and right subwoofer line level outputs, which I presently use with a dual voice coil, powered subwoofer. The center channel mode is set to "normal", routing the low frequency information to the mains.
I am thinking of replacing the LCR speakers
with 3 identical MTM satellites, none of which would really handle
the below 60 Hz info from
the front 3 channels. I planned to continue to use the center
channel "normal mode" and high-pass the left and right
channels using the speaker
level input/output on the sub, thereby routing all the low frequency
from the LCR to the sub. In so doing, several questions arose:
1) Would the sub line outs from the receiver also remain connected to the sub line ins simultaneously (I assumed not)?
2) If not, is there sonic information in
the Pro Logic Subwoofer line level output that will never make
it to the sub or does the low pass from
the L&R speaker level inputs (including low frequency center
channel info) include everything?
3) Do you have any idea the maximum frequency a mass market receiver such as this one sends out via the sub line outs?
4) What is the recommended hookup (if any)
for using a sub in the system I describe with a receiver that
does not have the option to set the mains to "small"?
A If
you use the speaker-level inputs of the subwoofer, then do not
use the line-level inputs of the subwoofer. Set the main speakers
to "Normal" or "Large" so that you are not
using two sets of crossovers (one in the receiver and the other
in the subwoofer). Otherwise, you could end up with a hole in
the sound below 90 Hz for the front left/right channels. For Pro
Logic, the subwoofer output jack duplicates low frequencies that
are in the other channels. Setting the mains to "Small"
just removes the low frequencies from the mains, but keeps them
in the subwoofer output. The subwoofer output jack should send
frequencies down to as low as the movie or CD sends to the receiver.