Cheap/good digital-audio Boston Acoustics BA735

[LoveLearn]

Gateway Computer's designers once thought digital rather than analog
output systems were probably going to become the new default standard.
So far, that hasn't happened. But they sold lots of systems with Boston
Acoustics model BA735 sound systems. These ONLY accept digital audio
input, not analog. So their current resale value, driven by trivial
demand, is very depressed. In other words, if we can use them, they are
available for almost "give away prices." Test reports from when they
were newly released say they have a clean sounding amplifier with
electronics driving 3 speakers. One left, one right and a larger ported
low frequency speaker contained in a center box with the electronics.
They
require a DC input, most typically provided by the included Boston
Acoustics "wall wart" which acts as a "phantom load" even when not being
used. Owing to analog audio's continued dominance in computer sound
output devices, used BA735 systems are being offered on eBay for
ridiculously low prices, like $9.99 to $15. Of course buyers still have
to pay for shipping. I'm hoping these might be used as wonderful Archos
accessories.

BA735's audio input is a female "phono" audio style jack, like those
used between audio components for 50 years. I don't know about polarity
or whether Archos player/recorders will drive them, but if they can be
connected easily, I expect lots of Archos owners would love to know
what's required. Has anyone driven one of these with their Archos? I'd
like to know before buying a set.
John
LoveLearn

[David McIntyre]

Kinda makes me wonder if it uses S/PDIF.

Post by LoveLearn
Gateway Computer's designers once thought digital rather than analog
output systems were probably going to become the new default standard.
So far, that hasn't happened. But they sold lots of systems with Boston
Acoustics model BA735 sound systems. These ONLY accept digital audio
input, not analog. So their current resale value, driven by trivial
demand, is very depressed. In other words, if we can use them, they are
available for almost "give away prices." Test reports from when they
were newly released say they have a clean sounding amplifier with
electronics driving 3 speakers. One left, one right and a larger ported
low frequency speaker contained in a center box with the electronics.
They
require a DC input, most typically provided by the included Boston
Acoustics "wall wart" which acts as a "phantom load" even when not being
used. Owing to analog audio's continued dominance in computer sound
output devices, used BA735 systems are being offered on eBay for
ridiculously low prices, like $9.99 to $15. Of course buyers still have
to pay for shipping. I'm hoping these might be used as wonderful Archos
accessories.
BA735's audio input is a female "phono" audio style jack, like those
used between audio components for 50 years. I don't know about polarity
or whether Archos player/recorders will drive them, but if they can be
connected easily, I expect lots of Archos owners would love to know
what's required. Has anyone driven one of these with their Archos? I'd
like to know before buying a set.
John
LoveLearn

[LoveLearn]

David said "Kinda makes me wonder if it uses S/PDIF."

Naturally I tried to determine that by going to the Boston Acoustics web
site. BA735 systems aren't directly listed, but I found their
search-string entry box where I entered "BA735." That displayed a link
described as "Gateway Computers." Clicking on that link displayed a
blank screen. This reference page also asked if that link addressed what
I wanted to learn. I answered no, hoping it would give an opportunity to
request information about BA735 digital audio standards compliance. But
it just produced a survey "Thank you" screen. That's why I asked if
anyone has tried connecting them to their Archos. If we knew they are
S/PDIF compliant, we'd already know if they'll plug and play with our
Archos units.

Hopefully some subscriber has access to a BA735 audio system.
John
LoveLearn

[Joris van den Heuvel]

Have you ever heard of a place called "Google"?

I typed in BA735 and within 1 minute found out it has an S/PDIF input. I
quote:



3-Pieced Subwoofer & Satellite Digital Speaker Set by Boston Acoustics

The BA735 is the Boston Acoustics most compact, powered desktop audio
system. Incredibly portable and affordable, the 735 sacrifices nothing when
it comes to delivering high-fidelity audio. In a close environment, like at
a computer workstation, the BA735 offers an intimate and defined sound even
at low volumes. Crank the volume however, and you'll wonder how such a
room-filling sound can come from such a compact system. Color: Beige. Brown
box.

Specifications: Frequency response: 55-20,000Hz(+/-3dB); Maximum sound
pressure level: 100dB (0.5m); Crossover frequency: 200Hz; Subwoofer: 7-3/4 x
6 x 6-11/16inches/ Bass driver: 4-1/2 inches. Satellites: 3-1/4x3-1/4x3-1/2
inches.

System Requirements: Digital output sound card; Digital output must be a
3.5mm mini-din digital out; Available power outlet.

Contents: Subwoofer; Satellite speakers with stands; 120VAC, 60Hz power
supply; 3.5mm mini-din to digital in cable.



----- Original Message -----
From: LoveLearn <***@iw.net>
To: <***@cool.haxx.se>
Sent: Friday, September 05, 2003 12:10 AM
Subject: Re: Cheap/good digital-audio Boston Acoustics BA735


| David said "Kinda makes me wonder if it uses S/PDIF."
|
| Naturally I tried to determine that by going to the Boston Acoustics web
| site. BA735 systems aren't directly listed, but I found their
| search-string entry box where I entered "BA735." That displayed a link
| described as "Gateway Computers." Clicking on that link displayed a
| blank screen. This reference page also asked if that link addressed what
| I wanted to learn. I answered no, hoping it would give an opportunity to
| request information about BA735 digital audio standards compliance. But
| it just produced a survey "Thank you" screen. That's why I asked if
| anyone has tried connecting them to their Archos. If we knew they are
| S/PDIF compliant, we'd already know if they'll plug and play with our
| Archos units.
|
| Hopefully some subscriber has access to a BA735 audio system.
| John
| LoveLearn
|
| ================================================================
| Deze e-mail is door E-mail VirusScanner van Planet Internet gecontroleerd
op virussen.
| Op http://www.planet.nl/evs staat een verwijzing naar de actuele lijst
waar op wordt gecontroleerd.
|

[David McIntyre]

I see a lot of resources that confirm that the sound input on the BA735 is
S/PDIF. But everything talks about the mini-DIN cable. Anyone know the
pin-outs?

Post by Joris van den Heuvel
Have you ever heard of a place called "Google"?
I typed in BA735 and within 1 minute found out it has an S/PDIF input. I
3-Pieced Subwoofer & Satellite Digital Speaker Set by Boston Acoustics
The BA735 is the Boston Acoustics most compact, powered desktop audio
system. Incredibly portable and affordable, the 735 sacrifices nothing when
it comes to delivering high-fidelity audio. In a close environment, like at
a computer workstation, the BA735 offers an intimate and defined sound even
at low volumes. Crank the volume however, and you'll wonder how such a
room-filling sound can come from such a compact system. Color: Beige. Brown
box.
Specifications: Frequency response: 55-20,000Hz(+/-3dB); Maximum sound
pressure level: 100dB (0.5m); Crossover frequency: 200Hz; Subwoofer: 7-3/4 x
6 x 6-11/16inches/ Bass driver: 4-1/2 inches. Satellites: 3-1/4x3-1/4x3-1/2
inches.
System Requirements: Digital output sound card; Digital output must be a
3.5mm mini-din digital out; Available power outlet.
Contents: Subwoofer; Satellite speakers with stands; 120VAC, 60Hz power
supply; 3.5mm mini-din to digital in cable.
----- Original Message -----
Sent: Friday, September 05, 2003 12:10 AM
Subject: Re: Cheap/good digital-audio Boston Acoustics BA735
| David said "Kinda makes me wonder if it uses S/PDIF."
|
| Naturally I tried to determine that by going to the Boston Acoustics web
| site. BA735 systems aren't directly listed, but I found their
| search-string entry box where I entered "BA735." That displayed a link
| described as "Gateway Computers." Clicking on that link displayed a
| blank screen. This reference page also asked if that link addressed what
| I wanted to learn. I answered no, hoping it would give an opportunity to
| request information about BA735 digital audio standards compliance. But
| it just produced a survey "Thank you" screen. That's why I asked if
| anyone has tried connecting them to their Archos. If we knew they are
| S/PDIF compliant, we'd already know if they'll plug and play with our
| Archos units.
|
| Hopefully some subscriber has access to a BA735 audio system.
| John
| LoveLearn
|
| ================================================================
| Deze e-mail is door E-mail VirusScanner van Planet Internet gecontroleerd
op virussen.
| Op http://www.planet.nl/evs staat een verwijzing naar de actuele lijst
waar op wordt gecontroleerd.
|

[LoveLearn]

I'll have a BA735 system in hand shortly.

My initial selection of search strings brought up pages and pages of
links. Those I first selected as appearing most interesting didn't
mention S/PDIF input. That caused Joris van den Heuvel to say "Have you
ever heard of a place called "Google"?" That unwelcoming sarcasm was
justified? Let's be kind to each other.

I've now found over 30 I-net references claiming BA735 systems only
accept digital input. I assumed those reports must be true because they
were uncontested, so I repeated that opinion in my earlier post. But
frequency of repeating common misunderstanding about Archos non-standard
audio connections, which require special plugs for some options, does
not make those opinions correct. I've now found information which
indicates Boston Acoustics also configured their BA735s for Gateway in
some poorly documented but versatile non-standard way. Read this copy
from the Gateway Support link which follows:
*********
The speaker has analog input and a cable, digital S/PDIF input, and a
cable for direct connection to a sound card with a digital S/PDIF
output. . . . . . . . . . Note: If a digital cable is connected but the
sound card does not support digital output, no sound is heard. The
analog cable needs to be used in this instance. This is important to
remember when troubleshooting these speakers."
*********
http://support.gateway.com/s/SOUND/bostonac/7001332/U0133201.shtml

Now it appears likely that BA735 systems can interface with our Archos
digital output. This Gateway support page references two differently
configured cables, one for analog input, the other for S/PDIF digital
feeds. So their current unpopularity, based on a widely held opinion
that they can ONLY accept digital input, is unjustified if Gateway's
support page is right. That makes their depressed used market pricing
even more attractive.

I know little about loading S/PDIF outputs. How far can we extend those
lines? Could we split them so one Archos output could control several
BA735 inputs simultaneously? Various possible applications come to mind.
Consider motorhomes where "house" 12 volt DC might substitute for the
stock 12 volt BA735 power supply. Or consider domestic home feeds with
remote S/PDIF sound systems that can be switched on where and when
they're sound is wanted. If S/PDIF inputs are super low impedance and
coax would allow output sharing over long distances, I'd like a bunch of
these for $10 a pop by visiting a vendor dumping them. If someone knows
about S/PDIF systems, I expect several participants would be interested
to learn what limits their distribution capabilities.

After I have a BA735 system in hand, I'll report how my Archos JBR 20
digital audio interconnection works with it.
John
LoveLearn

[Brian Wolven]

Post by LoveLearn
After I have a BA735 system in hand, I'll report how my Archos JBR 20
digital audio interconnection works with it.

I'd like to hear what you have to say - I'd probably pick up one or two if
they work out well for you.

[LoveLearn]

Sharing research results:

1984 standard S/PDIF is unbalanced .5 volt originally designed for
lengths up to 1 meter.
For long feeds, lots of vendors sell S/PDIF converters to produce 1985
AES/EBU (Audio Engineering Society/European Broadcast Union), a balanced
5 volt similar standard reportedly useful to 100 or 200 meters,
depending on which description you read.

From http://www.soundonsound.com/sos/Jun03/articles/qa0603.asp

"You can run S/PDIF up to a metre or two without any problems at all,
almost regardless of the type of cable, and if you use decent 75(omega)
coaxial cable (proper 'digital' cable or standard video coax) you can
run an S/PDIF signal several metres.
However, if you are intending to run an S/PDIF signal to a D-A converter
I would say keep the cable as short as you possibly can, because
cable-induced jitter will affect the decoder's clock in a detrimental
way. The D-A relies directly on the embedded clock signal and cable
jitter will mess this up. The longer the cable, the more capacitive it
is and the greater the jitter will become. Very few budget D-A
converters have decent jitter-rejection properties able to cope with the
effects of long cables. Jitter can be heard as a vagueness in the stereo
imaging and very flat, two dimensional sound stages on well-recorded
acoustic material."

Satisfied S/PDIF cable user reports seem to stop at about 12 feet. So
much for the cheap long runs pipe dream. I still don't know if a single
S/PDIF output can simultaneously drive two inputs using a simple in-line
splitter.

Here's an instructive S/PDIF site:
Andrew's S/PDIF Stuff
http://www.andrewkilpatrick.org/mind/spdif/

[David McIntyre]

The MAS data sheets have an errata that covers unstable S/PDIF clock signals.
They recommend using parity and checking after every frame. Talk about a pain
in the butt! I wonder if that's handled in the Archos code.

Post by LoveLearn
1984 standard S/PDIF is unbalanced .5 volt originally designed for
lengths up to 1 meter.
For long feeds, lots of vendors sell S/PDIF converters to produce 1985
AES/EBU (Audio Engineering Society/European Broadcast Union), a balanced
5 volt similar standard reportedly useful to 100 or 200 meters,
depending on which description you read.

From http://www.soundonsound.com/sos/Jun03/articles/qa0603.asp

"You can run S/PDIF up to a metre or two without any problems at all,
almost regardless of the type of cable, and if you use decent 75(omega)
coaxial cable (proper 'digital' cable or standard video coax) you can
run an S/PDIF signal several metres.
However, if you are intending to run an S/PDIF signal to a D-A converter
I would say keep the cable as short as you possibly can, because
cable-induced jitter will affect the decoder's clock in a detrimental
way. The D-A relies directly on the embedded clock signal and cable
jitter will mess this up. The longer the cable, the more capacitive it
is and the greater the jitter will become. Very few budget D-A
converters have decent jitter-rejection properties able to cope with the
effects of long cables. Jitter can be heard as a vagueness in the stereo
imaging and very flat, two dimensional sound stages on well-recorded
acoustic material."
Satisfied S/PDIF cable user reports seem to stop at about 12 feet. So
much for the cheap long runs pipe dream. I still don't know if a single
S/PDIF output can simultaneously drive two inputs using a simple in-line
splitter.
Andrew's S/PDIF Stuff
http://www.andrewkilpatrick.org/mind/spdif/

[Leslie Donaldson]

Well according to the page :

http://www.epanorama.net/documents/audio/spdif.html

there is the wire version that feeds into a 75ohm cable (think networking
cables here) and a fiber version. The fiber version you could easily
make a splitter the cable version could be tough.
Also the S/PDIF IO is unidirectional..

from web site

Characteristics

Standard IEC958 "Digital audio interface" from EBU (European Broadcasting Union) details:

* Audio format : linear 16 bit default, up to 24 bit expandable
* Allowed sampling frequencies (Fs) of the audio:
o 44.1kHz from CD
o 48 kHz from DAT
o 32 kHz from DSR
* One way communication: from a transmitter to a receiver.
* Control information:
o V (validity) bit : indicates if audio sample is valid.
o U (user) bit : user free coding i.e. running time song, track number.
o C (channel status) bit : emphasis, sampling rate and copy permit.
o P (parity) bit : error detection bit to check for good reception.
* Coding format: biphase mark except the headers (preambles), for sync purposes.
* Bandwidth occupation : 100kHz up to 6Mhz (no DC!)
* Signal bitrate is 2.8Mhz (Fs=44.1kHz), 2Mhz (Fs=32kHz) and 3.1Mhz (Fs=48kHz).

Physical connection:

* Cable: 75ohm +/-5% (l<10m) or 75ohm +/-35% (l>10m)
* Line driver:
o Zout: 75ohm +/-20% (100kHz .. 6Mhz)
o Vout: 0.4Vpp .. 0.6Vpp, <0.05Vdc (75ohm terminated)
* Line receiver:
o Zin: 75ohm +/-5%
o Vin: 0.2Vpp .. 0.6Vpp

[Chris Holt]

Post by Leslie Donaldson
S/PDIF IO is unidirectional..

Or perhaps to say, S/PDIF input only.

"IO is unidirectional" is as much of an oxymoron as "Government
Intelligence" :)

Looks like a cool set! Thanks for the good specs!

Chris

[DarkAngel]

just a question : is it possible to use the numeric output on the jukebox
recorder (model20) ?
I've not tested it yet and I found no info about this on archos web site !!
so how to activate it ? supported in rockbox ?
thanx,
Stéphane

PS: flashed AJBR20 is working great ! thousands of thanx for it !!!

----- Original Message -----
From: "Chris Holt" <***@cox.net>
To: <***@cool.haxx.se>
Sent: Saturday, September 06, 2003 1:02 AM
Subject: Re: Cheap/good digital-audio Boston Acoustics BA735

Post by Chris Holt

Post by Leslie Donaldson
S/PDIF IO is unidirectional..

Or perhaps to say, S/PDIF input only.
"IO is unidirectional" is as much of an oxymoron as "Government
Intelligence" :)
Looks like a cool set! Thanks for the good specs!
Chris

[Leslie Donaldson]

Okay a better way would be to say

I^O (xor operator)
because it all depends on which end of the pipe you're looking
down.

Anybody know of an usb bridge device? Connect to slave usb
devices together. hmmm ..

Post by Chris Holt

Post by Leslie Donaldson
S/PDIF IO is unidirectional..

Or perhaps to say, S/PDIF input only.
"IO is unidirectional" is as much of an oxymoron as "Government
Intelligence" :)
Looks like a cool set! Thanks for the good specs!
Chris

[BlueChip]

Post by Leslie Donaldson
Okay a better way would be to say
I^O (xor operator)
because it all depends on which end of the pipe you're looking
down.
Anybody know of an usb bridge device? Connect to slave usb
devices together. hmmm ..

the dilemma there is that the device in the middle will need to know the
protocols for both of the communicating devices, on the hdd side it is a
standard "USB hard drive" I don't know if cameras are the all the same!?

Post by Leslie Donaldson

Post by Chris Holt

Post by Leslie Donaldson
S/PDIF IO is unidirectional..

Or perhaps to say, S/PDIF input only.
"IO is unidirectional" is as much of an oxymoron as "Government
Intelligence" :)
Looks like a cool set! Thanks for the good specs!
Chris

[Chris Holt]

Post by BlueChip

Post by Leslie Donaldson
Okay a better way would be to say
I^O (xor operator)
because it all depends on which end of the pipe you're looking down.
Anybody know of an usb bridge device? Connect to slave usb devices
together. hmmm ..

the dilemma there is that the device in the middle will need to know
the protocols for both of the communicating devices, on the hdd side it
is a standard "USB hard drive" I don't know if cameras are the all the
same!?

Actually the terminology is Mass Storage Device or MSD. There are several
devices with HDD onboard that will connect to most any MSD conforming
device, as most digital cameras (and a few MP3 players) are, and these
devices typically include a card reader. I have not run across a USB
"bridge" device as described though. It is technically possible, but the
key would be if there was a market for such a device.

Of course the JBMM with card reader could act as one of these devices, but
I do understand the desire to use already purchased devices for additional
functionality.

Chris

[Leslie Donaldson]

Very true on the proticols. The slave protocoil you can snip and
clip so much of it away. My problem is I haven't found any embedded
style master USB ports (of any speed). I work with PICS some and they
are easy to hook up as slaves but no master. Sigh. Other projects..

Donaldson

Post by Leslie Donaldson
Okay a better way would be to say
I^O (xor operator)
because it all depends on which end of the pipe you're looking
down.
Anybody know of an usb bridge device? Connect to slave usb
devices together. hmmm ..

the dilemma there is that the device in the middle will need to know the protocols for both of the communicating devices, on the hdd side it is a standard "USB hard drive" I don't know if cameras are the all the same!?

Post by Leslie Donaldson

Post by Chris Holt

Post by Leslie Donaldson
S/PDIF IO is unidirectional..

Or perhaps to say, S/PDIF input only.
"IO is unidirectional" is as much of an oxymoron as "Government
Intelligence" :)
Looks like a cool set! Thanks for the good specs!
Chris