Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: Cheap/good digital-audio Boston Acoustics BA735
From: Chris Muth (rockbox_at_muth.cc)
Date: 2003-10-18


Hey,

I also acquired a set of BA735 speakers off of eBay.

When I hooked them up to my JBR15, the audio level was extremely low, even at full volume.
I sent them back the the seller said that they were defective. The seller said that he tested the new
set and they worked. There was evidence of testing. The plastic on the subwoofer was torn near the
connectors on the back/bottom. The new set acts identical to the old set. They are very quiet.
How he could find the old speakers to be defective, and not the new ones, I don't know.

The connector on the JBR for the digital out, has three contacts. From the outside in, they are;
ground, digital out (of JBR), and digital in (to JBR). I used the cable that came with the speakers by simply not
inserting in fully. That way it would only contact the ground and the digital out. The volume was very low.
I used two different pairs of stereo mini-jack->RCA cables. Both worked, and produced the same results as the
cable provided with the speakers.

It is not a cable issue. The signal is digital. It is either going to get to the speakers without corruption and work,
or it will be too corrupted for the speakers to understand. Low volume would not be a symptom of a corrupted signal.
A corrupted signal would produce similar things to a corrupted mp3, such as crackling, popping, and so on.

My best guess is that the S/PDIF format that the JBR is sending is not quite what the speakers want.

On a side note, I was also seriously disappointed with the signal to noise ratio of the BA735 speakers..
Notice now you can go to your local electronics store and buy dirt cheap amplified analog computer speakers and they will
have a terrible signal to noise ratio? Well, these are simply the digital counterpart of the analog ones. Don't thing that because
they are digital that they will be high quality speakers. Remember that Gateway (note Gateway's general quality) was
giving these away.

-Chris

On 10/17/03 at 3:26 PM LoveLearn wrote:

>More than a year ago I heard and was favorably impressed with sounds
>produced by a Boston Acoustics BA735 digital digital decoder/amps/3-way
>speaker system. Boston Acoustics made these for Gateway as OEM digital
>output systems. Recently I encountered eBay offers for them at very low
>prices. Last month I suggested that we consider using them with our
>Archos digital output jacks. I just acquired a set. They were tested
>before shipping and worked well with Gateway computer digital output.
>
>I just opened a new Belden cable package I happened to own. The cable
>has a stereo 3-contact mini phone plug on one end. The other end splits
>into a pair (left and right) of male RCA phono plugs. I don't have an
>Archos manual which might list specifications for the required cable.
>Using either of this audio cable's 2 RCA phono plugs enables the BA735s
>to produce very quiet audio output, depending on how far the plug is
>inserted into the Archos. It seems pretty clear that this isn't an
>appropriate cable.
>
>I think my ARJ 20 digital jack has 4-connectors. What plug and a cable
>do I need? Does it need to be specially configured to carry high
>frequency signals? The BA735 digital input jack appears to be a common
>female RCA phono jack. A low cost suitable cable is preferred to high
>Archos prices. If this works out well, other Archos owners may acquire
>these systems and need cables. Thanks for your consideration.
>John



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa