Re: Confused on which DTV converter box... (Zenith Box Audio)

"Del Mibbler" <mibbler@[EMAIL PROTECTED]
> wrote in message 
news:0apg2451msb02sts6hj549lnt8prfo6b2j@[EMAIL PROTECTED]
> "trigonometry1972@[EMAIL PROTECTED]
 |" 
> <trigonometry1972@[EMAIL PROTECTED]
> wrote (in
> part):
>>
>>Manual bypass instead of pass thru is a real pain 
>>especially if
>>one has problems with a weak signal.
>>
>>The Zenith box while lacking the im****tant pass thru 
>>feature
>>seems to work well on the digital signal even when
>>subject to really nasty interference from high power 
>>lines.
>>The converter box form Radioshack has more features
>>though it also lacks pass thru.
>
> Re****tedly the Zenith DTT901 will have passthrough as well 
> as a fix
> for the DTT900's widely-re****ted audio problems.  But it's 
> not
> available yet (June, maybe), nor is it on the approved 
> CECB list.
>
> Del Mibbler

I have a DTT900 Zenith box (Feb '08 manufacture) and there 
is indeed an audio problem on the baseband audio from the 
RCA jacks. It appears they apply the 75 micro-second 
pre-emphasis to the audio as required by the NTSC standard 
for the channel 3,4 modulator, but also send the 
pre-emphasized audio to the RCA baseband outputs. The error 
is in both channels (not just the left channel as re****ted 
on some forms). The board layout allows an easy fix for 
this. The series impedance between the audio driver and the 
output jacks is 4300 ohms composed of 1K and 3.3K resistors. 
You need to shunt the audio outputs with 0.018 microfarad 
capacitors to get the response flat. If you are handy with 
soldering surface mount capacitors, there are places on the 
top of the board to mount them. If not, you can solder 
leaded capacitors directly across the audio outputs or use 
external capacitors.

David