Originally Posted by DDaveBB:
“I've spent a 'happy' half-hour replacing the ceramic filters on the 2nd Sony SB920. The hardest bit was getting the SIL sockets to stay in place. (Homemade from chopped up DIL IC sockets).
I've fitted 3 x 180 + 1 x 110 kHz filters - which for me seems to be the 'best' compromise. I haven't done any mixing and matching yet and now the reception cuts off more sharply on the high side - it must be down to how closely the filters are matched which I'm sure doesn't happen when they were made. So on another occasion I'll try using some other of the filters.
Switching to narrow makes a very noticeable reduction in splatter from adjacent channels and can be the difference between hearing and not hearing a station - so I don't understand a comment elsewhere that there is a lot of signal leakage. Also there seems to be very little difference in the RDS sensitivity betweeen the wide and narrow positions - although in comparison with the previously modded SB920 I can see that the overall RDS sensitivity has been reduced - as the two respond almost identically now.
I keeping waiting for some 'good' tropo - out beyond 500km - I've had days and days of 'local' stuff up to 400-450km away but apart from a duct to Norway a couple of weeks ago it has quite developed.
David
Sittingbourne”
“I've spent a 'happy' half-hour replacing the ceramic filters on the 2nd Sony SB920. The hardest bit was getting the SIL sockets to stay in place. (Homemade from chopped up DIL IC sockets).
I've fitted 3 x 180 + 1 x 110 kHz filters - which for me seems to be the 'best' compromise. I haven't done any mixing and matching yet and now the reception cuts off more sharply on the high side - it must be down to how closely the filters are matched which I'm sure doesn't happen when they were made. So on another occasion I'll try using some other of the filters.
Switching to narrow makes a very noticeable reduction in splatter from adjacent channels and can be the difference between hearing and not hearing a station - so I don't understand a comment elsewhere that there is a lot of signal leakage. Also there seems to be very little difference in the RDS sensitivity betweeen the wide and narrow positions - although in comparison with the previously modded SB920 I can see that the overall RDS sensitivity has been reduced - as the two respond almost identically now.
I keeping waiting for some 'good' tropo - out beyond 500km - I've had days and days of 'local' stuff up to 400-450km away but apart from a duct to Norway a couple of weeks ago it has quite developed.
David
Sittingbourne”
Hi David,
I'm glad to hear you've sorted the installation of SIL sockets in your Sony ST-SB920.
I had my heart in my mouth when I performed this soldering operation, but all is well now
.You've completed the most difficult job, so you can now enjoy the next stage (mixing and matching filters).
My final/best filter arrangement is as follows ->
Filters 1, 2 & 3 (wide) = 150Khz (x3)
Filter 4 (narrow) = 110Khz (x1)
As I'm using (fairly narrow) 150Khz filters for "Wide" mode, there is a less noticeable difference when I switch to "Narrow" (110Khz), compared to what I would expect from 3x 180Khz and 1x 110Khz (as you have), but there is still a difference.
I've also read elsewhere about the 3rd & 4th filters not being very effective, due to "leakage", but I'm quite happy with the results I have.
You may need to adjust the "Stereo Level" and "Narrow Gain" controls, now that you have different filters installed.
The "Stereo Level" adjustment seems to also affect the display (or otherwise) of RDS. I have now set mine to maximum. (If you end up with weak stations giving noisy stereo, just press "Mono" on the front of the tuner).
The "Narrow Gain" control is now also set to maximum. This gives me the best reception on weak stations.
Chris.





