Hello everybody,
my 23 y.o. Sonic Frontiers Line sometimes generates a low frequency humming that persists for a few seconds and then disappears. And also its S/N ratio is not so good, despites the 6 tubes are brand new.
Guys from Parts Connexion suggest to replace all the electrolytics, the two volume control IC's (Burr Brown PGA2311 in place of the old Cirrus Logic CS3310) and all the linear regulators (LM317 and LM7805).
Electrolytics are obiuously over the enad of life, and the PGA2311 should be an improvement over the current CS3310 in terms of S/N ratio. But what about the regulators ? Does a linear regulator exhibit aging problems ?
Any other suggestions ?
Thank you
Davide
my 23 y.o. Sonic Frontiers Line sometimes generates a low frequency humming that persists for a few seconds and then disappears. And also its S/N ratio is not so good, despites the 6 tubes are brand new.
Guys from Parts Connexion suggest to replace all the electrolytics, the two volume control IC's (Burr Brown PGA2311 in place of the old Cirrus Logic CS3310) and all the linear regulators (LM317 and LM7805).
Electrolytics are obiuously over the enad of life, and the PGA2311 should be an improvement over the current CS3310 in terms of S/N ratio. But what about the regulators ? Does a linear regulator exhibit aging problems ?
Any other suggestions ?
Thank you
Davide
No, the regulators either work or don‘t work, its the caps that age.
Yes change the electrolytics. But its not likely the caps, they don’t get better in a few seconds, then are good, then go bad, their either bad or not. If its just at turn on maybe a cap, but
Yes Change the volume control chip, and get rid of the TO 92 +/- 5 volt regulators that feed the volume control and run it off the 12 volt supplies, ( prevents clipping with high output dacs). You can‘t remove the 5 volt regulators without doing the volume control chips. This won‘t cure the hum, just sound better
Hum, if it isn’t the electrolytics, then either a bad transfomer, or DC on your power line (get the DC line filter group buy).
Yes change the electrolytics. But its not likely the caps, they don’t get better in a few seconds, then are good, then go bad, their either bad or not. If its just at turn on maybe a cap, but
Yes Change the volume control chip, and get rid of the TO 92 +/- 5 volt regulators that feed the volume control and run it off the 12 volt supplies, ( prevents clipping with high output dacs). You can‘t remove the 5 volt regulators without doing the volume control chips. This won‘t cure the hum, just sound better
Hum, if it isn’t the electrolytics, then either a bad transfomer, or DC on your power line (get the DC line filter group buy).
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Before removing the electrolytics I have checked all the test points and found a couple of issues, but no idea whether these can affect the sound:
1. The voltage FIL 1 REG. coming from the regulator SLIC1 exhibit a little drop for some milliseconds at 50 Hz (see attahced picture)
2. The floating 165V-UNR was only 129 V (with Vmain = 226 Vac), actually too low to make the negative linear regulator work correctly (see attached picture).
Maybe these issues could depend on the leaky old caps ?
I don't think so.... in particular the issue #1 demonstrate that there's a problem with the rectifier, that operates as a half wave rectifier !! Do you agree ?
1. The voltage FIL 1 REG. coming from the regulator SLIC1 exhibit a little drop for some milliseconds at 50 Hz (see attahced picture)
2. The floating 165V-UNR was only 129 V (with Vmain = 226 Vac), actually too low to make the negative linear regulator work correctly (see attached picture).
Maybe these issues could depend on the leaky old caps ?
I don't think so.... in particular the issue #1 demonstrate that there's a problem with the rectifier, that operates as a half wave rectifier !! Do you agree ?
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It is not at turn on: it rarely happens, sometimes after hours of operation... I have the feeling that it happens when the main voltage drops a little bit, maybe caused by the issue #2 explaied in my previous post.
Sorry I don't understand: the PGA2311 must be feed with +5V as the CS3310..... Please can you explain better ?
Opps , wrong part number
you want PgA 2310 and take out the 5 volt regulators and run them on the 12 volt supplies
you want PgA 2310 and take out the 5 volt regulators and run them on the 12 volt supplies
ticknpop the PGA 2311 was recommended directly from Parts Connexion’s guys.... why do you recommend the 2310 instead ?
i guess the right device is PGA2311
i own the Line 1 SE and i have replaced the old CS3311 wiht the BB but i am not sure if the technician used the 5V or 12V
there is a way to chech the voltage used?
Subscribed. I hope you keep us updated with your progress. I literally just picked up a Line 1 on consignment at a local shop for a very good price last week and am planning to update the electrolytics at the very least.
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