It's a long shot (seeing as searches throw up zilch) but would anyone have a schematic or service info for a cary ph301. It's an all valve mm/mc unit with 2 x 12au7 2 x 12ax7 and a 5814a as an output buffer. I'm particularly looking for operating points, voltages etc.
Alternatively, could someone point me towards a similar schematic? Searches haven't thrown up much.
Also, can a 5814a be a substitute for a 12au7?
Any info most appreciated!
Fran
Alternatively, could someone point me towards a similar schematic? Searches haven't thrown up much.
Also, can a 5814a be a substitute for a 12au7?
Any info most appreciated!
Fran
Cary seems to be holding their cards extremely tight. Two of my brothers drive Carys ( and the third one McIntosh...). One of the Carys haveing been causing him some trouble, and we've both been searching for quite some time.
I'll be following this closely....if you succeed, please let me know.....?
I'll be following this closely....if you succeed, please let me know.....?
Will do......
When I got this in for repair (and hey, since when did I become a repair man? - since friends found out I could scrape through a repair!) there was a tantalum cap on the heater supply burnt out. The 12V reg for the heaters was also dead. So I replaced the cap and the reg and she all powered up OK.
A couple of the resistors in the power supply also were gone - probably as a result of the others going, and I replaced those with my best guess at voltages etc.
So I have it connected and powered up and it actually sounds good!! Within 20 mins though, another of the tantalum caps gave out in an interesting puff of pink smoke!! Now I think these really don't like AC at all, so I reckon there is insufficient filtering on the DC heater supply (bridge rectifier into 2200uF cap, then on to a metal can 7812), probably could set up a little filter there easily enough.
I can probably get it running without Cary's help, but it would be nice to be sure. I'm going to replace all the electrolytics (some of them bulging a bit) and the tants with electrolytics. I reckon they used the tants (10uf) just because the build is tight enough and it made life easy. Small low impedance 16V electrolytics are cheap enough it seems.
Fran
When I got this in for repair (and hey, since when did I become a repair man? - since friends found out I could scrape through a repair!) there was a tantalum cap on the heater supply burnt out. The 12V reg for the heaters was also dead. So I replaced the cap and the reg and she all powered up OK.
A couple of the resistors in the power supply also were gone - probably as a result of the others going, and I replaced those with my best guess at voltages etc.
So I have it connected and powered up and it actually sounds good!! Within 20 mins though, another of the tantalum caps gave out in an interesting puff of pink smoke!! Now I think these really don't like AC at all, so I reckon there is insufficient filtering on the DC heater supply (bridge rectifier into 2200uF cap, then on to a metal can 7812), probably could set up a little filter there easily enough.
I can probably get it running without Cary's help, but it would be nice to be sure. I'm going to replace all the electrolytics (some of them bulging a bit) and the tants with electrolytics. I reckon they used the tants (10uf) just because the build is tight enough and it made life easy. Small low impedance 16V electrolytics are cheap enough it seems.
Fran
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