Marantz 8B help needed!
- Thread starter callahan1973
- Start date
-
- Tags
- amp amp bias marantz marantz 8b
kstlfido
Member
Hope you find the issue.
Regarding replacing signal caps- do your homework first. Some caps produced back in the day were mylar-paper and do not have the leakage issues that other caps have (like sprague bumblebees). Usually, the red-print black body spragues are mylar film. As is the Cornel-Dublier avocado green caps and some El Menco's. I can't recall if the good-alls are mylar. Test for leakage. Have an old Radio-Master catalog and check the cap codes. If mylar & good, leave them in place; they will last. Keep it original if possible. A truly legendary amplifier.
Regarding replacing signal caps- do your homework first. Some caps produced back in the day were mylar-paper and do not have the leakage issues that other caps have (like sprague bumblebees). Usually, the red-print black body spragues are mylar film. As is the Cornel-Dublier avocado green caps and some El Menco's. I can't recall if the good-alls are mylar. Test for leakage. Have an old Radio-Master catalog and check the cap codes. If mylar & good, leave them in place; they will last. Keep it original if possible. A truly legendary amplifier.
If you are still having problems, let me know and I will measure B+ etc., it won't be difficult to isolate the problem.
8B's are a legend, sell for a lot, less changes the higher the value. So it can be difficult to decide how much to update. I updated one, left another stock, so I could compare the sound. Coupling caps I mixed PIO's and film in the one I updated. I have used orange drops in lesser value amps, they sound ok. Since they have already been changed to orange drops, I suggest fix your problem first then upgrade them. I have seen original replacements on ebay, that would help the value, but you would need to keep an eye on them.
8B's are a legend, sell for a lot, less changes the higher the value. So it can be difficult to decide how much to update. I updated one, left another stock, so I could compare the sound. Coupling caps I mixed PIO's and film in the one I updated. I have used orange drops in lesser value amps, they sound ok. Since they have already been changed to orange drops, I suggest fix your problem first then upgrade them. I have seen original replacements on ebay, that would help the value, but you would need to keep an eye on them.
Wow, whomever worked on that did a real hatchet job! So sorry . . . ;-)
junkscience
New Member
I see that there are AudioCap Thetas at the "input" (as is mine).
That said, a note to those researching the Marantz 8b set up: connect the amp input RATHER through the "TEST"! Counterintuitive, but true.
There are many authoritative references such as Steve Hoffman who wrote: "By the way, always use the TEST inputs on the back with your interconnects. This insures you get the full bandwidth". The posters go on to say that, the "PREAMP" inputs added low-frequency filtering to the circuit for turntable rumble (not a feature in modern decks), whereas the "TEST" input does not.
detroithifi
New Member
The PO did the replacement, a 400V/1A diode should do fine.
