There's a shielded cable connecting one end of the loudness control, can the shield have been disconnected?
McIntosh C26 Manual - Stereo Pre Amplifier - HiFi Engine
McIntosh C26 loudness humming after recap solved.
McIntosh C26 loudness control humming solved !
Do not place ground leads on the first stage electrolytic or star ground off that first stage ( there other ground paths elsewhere which create a loop and get you into trouble! ). Respect the same grounding scheme as the original can electrolytics as per on the schematic. First stage cap ground is attached to ground lug of center tap of power transformer. And you're all set !
McIntosh C26 loudness control humming solved !
Do not place ground leads on the first stage electrolytic or star ground off that first stage ( there other ground paths elsewhere which create a loop and get you into trouble! ). Respect the same grounding scheme as the original can electrolytics as per on the schematic. First stage cap ground is attached to ground lug of center tap of power transformer. And you're all set !
Attachments
Yet another recapping adventure that went badly wrong.
This one had a happy end for some, but apparently not for the OP.
How many times will we need to hammer this: if it ain't broke, don't fix it.
Most quality caps used in quality gear do not age, or do so gracefully.
They sometimes fail, and need to be replaced, but generally they are perfectly OK.
I still have unopened bags of Siemens E-lytics dating back from the mid-seventies, and I when I use them (yes, I still use them), I don't even care to reform them: I just put them to work in circuit, and they just work. They are bulky, by today's standards, but they are excellent, even by today's standards: they manage to outperform some modern low-ESR types.
I have had to replace numbers of worn caps, even in equipments made by reputable manufacturers, like HP, MacIntosh and others, but I only do so when it is actually necessary.
So-called "preventative maintenance" often ends up doing more harm than leaving things in their condition.
If you are still unconvinced, search for recapping stories that turned sour on the forum. It should make you think twice about "ornamental tweaks", like unnecessary recappings.
This one had a happy end for some, but apparently not for the OP.
How many times will we need to hammer this: if it ain't broke, don't fix it.
Most quality caps used in quality gear do not age, or do so gracefully.
They sometimes fail, and need to be replaced, but generally they are perfectly OK.
I still have unopened bags of Siemens E-lytics dating back from the mid-seventies, and I when I use them (yes, I still use them), I don't even care to reform them: I just put them to work in circuit, and they just work. They are bulky, by today's standards, but they are excellent, even by today's standards: they manage to outperform some modern low-ESR types.
I have had to replace numbers of worn caps, even in equipments made by reputable manufacturers, like HP, MacIntosh and others, but I only do so when it is actually necessary.
So-called "preventative maintenance" often ends up doing more harm than leaving things in their condition.
If you are still unconvinced, search for recapping stories that turned sour on the forum. It should make you think twice about "ornamental tweaks", like unnecessary recappings.