The heaters are 6.6. It's a GZ32, the original Mullard tube, and the caps are 22uF. Hmm!
I powered up the other amp which had had the same treatment and got exactly the same results - the KT66 which didn't heat up originally now does heat up so I think perhaps it was a dirty tube socket. I've cleaned them all and tightened the pins.
One thing I've noticed also is that the chokes get quite hot after a while. I've not had Quad IIs before so I'm not sure if this is typical or because of the high line voltage.
I powered up the other amp which had had the same treatment and got exactly the same results - the KT66 which didn't heat up originally now does heat up so I think perhaps it was a dirty tube socket. I've cleaned them all and tightened the pins.
One thing I've noticed also is that the chokes get quite hot after a while. I've not had Quad IIs before so I'm not sure if this is typical or because of the high line voltage.
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I just measured 375V at C4 on a Quad II, and over 200 degrees F on the KT66s. Line voltage here is 247VAC and the power transformer is set to 235-240. I can't identify the rectifier. Possibly you have a GZ34 instead of a GZ32, and possibly this one in front of me does too. The KT66s in the Quad II run at 2/3 their power rating, so a little extra voltage does no real harm.
It is normal for the choke to run a little warm.
EJP
It is normal for the choke to run a little warm.
EJP
The CL90 is a worthwhile change, you will lose a few volts too.
Do you live next to a power station ;-)
Maybe your meter is not accurate - what do you get for mains?
6.6v is probably ok, and as the previous poster pointed out, KT66s are not being abused by the B+. If the transformers get too hot you will see leaking tar inside the amp. But if they run cool, it is probably nothing to fret about.
Do you live next to a power station ;-)
Maybe your meter is not accurate - what do you get for mains?
6.6v is probably ok, and as the previous poster pointed out, KT66s are not being abused by the B+. If the transformers get too hot you will see leaking tar inside the amp. But if they run cool, it is probably nothing to fret about.
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