R28 is the ballance control, R18 is the volume control
with two taps. The bottom one is for the loudness
circuit, but what is the top one for with R32 100k
to ground for? Won't thiis affect the loading
of the 12AT7 with changes to the ballance control?
with two taps. The bottom one is for the loudness
circuit, but what is the top one for with R32 100k
to ground for? Won't thiis affect the loading
of the 12AT7 with changes to the ballance control?
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No, it won't effect loading.
It basically is to modify the volume taper as the wiper is increased.
It basically is to modify the volume taper as the wiper is increased.
It adjusts the taper.
The loading due to the volume control is constant, but the R32 loading varies with the volume setting.
You can always change the volume control if you like. The balance control is worse, just a pot.
The loading due to the volume control is constant, but the R32 loading varies with the volume setting.
You can always change the volume control if you like. The balance control is worse, just a pot.
Yes, but what I see is that the load on the 12AT7 will vary between 147K at one end of the balance control
and 347K at the other end. Also I wonder if the altered taper to a log pot is worth it when going from a 500k load after the balance to a 100k load with adding R32, the increased load would seem to add to distortion. Would'nt a 100k pot with one tap cost less then a 500k pot with two taps and have less noise if the load is ok at 100k?
and 347K at the other end. Also I wonder if the altered taper to a log pot is worth it when going from a 500k load after the balance to a 100k load with adding R32, the increased load would seem to add to distortion. Would'nt a 100k pot with one tap cost less then a 500k pot with two taps and have less noise if the load is ok at 100k?
The balance control is normally just all the way up.
I won't second guess Stewart Hegeman here, and some of his design considerations may not be so obvious.
I doubt that price was the primary factor, though.
I won't second guess Stewart Hegeman here, and some of his design considerations may not be so obvious.
I doubt that price was the primary factor, though.
You're overthinking things here.Yes, but what I see is that the load on the 12AT7 will vary between 147K at one end of the balance control
and 347K at the other end. Also I wonder if the altered taper to a log pot is worth it when going from a 500k load after the balance to a 100k load with adding R32, the increased load would seem to add to distortion. Would'nt a 100k pot with one tap cost less then a 500k pot with two taps and have less noise if the load is ok at 100k?
Whatever 'loading' you're worried about is trivial and not worth obsessing over.
There is no 'distortion' adding involved in harman kardon's designs here.
Be reasonable.