Hello!
Have the relay volume controls any advantage over a good old volume potentiometer?Do they have a other sound characteristic?maybe cleaner?Good for a tube preamp?
Best regards
Reza
Have the relay volume controls any advantage over a good old volume potentiometer?Do they have a other sound characteristic?maybe cleaner?Good for a tube preamp?
Best regards
Reza
Relay or otherwise switched volume networks can have performance advantages over potentiometers. Potentiometers can sometimes generate distortion from the imperfect wiper contact to the track. The track can also wear out, or cause dropouts if the pot is used heavily or if it's low quality. Switched resistors can be stable, low noise, and low distortion film types. A pot can have tracking problems between channels, and can be hard to precisely set and re-set. If the pot is wired improperly, HF feedthrough can cause timbre changes with different attenuations. This could also happen with any sort of circuit, but the packaging of a pot makes it easier for a person to get too much capacitive coupling from the wiper lead to the top of the track, causing this problem.
The disadvantages are that a switched network can be really expensive to build due to the number of relays required, the number of resistors required, or for a rotary switch, the high cost of a switch with many poles and multiple sections. Switching is also "hard on" and "hard off", and will almost always generate some form of glitch or click, unless an output soft mute and soft un-mute circuit is added. Relays are also not easy to get to switch at exactly the same time, and turning on and off take different times. So, odd code dependent glitches can be caused that, depending on the network, could make pretty large spikes in the output as the device is switched.
Most of the problems can be eliminated by good design, so any useful discussion has to be in the context of a specific circuit and design. That can also be said of pots too - some potentiometers are really very nice, and can work pretty well, despite the possibility of various problems.
The disadvantages are that a switched network can be really expensive to build due to the number of relays required, the number of resistors required, or for a rotary switch, the high cost of a switch with many poles and multiple sections. Switching is also "hard on" and "hard off", and will almost always generate some form of glitch or click, unless an output soft mute and soft un-mute circuit is added. Relays are also not easy to get to switch at exactly the same time, and turning on and off take different times. So, odd code dependent glitches can be caused that, depending on the network, could make pretty large spikes in the output as the device is switched.
Most of the problems can be eliminated by good design, so any useful discussion has to be in the context of a specific circuit and design. That can also be said of pots too - some potentiometers are really very nice, and can work pretty well, despite the possibility of various problems.
Once you use a switched resistor volume control, you'll never go back, even a good low cost one.
DACT Type SMD Stepped Attenuator 21 step volume control pot D Shape Shaft | eBay
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