Power-switch & Volume-control in one?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Member
Joined 2017
Paid Member
Hello everyone!

I‘m in the process of Building my own gear, quite basic, and think about making it as minimalistic (looking 🤓) as possible. (I‘ll end up with some rather fancy stuff inside but that‘s ok.)
Here‘s what bites me for the moment: I‘d like to combine the power on/off and the volume-knob, just like in these old pocket-transistor-radios... on the other hand, I‘m drooling over those ladder-attenuators...
Can they be brought together somehow (electronically, mechanically, ...)

Thanks already!
Da.
 
Member
Joined 2017
Paid Member
Here‘s what bites me for the moment: I‘d like to combine the power on/off and the volume-knob, just like in these old pocket-transistor-radios... on the other hand, I‘m drooling over those ladder-attenuators...
It's ok ONLY if that is a battery-powered device or you put a switch in low-voltage secondary power lines, isolated from primary mains (mains are always connected).
 
Last edited:
Member
Joined 2017
Paid Member
- they are all battery powered! Don't do that with 110-230 VAC!
:eek:

Thanks for the advice!
I was thinking of a tricked design: Having the attenuator-knob mechanically switching the power-switch... Or, like, have the Attenuator trigger a relay which switches the mains on/off...
I'm sure you can read out of these that I am no expert... and, I know it's not thought through, but I'm "having visuals". I may try to build something (someday).

da.
 
Old tube TV were far from today safety standarts. So they are not a good example
In modern audio-devices, usually it is used a way with auxiliary power supply and low-voltage low-current switch (button), which operates a power relay or semicunductor switch, which turns on main power supply.
 
Yes, but it generates other problems, like power spent continuously from this stand by circuitry. I prefer the classic switch.

I have built circuits in the past that used a battery to initially turn on the power relay, which was then switched out by one of the relay contacts once the ac power supply came on. This way there is no current draw at all until the power switch is turned on and since the battery supplies only a short pulse of power it lasts a very long time before needing replacement.

Take care,
Doug
 
Here is an example of a circuit to do this.

K1 is a relay with a 9 volt rated coil and needs to have a sufficient contact rating for powering all of the desired power supplies. The LM311 comparator senses the power switch position and activates the relay using the 9 volt battery. The 100uF capacitor across the relay coil holds it on until the AC powered 9 volt power supply can take over. The 9 volt power supply actually supplies about 11 volts, ensuring that it powers the relay and circuit instead of the battery. I have had the batteries in these power supplies last many years before requiring replacement.

Take care,
Doug
 

Attachments

  • powercircuit.gif
    powercircuit.gif
    5 KB · Views: 77
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.