I have a modulus86 and a parallel86 and both have an IEC module, mounted on the back panel, with a power switch so I have to reach around the back to turn on the power. I want to put an illuminated power switch on the front panel. My question should I use a 125VAC switch connected to the IEC module or a 36VDC switch connected to the PCBs?
I would go for the 125VAC switch. You save power as the transformer is not energized.
Thanks. I was leaning that way but also thought the transformer would not be energized because there would be no current flow.
Large power transformers use current even when their secondary's are disconnected.
It's due to the inherent losses within the transformer caused by the magnetic field generated.
And these days, are frowned upon by energy advocates.
A better solution that's been used by manufacturers is to have a tiny "standby" transformer always powered, feeding a relay circuit which is then used as a main power switch.
Those tiny transformers use maybe a watt or so, perhaps even less.
Then, a light-weight power switch can be used to trigger on the relay control circuit.
Such a switch can be rated for less than an amp, and some are illuminated.
So is the bottom line that it is better to use a 125VAC switch such that the transformer sees no votlage unitl the illuminated switch is turned on?
I would think so.
Besides, using a standby/relay design, the power switch wouldn't have the "strain" of line current, the relay would, and it's musch easier to replace if faulty, and save having to replace a (visible) AC switch due to contact failure.
Some push button switches have pretty limited current carrying capacity. I tried a 2 A, 250 V rated switch a while back. It lasted maybe 10 on/off cycles with an SMPS as the load. So you definitely want to use an inrush limiter with such a switch. Or get a beefy one.
And, yes. Switch the mains voltage.
Tom
And, yes. Switch the mains voltage.
Tom
Am I OK just reaching around the back of the amp to turn on the power? Both amps have an led on the front panel indicating when the power is on. I was just trying to find a simple way to trurn on the porwer without reaching around the back of the amps.
Then just drill a hole for a good switch rated 10-15A at least, and put a 0.047uF - 630V mylar cap across it to quell any internal contact sparking.
I'm more a fan of this solution. I find it is better for safety and radiated noise control to not bring mains AC all the way to the front chassis and back again. I also have trust issues with mains power going to a switch attached to the front chassis of any amp I build due to the amount of substandard switches out in the wild.
Having a small 12v transformer near the IEC which can (with simple rectification) power a 12VDC coil power relay, switching the AC primary, works well for me.
But that still puts mains AC along the length of the amp chassis and into a switch that may or may not be rated for what it says it's rated for.
The idea of the small transformer is to drop the voltage at the switch to safe levels and relatively noise free DC, and also to keep the magnetic noise at the rear of the chassis where it can be shielded away from the input circuitry.
Mark Johnson made a project on the subject: https://www.diyaudio.com/community/...ains-relay-includes-soft-start-h9kpxg.354971/
The idea of the small transformer is to drop the voltage at the switch to safe levels and relatively noise free DC, and also to keep the magnetic noise at the rear of the chassis where it can be shielded away from the input circuitry.
Mark Johnson made a project on the subject: https://www.diyaudio.com/community/...ains-relay-includes-soft-start-h9kpxg.354971/
I use this ultra-simple design based on a 4017 chip.
The momentary switch only handles a few milliamps, so any fancy switch can be used.
Additionally, pin 14 can be connected to a thermal overheating or DC protection circuit because a pulse at 14 will kill power.
The momentary switch only handles a few milliamps, so any fancy switch can be used.
Additionally, pin 14 can be connected to a thermal overheating or DC protection circuit because a pulse at 14 will kill power.
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One solution is to twist the AC wires along its run, and/or wrap those wires inside a shielded tube grounded to the chassis.
Some vintage manufactured amps/preamps used that design to keep interference contained.
Would connecting the mains and the antek as3224 to your ISS be a good solution. If so can a push button switch on the front panel control it? And what are the dimensions of the ISS?
That's what I'd recommend. Dimensions: 2.65 × 3.50 inch (68 × 89 mm) board footprint. The assembled module measures approximately 35 mm in height.
If you use the ISS you might as well use the low-voltage control of the ISS with your power switch. Just connect the power switch to the ISS and let it do the work. The ISS can be used both with toggle switches and momentary (doorbell) switches.
Tom
If you use the ISS you might as well use the low-voltage control of the ISS with your power switch. Just connect the power switch to the ISS and let it do the work. The ISS can be used both with toggle switches and momentary (doorbell) switches.
Tom
Got the ISSs today. Amazingly fast shipping. Not sure I understand anti-reverse but is my attached drawing correct?
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The image below is a screen shot from the ISS Rev. 2.02 design documentation.
On the PV6 you'll find four terminals. Two are gold plated and are unmarked. Those are for the switch. Two are tin plated and are marked R1.8V+ and G2.8V-.
The terminal marked R1.8V+ is the anode for the red LED. If you want the switch to glow red when the ISS is in standby you will want that connected to terminal 3 on the ISS. The terminal marked G2.8V- is the anode for the green LED. It goes to terminal 4 on the ISS. Then connect the switch to terminals 5 and 6.
See here for how to identify the switch terminals:
...and here for the connections to the ISS:
I'm not sure how you came up with the connection at S. That will short out both LEDs and you will get no indication of Standby/ON. If that's your goal, just don't connect the LEDs.
If you want to only have indication of Power ON, just turn the standby LED dimmer (white trimpot marked STBY) to minimum. Similarly if you only want Standby indication, just turn the Power ON LED dimmer (white trimpot marked PWR) to minimum.
For future reference (and everybody else's benefit): The best way to reach me for customer service type questions is to email me directly. Simply take my user ID here and add @neurochrome.com. You can also go through the Contact Us form on my website (www.neurochrome.com). I often respond within an hour - assuming I'm awake and in front of a computer anyway. And if I'm travelling (as I currently am) you'll get an auto response so at least you can set your expectations. I do my best but I'm a one-man show here. 🙂
Tom
On the PV6 you'll find four terminals. Two are gold plated and are unmarked. Those are for the switch. Two are tin plated and are marked R1.8V+ and G2.8V-.
The terminal marked R1.8V+ is the anode for the red LED. If you want the switch to glow red when the ISS is in standby you will want that connected to terminal 3 on the ISS. The terminal marked G2.8V- is the anode for the green LED. It goes to terminal 4 on the ISS. Then connect the switch to terminals 5 and 6.
See here for how to identify the switch terminals:
...and here for the connections to the ISS:
I'm not sure how you came up with the connection at S. That will short out both LEDs and you will get no indication of Standby/ON. If that's your goal, just don't connect the LEDs.
If you want to only have indication of Power ON, just turn the standby LED dimmer (white trimpot marked STBY) to minimum. Similarly if you only want Standby indication, just turn the Power ON LED dimmer (white trimpot marked PWR) to minimum.
For future reference (and everybody else's benefit): The best way to reach me for customer service type questions is to email me directly. Simply take my user ID here and add @neurochrome.com. You can also go through the Contact Us form on my website (www.neurochrome.com). I often respond within an hour - assuming I'm awake and in front of a computer anyway. And if I'm travelling (as I currently am) you'll get an auto response so at least you can set your expectations. I do my best but I'm a one-man show here. 🙂
Tom
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