Thanks xrk, I’ll order a 24v Meanwell and see how it goes! Does running from a dedicated supply rather than the amplifiers supply have any effect on the DC protect side of things?
Let me ask Jhofland if we can incorporate this feature into the single trafo version. Sounds like time to start a dedicated thread.
Hi Folks,
Actually, before starting production of GB2, it seems maybe adding two changes would be in order. (1) isolating the speaker -ve from the PSU ground will allow use of this with BTL amps where both +ve and -ve speaker outputs are live; (2) a remote enable feature that allows a 1mA remotely provided signal from an external logic device like an MCU or relay to shut off the SSR's (typical 3.3v or higher logic levels from micro-controller general purpose I/O pins will work). This may be useful for folks who want to control the SSR themselves to follow a certain startup or shutdown sequence, or even to provide user-directed speaker muting. It will also tie in nicely with the to be built Soft Start circuit. We think a small change of an added optoisolator, a MOSFET, a resistor, and set of PCB header pins for bypassing the "enable" feature, and a second Molex KK connector should not be too difficult to do and is a minor change that we will test and verify via P2P prior to the fabrication.
Here is the proposed circuit from Jhofland:
Actually, before starting production of GB2, it seems maybe adding two changes would be in order. (1) isolating the speaker -ve from the PSU ground will allow use of this with BTL amps where both +ve and -ve speaker outputs are live; (2) a remote enable feature that allows a 1mA remotely provided signal from an external logic device like an MCU or relay to shut off the SSR's (typical 3.3v or higher logic levels from micro-controller general purpose I/O pins will work). This may be useful for folks who want to control the SSR themselves to follow a certain startup or shutdown sequence, or even to provide user-directed speaker muting. It will also tie in nicely with the to be built Soft Start circuit. We think a small change of an added optoisolator, a MOSFET, a resistor, and set of PCB header pins for bypassing the "enable" feature, and a second Molex KK connector should not be too difficult to do and is a minor change that we will test and verify via P2P prior to the fabrication.
Here is the proposed circuit from Jhofland:
Attachments
It sounds like the Meanwell has internal capacitance. 15w at 24v is capable of 625mA. The SSR’s need 40mA for the pair.
To drain 625mA in 1 second will take something like 39R 25w resistor. And it will get hot.
You could use the Meanwell to power a DC-DC with almost zero storage - that’s what I used.
Maybe something like this? (Not same as what I used)
2A DC Boost Step up Adjustable Converter Micro USB 2-24V to 5v-28v 6v 9v 12v 15v | eBay
To drain 625mA in 1 second will take something like 39R 25w resistor. And it will get hot.
You could use the Meanwell to power a DC-DC with almost zero storage - that’s what I used.
Maybe something like this? (Not same as what I used)
2A DC Boost Step up Adjustable Converter Micro USB 2-24V to 5v-28v 6v 9v 12v 15v | eBay
Hi X, not yet, but will do a stand alone test on all SSR boards I have received next month before wiring them into the many power amp projects I have planned for 2020 and beyond!!
The biggest issue with power amps is the cost and procuring the enclosures.
Happy New Year to all, my god 2020 starts tomorrow!! The years seem to fly by these days - must be part of getting older
The biggest issue with power amps is the cost and procuring the enclosures.
Happy New Year to all, my god 2020 starts tomorrow!! The years seem to fly by these days - must be part of getting older
Yes the enclosures and psu cost is 90% cost of the amp. You have heard this before: with the new quick connect flying leads for output MOSFETs, PSU, and speakers, we can keep the chassis/psu/connectors constant and swap out amp PCBs if the PCB format is standardized. The Alpha Nirvana is the first of such a format. After all, we can’t listen to more than 1 amp at a time unless you have an active multi-way setup.
Yes X, your newer designs make that a lot easier task.
I have three stereo Hi Fi set ups so can be evaluating and listening to three different power amps at a time, but I am also planning on how to build them to be able to re use enclosures more efficiently without stripping them back to scratch.
Still a task though with different outputs on the heat sinks namely, Lateral fets , Mosfets, BJT's, and some more exotic types like the Semisouth SIC's.
I have three stereo Hi Fi set ups so can be evaluating and listening to three different power amps at a time, but I am also planning on how to build them to be able to re use enclosures more efficiently without stripping them back to scratch.
Still a task though with different outputs on the heat sinks namely, Lateral fets , Mosfets, BJT's, and some more exotic types like the Semisouth SIC's.
The BJTs and LatFETs can also be flying lead connected. The helper boards from the ABBB are more universal and can be used on BJTs too. If the connector is on the snubber, then flying leads can be soldered or connected to PCB. But a flying lead output is much easier to swap out once you have clear access.