I wasn't familiar with the FlexReg PSU but looking at it now, I would say that would be a really good choice. Rhthatcher did a great job with the documentation. Here is the thread with more info FlexReg PSU
Hmmm.
My build is almost done but I have no output. I've tried it with my sacrificial Sansa Clip, a USB-powered DAC and a real life CD player (yes, I still have one.) Nada. I've cleaned and checked the undersides of all boards and have done some basic continuity checks. The ISS board, as well as each BA2018 channel, has it's own power supply.
I configured the Muses ISS board from Academy Audio as it was described in the ISS manual for that board to be in "passive volume control" mode. There is an alternative mode to set up on the ISS board which I can turn to. This could be my issue.
Each BA2018 channel has sockets for R16/R17 and R29/R43 so that I can change the gain in the future.
Before I break out the Hakko desoldering gear so that I can change the ISS configuration, is there anything I am missing here that would affect both channels? It's pretty weird.
Quickie but marginally acceptable cell phone pics attached.
Thanks!
My build is almost done but I have no output. I've tried it with my sacrificial Sansa Clip, a USB-powered DAC and a real life CD player (yes, I still have one.) Nada. I've cleaned and checked the undersides of all boards and have done some basic continuity checks. The ISS board, as well as each BA2018 channel, has it's own power supply.
I configured the Muses ISS board from Academy Audio as it was described in the ISS manual for that board to be in "passive volume control" mode. There is an alternative mode to set up on the ISS board which I can turn to. This could be my issue.
Each BA2018 channel has sockets for R16/R17 and R29/R43 so that I can change the gain in the future.
Before I break out the Hakko desoldering gear so that I can change the ISS configuration, is there anything I am missing here that would affect both channels? It's pretty weird.
Quickie but marginally acceptable cell phone pics attached.
Thanks!
The BA2018 was designed to run at 15-24V. Make sure your have a bipolar power supply: it should supply + - and ground, not just + and ground.
Hey Craig! 1) Yes. 2) No: I didn't have an opportunity to do so since the input RCAs are directly soldered to the ISS board. Thanks!
Don't know anything about the ISS input selector but the AcademyAudio Internet store suggests they are analog and, I presume, allow for remote control volume operation. If your build accomplishes this would much like to see the eventual configuration.
I would check it with some separate stripped RCA cables coming from the CD player if it has a volume control to the BA2018 inputs direct but that might not be helpful for your design expectations. Let us know.
I would check it with some separate stripped RCA cables coming from the CD player if it has a volume control to the BA2018 inputs direct but that might not be helpful for your design expectations. Let us know.
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Like your handling of R16/17/29/43 and would order some of those adapters if I knew the source. They would be ideal for R27 on the Pearl 3 Phono Stage. Do they work with a pressure fit on the resistor?
Pressure fit: yes. I did find that the ends of resistors with smaller gauge leads could float around so I add a subtle bend to ensure they would stay in. Resistors with larger leads stay in just fine.
The socket is a Mill-Max socket at Mouser, part # 575-113120. They're a little teetery when you first try to get them soldered in. I tape them on the top side, solder on the bottom side. Then hold it straight on the top side and apply the solder iron on the bottom side - quickly guide them to their correct position. That way they end up nice and straight.
The socket is a Mill-Max socket at Mouser, part # 575-113120. They're a little teetery when you first try to get them soldered in. I tape them on the top side, solder on the bottom side. Then hold it straight on the top side and apply the solder iron on the bottom side - quickly guide them to their correct position. That way they end up nice and straight.
Okay, for what it's worth I can safely say it is not my BA2018 boards. I'll move on to the ISS board which will take some time since I will not be desoldering all 12 input jacks. 😵 Will just have to...figure out how to get that board in a position where I can work on it. fiddle.
Fixed my issues with the ISS board, I believe.
Question: float the signal ground as well as connect the VRDN 0V/GND to the star ground inside the chassis? I'm not proposing to connect signal GND to chassis GND.
Am I getting this right?
Question: float the signal ground as well as connect the VRDN 0V/GND to the star ground inside the chassis? I'm not proposing to connect signal GND to chassis GND.
Am I getting this right?
@bhjazz: Congrats. Can't help with your ground question but do know L/R channels on the BA2018 board are common -- so using discrete grounds from RCA inputs will have no purpose. Is your ISS using an analog attenuator? If so, which one? Can you configure the ISS with a ladder-type attenuator and control it with a remote? Will it accept two mono attenuators (for channel balancing)?
Looking at the pictures it looks to me that the BA2018 channels on the board are not connected together. They are independent. And bhjazz mentioned that he has separate power supplies for each channel, so dual mono. So grounds are not shared.
Even if not dual mono, discrete grounds for left and right channel inputs are beneficial as that minimizes loop area and noise, and maximizes channel separation.
As for power supply ground, yes, each channel's power supply ground at power supply output should be connected to chassis safety ground.
Even if not dual mono, discrete grounds for left and right channel inputs are beneficial as that minimizes loop area and noise, and maximizes channel separation.
As for power supply ground, yes, each channel's power supply ground at power supply output should be connected to chassis safety ground.
@Ben Mah , Thanks for the detailed answer. I'll connect the power supply output ground to my current star ground inside the chassis.
Ultimately, then, the floating signal ground is connected to the chassis ground through the power supply - since that same ground connection also connects to the BA2018 boards. At first that didn't make sense to me but now it seems that all grounds end up with the same ground potential. I am endlessly fascinated.
@Craigl59 : the ISS uses the plug-in VCM module which handles the volume attenuation. That module contains the Muses 72320 chip.
Thanks again, Craig and Ben.
Ultimately, then, the floating signal ground is connected to the chassis ground through the power supply - since that same ground connection also connects to the BA2018 boards. At first that didn't make sense to me but now it seems that all grounds end up with the same ground potential. I am endlessly fascinated.
@Craigl59 : the ISS uses the plug-in VCM module which handles the volume attenuation. That module contains the Muses 72320 chip.
Thanks again, Craig and Ben.
BenMah: Thanks for the correction; had not seen the separation. On my connected boards the input ground shorts to both the power supply ground and the output signal ground (as bhjazz notes above). So any PSU ground sharing will also make the signal grounds common, right? Am assuming, by the way, that the power supply inputs are discrete regardless of board separation. Am also using dual power supplies for all of my connected board builds.
I believe where the grounds are connected makes a difference.
The input and output grounds are best connected to the audio board only.
The input and output grounds are best connected to the audio board only.
Yes. (and I double-check measured them!)
But as I've learned from previous builds (and am learning again with this one) Ben Mah's statement is right: where the grounds are connected makes a difference. I had a headphone amp a number of years back that gave me the opportunity (gah!) to chase ground noise around for some time. Then final fix was to ground everything to the exact same spot inside the chassis.