It seems that the external 15V supply is not the problem:
I left that supply disconnected but set the jumpers and switch for external 15V.
I left the RPi unpowered.
I powered up the Katana and Controller and I still got regular popping noises through the speakers, but just at lower volume than when I had the 15V supply connected. The LED on the Controller board was lit.
I changed some jumpers in order to power both Katana and Controller through one supply: Same result.
I tried a different 5V supply: Same result.
Any ideas please guys? It works perfectly when I return to internal 15V.
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Yes, the external rail is exactly + and - 15V and can supply over 250mA per rail.
But the point I was making is that I get the same popping noises at lower volume even when the external supply is not connected (with the switch and jumpers remaining set to External 15V).
Yes, Ess board and uController powered with 5V.
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Yes, but I get the same result (popping noises) whether the RPi is powered or not.
Hmmm that might create issues , I will need to check . This is your leakage current but seems high at tens of volts. What type of LPS are you using ?
No, the Katana worked perfectly and still does if I'm using the internal 15V supplies.
Thanks for your rapid responses btw.
I'm off out now, back later.So try 2 things. First earth the Gnd of your LPS so we get rid of leakage current . Second make sure your regulator outputs 70mA at 15V rail.
@jonners, @fabio1068, @cdsgames, @Markw4,
Given two problems running the Katana with that particular supply sourced from Audiophonics, I suggest it may not be a suitable supply. We should still help jonners & fabio1068 get theirs running if possible, but I'd would not suggest getting one of these for use with the Katana anymore.
On grounding, in my RPi setups in my upstairs system, I typically have 4 galvanically-isolated zones...
1. Micro-PC LMS server, switch, WiFi access point (for controlling the system via cellphone), and a sending Fiber Media Converter (FMC) to the RPi. Note, I don't stream, so none of this is connected to the outside world.
2. Receiving FMC, RPi, and the input side of an isolator board (Allo's or Ian's).
3. Output side of an isolator board, possibly a Kali reclocker (though not with the Katana or Boss 1.2), a DAC, and the input side of a S&B TX102 Transformer volume control.
4. Output side of the TX102, amplifier, speakers.
ALL of the power supplies in segments 1-3 are DIY'd linear supplies, are galvanically isolated via the power transformers, and have no inherent connection to ground on the output side.
Segment 1 only has the power supply transformer laminations grounded, but nothing else. This hasn't caused any issues.
Segment 2 is grounded via a short piece of a USB cable inserted into one of the RPi USB connectors with a clip lead attached to the cables's ground wire and connected to the AC ground. This is required for some of my amplifiers (ones with SMPS power supplies) or I get a buzzing sound.
Segment 3 was not grounded before, but with the Katana, after we got cold weather I started hearing popping, likely static electricity-related. I ground the Katana with a clip-lead attached to the brass standoffs in the 'earth connection' mounting hole (illustrated in the Katana manual).
Segment 4 is grounded via the amplifier(s).
IF you are hearing popping noises, especially with colder outside temperatures, grounding the Katana via the 'earth connection' may resolve that.
Greg in Mississippi
Given two problems running the Katana with that particular supply sourced from Audiophonics, I suggest it may not be a suitable supply. We should still help jonners & fabio1068 get theirs running if possible, but I'd would not suggest getting one of these for use with the Katana anymore.
On grounding, in my RPi setups in my upstairs system, I typically have 4 galvanically-isolated zones...
1. Micro-PC LMS server, switch, WiFi access point (for controlling the system via cellphone), and a sending Fiber Media Converter (FMC) to the RPi. Note, I don't stream, so none of this is connected to the outside world.
2. Receiving FMC, RPi, and the input side of an isolator board (Allo's or Ian's).
3. Output side of an isolator board, possibly a Kali reclocker (though not with the Katana or Boss 1.2), a DAC, and the input side of a S&B TX102 Transformer volume control.
4. Output side of the TX102, amplifier, speakers.
ALL of the power supplies in segments 1-3 are DIY'd linear supplies, are galvanically isolated via the power transformers, and have no inherent connection to ground on the output side.
Segment 1 only has the power supply transformer laminations grounded, but nothing else. This hasn't caused any issues.
Segment 2 is grounded via a short piece of a USB cable inserted into one of the RPi USB connectors with a clip lead attached to the cables's ground wire and connected to the AC ground. This is required for some of my amplifiers (ones with SMPS power supplies) or I get a buzzing sound.
Segment 3 was not grounded before, but with the Katana, after we got cold weather I started hearing popping, likely static electricity-related. I ground the Katana with a clip-lead attached to the brass standoffs in the 'earth connection' mounting hole (illustrated in the Katana manual).
Segment 4 is grounded via the amplifier(s).
IF you are hearing popping noises, especially with colder outside temperatures, grounding the Katana via the 'earth connection' may resolve that.
Greg in Mississippi
In order to leave my 'Audiophonics' psu out of the equation, I connected just a 5V iFi iPower supply to the Katana DAC/uController combination.
Switch and jumpers were set to internal 14V.
I left the RPi unpowered.
On powering up there was silence, but when I switched the internal 14V supply off with Sw3 the regular popping sounds started. The jumpers were still set to internal supply.
When I turned Sw3 on again the popping sounds stopped.
I tried making an Earth connection to the uController board but this made no difference.
I hope this may assist you helpful guys in making a diagnosis.
Switch and jumpers were set to internal 14V.
I left the RPi unpowered.
On powering up there was silence, but when I switched the internal 14V supply off with Sw3 the regular popping sounds started. The jumpers were still set to internal supply.
When I turned Sw3 on again the popping sounds stopped.
I tried making an Earth connection to the uController board but this made no difference.
I hope this may assist you helpful guys in making a diagnosis.
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AVCC would still be powered up on the output stage board by the Katana board. Without looking at a schematic of the output stage to see where some current might go in the absence of +-15v bias, who knows? Probably doesn't matter, or doesn't necessarily indicate a problem other than that you should operate the system with +-15v applied.
Does look like there is no +-15v making it to the output stage from the Audiophonics supply though. Did you ever measure on the big black cap? If not, do it. You can push the insulation back a little to get on there with a probe tip. It's soft enough.
Does look like there is no +-15v making it to the output stage from the Audiophonics supply though. Did you ever measure on the big black cap? If not, do it. You can push the insulation back a little to get on there with a probe tip. It's soft enough.
With the Audiophonics PSU connected, the -ve side of the large black cap measures -14.1V to earth, the +ve side has only 0.3V to earth. The PSU outputs measure +15.0V and - 15.0V.
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Well the PSU is supplying the right voltages + and -. And I've checked by connecting resistors that it can supply 150mA to each rail.
I'll leave it on for a while and see what happens. Thanks.
In post #2977 Greg reported that when he unintentionally booted up the stack without the external +-15V connected he got low volume distorted sound, not popping. This makes me suspect that my problem is in one of the boards.
@jonners,
Actually the first time I heard the popping was one of the times I forgot to power up the +-15V supply. The popping was louder than the distorted music and I could barely hear it with the popping. I thought something was wrong... I powered up the +-15v, still heard the popping (though the music was now louder AND the popping less constant) and at that point tried grounding the Katana via the 'earth connection'.
This might be useful for your situation.
Greg in Mississippi
Actually the first time I heard the popping was one of the times I forgot to power up the +-15V supply. The popping was louder than the distorted music and I could barely hear it with the popping. I thought something was wrong... I powered up the +-15v, still heard the popping (though the music was now louder AND the popping less constant) and at that point tried grounding the Katana via the 'earth connection'.
This might be useful for your situation.
Greg in Mississippi