So I did nothing other than connect a 2.49K ohm resistor at R124 and measure from that resistor to ground. I got ~1.39V on both sides of it, and it started partially working.
Halfband and Apodizing both light up when selected, but no other lights nor the surprise button did anything. I also do not hear the relays clicking as I change settings. I checked continuity between SW1-5 and the physical switches and the LED plugs, all good, and all LEDs are still good.
EDIT: I restarted the DAC and the lights are no longer working. I made no changes other than power cycling. Could an in-rush current limiter cause this?
Halfband and Apodizing both light up when selected, but no other lights nor the surprise button did anything. I also do not hear the relays clicking as I change settings. I checked continuity between SW1-5 and the physical switches and the LED plugs, all good, and all LEDs are still good.
EDIT: I restarted the DAC and the lights are no longer working. I made no changes other than power cycling. Could an in-rush current limiter cause this?
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When you measure the voltage across an open switch while the DAC is on, you should see a value of about 3.3 V. Do you?
I have to dig into my Verilog code to see exactly what conclusion to draw from the fact that the lights sometimes work, but without clicking relays.
I have to dig into my Verilog code to see exactly what conclusion to draw from the fact that the lights sometimes work, but without clicking relays.
I feel so stupid. I tore everything down and went over everything with a microscope once again and saw that U24 had a solder point not connected. I fixed that and now most everything works?
For the Filter settings, Apodizing and Halfband both turn on when selected, Steep does not.
For s/d, no lights work when manually selecting them.
When changing the Filter, the relays are clicking every time. They also click when changing input. They do not click when changing s/d or between soft-med-loud.
Interestingly, using the Surprise switch (which triggers relays), all of the lights will eventually trigger except for Steep. I will check the connections, because the LED is good.
Additionally, the clipping light is on the entire time, but much dimmer than before.
For the Filter settings, Apodizing and Halfband both turn on when selected, Steep does not.
For s/d, no lights work when manually selecting them.
When changing the Filter, the relays are clicking every time. They also click when changing input. They do not click when changing s/d or between soft-med-loud.
Interestingly, using the Surprise switch (which triggers relays), all of the lights will eventually trigger except for Steep. I will check the connections, because the LED is good.
Additionally, the clipping light is on the entire time, but much dimmer than before.
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I connected an optical source into the input board I made and connected the DAC to an amp. I only hear buzzing. I tried Surprise mode since that seems to activate both lights, still nothing.
I'm going to order a BNC cable because it's possible my optical implementation isn't working.
I'm going to order a BNC cable because it's possible my optical implementation isn't working.
If it makes you feel any better, I also had lots of problems with poor soldering 😉
They are not supposed to click when switching between soft, medium and loud, but they should click when switching between sigma-delta settings. Do you get 3.3 V to ground on all open contacts of the sigma-delta switch, and 0 V on the closed one?
The most obvious reason for the issues you report would be the common contact of the sigma-delta method switch SW1 not being connected to ground and terminal 2 of SW2 not making any contact. This would explain everything.
When none of the SW1 contacts 1, 2, 3 and 4 are pulled down, or when more than one is pulled down simultaneously, the sigma-delta modulator is set to its default mode, which is mode 0: only producing silence.
Pressing the surprise button makes the neon lamps or LEDs show what the latest surprise setting was and releasing it will generate a new surprise setting, but it does not switch the mode of the sigma-delta and filter unless the rotary switches happen to be set to the surprise modes. So for example, when you are in chaotic mode and press surprise, the sigma-delta modulator remains in chaotic mode, but the LEDs show what the latest surprise mode was. When you then release the surprise button, the sigma-delta modulator remains in chaotic mode, the "chaos" LED lights up again and a new surprise mode is drawn.
Edit: what I wrote about the clipping light being suppressed depends on a DIP switch setting.
When none of the SW1 contacts 1, 2, 3 and 4 are pulled down, or when more than one is pulled down simultaneously, the sigma-delta modulator is set to its default mode, which is mode 0: only producing silence.
Pressing the surprise button makes the neon lamps or LEDs show what the latest surprise setting was and releasing it will generate a new surprise setting, but it does not switch the mode of the sigma-delta and filter unless the rotary switches happen to be set to the surprise modes. So for example, when you are in chaotic mode and press surprise, the sigma-delta modulator remains in chaotic mode, but the LEDs show what the latest surprise mode was. When you then release the surprise button, the sigma-delta modulator remains in chaotic mode, the "chaos" LED lights up again and a new surprise mode is drawn.
Edit: what I wrote about the clipping light being suppressed depends on a DIP switch setting.
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Pin 2 of SW2 connection (steep) to the switch is good. When not selected, I get 3.3V from Pin 2 to ground. The LED is now working, the wire had gotten internally severed from being pinched.
SW1 gives 0V on all contacts. So as of now, everything seemingly works except SW1 stuff, but those lights will light up via the Surprise function. I was measuring at the pin header, so the issue is not related to the connection to the rotary switch.
EDIT: DIP settings are off-on-on-off for 1-2-3-4 on the module
SW1 gives 0V on all contacts. So as of now, everything seemingly works except SW1 stuff, but those lights will light up via the Surprise function. I was measuring at the pin header, so the issue is not related to the connection to the rotary switch.
EDIT: DIP settings are off-on-on-off for 1-2-3-4 on the module
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The switched-off DIP switch S1D / switch 4 explains why the clipping lamp isn't suppressed when SW1 doesn't work as intended, so that discrepancy is solved.
I've been thinking about what could cause all contacts of SW1 to be at 0 V, but apart from a solder bridge going all the way from pin 60 to pin 68 of J4 or incorrect components (for example ferrite beads instead of capacitors for C98...C101), I can't think of anything.
If R102 on the FPGA module wouldn't make contact, none of the switches would work, but the filter and input selection switches do work. The FPGA pins that are connected to the switches that don't work also have nothing in common with the FPGA I/O that is connected to nswitch85A2 and that may have been slightly stressed due to the mistake with the -300 V supply - besides, the current flowing into the FPGA must have been very small, so I don't expect this to have damaged the FPGA at all.
When you do a resistance measurement from SW1 contacts 1...4 to ground with everything powered down, do you measure close to 0 ohm, 330 ohm or some high value? Do you see or measure anything wrong around R62...R65, C98...C101 or J4 pins 60...68?
I've been thinking about what could cause all contacts of SW1 to be at 0 V, but apart from a solder bridge going all the way from pin 60 to pin 68 of J4 or incorrect components (for example ferrite beads instead of capacitors for C98...C101), I can't think of anything.
If R102 on the FPGA module wouldn't make contact, none of the switches would work, but the filter and input selection switches do work. The FPGA pins that are connected to the switches that don't work also have nothing in common with the FPGA I/O that is connected to nswitch85A2 and that may have been slightly stressed due to the mistake with the -300 V supply - besides, the current flowing into the FPGA must have been very small, so I don't expect this to have damaged the FPGA at all.
When you do a resistance measurement from SW1 contacts 1...4 to ground with everything powered down, do you measure close to 0 ohm, 330 ohm or some high value? Do you see or measure anything wrong around R62...R65, C98...C101 or J4 pins 60...68?
Marcel, I can't thank you enough for your patience and help. Everything is working as intended and I got music out of it!
The legs on the J4 connector had lifted a bit on the bottom end from pulling the FPGA out presumably. The pads were all intact, so I used a heat gun and got it set back in place. The pins on the opposite side were also affected (the ones that go to P9). Those are all fixed now as well, I checked continuity of every pin on both connectors under a magnifying lens.
I used my optical implementation to play music, using XLR to RCA adapters to connect to my single-ended headphone amp. Music was kinda "garbled," especially in the lower end. I have not touched R42 and C7 since I fixed everything, nor the other trimpots. I'll do that tomorrow.
Ordered a BNC cable overnight that will be here tomorrow as well, to make sure my optical implementation isn't the issue.
Used cardboard to mock up the case fit and hold things in place.
The legs on the J4 connector had lifted a bit on the bottom end from pulling the FPGA out presumably. The pads were all intact, so I used a heat gun and got it set back in place. The pins on the opposite side were also affected (the ones that go to P9). Those are all fixed now as well, I checked continuity of every pin on both connectors under a magnifying lens.
I used my optical implementation to play music, using XLR to RCA adapters to connect to my single-ended headphone amp. Music was kinda "garbled," especially in the lower end. I have not touched R42 and C7 since I fixed everything, nor the other trimpots. I'll do that tomorrow.
Ordered a BNC cable overnight that will be here tomorrow as well, to make sure my optical implementation isn't the issue.
Used cardboard to mock up the case fit and hold things in place.
Attachments
Great that it works, pity that it sounds kind of garbled.
Do you use the latest configuration file, so the one from post #1519, not the one from post #1495?
I noticed a weird crackling sound with the file from post #1495. I could hear it on music and I could hear it very well on 0 dBFS sine waves with frequencies just above my hearing range, using the steep or the halfband filter. It turned out that the SRC4392 was going into and out of lock all the time, a problem I never had with the LX75 versions.
A difference between the LX75 versions and the LX45 version of post #1495 is that the latter has an irregular bit clock and a non-50 % word clock duty cycle at the output interface of the SRC4392, so I fixed that and for me that solved the problem. The improved clocking is included in the LX45 version of post #1519.
Another thing you can try is to check whether some sigma-delta modes sound better than others, if you haven't already done so.
Do you use the latest configuration file, so the one from post #1519, not the one from post #1495?
I noticed a weird crackling sound with the file from post #1495. I could hear it on music and I could hear it very well on 0 dBFS sine waves with frequencies just above my hearing range, using the steep or the halfband filter. It turned out that the SRC4392 was going into and out of lock all the time, a problem I never had with the LX75 versions.
A difference between the LX75 versions and the LX45 version of post #1495 is that the latter has an irregular bit clock and a non-50 % word clock duty cycle at the output interface of the SRC4392, so I fixed that and for me that solved the problem. The improved clocking is included in the LX45 version of post #1519.
Another thing you can try is to check whether some sigma-delta modes sound better than others, if you haven't already done so.
I'll evaluate more in the morning and still have to make the adjustments, but I assume something is still slightly wrong because when I say garbled, it's almost like a radio station with poor reception. Hard to describe, but I think it might be my optical input. I can test BNC tomorrow once the cable arrives.
Excellent news Sonny - light at the end of the tunnel - I know you've had some pretty dark moments in there!
Ok got the crystal adjustment settled in. In one channel, I ran out of trimpot trying to lower the noise floor. I'll probably swap some tubes around. Left channel is pretty silent. Right channel still has a slight fuzz and there is an occasional faint pop, only in the right.
Music still working through optical, but it's constantly crackling. I have to wait till later today to get my BCN cable to eliminate a bad optical implementation.
Could it be my XLR to RCA adapters? Right now the XLR outputs of the DAC have pin 1 attached to ground on the output board. My adapters short pins 1 and 3, grounding the negative side.
I don't know if this is informative, but bass notes really break apart. Sound like explosions in old 8-bit video games.
Music still working through optical, but it's constantly crackling. I have to wait till later today to get my BCN cable to eliminate a bad optical implementation.
Could it be my XLR to RCA adapters? Right now the XLR outputs of the DAC have pin 1 attached to ground on the output board. My adapters short pins 1 and 3, grounding the negative side.
I don't know if this is informative, but bass notes really break apart. Sound like explosions in old 8-bit video games.
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Pin 3 has to be connected to the ground of the headphone amplifier, but you can experiment with not connecting pin 1, or connecting pin 1 through 220 ohm//100 nF to break any ground loops while compromising the RF shielding less than with no connection at all.
Floating pin 1 doesn't seem to change much. I think things might be on hold until I get the BNC cable.
Is there anything that could have been damaged that would cause the "break-up" sounds? I suppose the tubes could be bad since I've never tested them. I'm starting to think it could be a tube given that only the right channel has noise and periodic pop sound, even with no input.
Is there anything that could have been damaged that would cause the "break-up" sounds? I suppose the tubes could be bad since I've never tested them. I'm starting to think it could be a tube given that only the right channel has noise and periodic pop sound, even with no input.