Sorry to be so confusing Russ. Previously I had not attempted to "play" the preamp through speakers, I had only passed signal through the preamp and attempted measurement.
In this case what I was referring to was moving the Pot to activate the relays. When I moved the pot sufficiently to hear music, I had constant relay run on. It sounded something like very low frequency osculation.
I am in the process of building a ribbon cable adaptor that will allow me to move the controller around while leaving the relay boards in place to see if this makes any difference in performance.
Since the stacked JT structure works without problems outside the preamp this might isolate the problem to interference with the controller.
Roy
In this case what I was referring to was moving the Pot to activate the relays. When I moved the pot sufficiently to hear music, I had constant relay run on. It sounded something like very low frequency osculation.
I am in the process of building a ribbon cable adaptor that will allow me to move the controller around while leaving the relay boards in place to see if this makes any difference in performance.
Since the stacked JT structure works without problems outside the preamp this might isolate the problem to interference with the controller.
Roy
If you have a constant relay switching (I have that on occasion) try tapping the end of the pot, or adjusting it another notch up or down. I've not yet tried any other pots in mine yet, since I have bigger issues. But I think that the supplied pot and setup can sometimes hit a spot where a relay will constantly be in an open/close cycle.
C
C
C,
If I read Roy's posts correctly Roy's issue does not occur when the JT is outside his case, So I think the pot istelf is fine, but testing with another POT would be a good test in any case.
If you get to the end of your rope you can send your JT to me and I will do my best to debug it.
Cheers!
Russ
If I read Roy's posts correctly Roy's issue does not occur when the JT is outside his case, So I think the pot istelf is fine, but testing with another POT would be a good test in any case.
If you get to the end of your rope you can send your JT to me and I will do my best to debug it.
Cheers!
Russ
I have done additional testing and found the moving the entire stack outside the case but maintaining all power connections reduces the instability but doesn't completely remove it. If I disconnect the Balanced Darwin Stack power it becomes a little more stable but their are still places where one relay (on both relay boards) will continue slowly clicking every second or two. I am looking in my scrap box for a replacement pot to test and will reply with results.
Roy
Roy
installed a replacement pot. It didn't change the results.
I do have new information that changes things somewhat.
I can no longer duplicate relay stability outside the case. I still get some relay chatter even with the TJ stack disconnected from the preamp, the boards separated from each other and the stack running on a different AC power source (my varistat)
Brian, the pot pins were not grounded to the chassis.
Could this be a problem with the PIC?
I do have new information that changes things somewhat.
I can no longer duplicate relay stability outside the case. I still get some relay chatter even with the TJ stack disconnected from the preamp, the boards separated from each other and the stack running on a different AC power source (my varistat)
Brian, the pot pins were not grounded to the chassis.
Could this be a problem with the PIC?
Hi Roy,
At this point I would no rule out anything, the PIC included.
To me it sounds like the PIC is reacting to external influences. A couple of things to check.
1) The diodes on the relay PCB. Make sure they are only contacting their pads. It is ok if they contact the power pins of the realay (pin 1 and pin 8).
2) Make sure the diodes are oriented correctly.
3) Check continuity between each pin of the IDC header and signal out and signal ground. There should be no continuity from any IDC pin to either signal GND or signal hot.
4) Check the supply voltage to the PIC with the pot at various positions.
5) Check the voltage from V+ to GND on the pot at various positions.
6) Check for shorts to any of the relay at the controller end by checking for continuity at the controller end betwen D_GND on the controller and each of the relay output pins on the IDC connector (the pins with traces which run to transistor collectors).
Cheers!
Russ
At this point I would no rule out anything, the PIC included.
To me it sounds like the PIC is reacting to external influences. A couple of things to check.
1) The diodes on the relay PCB. Make sure they are only contacting their pads. It is ok if they contact the power pins of the realay (pin 1 and pin 8).
2) Make sure the diodes are oriented correctly.
3) Check continuity between each pin of the IDC header and signal out and signal ground. There should be no continuity from any IDC pin to either signal GND or signal hot.
4) Check the supply voltage to the PIC with the pot at various positions.
5) Check the voltage from V+ to GND on the pot at various positions.
6) Check for shorts to any of the relay at the controller end by checking for continuity at the controller end betwen D_GND on the controller and each of the relay output pins on the IDC connector (the pins with traces which run to transistor collectors).
Cheers!
Russ
Russ,
I have gone through your checklist and have the following results:
"1) The diodes on the relay PCB. Make sure they are only contacting their pads. It is ok if they contact the power pins of the relay (pin 1 and pin 8)."
All diodes check out ok with no shorts to the signal relay pins.
"2) Make sure the diodes are oriented correctly."
The diodes follow the orientation on the PCB and the picture on your web site.
"3) Check continuity between each pin of the IDC header and signal out and signal ground. There should be no continuity from any IDC pin to either signal GND or signal hot."
Checked continuity and confirmed that there were no shorts.
"4) Check the supply voltage to the PIC with the pot at various positions.
5) Check the voltage from V+ to GND on the pot at various positions."
The voltages for tests 4 and 5 are the same which should be expected since they are connected to the same pins on the voltage regulator. Therefore, I am combining the results for both.
Testing was done with the JT in its most stable position. It should be emphasized, that the chatter/run-on is much worse with the JT stack fully installed in the preamp.
The Balanced JT Stack was removed from the preamp and powered through an external varistat. The stack was not connected to the Darwin through either signal or power. I was using a replacement pot which was also 5K; however, it was log rather than linear. The pot change did not impact the stability of the JT; however, it did push the chattering/run-on further to the clockwise side of the pot.
In this configuration, when the pot was moved slowly clock wise chatter/run-on was found at a spot just before the full clock wise position. Interestingly enough the run-on stopped in the full clockwise position. Also, the results were the same with either or both relay board in the configuration.
The voltage with the pot "off", i.e., in the far counter clockwise position was 5.003V. This voltage remained constant until just before the end of the clockwise movement when it dropped to about 4.996V during relay run-on. The voltage dropped to 4.939V at the full clockwise position of the pot.
“6) Check for shorts to any of the relay at the controller end by checking for continuity at the controller end between D_GND on the controller and each of the relay output pins on the IDC connector (the pins with traces which run to transistor collectors).”
Assuming that by D_GND you mean pin 20 of the PIC, no shorts were found during testing.
I have gone through your checklist and have the following results:
"1) The diodes on the relay PCB. Make sure they are only contacting their pads. It is ok if they contact the power pins of the relay (pin 1 and pin 8)."
All diodes check out ok with no shorts to the signal relay pins.
"2) Make sure the diodes are oriented correctly."
The diodes follow the orientation on the PCB and the picture on your web site.
"3) Check continuity between each pin of the IDC header and signal out and signal ground. There should be no continuity from any IDC pin to either signal GND or signal hot."
Checked continuity and confirmed that there were no shorts.
"4) Check the supply voltage to the PIC with the pot at various positions.
5) Check the voltage from V+ to GND on the pot at various positions."
The voltages for tests 4 and 5 are the same which should be expected since they are connected to the same pins on the voltage regulator. Therefore, I am combining the results for both.
Testing was done with the JT in its most stable position. It should be emphasized, that the chatter/run-on is much worse with the JT stack fully installed in the preamp.
The Balanced JT Stack was removed from the preamp and powered through an external varistat. The stack was not connected to the Darwin through either signal or power. I was using a replacement pot which was also 5K; however, it was log rather than linear. The pot change did not impact the stability of the JT; however, it did push the chattering/run-on further to the clockwise side of the pot.
In this configuration, when the pot was moved slowly clock wise chatter/run-on was found at a spot just before the full clock wise position. Interestingly enough the run-on stopped in the full clockwise position. Also, the results were the same with either or both relay board in the configuration.
The voltage with the pot "off", i.e., in the far counter clockwise position was 5.003V. This voltage remained constant until just before the end of the clockwise movement when it dropped to about 4.996V during relay run-on. The voltage dropped to 4.939V at the full clockwise position of the pot.
“6) Check for shorts to any of the relay at the controller end by checking for continuity at the controller end between D_GND on the controller and each of the relay output pins on the IDC connector (the pins with traces which run to transistor collectors).”
Assuming that by D_GND you mean pin 20 of the PIC, no shorts were found during testing.
rpafenberg said:
Hmmm... Intersting. The Regluation seems a bit poor. Tell me more about the Varistat input. What is the AC voltage in. And how much current can the unit supply.
I can send you a new PIC with some new firmware to try, but I am still confused as to why this is happening. I cannot replicate it here.
So I think you might have a deeper problem than the PIC.I just measured mine and my voltage stays right at 5.087 Volts +/- .01 volt the entire range.
I am starting suspect a bad relay or a bad transistor.
Try this... measure the total current the JT consumes from volume 0 to full volume. If there is one bad transistor or relay it will spike the current draw when it is activated. If you turn the pot slowly and measure one click at a time you can tell which trasistors are active by measuring the voltage at the base.
I hope we can get this thing squared away.
:EDIT: Max current draw for the JT alone will be about 150ma for each relay PCB. So 300-310ma or so for two relay PCBs. Add 20ma or so for the controller itself.
Cheers!
Russ
Russ,
I don't think I have a problem with power. The varistat can support 630VA. I set it a 10VAC and measured 9.85VAC output.
I'll try the measurements tomorrow and get back to you.
Thanks for working with me on this!!!
Roy
I don't think I have a problem with power. The varistat can support 630VA. I set it a 10VAC and measured 9.85VAC output.
I'll try the measurements tomorrow and get back to you.
Thanks for working with me on this!!!
Roy
rpafenberg said:
Its my pleausre. 🙂 I love a good mystery.
If I have a spare PIC laying around the shop I will program it with some new firmware for you to try, or possibly you just have a flaky PIC. I will send you the PIC as soon as I can. if you could send me the old one back I would appreciate it as I would like to analyze it to see what could be wrong.
Cheers!
Russ
Since your mailsystem don't work...
I have a question...can the pot-meter be swapped for a 50k?
Arne K
I have a question...can the pot-meter be swapped for a 50k?
Arne K
Great !
The idea is to install the attenuator in an existing pre-amp, bypassing the original pot.
Arne K
The idea is to install the attenuator in an existing pre-amp, bypassing the original pot.
Arne K
Roy,
I have found a potential issue withe the firmware. I have created a new version which will not allow the motor boating behavior you are seeing. So far in testing this afternoon It has been demonstrated to fix the relay run-on. Brian and I will make arrangements to get the updated firmware to you and all the others who have purchased Kits so far.
My since apologies for any inconvenience. I can only promise to make it right and to be sure all new kits have the corrected firmware.
Thanks so much for bringing this to my attention. I really appreciate the way you have worked with me to help me find the problem. You are a good fellow.
I will post the updated HEX here shortly as soon as I feel it is thoroughly tested.
Just for information, the problem is really a combination of things. First its an issue of arithmetic and the number of samples I am taking not being odd. Also it seems that the problem is made worse when the voltage feed the regulator is less than 10VDC or so. I found that when a used a variac to drop the AC in to about 6-7 VAC (which resulted in roughly 10VDC rectified) I started seeing the exact behavior Roy was reporting. This had not ever happened to me before because I was using 12VAC in from my XBOSOZ.
I have only done a few of these PIC projects so far, so I really appreciate the patience when I make a flub like this.
I take full responsibility, I should have tested with a wider range of supply voltage and under more diverse conditions. But this is DIY for me to, I am no pro. So I only have limited capability to test. I depend on the community to help me get it right. Which I know I will eventually.
Cheers to all, and thanks for the good will.
Cheers!
Russ
I have found a potential issue withe the firmware. I have created a new version which will not allow the motor boating behavior you are seeing. So far in testing this afternoon It has been demonstrated to fix the relay run-on. Brian and I will make arrangements to get the updated firmware to you and all the others who have purchased Kits so far.
My since apologies for any inconvenience. I can only promise to make it right and to be sure all new kits have the corrected firmware.
Thanks so much for bringing this to my attention. I really appreciate the way you have worked with me to help me find the problem. You are a good fellow.
I will post the updated HEX here shortly as soon as I feel it is thoroughly tested.
Just for information, the problem is really a combination of things. First its an issue of arithmetic and the number of samples I am taking not being odd. Also it seems that the problem is made worse when the voltage feed the regulator is less than 10VDC or so. I found that when a used a variac to drop the AC in to about 6-7 VAC (which resulted in roughly 10VDC rectified) I started seeing the exact behavior Roy was reporting. This had not ever happened to me before because I was using 12VAC in from my XBOSOZ.
I have only done a few of these PIC projects so far, so I really appreciate the patience when I make a flub like this.
I take full responsibility, I should have tested with a wider range of supply voltage and under more diverse conditions. But this is DIY for me to, I am no pro. So I only have limited capability to test. I depend on the community to help me get it right. Which I know I will eventually.
Cheers to all, and thanks for the good will.
Cheers!
Russ
No apology is necessary
Russ,
You are doing a great job. Given the sample size you are working with you can't expect to provide totally perfect product from the beginning. Even commercial products have problems and they have much better control of the parts that are used.
It seems to me that in a DIY environment a minor problem or two is nothing. The important thing is the qualitity of the support to resolve these issues.
I spent almost 25 years in the computer industry. This is an environment where the large number if third party products make the stability of "standards" based products interesting to say the least. I can say that the support you provided for what can only be considered a not profit activity is far better than that I received from the majority of vendors I have had dealings with.
You both are doing a great job!!!
Roy
Russ,
You are doing a great job. Given the sample size you are working with you can't expect to provide totally perfect product from the beginning. Even commercial products have problems and they have much better control of the parts that are used.
It seems to me that in a DIY environment a minor problem or two is nothing. The important thing is the qualitity of the support to resolve these issues.
I spent almost 25 years in the computer industry. This is an environment where the large number if third party products make the stability of "standards" based products interesting to say the least. I can say that the support you provided for what can only be considered a not profit activity is far better than that I received from the majority of vendors I have had dealings with.
You both are doing a great job!!!
Roy
Update
Good evening all,
Finally got a chance to thoroughly test new firmware. It has not let me down yet. 🙂 So I post it here for those who can program it for themselves, for those who can't we will be sending new programmed PICs.
Thanks to all for the good will and patience.
The new firmware attacks the problem several different ways. The most significant is that it detects and corrects ADC (the best it can) ripple which can happen because the digital supply is being loaded/unloaded by the relays. It does this by detecting flip flops in the samples and resampling when they are detected to see if they are valid.
Here is the revised HEX version 1.1;
Cheers!
Russ
Good evening all,
Finally got a chance to thoroughly test new firmware. It has not let me down yet. 🙂 So I post it here for those who can program it for themselves, for those who can't we will be sending new programmed PICs.
Thanks to all for the good will and patience.
The new firmware attacks the problem several different ways. The most significant is that it detects and corrects ADC (the best it can) ripple which can happen because the digital supply is being loaded/unloaded by the relays. It does this by detecting flip flops in the samples and resampling when they are detected to see if they are valid.
Here is the revised HEX version 1.1;
Cheers!
Russ
Re: Update
Russ,
When should we expect the new PIC & would you like me to send the old one back?
Also from looking at the wiring diagram I assume I am suppose to connect the the grounds of the Left & right channel together and the run a single wire from them tto the board. Is that right?
Thx
Mike
Russ White said:
Russ,
When should we expect the new PIC & would you like me to send the old one back?
Also from looking at the wiring diagram I assume I am suppose to connect the the grounds of the Left & right channel together and the run a single wire from them tto the board. Is that right?
Thx
Mike
I have a bunch of PICs programmed with the 1.1 code. I hope to send them out this week. You are more than welcome to send back your old pic, but it's up to you. This is more of a fix then an upgrade.
You have two options:
1) You can split your grounds before the board and run Signal and GND to each side of the board (for balanced: IN+ and GND to one side, and IN- and GND to the other, one channel per board; for SE, R+ and GND to one side and L+ and GND to the other side), or
2) You can run a single ground to one side and add a jumper at J2, which will supply GND to the other side.
Which ever is easier for your wiring setup.
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