troystg said:
Hi Troy,
Here it is:
http://www.diyaudio.com/forums/showthread.php?postid=848119#post848119
Cheers!
Russ
Kookaburra Issue
I'm not sure what exactly is going on, but I think I may have found a bug in the Kooka 1.1 code and I'm not sure how to completely identify it.
The problem occurs when slowly turning up the pot from 0. Just as it transitions from about .0197 to .0201 volts, it goes from silent to full volume for just a split second. I can set the pot so that it rests exactly at the problem voltage and the Kooka will emit that short blast of signal about twice per second. If I move the pot quickly, the problem doesn’t occur.
Interestingly, if you take 5 divided by 256 (the precision of the ADC) you get 0.01953125 which is very close to the voltage I measured at the trouble spot.
It seems like there may be a rounding error or some edge condition that causes the PIC to send a max volume command to the PGA or the PGA doesn't understand the value sent by the PIC under that condition.
In normal volume changes, there seems to be some sort of smoothing code that prevents sudden jumps in volume. I tested this by suddenly switching in and out various resistor values in parallel with the pot. I don't know if this is in the PIC code or if it's in the PGA. Wherever the bug occurs, it bypasses the smoothing code somehow.
Can anyone shed some light on what might be happening? It it possible to take a look at the 1.1 code?
I'm not sure what exactly is going on, but I think I may have found a bug in the Kooka 1.1 code and I'm not sure how to completely identify it.
The problem occurs when slowly turning up the pot from 0. Just as it transitions from about .0197 to .0201 volts, it goes from silent to full volume for just a split second. I can set the pot so that it rests exactly at the problem voltage and the Kooka will emit that short blast of signal about twice per second. If I move the pot quickly, the problem doesn’t occur.
Interestingly, if you take 5 divided by 256 (the precision of the ADC) you get 0.01953125 which is very close to the voltage I measured at the trouble spot.
It seems like there may be a rounding error or some edge condition that causes the PIC to send a max volume command to the PGA or the PGA doesn't understand the value sent by the PIC under that condition.
In normal volume changes, there seems to be some sort of smoothing code that prevents sudden jumps in volume. I tested this by suddenly switching in and out various resistor values in parallel with the pot. I don't know if this is in the PIC code or if it's in the PGA. Wherever the bug occurs, it bypasses the smoothing code somehow.
Can anyone shed some light on what might be happening? It it possible to take a look at the 1.1 code?
Additional thinking about the blast problem mentioned above...
After reading the PGA spec, it looks like the issue may be related to the software mute function. Loading all zeros into the PGA enables the software mute. When the first non-zero value is loaded to the PGA the mute function is turned off. When the software mute is turned off, there could be a delay between when the input ground is disconnected and the internal amps are changed from unity gain to their attenuated setting.
If this is the case, the PIC code should be altered so that zeros are not loaded to the PGA. For bonus points you could enable the hardware mute when the ADC hits zero and keep the PGA value at 1.
Does this sound like a good guess / solution?
After reading the PGA spec, it looks like the issue may be related to the software mute function. Loading all zeros into the PGA enables the software mute. When the first non-zero value is loaded to the PGA the mute function is turned off. When the software mute is turned off, there could be a delay between when the input ground is disconnected and the internal amps are changed from unity gain to their attenuated setting.
If this is the case, the PIC code should be altered so that zeros are not loaded to the PGA. For bonus points you could enable the hardware mute when the ADC hits zero and keep the PGA value at 1.
Does this sound like a good guess / solution?
Hi,
Yes this is a bug, and specifically what changed was that this new firmware is interrupt driven. I will have to spend some time debugging to see what is actually happening.
We will probably just revert back to the previous version which worked fine. Sorry for the problem. Thats what I get trying to make a good thing better.
Cheers!
Russ
Yes this is a bug, and specifically what changed was that this new firmware is interrupt driven. I will have to spend some time debugging to see what is actually happening.
We will probably just revert back to the previous version which worked fine. Sorry for the problem. Thats what I get trying to make a good thing better.
Cheers!
Russ
I don't want to discourage you from trying to improve things in any way. You've done really good work here.
Hmm... interrupt driven now. I might change my theory. Could it be that the data in the ADC buffer is corrupt when it wakes up from sleeping and this corrupt data is used to set the value of the PGA? If so, waiting until the first sample is complete will probably fix it.
Thanks again for the fun project -- bugs and all. Being a software guy by trade, I really enjoy figuring out and solving bugs. Unless they're in my own code and I have a deadline.
Hmm... interrupt driven now. I might change my theory. Could it be that the data in the ADC buffer is corrupt when it wakes up from sleeping and this corrupt data is used to set the value of the PGA? If so, waiting until the first sample is complete will probably fix it.
Thanks again for the fun project -- bugs and all. Being a software guy by trade, I really enjoy figuring out and solving bugs. Unless they're in my own code and I have a deadline.
Pls Help with My Kook
So I'm finally got back to My Kook after recovering from my sister-in-law's visit. But I may have run into a bit of a problem I wired up the torroid that came with the kit and I'm getting 20V readings before any rectification. Shouldn't I be getting around 12 V?
I guess it could be my DMM but it's brand new, since my old Radio Shack model died. And it provides correct readings for batteries.
Any ideas? Do I need to buy a new transformer? Or will the Kook work with this hi of voltage?
Thx
Mike
So I'm finally got back to My Kook after recovering from my sister-in-law's visit. But I may have run into a bit of a problem I wired up the torroid that came with the kit and I'm getting 20V readings before any rectification. Shouldn't I be getting around 12 V?
I guess it could be my DMM but it's brand new, since my old Radio Shack model died. And it provides correct readings for batteries.
Any ideas? Do I need to buy a new transformer? Or will the Kook work with this hi of voltage?
Thx
Mike
Re: Pls Help with My Kook
Unloaded that voltage is probably normal. How are you measuring? From one hot to the other? or front one hot to GND? You need to wire the secondaries in series and take your GND point fron the place where you join them. See the wiring diagram earlier in the thread to be sure you are doing it correctly.
When you have the trafo wired correctly the center pin of the three pin connector will be GND and the outer two hot. 12-20V from either hot side to GND would be acceptable.
Have fun!!!
Cheers!
Russ
kestrel200 said:
Unloaded that voltage is probably normal. How are you measuring? From one hot to the other? or front one hot to GND? You need to wire the secondaries in series and take your GND point fron the place where you join them. See the wiring diagram earlier in the thread to be sure you are doing it correctly.
When you have the trafo wired correctly the center pin of the three pin connector will be GND and the outer two hot. 12-20V from either hot side to GND would be acceptable.
Have fun!!!
Cheers!
Russ
Hi Russ!
Thanks for replying so quickly. I've checked my wiring several times based on your pics and diagram. I'm taking my measurements between the ground and each of the outer two hots, blue & green. I'm getting 5v off of the hot leading to the pot. So I guess it's ok like you said. Just wanted to make sure before I let the majic smoke out. I've spent far too much time on the chassis and layout to mess this up now.
Thx
Thanks for replying so quickly. I've checked my wiring several times based on your pics and diagram. I'm taking my measurements between the ground and each of the outer two hots, blue & green. I'm getting 5v off of the hot leading to the pot. So I guess it's ok like you said. Just wanted to make sure before I let the majic smoke out. I've spent far too much time on the chassis and layout to mess this up now.
Thx
Possible Upgrade?
Can we switch the PGA2311 for the PGA2310 with just changing the analogue side regulators for +-15? The pins match to a "T".
Do you think there would be a drastic change in the Dip programing?
Chuck
PS its been done beautifully here.
http://www.diyrealaudio.com/user_report/biru/biru_en.htm
Can we switch the PGA2311 for the PGA2310 with just changing the analogue side regulators for +-15? The pins match to a "T".
Do you think there would be a drastic change in the Dip programing? Chuck
PS its been done beautifully here.
http://www.diyrealaudio.com/user_report/biru/biru_en.htm
Re: Possible Upgrade?
You would have to do some circuit changes. The +5V regulator feed both the digital side and the +5V on the ananlog side of the PGA. So you would have to add a seperate 5V supply for the digital side. You could then simply omit the LM7805 and LM7905 and jumper the input and ouput pads for those devices.
So you would need an external 5V supply or rig one off the relay power (which would be seperate from the analog supply).
It should work if you know you way around the circuit a bit.
Cheers!
Russ
angchuck said:Can we switch the PGA2311 for the PGA2310 with just changing the analogue side regulators for +-15? The pins match to a "T".
Chuck
PS its been done beautifully here.
http://www.diyrealaudio.com/user_report/biru/biru_en.htm
You would have to do some circuit changes. The +5V regulator feed both the digital side and the +5V on the ananlog side of the PGA. So you would have to add a seperate 5V supply for the digital side. You could then simply omit the LM7805 and LM7905 and jumper the input and ouput pads for those devices.
So you would need an external 5V supply or rig one off the relay power (which would be seperate from the analog supply).
It should work if you know you way around the circuit a bit.
Cheers!
Russ
Hello Russ.
I'm trying to do a very similar thing and am also new to MicroControllers. I just got an EasyPIC2 Development board and have been playing around with that.
I really have wanted to build a amplifier preamp using all digitally controlled parts. My project is slightly different than yours though, because I want to have two buttons - Volume Up and Volume Down. When I push the buttons I want either the volume to go up or down.
I have PicBasic Pro and have been teaching myself how to use it. Is it possible and simple enough for a beginner to interface a PGA2311 to a PIC such as a 16F84A and allow simple up/down volume control?
Thanks,
Mike
I'm trying to do a very similar thing and am also new to MicroControllers. I just got an EasyPIC2 Development board and have been playing around with that.
I really have wanted to build a amplifier preamp using all digitally controlled parts. My project is slightly different than yours though, because I want to have two buttons - Volume Up and Volume Down. When I push the buttons I want either the volume to go up or down.
I have PicBasic Pro and have been teaching myself how to use it. Is it possible and simple enough for a beginner to interface a PGA2311 to a PIC such as a 16F84A and allow simple up/down volume control?
Thanks,
Mike
Need advice on remote vol control
Hello everyone,
I am looking for advice/recommendations on how to add a remote controlled pot on my recently completed Twisted pear chip amp (sounds fantastic ). It uses the kookaburra as a preamp. I've seen motorized pots out there. diyclub.biz has a nicely priced kit (http://eshop.diyclub.biz/product_info.php? Path=85&products_id=195.) Does anyone have any experience using this kit. Do you think that it would be possible to power this kit off of the kookaburra transformer or board ?
Thanks
PJN
Hello everyone,
I am looking for advice/recommendations on how to add a remote controlled pot on my recently completed Twisted pear chip amp (sounds fantastic ). It uses the kookaburra as a preamp. I've seen motorized pots out there. diyclub.biz has a nicely priced kit (http://eshop.diyclub.biz/product_info.php? Path=85&products_id=195.) Does anyone have any experience using this kit. Do you think that it would be possible to power this kit off of the kookaburra transformer or board ?
Thanks
PJN
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