If you send me the complete eagle file with your modified PCB, I'll ask for a quotation locally for maybe 20-25 PCB. Then I may proposed a group buy with this version. He guys, no more modifications, that will be this design that seems already excellent.
Thanks in advance...
SB
Thanks in advance...
SB
USB input would be nice to try.
But what i want the most is 2 double opamps instead of the quad,as I don´t like the quad and not much to change to.
A line output if possible.
SMD regulators maybee?🙂
But what i want the most is 2 double opamps instead of the quad,as I don´t like the quad and not much to change to.
A line output if possible.
SMD regulators maybee?🙂
If kct is willing to provide the modified files, that is great. Additional modifications might be nice, but if they are too extensive.....who is going to do them??? I would love to see another group buy in either case, but lets not kill the group buy by expecting too much.
Robert
Robert
You are going to do them..😀 😉 😉 Joke
No just suggestions,and if anyne can make them fine.Maybee it would be easy to change from qaud to 2 dual,if have only done a little testing in Eagle..not skilled enough,but if autoroute is easy...🙂
Ryssen,
auto route is not really needed nor desirable to use for a change like that.
If someone can pick or recommend dual OP amps to use then I can change
the Layout accordingly.
I will make the files available as soon as I finished my project and have not
encountered any show stoppers with the changes I have done so far.
Cheers
Kay
auto route is not really needed nor desirable to use for a change like that.
If someone can pick or recommend dual OP amps to use then I can change
the Layout accordingly.
I will make the files available as soon as I finished my project and have not
encountered any show stoppers with the changes I have done so far.
Cheers
Kay
I can tell wich ones I am chosing between at the moment,
http://bildarkiv.hififorum.nu./Ryssen/Pic/H%f6rlur/Opamp.jpg
http://www.analog.com/UploadedFiles/Data_Sheets/AD827.pdf
They have the same layout that allmost all dual opams have.
The LM4562 has a bipolar input,I don´t know if it is of any dissadvantage in this design?
http://bildarkiv.hififorum.nu./Ryssen/Pic/H%f6rlur/Opamp.jpg
http://www.analog.com/UploadedFiles/Data_Sheets/AD827.pdf
They have the same layout that allmost all dual opams have.
The LM4562 has a bipolar input,I don´t know if it is of any dissadvantage in this design?
Well, today I powered up the first one I build and so far I can report partitial success. Once the Atmega8 is programmed this fine unit comes to life, however it seems after I power the unit down it needs to see the programmer connected to it to start working. Without the programmer connected it is silent !
So I am not sure what needs to be done at this point, can someone
point me in the right direction and also re-verify the correct fuse settings ?
Pictures of the build progress coming soon...
Many Thanks
Cheers
Kay
So I am not sure what needs to be done at this point, can someone
point me in the right direction and also re-verify the correct fuse settings ?
Pictures of the build progress coming soon...
Many Thanks
Cheers
Kay
kct said:
Kay,
Here are the programming notes I have. They worked for me:
Programming:
(1) under the Program tab, select ATMega8 as the device type.
(2) Under the Fuses tab, make sure the fuses are programmed as follows and hit Program:
[ ] Reset Disabled
[ ] Watchdog timer Always On
[X] SPI downloading enabled (if it's grayed out, ignore)
[ ] Preserve EEPROM
[X] Boot flash size = 128
..
[ ] Boot Reset Vector Enabled
[ ] CKOPT fuse
[X] Brown out at 2.7V enabled
...
[X] Int RC Osc 4MHz, 6CK + 4ms
(3) Under the Program tab in the Flash area, point that at your .hex file and hit Program.
Additional Notes:
Check the ISP frequency in the "Board" tab of the ISP programming window... set it to something low (15KHz or so.....5.8khz....then program that in before continuing to another tab), if this is set too fast you'll get weird things happening.
Before you start writing fuses or programming, do the "Read Signature" thing in the Advanced tab and make sure you see "Signature matches selected device".
Robert
Hi Robert,
thanks for you help. I compared, this is exactly the setting I used as it was
posted earlier.
Well, I could not wait and took the second unit into operation as well.
Also this unit programmed fine and works as expected, but I believe there
is an issue with the power on reset.
For the initial power up I used a variable transformer to convince myself
there is not excessive current consumption. So while ramping up the AC
there may not be a good defined power on reset taking place. So far, Ok.
Anyway,
For unit #1:
If I ramp up the AC I need to once temporarily short pin 29 of U5 Atmega8
chip the unit comes to life without the programmer connected.
Same need to be done if I power it up without ramping up.
For unit #2:
same as unit #1, but when I power up without ramping up the unit
goes to full volume setting. Then the volume dial becomes ineffective
and does not respond.
This leads me to believe there is a Reset issue. On both the Atmel and/or
on the D/A converter.
Also, I was not quite sure how much capacitance it needed with the regulators,
so I may have used to much. On the 3.3V I have C22, C53 and C55 with
1000uF/10V each, which could be over kill.
Also on the 5V I have C19, C52 and C54 with 1000uF/10V each.
Should I reduce the capacitance to let's say 3x 100uF on those two power planes ?
Also, should I put a small capacitor, 100nF, from pin 29 to ground ?
At this point I am not to keen putting bleeders since the regulator chips
already get very warm. Pretty weired since I would not have expected
a current consumption of about 30mA on 120VAC. I have not measured
the current for each regulator circuit but I am crudely estimating about
750mW per regulator. 750mW may be in the ballpark for the +/-12V circuit
but for the 3.3V and 5V sounds too much for me, yet these regulators
get quite warm.
What is pulling such current on the 3.3V regulator that it converts an estimated
200+ mA into heat ?
And on the 5V reg. 150mA ? Where does all this current go ? The digital chips
seem cool compared to the regulators and analog chips.
Anyway,
While I start to believe I have too much capacitance on the 3.3V and 5V
I wish I would have more on the +/-12V.
Anyway, looking forward to your thoughts and comments.
Cheers
Kay
.
thanks for you help. I compared, this is exactly the setting I used as it was
posted earlier.
Well, I could not wait and took the second unit into operation as well.
Also this unit programmed fine and works as expected, but I believe there
is an issue with the power on reset.
For the initial power up I used a variable transformer to convince myself
there is not excessive current consumption. So while ramping up the AC
there may not be a good defined power on reset taking place. So far, Ok.
Anyway,
For unit #1:
If I ramp up the AC I need to once temporarily short pin 29 of U5 Atmega8
chip the unit comes to life without the programmer connected.
Same need to be done if I power it up without ramping up.
For unit #2:
same as unit #1, but when I power up without ramping up the unit
goes to full volume setting. Then the volume dial becomes ineffective
and does not respond.
This leads me to believe there is a Reset issue. On both the Atmel and/or
on the D/A converter.
Also, I was not quite sure how much capacitance it needed with the regulators,
so I may have used to much. On the 3.3V I have C22, C53 and C55 with
1000uF/10V each, which could be over kill.
Also on the 5V I have C19, C52 and C54 with 1000uF/10V each.
Should I reduce the capacitance to let's say 3x 100uF on those two power planes ?
Also, should I put a small capacitor, 100nF, from pin 29 to ground ?
At this point I am not to keen putting bleeders since the regulator chips
already get very warm. Pretty weired since I would not have expected
a current consumption of about 30mA on 120VAC. I have not measured
the current for each regulator circuit but I am crudely estimating about
750mW per regulator. 750mW may be in the ballpark for the +/-12V circuit
but for the 3.3V and 5V sounds too much for me, yet these regulators
get quite warm.
What is pulling such current on the 3.3V regulator that it converts an estimated
200+ mA into heat ?
And on the 5V reg. 150mA ? Where does all this current go ? The digital chips
seem cool compared to the regulators and analog chips.
Anyway,
While I start to believe I have too much capacitance on the 3.3V and 5V
I wish I would have more on the +/-12V.
Anyway, looking forward to your thoughts and comments.
Cheers
Kay
An externally hosted image should be here but it was not working when we last tested it.
.
An externally hosted image should be here but it was not working when we last tested it.
Maybe a problem with the supply or the ground line. Maybe the connected programmer complete a missing ground line, or supply a missing supply.
Bye...
SB
Bye...
SB
Sounds like you've got a power-on reset issue.
When the AVR ISP MKII detects power in a target, it resets the target briefly about a second afterwards which would explain why it works with the programmer connected.
Are both the "Brown out detection level @ 2.7V" and "Brown out detection enabled" fuses set?
When the AVR ISP MKII detects power in a target, it resets the target briefly about a second afterwards which would explain why it works with the programmer connected.
Are both the "Brown out detection level @ 2.7V" and "Brown out detection enabled" fuses set?
Hi Gary,
I had only "Brown out detection level @ 2.7V" checked,
"Brown out detection enabled" was unchecked.
That could explain it. I try that again with both checked.
Thanks for your help.
Cheers
Kay
I had only "Brown out detection level @ 2.7V" checked,
"Brown out detection enabled" was unchecked.
That could explain it. I try that again with both checked.
Thanks for your help.
Cheers
Kay
I apologize it took me this long for this post, other things have
come up and slowed me down with this. Also the weather improved
so I spend more time outside than in front of my computer.
Well, I tried again with the fuses set as below and there is
no change whatsoever. For now I put a 4.7 uF capacitor on pin29,
this seem to help in 95% to reset and startup without a glitch.
Anyway, I just finished to machine the front and rear panels from
some cool blue carbon fiber / fiber glass material. Looks quite nice.
[ ] Reset Disabled
[ ] Watchdog timer Always On
[X] SPI downloading enabled (if it's grayed out, ignore)
[ ] Preserve EEPROM
[X] Boot flash size = 128
..
[ ] Boot Reset Vector Enabled
[ ] CKOPT fuse
[X] Brown out at 2.7V enabled
[X] Brown out detection level @ 2.7V
...
[X] Int RC Osc 4MHz, 6CK + 4ms
come up and slowed me down with this. Also the weather improved
so I spend more time outside than in front of my computer.
Well, I tried again with the fuses set as below and there is
no change whatsoever. For now I put a 4.7 uF capacitor on pin29,
this seem to help in 95% to reset and startup without a glitch.
Anyway, I just finished to machine the front and rear panels from
some cool blue carbon fiber / fiber glass material. Looks quite nice.
[ ] Reset Disabled
[ ] Watchdog timer Always On
[X] SPI downloading enabled (if it's grayed out, ignore)
[ ] Preserve EEPROM
[X] Boot flash size = 128
..
[ ] Boot Reset Vector Enabled
[ ] CKOPT fuse
[X] Brown out at 2.7V enabled
[X] Brown out detection level @ 2.7V
...
[X] Int RC Osc 4MHz, 6CK + 4ms
An externally hosted image should be here but it was not working when we last tested it.
Well, as promised, here are a few more pictures from the build. Again I apologize for the delay as I am sure most will understand that there are other
things more important. I will also post the design files with the mods I have done to it soon, I still need to clean them up.
For future expansion, I think I would go with an On-Off switch in the Front as well as
the USB option as I think these two features are most desirable and would be the
icing on this cake.
Notice, there is still a gap of about 1.5mm between the transformers. Also notice the transformers still needed a bit rework to fit the case.
The case needed to have about 2.5mm clearance milled in some locations to avoid shorting the secondary side. Also notice the electrolytic capacitor
which I had to place to get the MC to boot correctly.
Notice the left regulator IC was moved and no longer needs the tab clipped off for clearance with the case. Now a LED can be installed for visual power up confirmation.
Notice the edge trimming on the transformers for clearance with the case.
Notice, lots of room on the bottom side for future expansion such as USB.
Fully assembled, tested and integrated into my home stereo. Notice the cool carbon look changes color slightly depending on the light angle incident.
I stopped short of having the panels engraved, I may still do that for final completion. Also I am hunting now for a nice Mahagony box as a nice
gift wrapper. Also I may get some sort of a custom leather jacket made for it to give it the high end look - at last.
Thanks Gary for sharing this fine design with us. This would make an awesome product for a small company I think.
things more important. I will also post the design files with the mods I have done to it soon, I still need to clean them up.
For future expansion, I think I would go with an On-Off switch in the Front as well as
the USB option as I think these two features are most desirable and would be the
icing on this cake.
An externally hosted image should be here but it was not working when we last tested it.
Notice, there is still a gap of about 1.5mm between the transformers. Also notice the transformers still needed a bit rework to fit the case.
An externally hosted image should be here but it was not working when we last tested it.
The case needed to have about 2.5mm clearance milled in some locations to avoid shorting the secondary side. Also notice the electrolytic capacitor
which I had to place to get the MC to boot correctly.
An externally hosted image should be here but it was not working when we last tested it.
Notice the left regulator IC was moved and no longer needs the tab clipped off for clearance with the case. Now a LED can be installed for visual power up confirmation.
An externally hosted image should be here but it was not working when we last tested it.
Notice the edge trimming on the transformers for clearance with the case.
An externally hosted image should be here but it was not working when we last tested it.
Notice, lots of room on the bottom side for future expansion such as USB.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Fully assembled, tested and integrated into my home stereo. Notice the cool carbon look changes color slightly depending on the light angle incident.
An externally hosted image should be here but it was not working when we last tested it.
I stopped short of having the panels engraved, I may still do that for final completion. Also I am hunting now for a nice Mahagony box as a nice
gift wrapper. Also I may get some sort of a custom leather jacket made for it to give it the high end look - at last.
An externally hosted image should be here but it was not working when we last tested it.
Thanks Gary for sharing this fine design with us. This would make an awesome product for a small company I think.
Looks good.
To fix the power-up issue permanently, I'd add an actual power-on-reset chip. The Microchip MCP120T series are my chip of choice for this. If you do this though, disable the onboard brownout detection fuse.
I still don't like the idea of adding USB, since you can't get anything other than 44.1/16 or 48/16 out of the usual TI PCM27/29xx series chip that everyone uses. You can buy USB soundcards that give you 24/96 or better and a SPDIF output, or you can buy a cheap Via Envy24HT based soundcard which gives you 192/24. I maintain you should just use one of those along with the DAC as-is, instead of going with USB.
Perhaps some day, TI or whoever will release a higher-sample-rate capable chip which can be integrated into this design.
To fix the power-up issue permanently, I'd add an actual power-on-reset chip. The Microchip MCP120T series are my chip of choice for this. If you do this though, disable the onboard brownout detection fuse.
I still don't like the idea of adding USB, since you can't get anything other than 44.1/16 or 48/16 out of the usual TI PCM27/29xx series chip that everyone uses. You can buy USB soundcards that give you 24/96 or better and a SPDIF output, or you can buy a cheap Via Envy24HT based soundcard which gives you 192/24. I maintain you should just use one of those along with the DAC as-is, instead of going with USB.
Perhaps some day, TI or whoever will release a higher-sample-rate capable chip which can be integrated into this design.
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