Re: Measuring of distortion on PA 03 ( LM 4780)
Pavel, for this kind of amp you should know magnitudes of higher order harmonics than only 2nd and 3rd.
Also, it can be seen that distortion rises with lowering signal value. This is contrary to class A amp or DPA 380. Of course, caused by circuit topology of the chipamp.
Upupa Epops said:
Pavel, for this kind of amp you should know magnitudes of higher order harmonics than only 2nd and 3rd.
Also, it can be seen that distortion rises with lowering signal value. This is contrary to class A amp or DPA 380. Of course, caused by circuit topology of the chipamp.
I suppose i'm kinda stupid but is the JP2 and 3 used for inverting the amp or just grounding a balanced signal??
This might just be my next project.
This might just be my next project.
JP 1 is multiconnector for connecting with prewiew stagge ( crossover, preamp etc. ). With JP 2 and 3 you can set up channel to the inverting or noniverting mode or to balanced mode. This connection make amp as quite universal. Look at PCB and all will be quite clear for you 😉 .
Has there been any reports on the amp being built by anyone??
I was planning on doing it myself but saw the the top PCB layer is not icluded in the PDF file.
Guess i'll have to wait for a group buy or until the top layer is included in the schematics.
//Patrik
I was planning on doing it myself but saw the the top PCB layer is not icluded in the PDF file.
Guess i'll have to wait for a group buy or until the top layer is included in the schematics.
//Patrik
First group of PBC have my friends from my country. As you know , now have every guys holiday and electronic goes away 🙁 . Personally I was built six pieces, all with the same results, so I think that build it can everybody. 'Cos all is on PCB, I hope that will be not any questions about grounding and connecting in general. For own made PCB forget - have you imagination how cost prototype ?
I have got a pcb from Pavel and they look really tasty, with thick copper (is it 70 or 105 um?), and I'm sorry to say that they aren't possible to etch at home. If you get one pcb from Pavel you won't get dissapointed.SlaitH said:
Check here:
http://czechaudio.com/Projects/PA03/PA03_EN.htm
The detail picture may give you a hint how they look.
http://www.sjostromaudio.com/dudek/pics/pa03_detail.jpg
http://czechaudio.com/Projects/PA03/PA03_EN.htm
The detail picture may give you a hint how they look.
http://www.sjostromaudio.com/dudek/pics/pa03_detail.jpg
Yep it would be kewl to build.
But I suppose he can't be sending to the entire world.
peranders: Haven't you got any connections on where to make fairly cheap PCB:s here in svedala??
I would think that there might become a high demand. Maybe if some more people got to test and hear the amp??
What's youre oppinion on the sound??
I haven't got a doubt on the design 😀
//Patrik
But I suppose he can't be sending to the entire world.
peranders: Haven't you got any connections on where to make fairly cheap PCB:s here in svedala??
I would think that there might become a high demand. Maybe if some more people got to test and hear the amp??
What's youre oppinion on the sound??
I haven't got a doubt on the design 😀
//Patrik
I have connections but if you are a private person 3000 SEK to 4400 SEK is where it starts, for 5-10 pcb's no matter the size.
http://www.olimex.com has really good prices but they has also serious limitations for getting this low price.
The main issue is what Pavel want to take his project. We should let him come back from vacation first (or whatever)? Does he want a group buy at all? Let him to deside.
then _maybe_ we can arrange something.
My personal view is that this pcb is more or less ready for production as a commercial product and both design and pcb are close to high-end or even it is high-end, just by the looks but also by it's content. I think this pcb is one of the best of it's kind and Pavel would do the DIY community a service if he would make it easy available.
My suggestion to Pavel is that now when the pcb is debugged and it seems that the design is a 100% success, why not upgrade some parts. One obvious thing is to make room for SO08 opamps and fast recovery diodes in the rectifier bridge and maybe also add more "normal" connectors for the input.
The downloading interest has been huge! More than 2 GB has left the server and Pavels' stuff stands for 95% and the tiny 5% is my stuff. 🙂
http://www.olimex.com has really good prices but they has also serious limitations for getting this low price.
The main issue is what Pavel want to take his project. We should let him come back from vacation first (or whatever)? Does he want a group buy at all? Let him to deside.
then _maybe_ we can arrange something.My personal view is that this pcb is more or less ready for production as a commercial product and both design and pcb are close to high-end or even it is high-end, just by the looks but also by it's content. I think this pcb is one of the best of it's kind and Pavel would do the DIY community a service if he would make it easy available.
My suggestion to Pavel is that now when the pcb is debugged and it seems that the design is a 100% success, why not upgrade some parts. One obvious thing is to make room for SO08 opamps and fast recovery diodes in the rectifier bridge and maybe also add more "normal" connectors for the input.
The downloading interest has been huge! More than 2 GB has left the server and Pavels' stuff stands for 95% and the tiny 5% is my stuff. 🙂
Yeah I can agree that it's to expensive for just one person.
Let's Pavel deside when he returns, it's his design.
Wouldn't be a bad idea to perhaps upgrade the connectors and I looked in the ELFA catalogue here in sweden. And I couldn't find any cooling that would fit the board, either to small or way to big.
No problem for me because I can do metal work at my job, but not everyone has those possibilities.
What is it about the board that makes it so hard to etch. Because of the two side design or the thick copper???
//Patrik
Let's Pavel deside when he returns, it's his design.
Wouldn't be a bad idea to perhaps upgrade the connectors and I looked in the ELFA catalogue here in sweden. And I couldn't find any cooling that would fit the board, either to small or way to big.
No problem for me because I can do metal work at my job, but not everyone has those possibilities.
What is it about the board that makes it so hard to etch. Because of the two side design or the thick copper???
//Patrik
1 Lot's of viasSlaitH said:
2 Small pads in many places. Especially the LM4780 is a sensitive part. Non-plated holes will make a very weak connection for the IC.
looking forward
hey guys... I think there's thousands of DIY's out there looking forward for Pavel's return AND the notice for avaliability of his boards... including me 😀
And I'm sure that hundreds of them are planning to make some mods on the boards also... it's easy if you know what you are doing...😎
The only problem... I still do not found LM4780 avaliable. Farnell and RS asks for 30 days or more in Brazil. ( 12,00 USD each)
Regards to all.
Hisatugo
🙄 🙄
hey guys... I think there's thousands of DIY's out there looking forward for Pavel's return AND the notice for avaliability of his boards... including me 😀
And I'm sure that hundreds of them are planning to make some mods on the boards also... it's easy if you know what you are doing...😎
The only problem... I still do not found LM4780 avaliable. Farnell and RS asks for 30 days or more in Brazil. ( 12,00 USD each)
Regards to all.
Hisatugo
🙄 🙄
Yup, even I feel there are a lot of eager DIY'ers waiting to make a higher-powered version of the GC. The big question .....Will Pavel offer the boards ?
cheers,
sunil
cheers,
sunil
No, is is not dead. I am preparing my own www. sites and some things about " business " 😎 . I had try to build more pieces of this module for test of reliability ( no problems ) and some of my friends was doing the same. In summer I was in hospital, so excuse me this delay. Now I have ready instruction manual in english, so who can, may get it before for preparing devices ( I only need your private mail ). I like " full range " projects 😉 , so I prepare now as second step electronic crossover and preamp ( maybe also in tube ( hybrid ) version. As you know, it is many work and I haven't any " developing team ", I'm alone 🙁 . Cheers, I'm watching for you mails 😎 .