err...Sachi...
which bangalore meeting are you talking off...?
the last one i believe was called in a restaurant, which would have made it look crowded..quite naturally you wouldnt have recognise anyone...!!
and as far as I know, that one was a meeting of two members as most of them couldnt turn up...!!!
Or have i missed something...???
ajju
which bangalore meeting are you talking off...?
the last one i believe was called in a restaurant, which would have made it look crowded..quite naturally you wouldnt have recognise anyone...!!
and as far as I know, that one was a meeting of two members as most of them couldnt turn up...!!!
Or have i missed something...???
ajju
Hi Sachi,
Who do you use to get pcb's done in Bangalore ? Will they accept files via email ?
I saw an advertisement in EFY with a Bangalore address .No idea how good their work is. There must be a very large number of pcb makers in Bangalore. I know some large pro ones , but they are too expensive or will not cater to small needs.
Thanks.
Ashok
Who do you use to get pcb's done in Bangalore ? Will they accept files via email ?
I saw an advertisement in EFY with a Bangalore address .No idea how good their work is. There must be a very large number of pcb makers in Bangalore. I know some large pro ones , but they are too expensive or will not cater to small needs.
Thanks.
Ashok
Hey Ashok,
Being a student i know it costs a bomb to get a PCB made here(better off buying it from Rod himself), but my uncle has an electronics firm and he orders pcbs for his products en masse. he said if u have the files he can get it done for me free of cost. that's why i'm asking to see any of u guys have the PCB files for the P3A amp.
Sachi
Being a student i know it costs a bomb to get a PCB made here(better off buying it from Rod himself), but my uncle has an electronics firm and he orders pcbs for his products en masse. he said if u have the files he can get it done for me free of cost. that's why i'm asking to see any of u guys have the PCB files for the P3A amp.
Sachi
Sachi,
Om Electronics, SP road, is a front-end for some (as yet unknown) PCB guy, who can do single and double sided PCBs with optional soldermask. Tolerances are more than adequate for audio work (I got him to do a board with 2 44-pin TQFPs). You give him a laser-print (on paper) of your layout, he'll do the rest. Make sure you get the orientation right (my fave way is to print some text). Good luck with your boards!
Oh, BTW, it's ILLEGAL to trade Rod's designs, it's his copyrighted work. I could dig up a design I did for the P3A, but I dunno, every time I've posted PCB designs here I've been flamed. I guess I'm not that good at it.
Damn, dont you guys *ever* start a new thread???
[EDIT]
Oh, it costs about Rs. 100 to do a 2x4 PCB (it's been a while, memory's all rusty )
Om Electronics, SP road, is a front-end for some (as yet unknown) PCB guy, who can do single and double sided PCBs with optional soldermask. Tolerances are more than adequate for audio work (I got him to do a board with 2 44-pin TQFPs). You give him a laser-print (on paper) of your layout, he'll do the rest. Make sure you get the orientation right (my fave way is to print some text). Good luck with your boards!
Oh, BTW, it's ILLEGAL to trade Rod's designs, it's his copyrighted work. I could dig up a design I did for the P3A, but I dunno, every time I've posted PCB designs here I've been flamed. I guess I'm not that good at it.
Damn, dont you guys *ever* start a new thread???
[EDIT]
Oh, it costs about Rs. 100 to do a 2x4 PCB (it's been a while, memory's all rusty
)Me and sunil, have had couple of PCB's made from OM..
We gave him the circuit and he made the layout...Though the layout in concept looked good and he had implemented what we asked for, he had screwed it up on the connectivity front. There were shorts as well as power tracks running along either side of the PCB, at the edges, which would cause a short when the assembly is mounted on a heatsink. All these prompts me to believe that these guys are not even semi professionals, else they could have easily isolated the shorts when by loading a netlist into the CAD program.
The quality of the PCB's are close to ..err pathetic. Finish was poor and even the thru holes werent that impressive. The costs...if i remember correctly is..
300Rs for the layout mask making and stuff..
and 2.50/ sq inch or something like that for double sided PCB..
Secondly, If you make a mistake while soldering, or want to replace a leaky cap...impossible...
the tracks would just come off... Certain Epoxy based substrates do suffer from such problems of course, but good enamels are effective in preventing these to a certain extent...
I agree with roadkill, Ideally we should not trade P3A PCB layout (if it has been sourced from him earlier) without his permission.
BTW, OM does accept files via e-mail...but you would be chasing him for the rest of your life to get the boards back..!!!
ajju
We gave him the circuit and he made the layout...Though the layout in concept looked good and he had implemented what we asked for, he had screwed it up on the connectivity front. There were shorts as well as power tracks running along either side of the PCB, at the edges, which would cause a short when the assembly is mounted on a heatsink. All these prompts me to believe that these guys are not even semi professionals, else they could have easily isolated the shorts when by loading a netlist into the CAD program.
The quality of the PCB's are close to ..err pathetic. Finish was poor and even the thru holes werent that impressive. The costs...if i remember correctly is..
300Rs for the layout mask making and stuff..
and 2.50/ sq inch or something like that for double sided PCB..
Secondly, If you make a mistake while soldering, or want to replace a leaky cap...impossible...
the tracks would just come off... Certain Epoxy based substrates do suffer from such problems of course, but good enamels are effective in preventing these to a certain extent...
I agree with roadkill, Ideally we should not trade P3A PCB layout (if it has been sourced from him earlier) without his permission.
BTW, OM does accept files via e-mail...but you would be chasing him for the rest of your life to get the boards back..!!!
ajju
ajju,
I have got pretty decent results from him when I've asked for glass epoxy boards. Even the phenolic boards which I've used for cheapo non-audio projects were not too shabby. Your Mileage May Vary. My main problem was that he sometimes missed drilling holes.
The tracks will come off easily if you're not careful, this is always a problem with the cheap substrates used in most single layer boards. I've asked him for a couple of double layer boards, these were better as the through-plating held the pads in place.
I would'nt advise anyone to allow them to do the layout. You know your circuit best, and there needs to be a lot of interaction b/w the PCB designer and the circuit designer, which is absent in this case. Besides, it's overpriced!
Now if we're talking pro PCBs, they cost a lot because prototype runs for most guys around B'lore (like Hi-Q, etc) are 6 boards. Their NRE costs are also very high, and I will be willing to bet money that if a hobbyist approaches them, they are not gonna be treated well!
In the US, however, the story's quite different, coz here the PCB cos squeeze in a prototype board on the same panel as a production board with similar specs. They offer spl discounts to students and hobbyists with prototype runs of 1 board! See www.4pcb.com
Damn, when I'm in this land of opportunity, I dont have time for my soldering iron!
I have got pretty decent results from him when I've asked for glass epoxy boards. Even the phenolic boards which I've used for cheapo non-audio projects were not too shabby. Your Mileage May Vary. My main problem was that he sometimes missed drilling holes.
The tracks will come off easily if you're not careful, this is always a problem with the cheap substrates used in most single layer boards. I've asked him for a couple of double layer boards, these were better as the through-plating held the pads in place.
I would'nt advise anyone to allow them to do the layout. You know your circuit best, and there needs to be a lot of interaction b/w the PCB designer and the circuit designer, which is absent in this case. Besides, it's overpriced!
Now if we're talking pro PCBs, they cost a lot because prototype runs for most guys around B'lore (like Hi-Q, etc) are 6 boards. Their NRE costs are also very high, and I will be willing to bet money that if a hobbyist approaches them, they are not gonna be treated well!
In the US, however, the story's quite different, coz here the PCB cos squeeze in a prototype board on the same panel as a production board with similar specs. They offer spl discounts to students and hobbyists with prototype runs of 1 board! See www.4pcb.com
Damn, when I'm in this land of opportunity, I dont have time for my soldering iron!
this one is long so bear with me.
u must mean the pcb u designed using eagle?. did u ever make use of the pcb u designed.
if not then whose design did u use for ur P3A amp.
posting PCB layouts designed individuals based on the P3A amp is also prohibited or only the layout Rod is selling.
BTW if i decide to buy the PCB from Rod directly will i have to pay any customs. also canu give me the total amount u spent on ur P3A.
i see that u are in DRDO now. but u are posted in Bangalore itself or elsewhere.
and i know abt Om electronics. he charges pcbs based on the number of solder points. but since i can get my PCbs for free i just want the pcb layout files.
if i decide to use eagle or orcad to design the pcb will i find all the necessary components in the library and will there be any restrictions on the size of the pcb u will be alloewd to design.
Sachi
p.s: just wanted to know which is better. peerless xls or adire shiva.
hey Raodkill,
u must mean the pcb u designed using eagle?. did u ever make use of the pcb u designed.
if not then whose design did u use for ur P3A amp.
posting PCB layouts designed individuals based on the P3A amp is also prohibited or only the layout Rod is selling.
BTW if i decide to buy the PCB from Rod directly will i have to pay any customs. also canu give me the total amount u spent on ur P3A.
i see that u are in DRDO now. but u are posted in Bangalore itself or elsewhere.
and i know abt Om electronics. he charges pcbs based on the number of solder points. but since i can get my PCbs for free i just want the pcb layout files.
if i decide to use eagle or orcad to design the pcb will i find all the necessary components in the library and will there be any restrictions on the size of the pcb u will be alloewd to design.
Sachi
p.s: just wanted to know which is better. peerless xls or adire shiva.
I got a couple of orders done from Om and the quality was horrible. The tracks seem to have been drawn by hand and were not at all neat. I could have done a better job at home. I am making the balanced zen line stage project and made the boards myself using the toner transfer method.
Ajju, when did you come back from the US?
Vivek
Ajju, when did you come back from the US?
Vivek
Hi!
My experience on PCB front has been varied.
a) The ones who make in small lots do it manualy. If they do the layout then most of the time it is just drafting done without any netlist generation. One of the reason you will find mistakes and grounding issue in such design cause the draftsman at the other end is not experienced in these matters.
Most PCB wallah use Protel for quick artwork only. Under such circumstances it is best you give them your own layout or at least the interconnections.
b) Professional companies who do proper CAD work with schematics and netlist make use of CNC machines it is simply not feasible to make few boards given the elaborate process and setting up required.
For PCB designing it is best to download Autotrax from net now it has been made free.
PCB development charges also include number of films that are being used ie track, top screen, solder masking etc. I find it economical to just give the track layout and ask him to roller tin the whole board in case of single sided ones. This not only makes the conductor stronger it also turns out cheaper for early prototype run.
Cost comes to approx Rs1.50/ per sq inch for single sided glass epoxy and abt Rs4./sq inch for double sided in these parts.
Regards
Rahul
My experience on PCB front has been varied.
a) The ones who make in small lots do it manualy. If they do the layout then most of the time it is just drafting done without any netlist generation. One of the reason you will find mistakes and grounding issue in such design cause the draftsman at the other end is not experienced in these matters.
Most PCB wallah use Protel for quick artwork only. Under such circumstances it is best you give them your own layout or at least the interconnections.
b) Professional companies who do proper CAD work with schematics and netlist make use of CNC machines it is simply not feasible to make few boards given the elaborate process and setting up required.
For PCB designing it is best to download Autotrax from net now it has been made free.
PCB development charges also include number of films that are being used ie track, top screen, solder masking etc. I find it economical to just give the track layout and ask him to roller tin the whole board in case of single sided ones. This not only makes the conductor stronger it also turns out cheaper for early prototype run.
Cost comes to approx Rs1.50/ per sq inch for single sided glass epoxy and abt Rs4./sq inch for double sided in these parts.
Regards
Rahul
OK, there seems to be some misunderstanding here: I meant that I used schematic entry (Eagle), designed a PCB for it and then printed out this PCB pattern onto paper with a laser printer. I then gave this in to Om Electronics, they made a bromide from this and used it in a screen printing process to lay down ink onto a copperclad. This board is then etched, the ink washed off and the copperclad is tinned in a tin bath. Suraj (the owner) explained this to me once. Sometimes if you look at a groundplane you can see the screenprinting's telltale signs (slightly uneven surface). The line quality was more than enough for audio boards. Now if you give him a circuit drawn on paper and ask him for a PCB, that's a different story (which I dont know much about).
sachi, I got the circuit for the P3A from Rod's site, I modified it slightly (the input stage current sink now uses two transistors instead of one to make it more stiff) and designed my own PCBs for it. I dont think Rod would object to sharing this with others, but he would mind if his original board design is copied. I just feel reluctant to post that design here because of all the flaming associated with posting PCB designs. And I guess you would have visited my dumdum website, I havent updated it in a bit, I used to work for DRDO (at LRDE, Bangalore), I quit and I'm studying for an MS now.
But seriously, it would always be a good idea to do your own PCBs, because it is a) a learning exp. and b) PCBs depend heavily on the components available, esp nonstandard stuff like pots, heatsinks, etc. Usually some footprint/library editing is required to get stuff just right.
Please note that in my design, the nodes X2-1 and X1-2 are connected to the speaker ground, but there is an additional ground lead from the speaker's binding post to the center tap of the power transformer. Those two nodes are only for the Zobel network. This PCB was from my "early days", it's not one of my best The board's now used as a bridged amp for a sub.
sachi, I got the circuit for the P3A from Rod's site, I modified it slightly (the input stage current sink now uses two transistors instead of one to make it more stiff) and designed my own PCBs for it. I dont think Rod would object to sharing this with others, but he would mind if his original board design is copied. I just feel reluctant to post that design here because of all the flaming associated with posting PCB designs. And I guess you would have visited my dumdum website, I havent updated it in a bit, I used to work for DRDO (at LRDE, Bangalore), I quit and I'm studying for an MS now.
But seriously, it would always be a good idea to do your own PCBs, because it is a) a learning exp. and b) PCBs depend heavily on the components available, esp nonstandard stuff like pots, heatsinks, etc. Usually some footprint/library editing is required to get stuff just right.
Please note that in my design, the nodes X2-1 and X1-2 are connected to the speaker ground, but there is an additional ground lead from the speaker's binding post to the center tap of the power transformer. Those two nodes are only for the Zobel network. This PCB was from my "early days", it's not one of my best
The board's now used as a bridged amp for a sub.hey rodkill,
i will definitiley attempt to design my own PCb as soon as i'm done with my final sem project.
BTW have u taken ur GRE yet. what course are u looking for.
i plan to take mine in the third week of august.
BTW what software should i use for opening ur files.
its not opening in ORCAD and also in eagle(4.11). maybe i'll try reinstalling eagle and try again.
Sachi
i will definitiley attempt to design my own PCb as soon as i'm done with my final sem project.
BTW have u taken ur GRE yet. what course are u looking for.
i plan to take mine in the third week of august.
BTW what software should i use for opening ur files.
its not opening in ORCAD and also in eagle(4.11). maybe i'll try reinstalling eagle and try again.
Sachi
Another PCB maker in Bombay
I thought I'll add a reference to this PCB maker in this thread, so that the thread can act as a repository for all Indian DIYers. Sangram has posted here that there's this PCB maker in Bombay, Pradeep Electronics, phone 23891567/3456, run by a Mr Shirodkar, who can make good PCBs. Just FYI.
I personally don't want to explore another PCB maker because I already have experience working with Charu Desai of Image, followed by Mr Subramaniam of Balaji Hertz. These two gentlemen do excellent work, and I've never had reason to complain.
One note about PCB makers. There are two types of PCB makers.
Some start with Gerber files, make films using a Gerber photoplotter, and then use those films to make silkscreens and then make PCBs. This process is necessary if you want, say, 8-12mil track widths or track gaps (i.e. if you want to pass a track through the gap between two pins of a DIP IC). Charu Desai and Balaji Hertz work this way. Their customers demand 12mil accuracy; Mr Subramaniam routinely delivers this level of precision.
Others are willing to start with a laser printout, and make films from them. These PCB makers are usually, not necessarily, catering to customers who need much less accuracy. These PCB makers can offer more attractive rates, but usually have poorer work processes and equipment, making even 16mil accuracy doubtful. This means that Sangram or Roadkill will find it difficult to make their Gainclones or other chip amps from these guys.
In Bombay, Visha Electronics is willing to make single-sided PCBs using this laser-printout method. They don't do solder masking or screen printing, but at least they are a useful option when you just need a simple PCB made with broad tracks. I've used them for making capacitor-bank PCBs for power amps. I'd never try them for IC-based designs. Perhaps a P3A PCB can be made by them... it's a simple enough layout. Most discrete power amps, in fact, can be laid out single-sided, and Visha can make their PCBs, since there are no ICs or other fine components to fuss with.
I have a feeling that our B'lore friends have encountered a Category 2 PCB maker when dealing with Om. If you deal with Balaji Hertz, he won't even accept a laser printout as starting material --- he won't even know what to do with it. Yes, I've tried.
(There's of course a third type, who use completely computer controlled equipment to make the PCBs without any human contact. Such PCB makers exist all over India, but they may not be willing to do prototypes, as Roadkill had mentioned. You have to use this third category if you're doing more than double-sided, i.e. if you're going multi-layer.)
I thought I'll add a reference to this PCB maker in this thread, so that the thread can act as a repository for all Indian DIYers. Sangram has posted here that there's this PCB maker in Bombay, Pradeep Electronics, phone 23891567/3456, run by a Mr Shirodkar, who can make good PCBs. Just FYI.
I personally don't want to explore another PCB maker because I already have experience working with Charu Desai of Image, followed by Mr Subramaniam of Balaji Hertz. These two gentlemen do excellent work, and I've never had reason to complain.
One note about PCB makers. There are two types of PCB makers.
Some start with Gerber files, make films using a Gerber photoplotter, and then use those films to make silkscreens and then make PCBs. This process is necessary if you want, say, 8-12mil track widths or track gaps (i.e. if you want to pass a track through the gap between two pins of a DIP IC). Charu Desai and Balaji Hertz work this way. Their customers demand 12mil accuracy; Mr Subramaniam routinely delivers this level of precision.
Others are willing to start with a laser printout, and make films from them. These PCB makers are usually, not necessarily, catering to customers who need much less accuracy. These PCB makers can offer more attractive rates, but usually have poorer work processes and equipment, making even 16mil accuracy doubtful. This means that Sangram or Roadkill will find it difficult to make their Gainclones or other chip amps from these guys.
In Bombay, Visha Electronics is willing to make single-sided PCBs using this laser-printout method. They don't do solder masking or screen printing, but at least they are a useful option when you just need a simple PCB made with broad tracks. I've used them for making capacitor-bank PCBs for power amps. I'd never try them for IC-based designs. Perhaps a P3A PCB can be made by them... it's a simple enough layout. Most discrete power amps, in fact, can be laid out single-sided, and Visha can make their PCBs, since there are no ICs or other fine components to fuss with.
I have a feeling that our B'lore friends have encountered a Category 2 PCB maker when dealing with Om. If you deal with Balaji Hertz, he won't even accept a laser printout as starting material --- he won't even know what to do with it. Yes, I've tried.
(There's of course a third type, who use completely computer controlled equipment to make the PCBs without any human contact. Such PCB makers exist all over India, but they may not be willing to do prototypes, as Roadkill had mentioned. You have to use this third category if you're doing more than double-sided, i.e. if you're going multi-layer.)
Re: Re: Another PCB maker in Bombay
In that case, he may not be able to make repeatable accurate PCBs of things like small ICs or even the Gainclone chips. A normal laser printer may not print accurately on film (they didn't in all my attempts), and a Gerber photoplotter won't print from .CDR or .PDF files.sangram said:
Toroidal transformers in India
This may be interesting for India diyers:
In the search for toroidal transformers, I looked at Canadian firm Plitron that is a manufacturer popular among diyers in NAmerica.
I contacted Plitron, but they recommended that I get in touch with their Indian partner Salzer who are in Coimbatore and also manufacture on behalf of Plitron to Plitron's specs.
The man to contact at Salzer is Raymond -- I sent him my requests for 4 toroidals, and he sent me a pdf design plan and pricing. In my case, 300 va 2x15v is 2,000 RS each and 160va 2x15v is 1,500 RS each -- roughly around what you'd pay for an off-the-shelf toroid from a big components retailer in the US like Parts Express, and far cheaper than what you'd pay in Europe. They can deliver anywhere in India and seem happy to do small custom orders. Postage for 4 transformers is 500 RS.
I should get the items in a couple of weeks, and will post a follow up.
This may be interesting for India diyers:
In the search for toroidal transformers, I looked at Canadian firm Plitron that is a manufacturer popular among diyers in NAmerica.
I contacted Plitron, but they recommended that I get in touch with their Indian partner Salzer who are in Coimbatore and also manufacture on behalf of Plitron to Plitron's specs.
The man to contact at Salzer is Raymond -- I sent him my requests for 4 toroidals, and he sent me a pdf design plan and pricing. In my case, 300 va 2x15v is 2,000 RS each and 160va 2x15v is 1,500 RS each -- roughly around what you'd pay for an off-the-shelf toroid from a big components retailer in the US like Parts Express, and far cheaper than what you'd pay in Europe. They can deliver anywhere in India and seem happy to do small custom orders. Postage for 4 transformers is 500 RS.
I should get the items in a couple of weeks, and will post a follow up.
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