Hi all,
building my first project, an lm3875 power amp. I want to use two power supplies for a dual mono setup. I am not looking for all the best here, just want to get this project off the ground finally. Would you mind looking over my parts list as I am planning on ordering from parts connexion? Thanks!
Transformers:
2 x HAMMOND-63179 182P22 225VA 44V ct @ 5.11A
Chassis:
3 x Hammond-56034 1441-16 Steel chassis 10"L x 6" W x 2"H
?? Is Steel or Aluminum better? They are the same price.
Potentiometer:
2 x ALPS 68581 Blue velvet mono 100k continuous rotation
Switches:
2 x SWITCH - 70154
AC Socket:
2 x Connex - 62491 male with fuse holder
Binding posts:
2 x Connex - 53466 5-way posts
RCA Jacks
1 x Connex - 53452 RCA femle outside chassis mount
Power umbilical from psu to amp:
2 x Neutrik - 53048 3 pin male XLR ends
2 x Neutrik - 53045 3 pin female chassis mount
Knobs:
2 x knobs - 64390
Isolation feet;
12 x EAR - 56858 small isolation feet
I am looking to see if I am missing anything or if i'm getting anything silly. I want to build the ultimate sonic device someday, but right now am just looking for a nice experience. I am not interested in scrounging for parts too much, i'd rather get them new and know i have the right stuff for now. I have only a soldering iron and flux right now.
I know i will also need:
Wire:
What guage what colours and how much?
heatshink tubing
standoffs
fuses:
what amperage, and fast or slo blow?
heatsinks:
recommendations?
I know this has probably been discussed a trillion times but it is so nice to have personal contact with the nice people on this board.
Thanks everyone!
building my first project, an lm3875 power amp. I want to use two power supplies for a dual mono setup. I am not looking for all the best here, just want to get this project off the ground finally. Would you mind looking over my parts list as I am planning on ordering from parts connexion? Thanks!
Transformers:
2 x HAMMOND-63179 182P22 225VA 44V ct @ 5.11A
Chassis:
3 x Hammond-56034 1441-16 Steel chassis 10"L x 6" W x 2"H
?? Is Steel or Aluminum better? They are the same price.
Potentiometer:
2 x ALPS 68581 Blue velvet mono 100k continuous rotation
Switches:
2 x SWITCH - 70154
AC Socket:
2 x Connex - 62491 male with fuse holder
Binding posts:
2 x Connex - 53466 5-way posts
RCA Jacks
1 x Connex - 53452 RCA femle outside chassis mount
Power umbilical from psu to amp:
2 x Neutrik - 53048 3 pin male XLR ends
2 x Neutrik - 53045 3 pin female chassis mount
Knobs:
2 x knobs - 64390
Isolation feet;
12 x EAR - 56858 small isolation feet
I am looking to see if I am missing anything or if i'm getting anything silly. I want to build the ultimate sonic device someday, but right now am just looking for a nice experience. I am not interested in scrounging for parts too much, i'd rather get them new and know i have the right stuff for now. I have only a soldering iron and flux right now.
I know i will also need:
Wire:
What guage what colours and how much?
heatshink tubing
standoffs
fuses:
what amperage, and fast or slo blow?
heatsinks:
recommendations?
I know this has probably been discussed a trillion times but it is so nice to have personal contact with the nice people on this board.
Thanks everyone!
THe transformer is too high voltage
44 x 1.414 = 62VDC
The voltage you need depends on if you will run 4 or 8 ohm speakers
You sure have a lot of nice stuff on there, but what are you doing in line of capacitors? first make sure you get good polypropylene and low ESR electrolytics, and then see what you have left before you start spending on aestetics.
It will be slow blow fuses, but we will need to know your mains voltage to advise...
44 x 1.414 = 62VDC
The voltage you need depends on if you will run 4 or 8 ohm speakers
You sure have a lot of nice stuff on there, but what are you doing in line of capacitors? first make sure you get good polypropylene and low ESR electrolytics, and then see what you have left before you start spending on aestetics.
It will be slow blow fuses, but we will need to know your mains voltage to advise...
I thought i needed 44V center tapped transformer to do +22v 0 -22v to give 22 * 1.414 = 31VDC. I'm running 8 ohm only speakers.
Is this incorrect?
I guess it would have been usefull to state that I've already build the LM3875 kit from Peter at audiosector.com with the non-luxury components. So I'm set for caps and diodes and the like.
oh and mains voltage is north american 110 or 115.
Is this incorrect?
I guess it would have been usefull to state that I've already build the LM3875 kit from Peter at audiosector.com with the non-luxury components. So I'm set for caps and diodes and the like.
oh and mains voltage is north american 110 or 115.
LM3875 dual mono kit (Carlosfm/BrianGT boards)
Hi, stupid question here.
I assembled some months ago these boards and lost my assembling instructions.
Now I want to install the led (place is on the PS board), but I guess I have to put in place R5 since it seems to be in series with the led.
Anybody could tell me what value is the R5 resistor? Is that all I need to install the led on that board?
Thanks in advance, guys. And soffy for going off topics: I tried to post a new thread but the system simply tells me to "search the forum" and does not allow me to post a new thread...
Hi, stupid question here.
I assembled some months ago these boards and lost my assembling instructions.
Now I want to install the led (place is on the PS board), but I guess I have to put in place R5 since it seems to be in series with the led.
Anybody could tell me what value is the R5 resistor? Is that all I need to install the led on that board?
Thanks in advance, guys. And soffy for going off topics: I tried to post a new thread but the system simply tells me to "search the forum" and does not allow me to post a new thread...
to avoid the "search the forum" message, be sure to check the box at the VERY TOP of the form when you post a new thread, which says "Have you Searched?". Then you can start your own thread.
i dont mind a little hijacking, but you'd probably be better off starting your own thread.
good luck!
i dont mind a little hijacking, but you'd probably be better off starting your own thread.
good luck!
meaghers said:to avoid the "search the forum" message, be sure to check the box at the VERY TOP of the form when you post a new thread, which says "Have you Searched?". Then you can start your own thread.
i dont mind a little hijacking, but you'd probably be better off starting your own thread.
good luck!
Got it, thanks.
Where are you getting this info from?Nordic said:THe transformer is too high voltage
44 x 1.414 = 62VDC
http://www.national.com/ds/LM/LM3875.pdf says the chip can handle upto 84VDC,
50W into 8ohm @ +/-35vdc (70vdc)
68W into 4ohm @ +/-28vdc (56vdc)
CarlosT said:
No, mine is the dual mono version kit, and it has 2 PSU boards. In this one there is not the R5 place and the led place...
Thanks anyway.
elementx said:
Where are you getting this info from?
http://www.national.com/ds/LM/LM3875.pdf says the chip can handle upto 84VDC,
50W into 8ohm @ +/-35vdc (70vdc)
68W into 4ohm @ +/-28vdc (56vdc)
I was going by the graph in the datasheet shown below. Where are you looking?
Attachments
To find out what value resistor to use for running the LED go here and use the LED resistor calculator....
http://led.linear1.org/1led.wiz
http://led.linear1.org/1led.wiz
meaghers said:[B
Chassis:
3 x Hammond-56034 1441-16 Steel chassis 10"L x 6" W x 2"H
?? Is Steel or Aluminum better? They are the same price.
fuses:
what amperage, and fast or slo blow?
[/B]
Go with aluminum. It is much easier to drill and has better heat disapation.
2 amp slow blow should do the trick.
Good luck.
Kooka said:
No, mine is the dual mono version kit, and it has 2 PSU boards. In this one there is not the R5 place and the led place...
Thanks anyway.
If its anything like the ChipAmp.com power boards then it is a 10k resistor for a bright LED or a 22k for a slightly less bright LED
I'll go for the poorly bright one! Thanks.ianpengelly said:
If its anything like the ChipAmp.com power boards then it is a 10k resistor for a bright LED or a 22k for a slightly less bright LED
Re: Re: My first LM3875: check my parts please?
thanks! I was wondering about that. Aluminum it is.
What about a fuse before my speaker to protect it from accidents until I'm sure i've got it right?
GG said:
Go with aluminum. It is much easier to drill and has better heat disapation.
2 amp slow blow should do the trick.
Good luck.
thanks! I was wondering about that. Aluminum it is.
What about a fuse before my speaker to protect it from accidents until I'm sure i've got it right?
Re: Re: Re: My first LM3875: check my parts please?
You could. But I wouldn't leave it in there permanently. It's possible that at low frequencies (or maybe also with low and high frequencies intermodulating), the fuse's resistance could change with the signal, causing distortion.
For anyone who's interested in checking it out: I haven't seen it, but there's an old JAES paper by Greiner of the University of Wisconson that charted nonlinear distortion due to fuse thermal effects.
- Tom Gootee
http://www.fullnet.com/u/tomg
meaghers said:What about a fuse before my speaker to protect it from accidents until I'm sure i've got it right?
You could. But I wouldn't leave it in there permanently. It's possible that at low frequencies (or maybe also with low and high frequencies intermodulating), the fuse's resistance could change with the signal, causing distortion.
For anyone who's interested in checking it out: I haven't seen it, but there's an old JAES paper by Greiner of the University of Wisconson that charted nonlinear distortion due to fuse thermal effects.
- Tom Gootee
http://www.fullnet.com/u/tomg
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