I have all the transistors, capacitors, resistors, speaker terminals, power terminal, transformer, and rca inputs ready to purchase, I just can't find a decent heat sink. Which of the transistors should I heat sink? Just the four output transistors? Any suggestions on a heat sink to get? I found this one but there is no thermal resistance given so I'm not sure if it would be good enough for 4x 250W transistor heat dissipation 1 Heatsink HS 250100 to 3 x5 Black Aluminium Size 250x100x25mm 10"x4"x1" LxWxH | eBay
and here's the amp website DIY 200Watts Power Amp
Do i need any heat sinks for the other transistors?
and here's the amp website DIY 200Watts Power Amp
Do i need any heat sinks for the other transistors?
Looking at the VERY fuzzy picture....one can make out the Heat-sink for the Four TO-3 transistors.....the picture shows the sink slightly bigger than the circuit-board, roughly 150% the size of your selected heat-sink.
On the upper side of the board, one can make out what MIGHT be a TO-220 case style....but I maybe wrong.....Four of them have suitable sinks.
Frankly without the board at least partially laid out....what's going where,how big is my enclosure, how much room do I have....etc., etc,.
I think your getting ahead of yourself.....get the enclosure case....figure out how your going to do the layout, then get the appropriate heat-sinks.
Find someone who will give you an endless array of choices.......not only for functionality, but for a Wow factor.
_______________________________________________________Rick.........
On the upper side of the board, one can make out what MIGHT be a TO-220 case style....but I maybe wrong.....Four of them have suitable sinks.
Frankly without the board at least partially laid out....what's going where,how big is my enclosure, how much room do I have....etc., etc,.
I think your getting ahead of yourself.....get the enclosure case....figure out how your going to do the layout, then get the appropriate heat-sinks.
Find someone who will give you an endless array of choices.......not only for functionality, but for a Wow factor.
_______________________________________________________Rick.........
Ok, Thanks.
Another few questions... I was looking on this page Power Amp THD & Power Test - AmpsLab and noticed the Power supply circuit. I need to build this too, right? I'm just confused as they are not on the parts list on the previous page...
For C1, what voltage? It just says 4700 pF X2
for C2 and C3, would these be better JAPAN 2PCS Elna Lao 10000uF 63V For Audio Electrolytic Capacitor New TOP HiFi | eBay than these ECO-S1JA103EA Panasonic Electronic Components | P7492-ND | DigiKey or does it not matter?
What exactly is B1, the bridge rectifier? I can't find any info on what diodes it uses.
For F1, what fuse should I use off of mouser? Again, no info from what I can see.
I assume SW1 is just connected to the main power switch?
Another few questions... I was looking on this page Power Amp THD & Power Test - AmpsLab and noticed the Power supply circuit. I need to build this too, right? I'm just confused as they are not on the parts list on the previous page...
For C1, what voltage? It just says 4700 pF X2
for C2 and C3, would these be better JAPAN 2PCS Elna Lao 10000uF 63V For Audio Electrolytic Capacitor New TOP HiFi | eBay than these ECO-S1JA103EA Panasonic Electronic Components | P7492-ND | DigiKey or does it not matter?
What exactly is B1, the bridge rectifier? I can't find any info on what diodes it uses.
For F1, what fuse should I use off of mouser? Again, no info from what I can see.
I assume SW1 is just connected to the main power switch?
The heatsink requirement depends on the dissipation of the design at worst case, around 50% maximum output power and working into it's toughest load. To be precise, you could extract more than 200W from those transistors, but safety is important, so we assume the current limiters (Q7,8) will do their job and prevent massive current meltdowns if using extreme low impedance loads. Don't forget that the bias regulating transistor (Q6) needs to go on the heatsink too, between the output transistor pairs, whether you also fit the driver transistors (Q9,10) there too or not. All 7 have to be heatsinked for one reason or another.
Look at the gallery pics or the Honeybadger sticky thread here for visual clues to the heatsink size/type and the transistor locations.
With 200W/4R output power rating as maximum, I suggest a conservative =< 0.4 deg. C/W static rating. That's when used vertically with free air circulation and no fan. That's also a big sink - about 250x100x45mm for each channel. Shallow, 1" heatsinks with tiny fins just don't cut it unless they have thick backplates and are really wide and high. If vendors can't supply ratings for their heatsinks, don't bother trying to deal with them, as the actual rating depends on the design quality and many are obviously naive and thermally inefficient.
Look at the gallery pics or the Honeybadger sticky thread here for visual clues to the heatsink size/type and the transistor locations.
With 200W/4R output power rating as maximum, I suggest a conservative =< 0.4 deg. C/W static rating. That's when used vertically with free air circulation and no fan. That's also a big sink - about 250x100x45mm for each channel. Shallow, 1" heatsinks with tiny fins just don't cut it unless they have thick backplates and are really wide and high. If vendors can't supply ratings for their heatsinks, don't bother trying to deal with them, as the actual rating depends on the design quality and many are obviously naive and thermally inefficient.
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has anyone ever put a "power output meter" or whatever it's called on an amplifier before? like in this picture http://www.mcintoshlabs.com/Assets/Images/Products/MC601/XL_MC601_D.jpg What is the actual name of a meter like this? Does anyone know how it gets a power reading without affecting the output?
does Electronic Components & Supplies | Mouser have anything like this that would be relatively easy to hook up to an amp?
does Electronic Components & Supplies | Mouser have anything like this that would be relatively easy to hook up to an amp?
The power consumption on a meter like this is in the region of uwatts.
Typically less than a mA and the do not affect the sound in any way.
Back in the seventies we never buildt any amp without a meter similar to this. But we often ended up with a lot cheaper one. Smaller in Size, but still we "had to have one".
how is it connected to an amplifier? like how does it get a reading? is it in parallel and it reads voltage? but then how does it know the resistance of the load or the current draw?
also, do you have a link to a website that sells one that would be good for the c200 amplifier? thanks.
say I use this one, 2pcs SD 315H A Panel Vu Meter 500UA 660? 64x53mm with 12V Amber Bulb Lamp | eBay
how do I know which dB level corresponds to what power output, and does it need anything other than the vu meter to work? Does it go in series or parallel with the output, and the two extra pins on it are the + and - for the 12v backlight on it, correct? so how would that be powered typically?
or this one too.. 500UA 700 Ohm Full Scale Rectangular Vu Watts Meter 0 500V | eBay
the first one is 660 ohm and the second one is 700 ohm, shouldn't it be something like 5k ohm and in parallel so it doesn't affect the speaker load?
how do I know which dB level corresponds to what power output, and does it need anything other than the vu meter to work? Does it go in series or parallel with the output, and the two extra pins on it are the + and - for the 12v backlight on it, correct? so how would that be powered typically?
or this one too.. 500UA 700 Ohm Full Scale Rectangular Vu Watts Meter 0 500V | eBay
the first one is 660 ohm and the second one is 700 ohm, shouldn't it be something like 5k ohm and in parallel so it doesn't affect the speaker load?
ampalab c200
the meter is connected across the dummy load thus showing the o/p power.. if you don't have a power meter you can connect your ddm and select the ac range of 200 volts.. next do the quick sum of ac volts then divided by the dummy load = ... example would be say 20 ac on a amplifiers o/p then divided by say 4 ohms works out at...5 amps times this by 20 volts =100 watts..before clipping...
the meter is connected across the dummy load thus showing the o/p power.. if you don't have a power meter you can connect your ddm and select the ac range of 200 volts.. next do the quick sum of ac volts then divided by the dummy load = ... example would be say 20 ac on a amplifiers o/p then divided by say 4 ohms works out at...5 amps times this by 20 volts =100 watts..before clipping...
dummy load? I want this to show the power output while using the amplifier with a speaker to see the power draw. not with a dummy load.
what i'm asking is, is it just connected in parallel with the + and - speaker outputs and that's it?
The typical cheap power meter in amplifiers does not measure power. It is a voltmeter scaled to express the volts output across an assumed 8 ohm load as power. If the load is some other impedance, well you need another scale, range or it's just tough luck.
There are indeed accurate instruments that integrate AC current and voltage measurements but as obsolete analog. instruments, they would not be cheap by any estimation.
These are really only for wow factor. (When they were once fitted in every power amplifier made, most would read the same power whether the speakers were connected or not. Go figure!)
There are indeed accurate instruments that integrate AC current and voltage measurements but as obsolete analog. instruments, they would not be cheap by any estimation.
These are really only for wow factor. (When they were once fitted in every power amplifier made, most would read the same power whether the speakers were connected or not. Go figure!)
Yeah it will give a general idea of the power being used though, maybe +/- 50% though won't it?
C200
The short anwser is yes the meter in connected across the amplifier's out put..
When checking the rated amplifier out put test loads are used.. The are also valid comments being made on this topic via members..
The short anwser is yes the meter in connected across the amplifier's out put..
When checking the rated amplifier out put test loads are used.. The are also valid comments being made on this topic via members..
http://www.diyaudio.com/forums/equipment-tools/252386-bulb-limiter-testing.html
There is more than 1 linked thread there and this gizmo is part of almost every repair thread. Read the operating method, limitations and safety details thoroughly and make sure you take great care with anything you mess with involving mains power supply.
Use mains rated wiring and local electricity authority approved components and construction methods. That's right, not Ebay junk!
There is more than 1 linked thread there and this gizmo is part of almost every repair thread. Read the operating method, limitations and safety details thoroughly and make sure you take great care with anything you mess with involving mains power supply.
Use mains rated wiring and local electricity authority approved components and construction methods. That's right, not Ebay junk!
never mind I understand now. When you plug the transformer in (in my case http://www.mouser.com/ds/2/177/5c0015-57873.pdf) It will automatically go to 40-0-40. This would be bad if there is a wiring problem, so you use a variac to limit the power in case of a short. Since I don't have a variac, I can use a light bulb limiter to make sure it doesn't draw a bunch of power and fry everything initially. If the light bulb lights up bright, there's a short, if it doesn't there isn't. How many watt bulb should I use? It's a 320 VA transformer and the amp can do 125w at 8 ohms and 200w at 4 ohms.
Because it should be essentially a resistor, the bulb cannot allow more current to flow than when fully lit, right? It really doesn't matter the bulb rating but safest is ~ 60W. Larger amps such as yours may be safe enough with 100W. Remember, it needs to be an incandescent bulb, so it's 100% resistive, as simple limiters should be.
You cannot run an amplifier at its power rating or anywhere near it through a limiter, or it wouldn't be a limiter! The idea is simply to apply low AC voltage like a variac can and see if the amplifier is safe, checking voltages relative to what the supply permits. Note any heating or smoking of parts and whether you goofed up by pre-setting bias full-on instead of full-off, reversed parts or misread their values. After an initial surge and glow for the transformer inductance and charging the electrolytics, the bulb should then dim as the amplifier should only be drawing a small magnetizing current for the power transformer plus the total of minimum-setting bias currents in the amplifier(s) at this point. Note though, you should only have one amp. powered at a time unless you just like doubling your risks and adding confusion.
Finding an old plain incandescent bulb is not easy but I have had some success with a newer, halogen type rated at 60W actual. Smaller types blow too easily with some loads on 230VAC - maybe not on 115VAC. CFLs, fluorescents, LEDs, low-voltage or any transformer driven types are not suitable.
Read this article (and the rest of this massive site when it suits you) right through and learn how any problems you might have can be sorted out. You must be methodical about this, doing it by the book because remote problem diagnosis and repair is very difficult - often hopeless unless it's very simple - remotely on a forum.
You cannot run an amplifier at its power rating or anywhere near it through a limiter, or it wouldn't be a limiter! The idea is simply to apply low AC voltage like a variac can and see if the amplifier is safe, checking voltages relative to what the supply permits. Note any heating or smoking of parts and whether you goofed up by pre-setting bias full-on instead of full-off, reversed parts or misread their values. After an initial surge and glow for the transformer inductance and charging the electrolytics, the bulb should then dim as the amplifier should only be drawing a small magnetizing current for the power transformer plus the total of minimum-setting bias currents in the amplifier(s) at this point. Note though, you should only have one amp. powered at a time unless you just like doubling your risks and adding confusion.
Finding an old plain incandescent bulb is not easy but I have had some success with a newer, halogen type rated at 60W actual. Smaller types blow too easily with some loads on 230VAC - maybe not on 115VAC. CFLs, fluorescents, LEDs, low-voltage or any transformer driven types are not suitable.
Read this article (and the rest of this massive site when it suits you) right through and learn how any problems you might have can be sorted out. You must be methodical about this, doing it by the book because remote problem diagnosis and repair is very difficult - often hopeless unless it's very simple - remotely on a forum.
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