hi,
I am sekhar from west bengal / Siliguri . i have been making amps for a long time now, first i started with chip amps , then moved on to making more complex transistor & mosfet amps ,,,,, things have worked out well with my amps ... my latest amp was "legend stage mk2 500W rms at 8E" I have moved on to making of Studio Se(dr bora) And B500 from Apex Audio , i design my own pcbs and a few circuits as and when needed .........
but there are a few problems
1. Avaiblity of Amp Cabinets & heat sink
2. Avaiblity of Quality Speakers
3. Avaiblity of components (Specifically high power mosfets & BJts)
Can anybody help me with the above mentioned stuff
regards
sekhar
I am sekhar from west bengal / Siliguri . i have been making amps for a long time now, first i started with chip amps , then moved on to making more complex transistor & mosfet amps ,,,,, things have worked out well with my amps ... my latest amp was "legend stage mk2 500W rms at 8E" I have moved on to making of Studio Se(dr bora) And B500 from Apex Audio , i design my own pcbs and a few circuits as and when needed .........
but there are a few problems
1. Avaiblity of Amp Cabinets & heat sink
2. Avaiblity of Quality Speakers
3. Avaiblity of components (Specifically high power mosfets & BJts)
Can anybody help me with the above mentioned stuff
regards
sekhar
R junkyards anywhere near your place. May be u should visit them.
Amp cabinets can be made with 'L' aluminium or iron plates. Make a welded frame of suitable size and fix panels to it. Go to some workshop.
Quality speakers: God help u with those.
For high power devices, visit ebay, digikey, mouser, farnell, etc
Gajanan Phadte
Amp cabinets can be made with 'L' aluminium or iron plates. Make a welded frame of suitable size and fix panels to it. Go to some workshop.
Quality speakers: God help u with those.
For high power devices, visit ebay, digikey, mouser, farnell, etc
Gajanan Phadte
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Heatsinks aren't a problem in Calcutta at least, you get good profiles with up to 0.5C/W with nice flat backs. Little expensive, but in line with international prices.
Toshiba C5200/A1943 are available pretty easily (others may also be easier to find), FETs are significantly more difficult because the ones that are available are used for power supply applications, I have only found 540/9540 pairs that are of any use (and that too, in TO-220 case so application is limited). Drivers are considerably more difficult to find, I've had to import them in the past due to non-availability of equivalent devices in complementary pairs.
Speakers - you have to import. There is simply no Indian speaker manufacturing of any quality or standard, there is a guy here called hunter audio who manufactures some speakers for the Pro market, look at the [India] threads for the saga of his speakers. For reasonable quality, one has to get stuff from abroad.
I (and others) have used the Peerless range of drivers and while they do offer some level of consistency, it is still a long way from being mid fidelity, at least the range that is offered in Indian retail. these are only available in Mumbai as of now.
Toshiba C5200/A1943 are available pretty easily (others may also be easier to find), FETs are significantly more difficult because the ones that are available are used for power supply applications, I have only found 540/9540 pairs that are of any use (and that too, in TO-220 case so application is limited). Drivers are considerably more difficult to find, I've had to import them in the past due to non-availability of equivalent devices in complementary pairs.
Speakers - you have to import. There is simply no Indian speaker manufacturing of any quality or standard, there is a guy here called hunter audio who manufactures some speakers for the Pro market, look at the [India] threads for the saga of his speakers. For reasonable quality, one has to get stuff from abroad.
I (and others) have used the Peerless range of drivers and while they do offer some level of consistency, it is still a long way from being mid fidelity, at least the range that is offered in Indian retail. these are only available in Mumbai as of now.
Just mail me at cred_audio@rediffmail.com
I can help you source parts for both Hi-Fi and PA including high power speakers.
Sam
I can help you source parts for both Hi-Fi and PA including high power speakers.
Sam
just reference sake can this type of amp cabinets be made ................
wat sort of generic types r u talking about ??????????? please post some pictures if possible and check ur mail i have sent some details of driver that i need if possible reply to that .............
regards
sekhar
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For quality full range speakers you can go for TV speaker manufacturer... as retailers in chandni chawk would collapse from shock if you ask them to get you a couple of better than average "fullranges", 4" 5watt TV speakers from Sweton can help you with small power needs. I have used them and they sound best amongst the 5watt range. Next would be Sunvoice. They also manufacture TV speaker, however, their site states there are Japanese influence on the technology they use to make the voicecoils and diaphragms. Yes I have bought a couple of 4" 15watt fullranges from Sunvoice... They sound decent and are my choice of speakers. For 6" and above there actually are a lot of supply in chandni chawk, BUT, most of the time you ask them to get you a fine fullrange they will say "NO SIR, we dont have it." But when you say to them "please bhai, woh jo 8" speaker dikhai de raha hai rack mei, woh zara dikhayenge?", they show you that speaker and after you buy it and test it at your home you find out its actually a excellent speaker, my discovery of the Sunvoice speakers went kinda like the same way. The problem is the retailers are almost always not at all interested to the info about what they sale nor do they care, you ask them for a speaker and buy it, there is chance that the speaker is faulty, there IS a trend of selling out and clearing the stock of faulty speakers. We can only be sorry about it.
Anyway, good luck.You can buy as much aluminium plates as you want from the dealers in Barabazar, Howrah and make decent cabinets from them and heatsinks too... unfortunately the same doesn't go for the speakers... so... all the best.
btw, Sunvoice have ranges of 16ohm speakers too... you may like to see this... the lowermost speaker in the page. >>> http://sunvoice.in/product2.html
Anyway, good luck.You can buy as much aluminium plates as you want from the dealers in Barabazar, Howrah and make decent cabinets from them and heatsinks too... unfortunately the same doesn't go for the speakers... so... all the best.
btw, Sunvoice have ranges of 16ohm speakers too... you may like to see this... the lowermost speaker in the page. >>> http://sunvoice.in/product2.html
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This thread has a lot of useful information and contacts, mostly limited to diy'ing in bombay though
http://www.diyaudio.com/forums/parts/28068-india-chassis-knobs-pcb-makers.html
http://www.diyaudio.com/forums/parts/28068-india-chassis-knobs-pcb-makers.html
The balance voltage will appear at the output as offset, and may damage your speaker.
You could use a simple cap multiplier after the rectifier on both rails from the rectifier/cap banks, and adjust the output of the two to output the exact same voltages. This can be done by using trimmers to vary the base voltage, or a combination of zener diodes to hit the desired voltage level.
It may be better to cut the CT and separate the two windings, combining them again after the cap multiplier. Obviously you will need two rectifiers, but those are cheap enough that that is not a problem.
You could use a simple cap multiplier after the rectifier on both rails from the rectifier/cap banks, and adjust the output of the two to output the exact same voltages. This can be done by using trimmers to vary the base voltage, or a combination of zener diodes to hit the desired voltage level.
It may be better to cut the CT and separate the two windings, combining them again after the cap multiplier. Obviously you will need two rectifiers, but those are cheap enough that that is not a problem.
I think trimmers and zeners are not useful in high current supply.if i shift the centre tap a little far away from higher voltage rail my problem will be solved but dissassemble a EI core transformer is itself a big problem.What about dropping some voltage with the help of diodes in series with higher rail.(0.6 volt per diode)
Cap multiplier uses a series pass active device with only the control currents flowing in the low-power devices in the control terminal.
Capacitance multiplier - Wikipedia, the free encyclopedia
Capacitance multiplier - Wikipedia, the free encyclopedia
The problem may be different to what you think.
If you make a supply like in the picture below, and the center-tap is not in the center, then you still get equal DC voltage on the positive and negative outputs.
The problem is that all of the current will be supplied by the winding with the higher AC voltage. The other winding will carry little or no current, so the maximum output current will be much less than it should be.
The ripple voltage will also be worse than it should be because the capacitors are only charged 50 (or 60) times a second, instead of 100 (or 120).
There may be a fairly easy way to fix the transformer, though.
Moving the center tap is almost impossible, but if there's a little bit of space left, you can add some extra turns of wire on top of the existing windings and connect them in series with the low-voltage side, to increase it's voltage and make it the same as the other side.
Sekhar designed and built a transformer not long ago. Perhaps he can help with advice.
Cheers - Godfrey
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