13th May 2008, 05:25 PM
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#11 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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Trim the leads after.
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www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 05:46 PM
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#12 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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We do the chips and caps next.
The capacitors are polarized and their orientation is critical. Each electrolytic has one pin longer and this should be installed in a pad marked with + on the board. Also, the golden stripe marks the negative side and it installs opposite the +. When those caps are mounted the other way, after connecting power to the amp, they will explode. Pin 1 and 4 on the chip are power pins and they connect to the planes in top layer. Please make sure that corresponding connection pads have enough solder in top layer as well. That concludes the amp board. For Premium version of the kit, please check this link (currently, only blue mask boards are available, Black Gates are optional): http://www.diyaudio.com/forums/showt...425#post584425
__________________
www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 06:00 PM
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#13 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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If you are planning on dual mono power amp (separate transformer per channel) and simplified wiring, please install now 4 jumpers between amp board and power supply board on pads marked V+, PG+, PG- and V-.
I use bare copper 18ga wire.
__________________
www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 06:10 PM
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#14 | |
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diyAudio Member
Join Date: Feb 2005
Location: Phoenix, Arizona
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Quote:
1. what is the benefit of the optional caps? 2. I want to end up with 50w/ch for stereo use can u recommend an appropriate transformer from a US vendor?-web page)? I have trouble interpreting electronic jargon I see on the figure to real world item I need to order.. I have used Partsexpress, ApexJr in past... gychang |
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13th May 2008, 06:19 PM
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#15 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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The optional cap are there to "manipulate" the sound. Originally, those were BG N 4.7/50 and they were supposed to add more warmth and image density to main filter Panasonic caps.
As BG are disconinued now, I supply 10uF Panasonics instead, and they can be used to sort of "improve" the sound of larger caps, as it is commonly practised by other manufacturers. I noticed that in most cases such additional caps only spoil things and it's best to test both setups and choose better sounding option. I normally use 300VA Plitron toroids, but 200VA (for stereo) is good too. In US PartsExpress carry Avel and more affordable prices. The voltage can be between 20 - 25VAC, either dual secondaries, or centertapped. Apexjr has ocasinally suitable transformers as well.
__________________
www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 06:21 PM
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#16 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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The diodes are installed now and their orientation is critical as well. Make sure that metal tab is on a side of a white stripe marking the footprint.
__________________
www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 06:27 PM
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#17 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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This concludes the assembly and we have two separate amp channels with separate bridge rectifiers. All is needed now is to connect 2 transformers (one per channel) as per schematic posted here: http://www.diyaudio.com/forums/attac...amp=1210694958 , connect the input (SG for ground, IN for signal input) and output ( OUT to positive binding post, OG to negative) and we have a working dual mono amplifier.
I will post tomorrow some instructions for stereo version, and later enclosure building ideas (any suggestions welcome here, as to which direction to go). Pictured below, is one amp channel.
__________________
www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 06:54 PM
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#18 |
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diyAudio Member
Join Date: Feb 2005
Location: Phoenix, Arizona
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which transformer?
I will be following this thread, but I get confused on the transformer to get about 55W/ch in stereo from GC.
Anyone know the website for the appropriate transformer?, need cost-effective solution for the classic GC kit from Peter. Any of the model here work? http://www.apexjr.com/miscellaneous.html#Toroids or here: http://www.partsexpress.com/webpage....e_ID=3&x=0&y=0 do I need one or 2 transformers. (please say 1  )gychang |
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13th May 2008, 07:08 PM
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#19 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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The question is, what is the impedance of your speakers?
__________________
www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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13th May 2008, 07:16 PM
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#20 |
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diyAudio Member
Join Date: Jul 2002
Location: Toronto, Canada
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The attached graph shows powers output vs supply voltage for different loads. Based on that, for 8 ohm speakers 2 x 22V AC transformer is recommended, and for 4 ohm speakers 2 x 18V AC transformer. In practice, I didn't find any drawbacks with using 2 x 22V AC secondaries with 4 ohms either, so that value can be a good overall choice. The amp will clip with 4ohm speakers when pushed hard, but you will soon learn not to push it on certain recordings (I had 2 or 3 such disks that I had to be careful about)
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www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC |
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