Here are a pair of un-used GB300 completed PCB with Rubycon ZL capacitors, etc.
I built them but was later unable to drill and tape the holes for the MOSFET on the heatsinks therefore abandoned the project. It was a pity. But I don't have time to complete the project now as I have moved onto something else.
Any reasonable offer is accepted. I have also good power supply capacitors that I can supply at cheap price to go with them.
Please send me a private email if you are interested.
Regards,
Bill
I built them but was later unable to drill and tape the holes for the MOSFET on the heatsinks therefore abandoned the project. It was a pity. But I don't have time to complete the project now as I have moved onto something else.
Any reasonable offer is accepted. I have also good power supply capacitors that I can supply at cheap price to go with them.
Please send me a private email if you are interested.
Regards,
Bill
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Here is a photo of the completed PCBs. I have followed some recommended mods made to this PCB, including eliminating the input caps. The sensing transistors are yet to be soldered and then mounted onto the MOSFETS when they are attached to the heatsinks. I have used Greg Ball's matching transistors. All electrolytic capacitors are Rubycon ZL, an upgrade from what was supplied from the original kits. I have also used larger 2W metal film capacitors in replace of the 1W carbon film capacitors, which required extra drilling. The larger Rubycon ZL filter caps have been soldered slightly above the PCB at an angle so that they do not block the access space required when tightening the screws to mount the MOSFET, something overlooked in the original PCB design. The large MOSFETs have only the middle pin soldered so that you could still make adjustment to the hole positions if need to.
The optional filter capacitors are Nippon Chemicon 95degree screw terminal type 10,000uF 75VDC 50mm width 85mm height. No screws are supplied. I ordered them from an extremely reliable source. I was verbally told that these are computer grade - meaning that they are long life low ESR type. Usually they last for 10,000 hours at maximum temporature so under normal temporature you can expect them to run for whole life. In my opinion they sound very neutral, uncolour. They were tested briefly on a different amplifier. I found them to be substantially better than the audiophile Macron caps I previously had, and only by a very small margin lost to my final choice of a particular series of Vishay capacitors, which were bought at Farnell Australia at around $85 each ($1,020 for 12). I am asking for $168 for the 12 caps, plus freight costs.
The optional filter capacitors are Nippon Chemicon 95degree screw terminal type 10,000uF 75VDC 50mm width 85mm height. No screws are supplied. I ordered them from an extremely reliable source. I was verbally told that these are computer grade - meaning that they are long life low ESR type. Usually they last for 10,000 hours at maximum temporature so under normal temporature you can expect them to run for whole life. In my opinion they sound very neutral, uncolour. They were tested briefly on a different amplifier. I found them to be substantially better than the audiophile Macron caps I previously had, and only by a very small margin lost to my final choice of a particular series of Vishay capacitors, which were bought at Farnell Australia at around $85 each ($1,020 for 12). I am asking for $168 for the 12 caps, plus freight costs.
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For the whole lot, i.e. two completed PCBs plus 12 x 10.000uF capacitors, the weight may be about 2.5kg.
Using Australia Post' online freight calculator (Australia Post - Home), it is about $76.95 for air mail to the U.K., and $60.05 for the U.S. For completed PCBs only, it is about $19.30 to the U.K., and $15.70 to the U.S. plus the costs of a cartoon box.
Using Australia Post' online freight calculator (Australia Post - Home), it is about $76.95 for air mail to the U.K., and $60.05 for the U.S. For completed PCBs only, it is about $19.30 to the U.K., and $15.70 to the U.S. plus the costs of a cartoon box.
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For the 2 completed PCBs, I am asking for $200. I am confident that the soldering quality is first class. I have just checked Greg Ball's site, his price is $486 + $14 p&p for 2 completed and tested PCBs, and $332 + $10 p&p for the kits. Please note that the kits came with most parts mixed and it takes many hours and hours of work to solder them correctly, with extra drilling to be done if you want to use metal film resistors. Also, I have replaced all of the cheap electrolytic capacitors with the expensive Rubycon ZL. I will attach Greg Ball's build instruction documentation.
Note: I remember one thing: Greg had the wrong parts BCXXXC sent to me and they were soldered on the PCBs. I can't remember if I have replaced them with the BCXXXB, the same transistor with lower speed. The B version is more suitable. So you may need to replace a pair of them. They may cost 10c each.
Note: I remember one thing: Greg had the wrong parts BCXXXC sent to me and they were soldered on the PCBs. I can't remember if I have replaced them with the BCXXXB, the same transistor with lower speed. The B version is more suitable. So you may need to replace a pair of them. They may cost 10c each.
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