Any interest in watching a dead KR-9600 revived as a 200WPC MOSFET receiver? :yes: :yes:
Amplifierguru (Greg Ball) has developed a rather nice MOSFET amp topology, christened the SKA, or Simple Killer Amp, using IRFP240/IRPF9240 International Rectifier HEXFET's. He has two basic amp kits available, the GB150D, using two pairs of output devices per channel and supply voltages of about +/-55V for outputs of 150W or so, and the GB300D, using four pairs of outputs per channel and capable of 300W with supply voltages of about +/-75V or thereabouts. Feedback from those who have built the amp is very positive.
I have had SPL db's dead KR-9600 here for a while, hoping to either luck out and run across some good output modules, or find a way to rebuild the output stage either using a small fabbed circuit board and discrete output devices, or perhaps fabricate a board and use an STK output. Any of these solutions would require much time and labor on my part. Yes, I know ilimzn and I came up with a replacement for the TA-200W, but there isn't much room inside to do the work, and I can see this eating up a very large about of time to make work.
After Amplifierguru joined AK recently (have known him for a while from DIYAudio.com), I paid a visit to his webpage. What caught my eye was the very small size of the GB150D amp module...it appeared that there might be enough room to mount it on the stock KR-9600 amp heatsink. The question was whether it could operate at the +/- 67V rails of the KR-9600, so I shot off an email. A disappointing reply from Greg followed:
The GB300D has a board length of about 180mm. There's no way to adapt this to the stock 9600 heatsink, but looking at the ones available from Conrad Heatsinks, they have some that are 200mm long, and the stock 9600 heatsink just happens to be 8" long. I see no reason why I can't use some of Conrad's heatsinks to replace the stock 9600 one. Yes, it increases the price (the configuration of heatsinks I will build will run about $80), but in the end it is a tradeoff of either many hours of my work to make a discrete replacement, or buy the parts I need for a reasonable price and cut the labor needed to bring the 9600 back to life down to something reasonable.
Once the parts arrive, I plan on documenting the revival of this receiver. Follow along with me if you're curious, but don't expect the first installments for a bit...both the boards from Greg and the heatsinks will come from Australia, and there are two choices for shipping - fair priced and slow as molasses (probably two months), and 'bend over and grab your ankles' but here in a week. I'm afraid that the slow method is the one I'm going to have to use...
In the meantime anyone considering an amp project should check out Greg's page (linked above), and perhaps some of the threads - either at http://www.diyhifi.org or http://www.diyaudio.com . Greg himself is quite the personable soul, so if you have questions or ideas or are just curious, send him a PM or email.
I'll try to be back soon with updates.
Amplifierguru (Greg Ball) has developed a rather nice MOSFET amp topology, christened the SKA, or Simple Killer Amp, using IRFP240/IRPF9240 International Rectifier HEXFET's. He has two basic amp kits available, the GB150D, using two pairs of output devices per channel and supply voltages of about +/-55V for outputs of 150W or so, and the GB300D, using four pairs of outputs per channel and capable of 300W with supply voltages of about +/-75V or thereabouts. Feedback from those who have built the amp is very positive.
I have had SPL db's dead KR-9600 here for a while, hoping to either luck out and run across some good output modules, or find a way to rebuild the output stage either using a small fabbed circuit board and discrete output devices, or perhaps fabricate a board and use an STK output. Any of these solutions would require much time and labor on my part. Yes, I know ilimzn and I came up with a replacement for the TA-200W, but there isn't much room inside to do the work, and I can see this eating up a very large about of time to make work.
After Amplifierguru joined AK recently (have known him for a while from DIYAudio.com), I paid a visit to his webpage. What caught my eye was the very small size of the GB150D amp module...it appeared that there might be enough room to mount it on the stock KR-9600 amp heatsink. The question was whether it could operate at the +/- 67V rails of the KR-9600, so I shot off an email. A disappointing reply from Greg followed:
Well, me being me, I wasn't ready to fold yet.
The GB300D has a board length of about 180mm. There's no way to adapt this to the stock 9600 heatsink, but looking at the ones available from Conrad Heatsinks, they have some that are 200mm long, and the stock 9600 heatsink just happens to be 8" long. I see no reason why I can't use some of Conrad's heatsinks to replace the stock 9600 one. Yes, it increases the price (the configuration of heatsinks I will build will run about $80), but in the end it is a tradeoff of either many hours of my work to make a discrete replacement, or buy the parts I need for a reasonable price and cut the labor needed to bring the 9600 back to life down to something reasonable.
Once the parts arrive, I plan on documenting the revival of this receiver. Follow along with me if you're curious, but don't expect the first installments for a bit...both the boards from Greg and the heatsinks will come from Australia, and there are two choices for shipping - fair priced and slow as molasses (probably two months), and 'bend over and grab your ankles' but here in a week. I'm afraid that the slow method is the one I'm going to have to use...
In the meantime anyone considering an amp project should check out Greg's page (linked above), and perhaps some of the threads - either at http://www.diyhifi.org or http://www.diyaudio.com . Greg himself is quite the personable soul, so if you have questions or ideas or are just curious, send him a PM or email.
I'll try to be back soon with updates.
