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200WPC MOSFET Kenwood KR-9600

The regulator is for voltages used in the preamp and tuner. Changing the amp to a MOSFET output will have no effect one way or another on the regulator.
 
So then it's an issue all of it's own... got it. :yes:

I assume that's one that you'll take a look at then? :D

Scott
 
Glenn,

For the future...I've seen numerous recommendations for an ebay seller by the handle of 'barrredboss' who is in the US. He apparently works in a foundry and can make and cut heatsinks to any dimension you wish and for very good prices. He usually has some listed on ebay at all times.

More info on the SKA amps can be found at diyhifi.org----Greg and several others who were barred or left diyaudio due to moderator issues can be found there.

Nice project!
Steve.
 
I have bought from him before...seems at the moment he has nothing wider than 5 3/8". I need about 200mm (just shy of 8").

Yes, I've read many of the posts at DIYHiFi. Looks encouraging.
 
Hi Glenn,

Great project. It's good to breathe new life into these old iconic amps rather than scrap all the goodies. I've done a few. I hope the heatsink solution works out. I can recommend the Conrads although I don't know how they'd anodise. I believe the high silica casting alloys don't anodise so well. Could be wrong.

Progress pics would be good.

I'm close by if needed.:thmbsp:

Don't forget to turn the power off first. :nono: Hehe.

Cheers,
Greg
 
I shan't anodize them...they'll pretty much get used just as they are when they arrive, with the exception of a bunch of holes. :D
 
I'd like to figger out a way to use an off the shelf STK output module (4048II ?)in place of the the stock one. Or, set it up with a BPJ transistor output section. I HATE mosfets, and I think it might be an easier conversion.
 
Hi Tarior,

Screaming generalisation that -

"I HATE mosfets" - I gather you dislike that spitty, sibilant, edgy sound of many poorly conceived MOSFET amplifiers. I'm with you!

This amp is very different. Give Glenn a chance.

Cheers,
Greg
 
>I'd like to figger out a way to use an off the shelf STK output module (4048II ?)in place of the the stock one. Or, set it up with a BPJ transistor output section. I HATE mosfets, and I think it might be an easier conversion

Mosfets are much cheaper the BJTs when it comes to power device. It is worth looking into from a cost standpoint. The drvier is not much different between the two.
 
Hi SolderIron,

This amp actually uses IRFP vertical MOSFETs in a common source configuration with emitter follower drivers ,which are 300Mhz TO92's that pull the MOSFETs off!

Cheers,
Greg
 
I used a pair of 200W STK4050ii, laid out a board that dropped in place of the old one, now measures 200W <.1% THD into 8 ohms and 300W into 4 ohm load. Have been running the KR-9600 as my bench test receiver for over 15 years and haven’t blown them yet !
 
dewickt said:
I used a pair of 200W STK4050ii, laid out a board that dropped in place of the old one, now measures 200W <.1% THD into 8 ohms and 300W into 4 ohm load. Have been running the KR-9600 as my bench test receiver for over 15 years and haven’t blown them yet !
Click to expand...

Tell me more!!
 
>MOSFETs in a common source configuration with emitter follower drivers

That is a preferred way to drive the gate which is equivalent to a cap. Do you lose much output peak volt due to gate drive vs base drive?
 
BPJ's are just easier for dummies like myself to understand and work on. :nerd:
Plus they are more forgiving, the gate on a FET is VERY fragile, and static sensitive. I have heard some very nice sounding MOSFET amps, but I always get a dread feeling about working on them.
 
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