K200B to K250 modifications [message #9482] |
Tue, 03 June 2008 15:19 ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
chicagobill
Messages: 2005 Registered: April 2003
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Senior Member |
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I recently bought a well used, but great sounding K250-2 Metal Front head. It just needed a little contact cleaner here and there it was sounding great.
I was very surprised to see how similar the power amp circuit was to the original K200B. The only difference that I can see is basically a handful of resistors and a few caps.
This got me to thinking, can I change the part values on a K200B to the values of a K250 power amp and increase the power output? Not a whole lot of power increase, but maybe just enough to add a little clean headroom.
I'm going to look into the values and see what I need to change, but I thought I'd open the idea up here for discussion. Has anyone done this before? Any opinions?
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Re: K200B to K250 modifications [message #9483 is a reply to message #9482] |
Wed, 04 June 2008 07:00 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) |
stevem
Messages: 4772 Registered: June 2004 Location: NY
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Senior Member |
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The dash 2 k250 head outputs about 8 to 10 watts less due to the added current use of the on board effects. The k250 -4 has evev less output to the tune of 10to 12 watts less than its stated 125 watts RMS.The basic K250 -1 model is the only one that will output its stated 125 watts RMS.
These amps to not clip the their preamp as bad as the K200s due to the fact that the preamp is some what better regulated.
What s needed in these amps is a better/bit more massive power transformer that is rated for CCS sevice, or a up grade to a nice torridal type PT.
In short making the mod`s` to a k200 with out installing a k250 power transformer will probibly not buy you much improvement, in fact I would say it would be better to use the amps own output as your monitor and then take the k200s signal out of its RCA jack and run that into a bridged output 150 to 200 watt power amp, and then drive your speaker cabinet with that.
If you can find and choke like they used in the k150 moldels. or buy two seperate chokes and install them in the power supply, that may provide you with that tad more clean head room with the least effort!
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