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Old 13th May 2008, 06:41 AM   #11
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Thanks for all the helpful replies!

I think I will go for the K1068/J162. As Karl writes, I need to drill the heatsink but that shouldn't be that difficult:-)

Thanks again

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Old 13th May 2008, 07:13 AM   #12
Mooly is offline Mooly  United Kingdom
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When you power the amp up, use a bulb in series with the mains to limit any current in case there is a problem.
Good luck
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Old 13th May 2008, 04:01 PM   #13
ventle is offline ventle  Norway
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Originally posted by eplegutt
I think I will go for the K1068/J162. As Karl writes, I need to drill the heatsink but that shouldn't be that difficult:-)

Better make that K1058/J162. 2SK1068 is a JFET, quite different from 1058 and not at all useful in this application
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Old 13th May 2008, 07:32 PM   #14
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Hehe, thanks :-) I did mean the K1058, not the 1068. Spelling error
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Old 5th June 2009, 08:14 PM   #15
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We still have some original FET'S used but okee; and the replacements.
Take care only to use THE SAME TYPE in a channel.
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Old 23rd January 2011, 04:16 AM   #16
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Default mosfets

hi not too sure how you have got on with your MOSFET problem do not use these forums much. 2SK227 2SJ83 early Hitachi devices k denotes N=k P=j spares H-pak package device electrically same as 2sk 2sk in To3 package 2sj50 2sk135 etc but have some used but workers here from DVT500s which were a very bad "Ground shifter" similar to Crowns grounded bridge bought some many years ago just to strip. even if they worked it was all they were good for that bad!!!! my e-mail DVT 250s nice amps proper old school had some nice in bridge got some 300s here now 1 dvt 500s of no use apart from outputs
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Old 16th August 2011, 05:40 PM   #17
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hi I have these K type devices in would you believe a Rauch DVT 500S from yhe maker when they folded here these amps were NOS got the last one just sitting in storage was gonna re-do the bad design over but never found the time 32 devices on heat xchangers msg me?
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Old 23rd May 2014, 04:21 PM   #18
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Location: South Africa
Originally Posted by eplegutt View Post
Hi everybody!

I've got a Rauch DVT 250S PA amp that needs some repair; several of the mosfets are damaged, and I have problems finding new ones.

The text on the mosfet says: "K227 4M1".

I've found a datasheet (se attachment) that might identify the chip as a SILICON N-CHANNEL ENHANCEMENT MOSFET Toshiba 2SK227. It seems its out of production and I'm struggling to find a replacement. Could please anyone help me?

Thanks in advance!

The Rauch amplifiers were designed by Ben Duncan. Why not contact him at BD @ Ben Duncan Research UK []
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Old 30th July 2014, 11:14 AM   #19
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I repaired a few of these about 10 years ago now. I had regular email convos with Den Duncan. One of his replies as follows regarding the FETs:

New FETs will be costly but a good unit is worth saving/repairing.
It's up to you whether it is cheaper to get old FETs off sacrificial Rauch amplifiers
(easier but FET lifespan is unknown = may last months or years)
or buy new ones (MUST be Hitachi, MUST be lateral, there are several types, need pairs, eg 2SK 1058, 2SJ 62),
which will require harder effort to drill & tap holes, adapt leads to fit PCB or re-drill PCB, etc.
Of course, you cannot mix types on one output stage.

Do you have my book 'HPAPA' ? - cost is 40, will save you that if you do anything with Power Amps.


A common fault I found was the 380Ohm resistor which ties the N and P FETs Gates together would dry joint allowing the N and P sides to go their separate ways often shorting the supply rails together. watch out for dry joints on the driver boards, quite common. Otherwise a fantastic amp.

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