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 it’s out of production and I'm struggling to find a replacement. Could please anyone help me?
Thanks in advance!
Regards
Joakim
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 it’s out of production and I'm struggling to find a replacement. Could please anyone help me?
Thanks in advance!
Regards
Joakim
Not in this package ? Have you contacted the manufacturer ? for suggestions.
There are some wierd older parts around, are these a lateral as can be obtained today, albeit in a different package.
Regards Karl
There are some wierd older parts around, are these a lateral as can be obtained today, albeit in a different package.
Regards Karl
Thanks for the reply.
I've made some more research and it seems like this http://www.diyaudio.com/forums/showthread.php?s=&threadid=24723 thread might help me.
I'm not 100% sure, but it seems like the K227 is similar to the SK227. If that's right the SK227 could be replaced by 2SK1058.
The board also has a chip named "J83" which I believe is similar to 2SJ83 and then could be replaced by 2SJ162.
The 2SJ162 and the 2SK1058 are for sale on eBay
I've made some more research and it seems like this http://www.diyaudio.com/forums/showthread.php?s=&threadid=24723 thread might help me.
I'm not 100% sure, but it seems like the K227 is similar to the SK227. If that's right the SK227 could be replaced by 2SK1058.
The board also has a chip named "J83" which I believe is similar to 2SJ83 and then could be replaced by 2SJ162.
The 2SJ162 and the 2SK1058 are for sale on eBay
Hi,
The 2SK1058 and 2SJ62 are what I was thinking of, BUT they are physically very different. You would have to fit new insulating washers and possibly drill the heatsink as well !
Regards Karl
The 2SK1058 and 2SJ62 are what I was thinking of, BUT they are physically very different. You would have to fit new insulating washers and possibly drill the heatsink as well !
Regards Karl
I would consider the IRFP240 and IRFP9240 devices.
Thye dont look too far away from the devices you mention.
I use them extensively in amps I build and they are good solid devices.
If you do use them you might have to fiddle with the bias voltage to get it right.
Thye dont look too far away from the devices you mention.
I use them extensively in amps I build and they are good solid devices.
If you do use them you might have to fiddle with the bias voltage to get it right.
DO NOT try to use IR transistors. Use the aforementioned 2SK1058 and its sibling. The Vgs of your older transistors match the 2SK1058. The pinout also. The IR Vgs are about 4V. They can not be used without redesigning the Vbe bias string. Also, the pinout on the IR are different.
Regards
Roar
Regards
Roar
Hi,
There is a lot of confusion with some of the early FET's as to just what type they are, vertical or lateral. The IRFP type are HEXFET's and these must NOT under any circumstances be used where a lateral is specified. The gate/source voltage is much higher and MOST important of all they have a positive temperature coefficient, which put simply means the amp will self destruct.
Regards Karl
There is a lot of confusion with some of the early FET's as to just what type they are, vertical or lateral. The IRFP type are HEXFET's and these must NOT under any circumstances be used where a lateral is specified. The gate/source voltage is much higher and MOST important of all they have a positive temperature coefficient, which put simply means the amp will self destruct.
Regards Karl
Mooly said:
What absolute nonsense !!!!
I use IRFP extensively and they certainly dont run away thermally ! I have one 300 watts RMS amp, a 100 watts RMS amp and a 600 Watts RMS amp which get flogged to death in disco work.
If the gate voltages are different then the bias needs altering accordingly.
Hi,
They dont run away thermally because the amp will have the equivalent of a VBE multiplier. Laterals due to the negative tempco don't require this. It's one of the great features.
Try running a HEXFET with fixed bias and see what happens
🙂
They dont run away thermally because the amp will have the equivalent of a VBE multiplier. Laterals due to the negative tempco don't require this. It's one of the great features.
Try running a HEXFET with fixed bias and see what happens
🙂
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
Regards
Joakim
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
Regards
Joakim
Hi,
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 🙂
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 🙂
eplegutt said:
Better make that K1058/J162. 2SK1068 is a JFET, quite different from 1058 and not at all useful in this application 🙂
RAUCH AMPLIFIERS
Hi,
We still have some original FET'S used but okee; and the replacements.
Take care only to use THE SAME TYPE in a channel.
Hi,
We still have some original FET'S used but okee; and the replacements.
Take care only to use THE SAME TYPE in a channel.
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 charlieb999@live.co.uk 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
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 charlieb999@live.co.uk 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
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?
The Rauch amplifiers were designed by Ben Duncan. Why not contact him at BD @ Ben Duncan Research UK [bd@bdr-uk.com]
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.
BD
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.
G
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.
BD
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.
G
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