Yamaha C1-preamp --Vfets - diyAudio
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Old 15th April 2012, 09:30 PM   #1
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Default Yamaha C1-preamp --Vfets

I have a not working Yamaha C1-preamp, I need for repair following parts ; transistors, "V-FETS" ??? 2SJ24 and 2SK78 ,
Who knows where I can find theme, or who knows are this items also used in other types of amps Yamaha or Sony , so I can take out and repair my rare Yamaha C1
Thanks for helping
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Old 16th April 2012, 04:03 PM   #2
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About the only place you'll find the parts you need are on/from another C-1 preamp.

Even if you had replacement parts, you or a qualified tech (which are becoming harder to find) will need to troubleshoot and find out what caused the v-fets to failed. V-fet failure is usually a symptom, not a cause, and the C-1 is quite complex to work on.
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Old 16th April 2012, 09:32 PM   #3
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Hello Bille,
thanks for answer,
Yes , I know it's a very complex preamp, but I have good tech found, he already repaired my Onkyo M-510 , and he already fixed my C1, exept the V-fets who we can't find till now, I had a little hope that those fets are also used in for exemple a C2 or other type,,,,,,
Best regards
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Old 17th April 2012, 12:43 AM   #4
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Good luck Luc. Persevere long enough and hopefully good things happen for you
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Old 11th December 2012, 08:02 AM   #5
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I got the same pre-amp and its not working
Is there any way we can contact Yamaha or someone who knows how to fix these vintage machines ?
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Old 18th December 2012, 07:16 PM   #6
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Hello Anastanef ,
sorry for late answer , but I didn't visit the site till now , I've tryed to contact Yamaha all over the world,the answer was still the same, there are no spare-parts available anymore , the only way to repair and to find parts is finding another C1 , the most parts are specialy produced for the C1 and are not used in any other amp , exept the B1-Poweramp which belong together with the C1 ,, or to find old stock by a local dealer ,but it's very difficult to find anything , I'm searching for a long time now.
When you should decide to sell your C1 , let me know ,
Friendly regards
Luc - Belgium
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Old 13th March 2013, 02:21 AM   #7
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Location: Sao Paulo
I've got 02 units of this Yamaha C1 pre amplifier ,in my laboratory! Now i`m trying to restore one of those, & the other, I think the I'll be able to sell some of those used V-fet(or stat-fet) transistors.
Franco-São Paulo/Brazil
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Old 20th March 2013, 06:24 PM   #8
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Default yamaha c1 pre-amp---parts

If anyone will sell parts or a complete not working Yamaha C1, please let me know ,
my email-adress ;
Thank you verry much
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Old 20th March 2013, 11:24 PM   #9
ilimzn is offline ilimzn  Croatia
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Location: Zagreb
Unfortunately, there are no sources for the 2SJ24 and 2SK78 except for the C1 itself. These were specially designed for the C1 and it's the only Yamaha commercial amp that used them, similar to other VFETs used in the matching B1 power amp, which are also unique along with several other FETs. Yamaha service network has not had any spares for these since 1988 or thereabouts, so for some 25 years. These were on-order from Yamaha central so services dod not keep them in stock.
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Old 27th October 2013, 05:56 PM   #10
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Hello , I will sell a YAMAHA C1 pre-amp , completly restored by Clinique Audio in France Boscuentin, near Paris,,,,, pre-amp is as new now ,asking-price is 3500 € , lucblarinckx@telenet.be
I will ship all over the world, or pick up in Belgium, Tessenderlo.
friendly regards
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