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Post by freddypipsqueek on Sept 9, 2014 13:33:55 GMT
I have a Cyrus One amp. I have replaced a large number of caps and resistors over the last 2 years to great effect. I have recently obtained two 10,000uf Kendeil caps to replace the main power caps. This should a simple out and in job other than rumour that the originals caps were very good (they are marked 7,000 uf split foil). I understand that it would be worthwhile fitting some bypass caps. If so I am open to recommendations regarding the type and value (and manufacturer) that I should use. There is not a great deal of room in the case however the Kendeil caps are smaller than the originals as per the photo below. If I got the Kendeil caps wrong I’m happy for alternative suggestions – I have a spare Cyrus One which I can always use them in. Happy to spend a bit. I would like to get this right as the Cyrus has personal attachment as well as being a great amp.  |
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jc
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Post by jc on Sept 9, 2014 15:30:39 GMT
I had a lot fun of tinkering with an old Inca Tech Claymore. Fortunately there was also input from the amps designer, who green lighted certain modifications as beneficial. Stating that such things weren't done originally at production because of physical size limits back then and costings. I ended up almost doubling the capacitance in the PSU on mine but this also required beefing up the bridge rectifier with more capable diodes. Do note that this can/will change the musical signature of the amplifier, increasing bass presence and control, for example. Having a quick read on Cyrus One mods the jury seems to be out on increasing its capacitance, some saying it becomes bloated others liking the change. I suppose if you like the balance in standard spec. there is a chance you may not like the result of beefing up the PSU caps. I did try bypassing on my Claymore and it had negative results, why I have no idea but the sound seemed blurred with this mod. I've read about the same done to other amps to a claimed positive result. I see you've already swapped out the vol pot for an Alps blue, there is also another mod to remove the ribbon cable and replace it with decent screened cables. Comme suit;  I like the case change on the above. |
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Post by freddypipsqueek on Sept 9, 2014 18:17:02 GMT
CJ - Thanks for your comments.
You make a good point - I like the sound so don't break it.
I've done the pot, cable and replaced the jacks on both amps. I have read about changing the transistors but I think this needs to be linked to the diodes and I'm a bit out of my depth at that point.
There is actually quite a bit of room under the board - it sits 20mm of the bottom of the amp - for extra caps so I could try and see . . .
I'm also impressed with the new case in the photo - The Cyrus pictured though is a version 1 which had a crap pressed steel case as opposed to the aluminum one the later ones have.
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jc
Fully Modded
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Post by jc on Sept 9, 2014 20:12:46 GMT
If you can change caps you can change diodes. You could try some ultra/super-fast replacements for the current fast ones in the bridge rectifier. I think I'm right in saying that a super fast replacement to the PFR852 is the NTE588, its recovery time is four times faster. The regular DIYers here have found these to be beneficial over those fitted as standard. NTE588 link |
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Post by freddypipsqueek on Sept 9, 2014 20:21:54 GMT
Thanks - I will look into that with interest.
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Post by freddypipsqueek on Dec 5, 2015 17:46:02 GMT
Done the diodes - well worth while.
On the 'spare' one I also changed the transisters to BUV28's but this was because they needed replacement after a short !!.
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jc
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Post by jc on Dec 6, 2015 17:37:26 GMT
I've just picked up some replacement fets and leg-out adaptors for my olde Claymore. The main intention from the designer was these to be replacements for the old unobtainiums if they had been shorted. The up shot being they are supposed to be a little better sonically too. Will report when done.
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Post by freddypipsqueek on Dec 6, 2015 18:00:05 GMT
Chris.
Please report back.
I'm not sure if the BUV's made a difference but they are used on the Cyrus two and were available.
I also replaced a number of other bits including the MJE power transformers and some resisters - a few had blown.
The sense of achievement in getting an otherwise 'for the bin' amp running was fantastic - Made my weekend !!.
A.
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Post by freddypipsqueek on Mar 20, 2016 18:18:28 GMT
Just fitted these - www.hificollective.co.uk/components/supertech-slit-foil-2t-capacitors.htmlSo far so good - Had to cut away a bit of the board but fortunately I'm still Ok with a fret saw. The originals had dropped to 6000uf from 7000uf so in the end needed replacement. The 10,000uf haven't made too much of a difference but they have only had 24 hours run in so far. |
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Deleted
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Post by Deleted on Mar 20, 2016 23:56:54 GMT
I have a Cyrus One amp. I have replaced a large number of caps and resistors over the last 2 years to great effect. I have recently obtained two 10,000uf Kendeil caps to replace the main power caps. This should a simple out and in job other than rumour that the originals caps were very good (they are marked 7,000 uf split foil). I understand that it would be worthwhile fitting some bypass caps. If so I am open to recommendations regarding the type and value (and manufacturer) that I should use. There is not a great deal of room in the case however the Kendeil caps are smaller than the originals as per the photo below. If I got the Kendeil caps wrong I’m happy for alternative suggestions – I have a spare Cyrus One which I can always use them in. Happy to spend a bit. I would like to get this right as the Cyrus has personal attachment as well as being a great amp. Hi Adrian If you have adequate room underneath, try connecting normal 1uF or 2.2uF poly capacitors across their terminals . This will give you an idea as to whether this area is worth further investigating.
Alex
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