Simple modification of Roksan Caspian - diyAudio
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Old 20th July 2003, 09:53 PM   #1
SimontY is offline SimontY  United Kingdom
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Cool Simple modification of Roksan Caspian

Hi everyone, this is probably one for novice modders, like myself.

I decided to try wiring in bypass/additional caps in my amplifier's PSU (Roksan Caspian integrated). These caps were mostly spare/used and are:
-22nf/400v film x2
-8.2uf/400v metal film MKP x2
-180uf/200v x2
-330uf/200v x2
-470uf/200v x2

10 caps in all, about 2,000uf to add to the existing 13,600uf.

The sound:
First impressions are of a cleaner, more sterile sound, uninvolving but powerful.
After some hours of play the sound has warmed up a lot and has more solid and controlled bass than ever before.

Overall, [probably] positive, and free! (because the caps weren't otherwise used)

I am going to try adding 4x 10,000uf to really beef it up, and we'll see what that does for the bass...

-Simon
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Old 20th July 2003, 10:01 PM   #2
SimontY is offline SimontY  United Kingdom
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Some pictures to go with that description....

Here is the amp in question.
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File Type: jpg caspian.jpg (37.1 KB, 922 views)
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Old 20th July 2003, 10:07 PM   #3
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Here is a poor pic of the unmodded internals, you can see the two 6,800uf 50v Aerovox reservoir caps.
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File Type: jpg unmodded casp.jpg (45.5 KB, 944 views)
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Old 20th July 2003, 10:09 PM   #4
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Here is the back of the main pcb, this wasn't much fun to remove, and I really am surprised and pleased the thing still works!
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File Type: jpg pcb.jpg (34.8 KB, 891 views)
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Old 20th July 2003, 10:15 PM   #5
SimontY is offline SimontY  United Kingdom
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I used some Shark (or is it Sharc?) 10ga. speaker cable to connect the new caps to the back of the original ones, all the little strands made it a real nightmare job. Oh, that and me being crap at soldering
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File Type: jpg wires.jpg (70.6 KB, 878 views)
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Old 20th July 2003, 10:22 PM   #6
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Testing for explosions etc. with the MKP film caps. - bypassing with these seemed to be a big improvement in itself actually, even just with the leads shoved in the wire...
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File Type: jpg test.jpg (26.8 KB, 854 views)
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Old 20th July 2003, 10:28 PM   #7
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Testing with the first electrolytic cap. I put newspapers over the open amp and ducked down when turning it on, I get so scared of stuff blowing up or electrocuting me! I wired the caps in parallel with the original caps btw, one of each type per side. I must say, the reservoir caps seem to be wired in a funny way, it makes no sense to me! The + side of one is wired to the common ground - maybe someone technical can explain this phenomenon...
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File Type: jpg cancap.jpg (25.0 KB, 798 views)
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Old 20th July 2003, 10:31 PM   #8
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Here are the five 'new' caps on one side.
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File Type: jpg oneside.jpg (36.6 KB, 781 views)
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Old 20th July 2003, 10:36 PM   #9
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Here is the lot completed, the caps are glue-gunned on with the loc-tite glue gun seen in the bg. I apologise for the file size for those with old, analogue modems, and I hope at least one person gains a modicum of happiness from seeing this basic mod

-Simon
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File Type: jpg done!.jpg (71.2 KB, 788 views)
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Old 20th July 2003, 10:51 PM   #10
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I'd be very surprised if any of these mods improved the sound at all. What a waste of pictures.
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