thegreatroberto
100+
The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Jan 15, 2006 12:25:00 GMT
The soldering iron is hot and i'm in the mood to improve/cock it up completely ! I've opened up some of my other musical fidelity kit,and those same crappy jamicon capacitors appear everwhere. My XA-s100 power amp has 4 63V,6800uF caps in the power supply that look ideal for an upgrade.However find audio grage caps of that size is proving tricky.Any ideas ? Some of the small sizes are already on order ! (there ain't much inside that power amp BTW) Similar sized ones appear in my Nuvista pre-amp........ My X-plora tuner also has a few cap swap opertunities. Any experience out there, or should I leave alone ?  |
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Post by colinh on Feb 17, 2006 23:01:08 GMT
Hi as I am new to the forum I hope you don't mind me offering my two peneth. For what it's
worth Any Power supply can be upgraded the problem is finding a good transformer suitable for audio use. If any one knows off any lets hear from you.
Then build the power supply in a separate case ,this gets any vibration away from the sensitive bits. Unless you know of a suitable make of capacitor its going to be suck it and
see RS do a good range . Then divide your total capacitance up say 2 @ 6800uF
could become 3@ 4700uF or 1@ 10000uF + 1@4700uF +1@2200uF the idea is to have
some smaller caps in the plan as they charge up faster giving the bigger ones a fraction
longer to be ready for the next high demand. If all you want to do is swap caps then dump
the case and just do the caps. I also fancy improving my MF amps so I have given you the basic plan that I have in mind . Hopefully others may offer some better ideas
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thegreatroberto
100+
The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Apr 1, 2006 19:02:51 GMT
I've been lazy.
I just swapped out the 4 6800uF caps in my MF power amp for................4 10,000uF caps !
OK so it does give me a 50% increase and all the electronics are still in the same case.
No noticeable changes............I could go on about sweeter top,clearer middle and tighter bass............but i would be makinking it up !However they do look good ! A straight swap with no obvious downside !
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Post by colinh on Apr 3, 2006 16:36:43 GMT
Well now you know. The main thing to keep in mind I would say is that if you like a particulat item
of kit it may be best to leave well alone. You might end up with a bad result . I am still undecided
about my A3.2cr pre and Power amps.MF do seem to be keen on the cheap capacitors.But I do like the sound of the combo as it is. So I might try a Stepped atenuator first ?
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thegreatroberto
100+
The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Apr 3, 2006 17:19:16 GMT
What MF power amps do you have ?
I'm looking for anotehr MF power amp to bi-amp with my X-as100........something to drive the bass units.
As a minimum it will be another x-as100.I'd line a 308CR or even a nu-vista 300.The problem is that second hand prices of these can be as much as an A5 new.
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Post by colinh on Apr 3, 2006 18:30:29 GMT
Hi ,the Power amp is also MF a A3.2cr also. driving a pair of Totem Signature Ones.I also have a
spare MF pre and power E200/E300 with a noisey volume control. CD playback is via a Meridian
500Mk2 Transport and 563 dac.
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thegreatroberto
100+
The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Apr 3, 2006 19:08:27 GMT
A spare !
Ideal for tweaking !
My Nuvista pre and X-as100 are easy for cap upgrades.The board just slides out of the case.
I've done all the caps in the power amp.the problem I have with the pre is that the caps are rated at 100V
the main caps are 1000uF,100V.there is little room to spare to increase this size.I may get away with 1500uF, but there aren't that many caps around rated for 100V with the dimensions that I need.
Your noisey volume pot should be easy to sort.Either some contact cleaner or a new Alps pot !
I really fancy the Nu-vista power amp.I think 300 W RMS should be just enough ! My wife would go mad at
1) the size of them and 2) the cost.
I recently saw a set of MF packaged nu-vista valves (6cw4's) sell on ebay for £120 !!!
Even MF only charge £90 for a set !
And anyway teh ones in my nu-vista pre are nothing special.I've bought them on eBay for less that £5 each...........mind you, they may not work ! Time will tell !
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Post by zanash on Apr 13, 2006 6:37:36 GMT
The X-DAC and its brothers are an easy candidate ......I've reworked one of these extensively
The main changes were the addition of a pulse transformer to smoothe the digital input, most of the caps swapped for stargets, Replaced the diodes for schottky's, RFI and EMI supression, cap bypassing, decent sockets and a brand new psu.
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Fergus
100+
Done a David Ike and is now known as Godkin 
Posts: 197
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Post by Fergus on Apr 13, 2006 12:41:05 GMT
 Zanash, Is that the X-DAC V3? I'm thinking about upgrading the "crappy" JAMICON general purpose caps to PANASONIC FCs. Was there a noticeable sound improvement? Fergus
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thegreatroberto
100+
The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Apr 13, 2006 18:47:33 GMT
Fergus
"noticable sound improvement" what's that got to do with things ?
I thought it was about just soldering random items onto the board and hoping it all still worked !
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Fergus
100+
Done a David Ike and is now known as Godkin
Posts: 197
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Post by Fergus on Apr 13, 2006 19:25:59 GMT
Yes, I'm very old fashioned about, aren't I? What the hell is a "pulse transformer?!" Sounds like something Scotty would shout to Captain Kirk! Apparently, AUDIO NOTE uses them in their DACs, but being AUDIO NOTE it's not any ordinary, common or garden "pulse transformer": it's a "silver wired, spun mumetal cores, torodial pulse transformer." I give up, Fergus
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Apr 13, 2006 22:27:35 GMT
If you can visualise a professional audio balanced line system there will be a circuit then a transformer to set the output to a very specific "standard" impedance which will then drive the cable that will in turn go to a very specific known impedance which will match the former output drive device and provide a proper load for it.This is the same thing but in the digital realm rather than analog : a known standard allowing the other parts to have a predictable response
.........but sadly many ring so bad they cure is worse than the disease so it is not a plug 'n play fix
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Post by zanash on Apr 15, 2006 9:22:16 GMT
I've not started it yet ......but those caps look total out of place ......
I'm thinking stargets or better.
Pulse transformers are 1:1 or 1:2 ratio tranformers that prevent amonst other things signal reflection ....which can cause havoc with the reciever chip [imo].....
Rs do some ok ones suitable for digital coms .....
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