marcm09
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Audio Monster
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Post by marcm09 on Mar 18, 2006 11:57:33 GMT
hey, I just pulled the lid off my nad home theater amp for a look, its got two main boards termed front and rear boards which would take a little bit of work to take out and pull the transistor chips off the heatsink etc so i could get at the back of the boards to desolder/ solder them.
By now i'm pretty familiar with the xcan mods etc but have never modded any other amps. I know that its a home theater amp but I still think that just about any middle of the road amp can be impoved ?
On each board there are SOA 85c 'C8' capacitors - 6 x 100uf 100volts and 3 x 470uf 16volts.
woundering if I should replace these with panasonic fc's of the same value and if there would be any gain doing so ?
The power supply has big caps and also the main board caps (I'm not sure what they do though -seem to be 105c ones)
Also the resistors, which there are lots of are the brown ones which I surpose I could replace with metal film ones if I had the time ?
I would value your comments, I know that on the xcan I swapped a pair of the caps to NP ones as well but im not sure if there will be caps in this amp which you could or should do the same. I Can take some photos and email them if anyone could help.
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thegreatroberto
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Post by thegreatroberto on Mar 18, 2006 17:45:55 GMT
Me again. I wouldn't bother with the Home theater amp. I took a look at my Yamaha A5 today and the work involved is too much.It already has 2 10,000uF caps on the psu.There are no other gaps to say fit another pair.That somewhat limits I can do, unless I can source some say 15000uF caps.Also what would the real benefit be ? Ok so it's not a bad amp for my DVD's etc, but as a piece of serious HiFi,it's pretty crappy. And as I said, there's a lot of work in getting to some of the caps...............
As for the other components,there may be some benefit, but there is a good chance you will cock it up as well !
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marcm09
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Post by marcm09 on Mar 19, 2006 0:38:37 GMT
I know what your saying and i've been in two minds. The NAD is increadibly musical and to improve it with a capacitor swap on the amplifer boards would be the icing on the cake.
It is a little harder than a normal amp to access these boards bu i've been examining it and the more I look the easiler it seems, I will have to unplug about 6 plugs from other boards, then the front and rear channel boards are directly attached to two big heatsinks in the middle of the amp with 4 fans at the bottom, all I have to do is unsrew the whole thing and lift it out.
Once its out I will have to unscrew and lift the transistors off the heatsinks, hopefully they have used paste and not a silicone based one, there are also about 6 which are soldered onto the edge of the board which would need to be desoldered to remove as they have no screws holding them to the heatsink.
I confident that i'd have to do someting pretty silly to cock it up thought, worth thninking about, but not sure how much of a change it would make replacing the 85c caps though ?
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thegreatroberto
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The Great Roberto "himself" The real deal on a stick!
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Post by thegreatroberto on Mar 19, 2006 8:45:54 GMT
There is only one way to find out,and that's by doing the swap.Just make sure the psu caps are swapped out for FM or FC types............If you can get bigger ones in then try that as well.
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marcm09
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Post by marcm09 on Mar 19, 2006 10:02:53 GMT
Hey , when I got home I spent about an hour pulling out the front and rear boards attached the the central heatsink, I have also lifted the boards and chips from the heatsink so that i can get to the back of them to desolder the old caps and fire the new ones in once I order them from RS tomorrow.
The transformer in the amp is HUGE and the power supply caps are two 12,000uf's which should be enough I'd imagine, they are very well shielded and hard to get to for a peek.
I will keep you posted and let you know when its up and running with my views.
I'd love a dedicated hifi amp but I have no room left on my amp rack and I already spent too much over the last year, with buying totally new gear and probably enjoy my headphones too much too worry, I would have to spend a considerable amount on an amp to make sure that its a significant step up.
I have spent about NZ$14,000 (1 NZ $ = about 2.5 pounds)on gear this year including a 43' Pioneer plasma, kef speakers, a Cambridge Audio azur 640 cd player, the NAD home theater amplifier, a xcan v2 headphone amplifer, a velodyne cht8r subwoofer and some quite expensive interconnect and speaker wires...
oh and speaking of speaker wires i'm thinking that i might upgrade the internal speaker wires from the two boards to the speaker terminals with silver slinkylinks cable that I have, the only fun part will be taking the pins out of the plugs into the board and fitting new ones, I know my work colleges have spare pins etc that they use on car ecu's etc , there prob is a special tool also that helps pull them out and reinsert your new one once soldered to the new cable... sounds like fun !
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thegreatroberto
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The Great Roberto "himself" The real deal on a stick!
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Post by thegreatroberto on Mar 19, 2006 16:46:49 GMT
Funny old thing interconnects and wires. I have a collection of Van den hal D102 MK3 and QED silver spiral...................Both make a significant differance. Then you look at the quality of the internal wiring in amps and speakers.Damp string. Maybe these bits of damp string need a swapping !
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marcm09
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Post by marcm09 on Mar 23, 2006 12:16:06 GMT
OK here is an update- All of the capacitors on the amplifer output stage have been replaced with panasonic FC'S, it was a reasonibly big job getting into the amplifer boards as it is the reciever model.
The difference is stunning, the sound is more detailed and transparent, I'm hearing only certain sounds which I only previously heard with my headphones on !
The sound stage apprears bigger with more space around the sperate instruments and singers ! I honestly never realised how musical a reciever could be, I always new that the NAD was one of the most musical recievers out there, its probably 20% better, must be very close to a dedicated amp with my mods.
Well worth the effort , wait until I get some hours through the caps should even sound better again.
Changing the caps wont make a bad amp sound good, but it will make an good amplifer sound stunning !
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thegreatroberto
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The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Mar 23, 2006 18:47:01 GMT
I'm considering a cap swap on my MF nu-vista pre-amp.The big caps are only 100uF but rated at 100V.The space available is very limited and I can't find any to fit so far.There are other caps that will benefit from a change.We'll have to see..........
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marcm09
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Post by marcm09 on Mar 25, 2006 4:26:10 GMT
I replaced 12 of the standard 100uf 100volt caps in the nad for panasonic FC's they fitted fine and are not alot bigger then the original ones, I'd be surprised if they wont fit ? Wish I had one of these, maybe in the future I go to something along that line... For now - a little while anyway I'm OK. Audio is so hard as I feel that no matter how good your equipment is that you alway crave for better and want to upgrade, maybe I need to just relax and enjoy wht i've got.
I'd love the b&W 800 series speakers as well, oh well maybe I'll come into some inheritance sometime soon !
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thegreatroberto
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The Great Roberto "himself" The real deal on a stick!
Posts: 157
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Post by thegreatroberto on Mar 25, 2006 20:30:33 GMT
When I said 100uF,100V............I meant 1000uF,100V ! There is only 5mm of additional clearance.I'm struggling to find 1000uF caps of that voltage.I can get 1500uF caps, but they are just too tall. I don't think it really matters too much.It's only a pre-amp.It's not going to draw any serious current, so teh DC ripple should be small.
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rickcr42
Fully Modded
Rest in peace my good friend.
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Post by rickcr42 on Mar 26, 2006 4:43:51 GMT
If your NAD HT amp is an older one then it is most definately worth upgrading and that because of the superior DSP chip they used to do the processing,the Motorola DSP.
why this decoder gets it more right with music than any other and has less of that "croakiness" added to voices I have no idea but it does so if this is your amp have at it !
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marcm09
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Audio Monster
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Post by marcm09 on Mar 26, 2006 6:57:44 GMT
No its a brand new NAD amp, Ive just upgraded all of my Hifi, home theater and headphone gear.
I would have though that when playing music in stereo that it would not have passed thru the chips that your talking about , only in dolby digital or pro logic 2 ?
Its getting close to the sound of an older naim nait 3 amplifer that ive tried.
One day I will organsise it so I can run a dedicated amp for my music and just use that reciever for movies and sound from the plasma.
Im really blown away how musical it sounds I wouldnt be ashamed to let my friend who owns an audio shop have a listen. There is always better though, the best is yet to come.
P.S still waiting on the valves for the xcan, Ive also come across some polysterene capaicitors which I could add to the amp's poly bypass caps. I was at the local electronics shop poking around when I spotted them, might try them to see if they help may a differrence, I will also post this under the correct forum.
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rickcr42
Fully Modded
Rest in peace my good friend.
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Post by rickcr42 on Mar 26, 2006 15:04:58 GMT
No.At least it would be extremely rare. The problem with HT receivers and in fact all modern receivers is they run everything through a CODEC or ADC/DSP/DAC stage instead of staying in the analog domain.Because of this everything that passes through will be only as good as this section no matter what comes before or what follows. Imagine how many use an external DAC for their CD player or do extensive upgrades of the digital section in a DVD player and you can get a hint of what you are facing. Upgrading can only be a plus in just about any consumer level audio gear but only to a point where no matter what you do you can not get around the limitations of the digital engine inside.once you reach that limit it becomes just tossing money at it with zero sonic return. wise upgrade paths are always : 1-improve the power supply using better rectifiers 2-replace power section electrolytics with better quality parts 3-concentrate on making the entry and exit of the digital core as good as you can get it-film caps in place of electrolytics in the signal path if present,better resistors in selective spots,etc 4-actual parts swaps where it is both easy to do and will actually enhance performance such as any low grade opamps 5-tap the lid and sides of the chassis.If it sounds "tinnie" or "hollow" maybe some selective damping to reduce ringing when using loudspeakers.. all theusual suspects
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Post by zanash on Apr 15, 2006 12:21:07 GMT
Your internal wire annalogy is of course correct.......rip em out and replace with solid core silver [or copper] in ptfe. IMO silver plated wire has the worst properties of both so I'd steer well clear!
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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 16, 2006 15:36:24 GMT
....or # 22 solid copper high purity magnet wire which is already insulated.Good for all signal wiring plus any DC voltages you will come across in solid state gear but needs additional HV rated insulation for tube gear power supply use or you risk the HV "jumping" from wire to wire and in effect causing a short.
not pretty when in the 300+ voltage range
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