CJ MF 2500

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JONTY
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CJ MF 2500

Post by JONTY »

Hi,
has anybody changed out the internal fuses in a MF 2500 power amp and replaced them with audio grade ceramic types from Furutech and other company's if so did it improve the sound and which ones did you use...? Mine has 1-7amp slow blow on the AC line
And 4- 6amp (5 fuses n total) on the DC power supplies. Also these are odd values apparently...?
Also people who have swapped out fuses on other CJ products welcome to comment on there experiences

Cheers,
Jonathan.
ronenash
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Re: CJ MF 2500

Post by ronenash »

I have swapped the stock fuses with "audiophile" fuses from Hi Fi Tuning in my ACT2 and Premier 14 preamps and can't say I heard a huge difference. I believe there are better ways to invest your money. 5 fuses will cost anywhere from $250 to $500 and more. A premier power cord will likely have a much better effect IMO.
ronenash
----
Power:CJ ART150, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura
JONTY
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Re: CJ MF 2500

Post by JONTY »

Hi Ronenash,
Thanks again for taking the time to reply to my post and for your feedback, incidently I have bypassed all the fuses in the plugs from the wall outlet power cords to my equipment,
And found this made a big difference (not that I would encourage people to do this themselves here) all equipment is protected internally as well on the AC power line.
Yes I agree if you constantly have to go backwards and forwards trying to hear the difference
Then then either it's too small to make any difference or no difference at all and as you point out they are costly these fuses.
The MF 2500 has a captive lead and an internal 7amp slow blow fuse so I will bypass the fuse in the power cord plug and see if my findings are consistent here also.
Thanks again.
Jonathan.
ronenash
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Re: CJ MF 2500

Post by ronenash »

I would not bypass any fuses if I were you. The disaster that can result is not worth any gain in sound quality. One accidental shorting of the speaker leads will result in your amp being toasted.
ronenash
----
Power:CJ ART150, Beard P100, McCormack DNA500, Krell FPB300
Pre:CJ ACT2.1, Pr14, Pr15
Analog:VPI Classic/Falcon/SoundSmith Denon 103R, Lenco L75 rebuild
Digital:J.River-->Chord 2Qude
Speakers:SF Amati Futura
Big Dog RJ
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Re: CJ MF 2500

Post by Big Dog RJ »

This was a typical problem we used to have big time, back in the hey day during our dealership. Some people were just never happy with the sound from the original designs. I would see far too many components coming back in with modified circuits of all sorts, and then they throw tomatoes at us for not being able to service- obviously due to third party fidgeting!

I just cannot understand "why" people want to change the sound... from fuses to internal wiring and the list goes on for bloody ever for absolutely no good reason.

There are obvious areas that one could change for the better, such as those external components that allow mods. Cross over units, power cords, cabling / interconnects, isolators, power conditioners, earth grounding accessories etc. Then there are some internal areas of improvement with capacitors, resistors, tube sockets, external fuses on maggies (back plate to protect the tweeter elements on older versions) and so on.

I also think most of these so called "upgrades" are psychological- since the upgrade was made- my gosh! it does sound better... I really don't think so.

At the end of the day, the main designers / founders of the company had a vision and they stuck to it, otherwise they wouldn't be around for so long. CJ, ARC, VTL, Pass Labs, McIntosh, Manley Labs and similar- they've been around for quite a while, hence might as well open up your own DIY outfit!

My best recommendation to such people trying to achieve this "improvement factor" was to start at the basics. First consider your room and its surroundings, speaker placement and equipment rack placement. Adjusting levels, ensuring cables are "dressed" properly (every CJ manual states this), using a high quality grounding system from many great companies (Nordost, Shunyata, Transparent, Tauras, Thor) plenty of good ones who do a proper job of power conditioning plus grounding.

Also the best approach is to get a dedicated AC line with a separate CB to your system. Not a shared circuit that shares other appliances in the house, like the fridge and the kettle! Simple solutions that go a long way are forgotten and these guys want to change fuses and build space stations with their CJ gear, thinking they can out do CJ themselves... seriously?

All of these companies mentioned above have been around for a very long time mate, and they have some of the best design teams to back them up, partly the reason why their gear costs as it does, hourly wages need to be paid. Therefore, still made in the USA, UK, Germany, Denmark, Italy, France and Japan... comes at a price. Obviously if Ferrari was made in China- perhaps then we could omit these fuses in their critical stages.

I just purchased an Ultra-sonic cleaner for my stylus, since the silly thing keeps getting dirty with gunk build up from playing old LP's. Plus, the Ortofon 2M Black stylus has a Shibata diamond profile, which is much narrower causing the needle to sit more firmly in the grooves, also causing this dirt build up from older LP's. This gadget is made in Germany and was not that cheap but I managed to save up a bit and paid for it. Why? because it does a marvellous job of cleaning your stylus.

Having said that, just sit back - relax - and enjoy your music the way it was intended by the original designer.
Cheers, RJ
JONTY
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Re: CJ MF 2500

Post by JONTY »

I would prefer it if my thread wasn't used to air other people grievances and stick to the subject/topic at hand.
I think that the other unrelated comments are better placed as a general discussion elsewhere on the forum.
Just my thoughts.
Big Dog RJ
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Re: CJ MF 2500

Post by Big Dog RJ »

Point taken Jonty;

Trust you are finding your experiences worthwhile, and the fuse changes / upgrades on your MF2500 have been to your expectations.

RJ
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