Musical Fidelity X-A1, Changing caps

This baby sounds fantastic has it is, but when i openned it i saw the big part of the caps in it are not "audio caps", far from it. Compared to my Rotel RA 840BX4 with great Nichicons Muse and Black Gates ( Yes, Black Gates! ) this baby has Teapo caps... so my intent is to change some of the electrolytic and polistyrene caps with good "audio caps" and see what happens.









Changing Caps Part One:

First i will change the average polistyrene caps with EVOX RIFA Metallized Polypropylene.

Later i'll put some pix.

I hope your upgrades make it sound better.

elroy

That's my hope too.
The Evox RIFA PHE 426 metallised polypropylene film there i began to change, are a real delicacy as capacitor-input filter. These capacitors has a high price/quality ratio. Dynamics are nice and snappy and the treble is well detailed but a little brighter. For now i'll compensate it with eq but my goal is matching them adding some capacitors with a more round character like the Elna Silmic.

Please note that this is only my personal opinion.

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The MF X-A1 have the toroidal transformer from the power supply in a box apart from the amp itself:




Here's the big toroidal:



Maybe i'll change this cap - AC noise supression - with a better one from OKAYA/Japan or i'll do that inside the amp...?!

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The polysterene caps after the rectifier bridge and on the star-ground pcb:




The new EVOX RIFA poyprops.
These Filter capacitor or smoothing capacitor, placed at the DC output of the rectifier are very important because there will still remain an amount of AC ripple.
Complemented with a choke ( "coils" in the pic - offers high reactance to the AC component but it offers almost zero reactance to the DC component. As a result the DC component flows through the choke while the AC component is blocked.) and a second filter so that a steadier DC output can be obtained across the terminals of the filter capacitor.
The goal here is to remove the last of the ripple, to obtain a better and steadier DC to the rest of the circuit. Better current = better sonics.




I'd ask Scott (dingus) a favour to find in the US the electrolytics that i need for the rest of this project, because here in Europe they are to expensive and hard to find, and he have ordered it already.
Tanx amigo.

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Two hours ago i bought to a friend of mine two used Rubycons 8.200UF/50V with almost 10 years, i'd measured them and they look just fine so i take a shot and change the Teapo caps to these ones. I haven't time to take a pic yet but i can tell you this, these output caps made a tremendous effect on sound. The depth and clarity this caps brings to soundstage is hard to believe..........

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you have a pm.
larry

Tanx.

Evox Rifa and Okaya polyprops for AC filtering and Noise Suppression


The old polyester




The new polyprops




Teapo caps




The "new" Rubycon electrolytics




This baby has great Sanken SPA 15 Transistors also used by Cambridge Audio, Pioneer AX-10 reciever and Sony STR-DA4ES and STR-DA7ES receivers, just to name a few...



Better dynamics and tight bass. It's incredible what a good ac filtering does to sonics....

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is there a break-in time required for optimum sound?

Black Gates are from personal experience caps that need a lot of time to burn-in.
I believe in warming up all sound components for about 5 to 10 minutes, but a guy in another forum made some interesting expriences about caps burn-in that contradict what i and others believe.

Here's what he have done, and i quote:

"Well, a few days ago I took a stock such Elgar (a 6006B) and added a few teflon capacitors bypassing the large electrolytics in the amplifier power supply. Wouldn't you know, I got the very same spike on the output I did when I replaced capacitors on my other Elgar. Here's a picture of the output a few minutes after firing the unit up.




Here's the output after one day of ..... burn-in, whoa.




Here's the output after two days of burn-in.
The output will be perfectly smooth by end of day tomorrow, or thereabouts.




I changed the rectifier bridge from the old, heavy workhorse (circa. 1985) to a new, sprite FRED module. No change in the spike. I also swapped out the three circuit boards, exchanging them with those in my other Elgar, and no change.

That leaves: the wiring, the two banks of output transistors, and the transformer.

And the capacitors.

Here's today's visual.







Tanx Tom.


Interesting, don't you think?
Sometimes i think i can perceive some differences in components in the process of break-in, other times i can't. Is this placebo effect or Tom is really right in his mesures...?!

Dingus will send me the caps monday so, maybe within a week or so the electrolytics arrived here.
Looking forward to it.........

Meanwhile, another pic:

This baby have also a great potentiometer Alps (Blue Velvet).



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I noticed you are using lesser capacity filters with lower temp rating. Did you measure power before and after?

If i listening music to high volume levels that was in fact one thing i need to take care, but in fact i'm using this amp in my comp setup with the speakers very close by. Even though, before i close the amp case i touched the caps to see if they were very hot and they were like the power transistors, only warm.

This is only a transitory option, later ( when I have the t$me ) I’d like to buy another caps with the original specs, probably Blackgate FK series or Elna Cerafine, but for now i'm very pleased with these Rubycon.

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As long as this is a transitional move and you are playing low power...

Interesting the notch is going away. What is that, a sine wave? What frequency?

Do you have a signal generator? If you can input a square wave, that will tell a lot about how fast and accurate your amp is.