Musical Fidelity X-A200 upgrade quandry

[the-chauffeur]

Hey folks . . . new fella here. Go easy.

I've had a pair of X-A200's in my (predominantly MF) system for the last eight years or so, and always thought they sounded pretty good for what they were.

A couple of months ago while trawling the web for nothing in particular, I stumbled across the details of a guy (John) not far from me who used to work for Musical Fidelity and upgrades their kit. At almost exactly the same time, I noticed that MF themselves had started offering an upgrade service of their own . . . which got me thinking about my options.

On the recommendation of several others, I spoke to John on the phone, and ended up taking my Nu-Vista pre-amp to him to work on. A few weeks later it came back tweaked, cleaned up and with a completely new power supply - apparently it's by far the weakest point of the NV Pre. And I'm very pleased to say that it sounds a whole lot better for it.

Whilst at his workshop, he showed me the internals of the X-A200's and said that he could upgrade them by adding in some bits that MF left out. Apparently the 200's were based on a similar design (albeit mono) to the A1000 amp, but to save a few quid, MF cut down on the number of components they used. You can probably see what I'm talking about from this picture:



John didn't give me a list of exactly what his upgrade work entailed, but it definitely included adding in 'missing' components (four of the MAG2013 9802's per amp). For their part, MF list the mods they make as part of their fine-tuning service here. Both charge pretty much the same for the work.

But having read though some of the posts on this site (and being good friends with a elec-tech) I was wondering if you could help me out with a few questions . . .

. . . firstly, anyone got any experience of getting the back off these things? Dumb, I know, but it doesn't want to shift. The front was easy enough, but I'm pretty sure the circuit board is attached to the back plate - and really doesn't want to leave.

Secondly, any suggestions for where to find a schematic?

And thirdly, any thoughts on the value of the MF upgrade work - or whether the addition of the extra bits will make all that much difference? I know it's a stab in the dark, but I thought it was worth a shot.

Thanks in advance - all help/guidance/ideas gratefully received.

Neil

[djx]

can you give contact details for John,I am looking to upgrade MF DAC 24 -want to replace NE5532 buffer stage,maybe with nuvistors ta

[raymondo]

well in terms of value it all depends on cost.
i own a few mf components and while they sound good they are badly engineered .
not to sound negative but little chance of a circuit diagram - i have been trying to get one for my E300 and pre 3a for years with no luck.
MF do not give them out no matter how old the design.
there are diagrams for the A1/B1 and derivatives, but they are very old now.
i certainly wouldnt pay MF to do any upgrade work, they charge crazy amounts. they wanted to charge me a fortune for some components that ended up costing pence.
i would like to speak to John guy myself if u have email for him :-)
good luck let us know how you proceed

[ringo_the_hifi]

Hello Neil.

I'm pretty new here too..

I too have the X-A200 mono's as well as 2 of the X-A100 amps which are both in mono.

I'm thinkinh of getting my amps uprated too, can you let me know John's contact details.

How is the upgrade?... Is it still worth doing you reckon?

Many thanks
Joe

[Gil36]

Hello Neil (and Others),

I was wondering if you've already obtained the schematics to the x-a200's. If so, I could really use them myself

Furthermore, is there anybody who knows which type of transistors need to be used to replace the 'missing' ones Neil has mentioned before? (MAG2013 9802 is a typenumber used by Musical Fidelity exclusively and they've proven to be very tight lipped as to what they actually are, apart from strongly advising against making further additions yourself of course). And do you just put them in (everything else seems to be in place already) or do you have to make further adjustements in this case?

Many thanks to anybody who can shine some light on the matter,

Gil

[jez]

I am not sure of moderator policy on "plugging" ones services here on DIY Audio.... but I too used to work for MF (kind of ran the service department) and offer a repair and rebuild service mainly for the older MF amps upto '91 or so (the era when I worked for them). Sorry but had left well before XA200 etc so can offer no specific advice on this model.
If anyone is interested then please pm me to take things further.

[the-chauffeur]

Hey folks - long time no post . . .

Following an e-mail from one of the previous posters, I thought I'd just add a quick update - although I'm sorry to say I don't have a lot to tell you on the X-A200's.

After spending a few hours pulling them about - and having no joy whatsoever on the circuit diagram front - I decided that I really couldn't afford to mess them up, so I gave up on the idea of trying to do the work myself. I came to the conclusion that I'd rather pay for someone who knows what they're doing to do the upgrade work and save myself (literally). I also stuck a post on the Pink Fish Media forums asking pretty much the same questions and if I remember correctly, the over-riding responses were 'don't give anything to MF to do'. I dunno whether they were informed opinions or just personal preference, but it's clear that a lot of folks really don't like MF . . .

News on the Nu-Vista - when I took it in for John to repair, I mentioned that it was sending a white noise signal through the right hand channel. I was worried that it might be one of the tubes on its way out, but I'm pretty sure John said it was an output stage problem. By the time I got it back, it had been fixed, but unfortunately, it has since returned, and it's worse than before. I've spoken to John again and he's going to take a look at it in the new year . . . it's such a shame to be without it for the time being, 'cos the power supply upgrade makes such a big difference. One of the basic differences is that the transformer coil John uses is nearly twice the size of the MF coil (and is put in a custom made case). Bigger coil - bigger audio gains. I've held off the powers for the time being, but if the gains with the pre are anything to go by, they are first on the list of next upgrade steps (in other words, when it's not Christmas!).

And an apology - sorry, I hadn't realised I'd didn't include John's contact details in my original post. If you want to contact him yourselves, he can be found here. When I was there last he had four (or was it five) Nu-Vista 300 power amps he was upgrading for one customer, and a whole bunch of high end US stuff for someone else. Frightening.

Hope that's some help to you.

Neil