Coop
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Post by Coop on Dec 11, 2019 13:43:34 GMT
Crispy,
Sorry for all of the Q's, but you guys seem to have experimented more and may have a better understanding of how to get the best out of these X-A200's. Also just wondered if upgrading the internal wiring to Kimber was worth the while.
I wonder what the quality of the standard toroidal transformer is like. Would it be worth upgrading these? Anyone have any experience?
Thanks again.
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Crispy
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Post by Crispy on Dec 11, 2019 20:41:28 GMT
Hi Coop, I am no expert - only a Driving Instructor with an interest in HIFI/music etc, unlike Frans who is an electronics Genius, so it is worth waiting to see what Frans says before you do anything. He will save you a lot of time and hard earned money  Here's what I think  I personally would not upgrade the toroid, but see what Frans says? I attempted to populate the two spare transistor openings and gave up after breaking too many drill and tap bits - that alloy heatsink is as hard as diamond. So unless you have very good workshop facilities I would not attempt it as it will cost you a lot of time, money and effort for What? I replaced the internal speaker cable with Kimber 4tc and signal wires with Evolution ofc cable.
I personally have got past that stage where one wire sounds better than any other. About a year ago I sold my QED genesis speaker cables that bi wired my Speakers and replaced them with ordinary house hold electric cable and did not even bother to bi wire them. Can I tell the difference? NO.
I think Bi Wire should really say BUY (MORE expensive) Wire. So to answer your question is it worth upgrading to Kimber internal cable I can only say its your money time and effort, but I personally would not do it again.
Make yourself an inexpensive A/B comparison box and listen to as many different types of cable as you can get your hands on - if you can tell the difference then buy the one that sounds best to you.
I would use any good make of cap - Panasonic/Rubycon/Vishay etc whatever is available for the value you want. List per amp as far as I know ? 1 x 220uf 6.3V 2 x 100uf 100V 1 x 100uf 16V NP 1 x 10uf 50V 1 x 1uf 50V 2 x 6800uf 100V My set up is Cambridge Audio Stream Magic into modified XCan V1 as a pre- amp into XA200 mono amps, single wire to Acoustic energy AE1 speakers and single wire from XA200 mono amps to MJ Acoustic Sub woofers. Pretty simple but sounds really good to my cloth ears.  I do not know if any of this will be of help to you? Regards Chris |
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solderdude
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Post by solderdude on Dec 11, 2019 21:54:33 GMT
Adding resistors does not change the sound. It increases idle current (heat) and lowers current by dividing it over more transistors.
I would only replace the electrolytic caps, no resistors, wiring, transformer or anything else unless it was broken.
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Coop
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Post by Coop on Dec 12, 2019 11:38:07 GMT
Chris/Frans,
Thanks very much for the advise guys. I'm in the process of simplifying my setup to be vinyl only...just got rid of my SA7-S1 player to go back to analogue only. I've always loved the X-A200's since adding them to the XA-2 which I have owned from new. I will be keeping these as they are hard to come by, but they will need a refresh of caps to keep them going for many more years.
That's the reason why I'm thinking of getting rid of the X-A2 along with a set of Chord Co. speaker cable and just buying a nice line level pre-amp....will obviously have to reconnect the brass connectors over the x-over speaker terminals on the back of my passive ATC's. I will test this simplified setup with the current X-A2 and just use it's pre outs to the X-A200's with a single run to the ATC's and see what {if anything to my ears} changes sound wise. If there is no degradation in sound as far as I can tell, then I will be looking for a nice line-level pre amp to connect my TT to. If anyone has any recommendations....
Coope
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Crispy
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Post by Crispy on Dec 13, 2019 18:29:14 GMT
Chris/Frans, Thanks very much for the advise guys. I'm in the process of simplifying my setup to be vinyl only...just got rid of my SA7-S1 player to go back to analogue only. I've always loved the X-A200's since adding them to the XA-2 which I have owned from new. I will be keeping these as they are hard to come by, but they will need a refresh of caps to keep them going for many more years. That's the reason why I'm thinking of getting rid of the X-A2 along with a set of Chord Co. speaker cable and just buying a nice line level pre-amp....will obviously have to reconnect the brass connectors over the x-over speaker terminals on the back of my passive ATC's. I will test this simplified setup with the current X-A2 and just use it's pre outs to the X-A200's with a single run to the ATC's and see what {if anything to my ears} changes sound wise. If there is no degradation in sound as far as I can tell, then I will be looking for a nice line-level pre amp to connect my TT to. If anyone has any recommendations.... Coope Depending on your budget I would sell your X-A2 & Chord speaker cables for as much money as you can get. I would then try to find some cheap XA50 mono amps to drive your tweeters. I would use either the Garage 1217 Ember or Polaris as a pre-amp so that you retain the option to listen through headphones. They both make excellent pre-amps. Then find a good phono pre-amp like the musical fidelity LX2-LPs (£200) phono stage or musical fidleity V90-LPS (£150) or Cambridge Duo phono stage £200). All three support MM & MC options. If you are not in any rush I would see ask Frans & Jeremy if they had any plans to make a compatible phono stage to their range of equipment, I am sure there is a market for one out there especially as there seems to be a resurgence of Vinyl lately. That's just my thoughts, maybe other members might have better solutions? |
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Post by nicholasb on Nov 21, 2021 1:06:46 GMT
Greetings All! I'm dragging up this older thread because I too have a pair of MF X-A200 amps. I bought them new in 1999 and they are still operating perfectly, as far as I can tell. Now that's starting to get a bit long in the tooth, so I'm considering replacing the electrolytic capacitors, especially the power supply ones, to prevent the chance of some catastrophic failure in future. I've taken the front plate off to have a peak at the board and caps - all looks clean and in pretty good shape - no bulges or leaks. I don't want to unnecessarily pull out the Jamicon 6800 uF caps just to work out their dimensions in order to find suitable replacements, then put it all together again while I await the replacement parts. I'd rather do it all in one sitting. Therefore (finally getting to the point!), my question is: do you think the attached datasheet represents suitable capacitors that will fit into the X-A200? Specifically, these are CDE 6800uF 100V 105C 8000 hour aluminium snap-in caps (model no. 381LL682M080A062). They appear to be available on Mouser here in Australia. I do have a capacitance meter and will also order an ESR meter. I will check the Jamicons - should be interesting, but prefer to replace them for the reasons mentioned. Any insight much appreciated! Cheers, Nicholas Attachments:381LL.pdf (750.88 KB)
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solderdude
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Post by solderdude on Nov 21, 2021 7:51:53 GMT
Greetings All! I'm dragging up this older thread because I too have a pair of MF X-A200 amps. I bought them new in 1999 and they are still operating perfectly, as far as I can tell. Now that's starting to get a bit long in the tooth, so I'm considering replacing the electrolytic capacitors, especially the power supply ones, to prevent the chance of some catastrophic failure in future. I've taken the front plate off to have a peak at the board and caps - all looks clean and in pretty good shape - no bulges or leaks. I don't want to unnecessarily pull out the Jamicon 6800 uF caps just to work out their dimensions in order to find suitable replacements, then put it all together again while I await the replacement parts. I'd rather do it all in one sitting. Therefore (finally getting to the point!), my question is: do you think the attached datasheet represents suitable capacitors that will fit into the X-A200? Specifically, these are CDE 6800uF 100V 105C 8000 hour aluminium snap-in caps (model no. 381LL682M080A062). They appear to be available on Mouser here in Australia. I do have a capacitance meter and will also order an ESR meter. I will check the Jamicons - should be interesting, but prefer to replace them for the reasons mentioned. Any insight much appreciated! Cheers, Nicholas How often is the amp used and how warm does it get during normal operation ? I would be more worried about the smaller electrolytics at the front of the amp than the smoothing caps. On the other hand when you pull the amp apart I would simply replace all electrolytic caps. Use 105 or 125 degrees caps and try to find higher voltage rated ones than they are now without increasing the height and diameter too much. |
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Post by nicholasb on Nov 21, 2021 13:10:08 GMT
How often is the amp used and how warm does it get during normal operation ? I would be more worried about the smaller electrolytics at the front of the amp than the smoothing caps. On the other hand when you pull the amp apart I would simply replace all electrolytic caps. Use 105 or 125 degrees caps and try to find higher voltage rated ones than they are now without increasing the height and diameter too much. There were some years I hardly used the amps at all. At other times I would listen daily. I'm afraid it is not practical for me to work out what the total listening time so far has been, even approximately. I suspect it is actually less than I would have imagined, over the last 22 years. The amps hardly get warm and draw about 30W at idle. The hottest part of the casing during listening at average levels (one or two watts) gets up to 30C for the left amp, and 27C for the right one. There always seem to be about three degrees difference between them. DC Offset after warming up is 38 mV for the left and ... wait for it ... 0 mV for the right (OK, actually it is 0.1 mV.) I have had my DSO on one of the amps while playing music, with peak signals of 20V rms (~100W into my four Ohm speakers.) I didn't see any issues there, although I guess that wouldn't have been much of a test given the amp's output capacity. Yes, the plan was to replace all the electrolytics. For the smoothing capacitors, I was just hoping someone might conveniently have their dimensions handy, to save me checking my own ones. Many thanks for your suggestions! I will see what I can find in terms of relevant caps! Cheers, Nicholas |
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Post by nicholasb on Nov 22, 2021 0:33:28 GMT
Upon further inspection, the existing PSU caps appear to be 35mm in diameter. Most higher rated snap-in caps (at least, in terms of temperature and life) tend to be 40mm in diameter.
I don't think 40mm caps will fit in the space provided UNLESS I solder some pins or similar to the PCB so that the caps can be mounted somewhat higher (there's room at the top), out of the way of surrounding components. Caps could then also be tilted slightly if necessary.
Would this be considered bad practice, or OK for this application? I could put a little physical (non-conducting) support under the capacitors if that seems necessary ...
Cheers,
Nicholas
EDIT: Ordered some CDEs (SLPX682M100H9P3 - through-hole, not snap-in, but readily available unlike some others) for the big ones - just 85C and 100V like the original Jamicons. I figured that the Jamicons lasted 22 years (and are still going), so some fresh, new CDEs should be fine - at least they will fit. With the rest of the electrolytics I had more flexibility and so, uprated the capacitors - mostly looking for the longest lived ones.
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Crispy
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Post by Crispy on Nov 22, 2021 18:34:23 GMT
Upon further inspection, the existing PSU caps appear to be 35mm in diameter. Most higher rated snap-in caps (at least, in terms of temperature and life) tend to be 40mm in diameter. I don't think 40mm caps will fit in the space provided UNLESS I solder some pins or similar to the PCB so that the caps can be mounted somewhat higher (there's room at the top), out of the way of surrounding components. Caps could then also be tilted slightly if necessary. Would this be considered bad practice, or OK for this application? I could put a little physical (non-conducting) support under the capacitors if that seems necessary ... Cheers, Nicholas EDIT: Ordered some CDEs (SLPX682M100H9P3 - through-hole, not snap-in, but readily available unlike some others) for the big ones - just 85C and 100V like the original Jamicons. I figured that the Jamicons lasted 22 years (and are still going), so some fresh, new CDEs should be fine - at least they will fit. With the rest of the electrolytics I had more flexibility and so, uprated the capacitors - mostly looking for the longest lived ones. Hi Nicholas, I used Panasonic 6800uf 100v 85C when I replaced my caps. link
At the time I could not find ANY caps that were either higher rated voltage wise or temperature wise
The rest of the caps were fairly easy to find replacements at a higher voltage and temperature ratings.
Good luck with the upgrade 
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Post by nicholasb on Nov 23, 2021 0:51:31 GMT
Hi Nicholas, I used Panasonic 6800uf 100v 85C when I replaced my caps. link At the time I could not find ANY caps that were either higher rated voltage wise or temperature wise The rest of the caps were fairly easy to find replacements at a higher voltage and temperature ratings. Good luck with the upgrade Hi Crispy! Thanks for that. I just view it as preventative maintenance . I'm not expecting to hear a difference (well, maybe a strong placebo effect). The smaller caps are a mixture from Wurth Electronik, Panasonic, and Nichicon. All parts are from rs-online (Australia). I'll report here once done - after I receive the parts - probably next week, especially if there are some spectacular explosions . EDIT: I don't recall anyone in this thread mentioning replacement of the thermal paste on the back of the heat sinks. Would it not be a good idea to clean off the old paste and put in some fresh stuff, such as Wakefield 120? |
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solderdude
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Post by solderdude on Nov 23, 2021 20:42:23 GMT
Best to wipe off the thermal paste on the heatsinks and on the amp enclosure and put some new on.
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Crispy
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Post by Crispy on Nov 24, 2021 16:26:55 GMT
Best to wipe off the thermal paste on the heatsinks and on the amp enclosure and put some new on. Yeh I did what Frans said and replaced the thermal paste on my amps with Eletrolube heat transfer paste link |
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Post by nicholasb on Nov 25, 2021 6:49:45 GMT
In case anyone is anxious to find out how I went with the e-caps change-over , it's now all done (received the parts yesterday)! Nothing exciting to report, just that it works as well as before and at least now, should be good for another 22 years! Many thanks for comments earlier . Cheers, Nicholas |
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Post by nicholasb on Nov 25, 2021 10:14:59 GMT
Back again.
I've noticed that before and after I renewed the e-caps in both amps, the temperature of one amp consistently runs about 3C hotter than the other. Could this be related to the bias current?
Would it be worth checking the bias current across the emitter resistors and adjusting as appropriate or is a three degree difference not worth worrying about (if it ain't broke, don't fix it)?
Many thanks.
Cheers,
Nicholas
EDIT: The cooler amp uses 34W while idle after 15min warm-up. The hotter amp, 40W.
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