Musical Fidelity AMS35i Class-A Integrated Amplifier Repair
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- เผยแพร่เมื่อ 14 ต.ค. 2024
- Welcome back folks! Come with me this time as I repair and service this gorgeous Musical Fidelity AMS35i class-A integrated amplifier.
I know this will make quite a few people happy - another article about many people's favourite brand, Musical Fidelity. I'll go one better, with the baby amplifier from arguably Musical Fidelity's greatest product line of recent years, the Antony Michaelson Series.
This one is the Musical Fidelity AMS35i, a pure class-A integrated amplifier.
As always, please excuse the minimal editing, dodgy sound etc, it's the only way I can get videos out these days due to workload issues.
Read more about this repair here:
► wp.me/p6vB28-auN
Liquid Audio is a specialist hi-fi equipment repairer based in Perth, Western Australia. To book in your hi-fi equipment or to check out all the latest hi-fi service, repair and restoration content, visit:
► Website: liquidaudio.co...
Visit our contact page for service, repair and restoration enquiries:
► Contact us: liquidaudio.co...
300 watts at idle. Class A, baby!
Thanks for another technically interesting video Mike. Its really good that you take us through your assessment with commentary on fault diagnosis of these fantastic audio pieces !
Looking forward to your next repair work. Very Enetertaining.
Really great video walking through the amplifier repair. Thank you :)
Looks like a nice Class "A" amp...maybe it was a Monday morning or Friday night shift build? regardless, you really straightened this unit out with careful attention to detail and just a bit more headroom on the fuse holders. Thanks for your time!
Thanks Craig and yes, it's a decent product but like all MF gear, could be better.
Another great repair and tidy-up of poor initial production. Maybe a thermal camera would have helped to identify the exact hot-spots when the amp is running normally?
Thank you and you're absolutely right it would! I finally bought a thermal imaging camera either shortly before or shortly after this repair and it has been very useful.
As always, fantastic work. Musical fidelity has always left me disappointed in terms of execution and parts quality. Non removable bottom panels and lead free solder is always a headache. Lots of cheap parts in this one. In a fully class A amp, you’d think they’d use higher quality electrolytic capacitors. Nope. They wanted to save as much money as they could here. Tie wrap blocks mounted directly on the PCB with double sided tape? Ugh.
Anyway, super happy to see another video from you Mike. Great work on this piece. It should work for years to come!
MF brings a least a better performance than Hegel (totally overrated in my opinion) in terms of transients and resolution in high frequencies.
@@jeromelester8 Agree, the hegel "schreezes" the high frequencies.
Hi Mike
What would you recommend to replace those Jamicon caps.
I see Jamicon inside Perreaux too. Will be great to learn from you.
Thank you.
Any better quality, brand and grade of parts will be an improvement. One must always look at the circuit and conditions to determine the best parts for a job. Heat resistance is important here, so 105-degree rated caps are essential. Power supply caps should be low impedance, high ripple, long life rated parts. Do some research with the data sheets for Elna, Panasonic, Nichicon, Nippon Chemicon, Kemet etc and great alternatives will be evident. They are more expensive of course, which is why Jamicons are used here!
@@LiquidAudio
Thank you for the informative reply.
I really like that design. It’s minimal, visually clean with minimal parts count from what I can see. Seems like a good candidate for cloning (because I could never afford an original). Does anyone have any leads?
Put some high time delay fuses it should last more than 60mins at engineered Power 😁
OMG why an Amp like this has Jamicon
A good question my friend!
Musical fidelity are always the same, in my experience, I owned a kw DAC and cd player seperats, that gave up and Jamicon capacitors inside, and now my xp200 has given up on me and its not as though I worked it to death... One of two running in bridged mode... It started whistling very loud then died..... Any thoughts on that sir?
@@Michael-zg8qw My advice is the same in any situation like this - get both to a specialist for the attention they need. The good news is that most MF gear can be saved. I'm sure these are no exception.
@@LiquidAudio Cheers thanks for the advice, keep up the good work sir
I have a question. Does ceramic fuses get less hot than glass fuses? The exact same value and type fuse I mean.
A fuse is not designed to dissipate heat, it is effectively a zero Ohm short, meaning there should be little to no voltage drop across it and therefore no power dissipation. Either style will be fine, just be sure to use the correct type (fast or slow) and rating. The fuse holders themselves are important though so the blades must be clean and tight and how they are soldered to the board is important. If they are degraded as these were, they must be replaced.
Do you know what may have caused the initial excess current draw or voltage drop in that area? I'm having a vaguely similar issue on my a308 power amp that is currently drawing too on one channel and it's driving me nuts... Blown fuses and running way too hot on one channel. Any idea's on what to check?
Its a range of issues in this case including traces and parts that are not adequate for the continuous current draw, lead-free solder of dubious quality, weak fuse holders, poorly thermally bonded bridges and of course the fairly high quiescent current draw of a class-A design like this. It's all discussed in my article, link in the description. This is a bit different to your example. You must power it up with a variac and check quiescent current draw which must be correct and symmetrical. It's always best to take your equipment to an experienced specialist repairer though. You don't want to risk blowing anything here, these Sanken output devices are heard to find!
@@LiquidAudio Thanks, I read the article as well. I even have my amp at a professional shop as we speak and they can't even figure it out. Very strange gremlin that we can't find....
This is the amplifier that I wanted but was warned off by being told that it runs very very hot and to pick something else.
Class-A designs always run hot, it's a design decision that yields better sonic performance but must be considered in terms of equipment positioning and power consumption. More on that here, if interested: liquidaudio.com.au/faq/what-are-the-advantages-of-class-a-amplifiers/
I would go for Sugden - my A21 has been bulletproof for many years.
Hi do you still service MF gear please
Yes we do, this article for example is from earlier this year. Business contact details are in the description.
Really disappointing to see cheap parts in high-priced gear.
Premium Amplifier, cheap capacitors😂
Made in China!