OK so I have a Fatman Mi-Tube 2. It has worked flawlessly for nearly 6 years. I packed it in 15m of bubble wrap so it is not damaged, yet when I plug it in it hums and buzzes really loudly. I took it apart and I know for sure it is totally not the valves/tubes as it still makes the same noise without them even plugged in. I know even moreso because the buzzing does not increase with volume and you can still hear the music and the buzzing does not increase with volume. So the valves I would say check out for sure. I've read it is probably power stage related. Under the lid is a small PCB with a few components on, then a very large round donut mosfet psu. I don't think it's the donut, as that is merely windings. Besides, it does power on and function (even the Bluetooth aspect). What should I be looking for? As I say inside there's really not that much, though under the PCB there is what looks like a 4-6 leg "thing" attached to a large heatsink. Why would my senses be telling me it's that? I desperately want to keep it because,well, there's nothing else really like it, nor in any way affordable. I would buy a newun but Fatman Audio are no more it seems. Thanks guys.
Has this started after shipping/relocating or just from sitting? Most likely capacitors crapped out, though might also be grounding problems.
It was fine for 6 years, though to be very honest I never power cycled it once after setup, it was always on. It worked the day I packed it, and is not damaged. However that thing I had a feeling about? Check this out https://www.st.com/en/audio-ics/tda7265.html It's the main part of the amp. the caps all look like new, no bulging or leaks but there are so few I will probably do them too. That amp chip above costs about £3 so it would be stupid not to try.
Have ordered a complete set of caps apart from one because it's so small I can't tell what it is. It looks fine though. Decided to go with all Nichicon, the larger ones being the gold variety as it will quite probably increase the sound quality.
Good detective skills there V-T, I wonder if the low pressure at 'higher altitude' in your new place has made them bulge? When we were in Morocco years ago, we had an 'altimeter' bag of crisps that got fatter and fatter and more bulgy as we went up the mountain roads in the Atlas mountains, they then returned to their normal state when we descended... They did the same through the 3 mountain ranges wed drove through that week, we could hardly bring ourselves to open the bag eat them in the end!
Absolute lowest tier capacitors you can get. Never reflected n the price though. Work in stages, replace the known popped cap and its friend then keep testing as you go along.
I've ordered a whole set, aside from the one I can't ID. To be fair to Fatman it was reflected in the price. It cost £200 brand new for a full valve pre and then a valve/TDA7265 combo with a mosfet PSU. Which is not much really, especially given the output valve is also a magic eye. It's lasted 6 years of being powered on 24/7 too. I do have another but it's too big to fit in the cabinet I bought. Well, more a bookshelf than a cabinet. I would buy another amp but the cheaper ones are all honking huge. I'm hopeful I can repair it. Aside about 4 resistors and some solid state caps there isn't much more to it. Edit. Lol Tre that did make me smile
In other words, its for people with more money than sense - TDA7265 is a crap amp on itself, adding "valve pre" just adds more distortion to it, what does "mosfet PSU" even mean? Also, those caps are not solid state.
The solid state caps are red fella. The rest is subjective and down to preference and I don't want to argue over it. I like it, that's all that matters really
IDed the last cap. It's 1000uf 10v. Have ordered two Nichicon gold.... I did have another question though. What is the black 4 legged thing above the two caps? The legs are very thick so I don't want to bend it and it's not labelled. Cheers.
Brilliant thanks ! The resistors look good, no charring or burning and all legible. Had a think and the noise it was making started with a buzz, then a deep hum, then a buzz again. Which deffo makes me think it was the cap being a knob. Either way I will find out once all the parts arrive
Changed out all of the caps for Nichicon and she works a treat Didn't need to replace the amp chip thankfully . Huge thanks for the help and advice! Now I can finish getting the stereo set up
Hi new to the forum here as I've been searching for info on exactly this problem, so I'm very glad to find this site and the solution! Now the only thing is, I'm stumped at opening up the mi 2, I've removed the screws under the feet and the four on the rear panel and although it feels looser it's not coming apart. I even took the label off the bottom in case there was a hidden screw there (I've done this kind of thing before). Am I being really dumb? Help please!
Dude I'll be honest I don't remember. It was four years ago and the amp is long gone now. I'm busy until this evening but I think that somewhere I may have a video of it apart. One thing I do remember is the new caps were bigger and it left a gap in the shell. It did however work flawlessly after the repair. I will do some digging later when I have the time.
OK before I hunt for pics (now). You need to remove the valves. Usually I fully document things like this, but I only discovered it was dead after moving into my new flat. I had left it on 24/7 in the last flat which was probably why it was OK. I guess the caps didn't need to energise with it being left on like that, so I only found out when I set it up at the new flat. Sadly the only pic I can find is this. This was after I had repaired it. Edit. No actually it wasn't, it was whilst I was trying to work out what was wrong with it. Now what I do know is you need to split the top from the bottom. IE, you need to split it, then remove the power connector from the donut shaped transformer. I then replaced all of the caps, even though it was only one of the two larger ones that had split. The actual amplifier chip is under the top of the board. It is about an inch or so wide and about 3/4" tall. Sorry I can't help any more than that. As you can see, the place was in disarray as I was trying to get that done first so I had sound on the TV.
Thanks for that, I can see I need to take the top off now, it's just proving difficult like it's attached by something else. It might just be very tight. I'll give it another go. Thanks for going to the trouble of finding the photo! Edit: Just discovered that the visible top is just a plastic cover which is a tight push fit over the actual metal top underneath. Sorted now!
