cgi_ Posted February 3 Report Share Posted February 3 TL;DR: Picked up a MZ-N710 that has already been modified for high headpone output. How common was that mod back in the day? Since 2002 I've had an MZ-N707 that I purchased (or rather, my mother did for me) while I was on holiday in Canada that's remained my daily driver ever since (if you exclude the ~15 year gap where I didn't really use Minidisc much at all, but like many people, some years ago I craved the tactile nature and limits of physical media again and started using it again). Before that I had a Sharp unit that I killed by crushing in my school bag. However, it's always been concerning that I only had the one working portable unit (I have a Sony MDS-B5 deck also), and also only one unit that supports Type R encoding and NetMD. The reality is if I'm rocking the MD out and about just as I was as a young guy in 2002 there's a risk it will get broken or lost in some way, so I've always been on the look out for some spare units. The used prices in Europe are insane, as many people are aware. MD portables were almost free even 10 years ago. Recently I found one guy selling an MZ-N710 and a MZ-NH700 locally in good external condition for an OK price, considering one is a Type S NetMD unit and the other is a HiMD unit. Seemed like a typical retired guy spending his time buying and selling random stuff he comes across, as he was surprised (and also worried) when I turned up to meet him with a selection of discs and accessories to check they worked. The sigh of relief he gave when they did was quite telling. As fully expected, both showed signs of battery corrosion - the MZ-N710 more so, but confirmed the units were working at least from external power and I knocked the price down a bit after explaining as best as I could in Finnish that I have no way of telling how f*cked they are until I spend time taking them apart and repairing them. I knew the European MZ-N710 had a very low power headphone amp, but I figured I'd just keep it as a backup unit. However, when I tested it, it had been left at max volume and it nearly blew my ears off (AT ATH-M60x headphones), so I wondered what all the complaining about low output was about. Maybe others like to use very high impedence headphones, I thought. When home I opened the MZ-N710 to begin the tedious task of cleaning up the battery contacts (vinegar, baking soda, IPA and plenty of scraping). Imagine my surprise to see mod wires staring back up at me. It seems that my unit has been already modified for high power output, and it also seems like a reasonably decent job (with the exception of one wire being trapped on a pad) has been done. This is pretty interesting to me, because I've no clue how common it was for the modification to be performed back in the early 2000s. Either it was somewhat commonplace or I've gotten extremely lucky to end up with an ex-enthusiasts unit. Does anyone have any insight into that? It sounds clear and powerful with no noise or distortion on the output, I couldn't wish for any more really. Considering this, I think I'll swap to using the MZ-N710 as a daily, as it's slightly slimmer and more robust feeling than the MZ-N707. I ordered some cheap gumstick batteries which seem to work OK but time will tell if their capacity is anywhere what it should be. Having the MZ-N707 as my spare is also appealing as it works from AA batteries. The MZ-NH700 unit is going to become my dedicated NetMD writing and ripping machine as it's really fast with Web Minidisc Pro for both operations and can be powered from the USB bus. The unit itself is rather too ugly and plastic for using out and about for my taste even if the internals are excellent. The next spare I need to obtain is a remote. I've already had to glue and put contact cleaner in my RM-MC11EL once to keep it going. Peril of a cheap accessory now asking for premium prices. Anyway just wanted to share my musings for fun. I'm not sure how active this forum really is these days - I perhaps see more activity on other platforms - but I already have an account here. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 3 Report Share Posted February 3 Nice find! I don't know how common such mods were tbh. Back in the day, I wasn't aware of anyone who had modded their player and I never felt the need to. I wasn't a member of a place like this back then though so maybe those "in the know" were doing it to all their MiniDisc players? Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 3 Report Share Posted February 3 Just did a quick test with my MZ-N710 and a pair of Beyerdynamic DT 990 Pros (250 ohms) and it was loud enough for me (although I did have the volume a fair way up). I suspect I don't blast things quite as loud as some people prefer though. That or my player has also been modified 🤔 Quote Link to comment Share on other sites More sharing options...
cgi_ Posted February 4 Author Report Share Posted February 4 10 hours ago, BearBoy said: Nice find! I don't know how common such mods were tbh. Back in the day, I wasn't aware of anyone who had modded their player and I never felt the need to. I wasn't a member of a place like this back then though so maybe those "in the know" were doing it to all their MiniDisc players? Same here. Didn't even know about there being European models with lower output back then, and was mostly using the basic earphones Sony provided. 9 hours ago, BearBoy said: Just did a quick test with my MZ-N710 and a pair of Beyerdynamic DT 990 Pros (250 ohms) and it was loud enough for me (although I did have the volume a fair way up). I suspect I don't blast things quite as loud as some people prefer though. That or my player has also been modified 🤔 With these AT headphones, half way is already loud, and matches up with my MZ-N707. Let's see how the MZ-N710 goes. I was using 1900mAh Enerloop batteries in the MZ-N707 so I was pretty spoiled for battery life, and may still decide to take it with me instead of the 710 for long trips. Nice to have the option! Quote Link to comment Share on other sites More sharing options...
cgi_ Posted February 4 Author Report Share Posted February 4 On 2/3/2025 at 11:09 PM, BearBoy said: Just did a quick test with my MZ-N710 Hey @BearBoy, seeing as you have an MZ-N710 to hand, would you mind doing me a favour? Assuming you have a gumstick battery installed in it, and a multimeter to hand, could you test if you measure voltage between the two brass contacts meant for the AA "sidecar" on the bottom of the unit? The internal gumstick battery voltage is exposed to those on mine and I'm wanting to determine if it's normal or not. I've been debugging a battery issue which I have a theory is related to the unit thinking it's being powered by an alkaline cell rather than NiMH. The switch inside the gumstick battery compartment that tells the unit there's one inserted appears to be making contact OK. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 5 Report Share Posted February 5 @cgi_ tried it in my MZ-N710 with a Doublepow gumstick (freshly charged) and got 1.450V. Got pretty much the same readings when doing the same test with an MZ-N910 and just testing the battery itself (give or take around 0.005V). Does that help at all? Quote Link to comment Share on other sites More sharing options...
cgi_ Posted February 5 Author Report Share Posted February 5 11 minutes ago, BearBoy said: @cgi_ tried it in my MZ-N710 with a Doublepow gumstick (freshly charged) and got 1.450V. Got pretty much the same readings when doing the same test with an MZ-N910 and just testing the battery itself (give or take around 0.005V). Does that help at all? Yes it does, it at least tells me that there should be voltage on those pins when using the internal gumstick. The issue I'm seeing is that the battery level (according to the player) will rapidly drop down over an hour and it will shut off, but I'm still measuring 1.3v on the cell, even when it's under load performing a read operation from the disc. If I immediately turn the player back on again the battery is showing full again and it will keep playing for a long time. The gumsticks I have are pretty generic ones, there's still a possibility that they're just crap. I'd been looking at those Doublepow ones that come with the USB charger. You've had success with those? The wires and extra diode around the AA battery input terminal are suspicious. There's also a crusty looking diode. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 5 Report Share Posted February 5 I bought one of the USB chargers that comes with two Doublepow batteries and they seem pretty decent. I've been playing my MZ-N910 for about two hours this morning and the battery is still showing as full on the player's display. I'll leave it running and see how long it lasts. I have had mixed results with gumstick batteries tbh. A couple of Vapex ones I had didn't hold much of a charge but I'd lost track of which ones I'd purchased new and which had come bundled with players I'd bought so couldn't be sure how old they were/how they'd been treated. I've also got a Jinmasi one, which seems fine. I have had instances where the player indicates the battery is dying only to subsequently show it as having plenty of charge left when you take it out and reinsert. Not sure if this is an issue with the battery or the player though. What I have found is that they don't always charge particularly well inside players. They never seem to charge long enough to get fully charged. A standalone charger does seem more effective in my experience. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 5 Report Share Posted February 5 6 hours ago, BearBoy said: I'll leave it running and see how long it lasts. It's been going for over seven and a half hours so far. The battery indicator is flashing to indicate low battery (has been for maybe 30 minutes or more - didn't notice when it started) but shows no sign of stopping just yet. The manual suggests a playback time of 31 hours with a gumstick battery (with power save mode engaged, which I haven't). I don't think it'll keep going that long... Quote Link to comment Share on other sites More sharing options...
cgi_ Posted February 5 Author Report Share Posted February 5 43 minutes ago, BearBoy said: It's been going for over seven and a half hours so far. The battery indicator is flashing to indicate low battery (has been for maybe 30 minutes or more - didn't notice when it started) but shows no sign of stopping just yet. The manual suggests a playback time of 31 hours with a gumstick battery (with power save mode engaged, which I haven't). I don't think it'll keep going that long... I also left mine playing when I went to work. It's been playing for about 8 hours now. When I left, the battery indicator only had one bar left and voltage was something like 1.26v when idle, and it still only has one bar left and voltage has only dropped to 1.22v! Really interesting to hear you also have experienced the issue where it shows low battery but reinsertion fixes it. I'm really suspecting there's some conditions that make the players think they have an alkaline battery. At the end of the day it's more important that it plays for a long time regaedless of what the indicator shows, but still, it would be nicer if it was more accurate. My MZ-N707 has always shown very accurate battery display when using Enerloop NiMH AA batteries. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 5 Report Share Posted February 5 About 15-20 minutes after I last posted, the battery gave out. I removed it and re-inserted and it's being playing for about another 30 minutes so far. Still showing low battery. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 5 Report Share Posted February 5 Apologies if the running commentary on my battery life is a bit tedious 🥱 Just wanted to record the results somewhere and this seemed as good a place as any. It's now been running for over two hours since the battery supposedly died. Still showing low battery. I tested the voltage using the AA battery case connectors and it's reading as 1.212V. I mentioned earlier that I'd had mixed results with some of my Vapex gumstick batteries. I've found one that is only registering 0.975V even after being charged with my USB charger. Looks like that one is destined for the recycling unless anyone knows whether Ni-MH batteries can be revived? I've found a couple of things suggesting you can bring a battery with 0V back to life by connecting it up to a working one (positive to positive, negative to negative) but not sure whether the same would work for one that's like mine. Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 5 Report Share Posted February 5 On 2/3/2025 at 4:43 PM, cgi_ said: I have a Sony MDS-B5 deck also I've only just picked up on this. Would be interesting to hear a bit more about that (and see some pictures) if you ever get the time. Quote Link to comment Share on other sites More sharing options...
cgi_ Posted February 6 Author Report Share Posted February 6 8 hours ago, BearBoy said: Apologies if the running commentary on my battery life is a bit tedious 🥱 Not at all. This is all useful information for those, like me, that only have one point of reference for the behaviour of the NiMH gumsticks in their players. 8 hours ago, BearBoy said: I've found one that is only registering 0.975V even after being charged with my USB charger. Looks like that one is destined for the recycling unless anyone knows whether Ni-MH batteries can be revived? I've found a couple of things suggesting you can bring a battery with 0V back to life by connecting it up to a working one (positive to positive, negative to negative) but not sure whether the same would work for one that's like mine. Hmm. If the charger is charging it up to somewhere around normal levels and then it's dropping by itself then it may be done for. You'd have to check with a meter what happens when it's charging. A bench power supply can be used for more advanced manual charging methods also (but you really need to do research on that to ensure you don't cause the battery to overheat). A deep discharge plus charge up again might sort it out but 0.9v is already considered about empty for a NiMH cell. Whether it can deliver any meaningful current might be more telling, but you'd have to find something to load it down to test (at a reasonable current, say 100-300mA). 8 hours ago, BearBoy said: I've only just picked up on this. Would be interesting to hear a bit more about that (and see some pictures) if you ever get the time. A few years ago I posted a thread about contolling it over the serial port to add track markers if you want to see some serial command nerding. It also contains a block-quote with some background information on it. At the time it was when the whole Web Minidisc stuff was kicking off, and I esentially abandoned that whole idea right away. Also because it's an older ATRAC version, it might be a fancy broadcast deck, but the reality is the recordings sound shit compared to any Type R portable. It's my main living room player though, so it's in frequent use. Because it's intended for broadcast it responds almost instantly to anything, including spitting the disc out without delay, and has chunky buttons, so I really enjoy the tactile nature of it compared to more consumer decks. It gets an outing every year at a large cybersecurity conference where it's used in an area as a public-facing background music player with a selection of discs next to it for people to swap between throughout the event (or I swap them when I notice the same disc has been playing for a long time). I made a Raspberry Pi based display that uses the info from the serial port to show what the last tracks and discs were to be played. The script is a complete hack and is available on GitHub. You know what, that really deserves a thread all of its own (later, I need to go to work!)... 1 Quote Link to comment Share on other sites More sharing options...
BearBoy Posted February 6 Report Share Posted February 6 Thanks for posting the pictures. I love the look of those pro devices and what you've done with the Raspberry Pi looks really interesting. Can you use that to control what it plays as well as showing that it is playing? I know @kgallen has a number of the pro Sony decks (the rack mount ones). They also have RS232 serial ports on the back. I wonder if they could connect up in the same way? Anyway, should probably save the questions for your new thread. In battery related news, my gumstick kept going until 10.30pm last night, when I finally turned it off. I got another 2 hours or so out of it this morning before it finally gave up the ghost for good. I think in total I got about 14-15 hours out of it, although for around half of that it was displaying the low battery indicator. When I tested the voltage at the end it was 1.228V but I couldn't coax it into playing any more. Quote Link to comment Share on other sites More sharing options...
cgi_ Posted February 7 Author Report Share Posted February 7 7 hours ago, BearBoy said: Thanks for posting the pictures. I love the look of those pro devices and what you've done with the Raspberry Pi looks really interesting. Can you use that to control what it plays as well as showing that it is playing? You can control it yes, if you look at the thread I linked it's all about controlling the device. You can essentially perform any action via the serial port and request data about the current status. The protocol is a bit awkward though, it took me a while to figure out how to translate what was written in the manual into actual bytes to send. 7 hours ago, BearBoy said: In battery related news, my gumstick kept going until 10.30pm last night, when I finally turned it off. I got another 2 hours or so out of it this morning before it finally gave up the ghost for good. I think in total I got about 14-15 hours out of it, although for around half of that it was displaying the low battery indicator. When I tested the voltage at the end it was 1.228V but I couldn't coax it into playing any more. The voltage is only half of the equation, the other is current. If the battery is exhausted then it might show an unloaded voltage of 1.2 volts but as soon as you put a load on it, it won't be able to deliver the necessary current, and the voltage will drop. I think I'm somewhere around 12 or 13 hours on this battery so far, and yes it's flashing. Quote Link to comment Share on other sites More sharing options...
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