Topic: KORG MR-1 pt.II

[Nick's Picks]

i use a power runner pr2e for mine.
works like butta.  will even charge the internal.

[H₂O]

I have found that the MR-1 pulls about 0.5 A on average but since it has an internal battery if the Charger kicks in it will start pulling more current.

So you need to make sure your power source can handle higher currents (I would say 1-1.5 A).

Also make sure the internal MR-1 battery is fully charged when ever you run an external battery.

I currently run a Tekkeon myPower 3400 and it works very well.  I could probably get about 20 hours of use out of this setup but it is a bigger battery.

I was thinking about getting a Tekkeon myPower go and loading it up with 4 2500mA Rechargables.  I would think you would get about 4-5 hours with this setup. http://www.tekkeon.com/site/products-mypowergo.php

I don't know if the myPower go would will work, as Tekkeon does not list the output voltage (only saying it should power most 5V devices) but it looks like it is very small and you can get them on eBay very cheap at around $20 (with no batteries).  You also may need to get a USB to Sony PSP power cable to connect it to the MR-1 - but it does look like it may come with the right adapter plug and cable (albiet it looks like it may be polarity reversable so you would need to be careful with it).

[guysonic]

I have just done some measurements.  MR-1 is said to draw ~1/2 ampere at 5 volts = 2.5 (running) watts,  measured ~.25 amps charge when off, NOT running.  

Connected to charger draw turned on running goes to .45 amps so charging/running together seems the maximum; near KORG's spec power.

Charger drops out to then run on the internal battery at ~4.6 volts external applied charger voltage, but ICON on LCD shows still charging until external voltage drops down to 4.1 volt.  At 4.1 input volts the BATT ICON shows the battery bars.

This means MR-1 hard connected to 4 NiMH cells will NOT work well to fully use NiMH cell's full capacity (to ~4.2 volts) before deck disconnects charging/running 4.6 volts and depending make/condition of NiMH cell, leaving as much as 50% external cell capacity untapped.  

Now I'm waiting for the battery to fully charge so just deck running power is measured to know external battery power budget for just running the deck.

[Nick's Picks]

I've found this deck to be finicky w/its power requirements.  Sounds like you are having the same discovery.
it likes a strong current...., that is for sure.

I tried doing all sorts of VR devices to run 7.2v or 6v sources w/a 5v, 1amp output.  still wouldn't work.

[guysonic]

I've found this deck to be finicky w/its power requirements.  Sounds like you are having the same discovery.
it likes a strong current...., that is for sure.

I tried doing all sorts of VR devices to run 7.2v or 6v sources w/a 5v, 1amp output.  still wouldn't work.

I did see momentary power spike to at least 0.7 amps when first connecting external power with deck on, but his quickly settled to <.45 amps. Using 1 amp external regulator should work OK.

Suggest putting  a large +330 mfd 'low impedance' type electrolytic capacitor maybe with +0.1 mfd ceramic/chip in parallel on the output of your regulator to soften momentary 'deck startup' current surges that might spike-drop the output voltage too low shutting down a deck having exhausted internal battery.  Also if using long battery cable to the regulator, or low capacity batteries, consider shorter or larger cable, and using batteries large enough to better handle the current surges; maybe a large capacitor at the input of the regulator is also a good idea if still having problems.

[H₂O]

Before I got the Tekkeon battery I ran it with 3A Max VR and it has worked most of the time, but on one occasion the internal battery drained all the way down (with a fully charged external battery), and it would only turn on again when connected to the AC Adapter.  It would try and turn on with the external battery but get stuck turning itself on and off repeatedly.

I tried turing the voltage up to about 5.5V and it still behaved the same way.

Also I have noticed theat with either the Tekkeon or the custom power source I built the Charging icon goes away after about 5 minutes and the battery bars appear, but they never go down even after 4-5 hours of use.

[guysonic]

MR-1 review is being updated new battery charge/use power draw that now takes the mystery out of what the MR-1 is doing.  Basically the deck TURNS OFF charging during recording, using the external 5 volts for running the deck.  See the below chart to be included in the revised page. 



Also realize the external supply is DISCONNECTED AT ~4.65 volts, even though the battery gage shows charging, it will not tell the truth until the external voltage further drops to 4.1 volts where internal battery then shows in the gage.  If your external supply momentarily drops with MR-1 power surges (accessing the disc), then the deck will disconnect temporarily, or for good if still below 4.75 volts, but maybe the battery ICON doesn't let you know the bad news.

[guysonic]

Version #3 of the review with better detail/discussion on MR-1's powering issues now at: www.sonicstudios.com/mr-1revw.htm#power

[BlackCrowe]

I`d love to get this unit for powering my new Korg..

http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&rd=1&item=180177120573&ssPageName=STRK:MEWA:IT&ih=008

Does anyone know if the Korg has that USB type A plug or does it have a different USB plug??

Best,

Karsten

[guysonic]

I`d love to get this unit for powering my new Korg..

http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&rd=1&item=180177120573&ssPageName=STRK:MEWA:IT&ih=008

Does anyone know if the Korg has that USB type A plug or does it have a different USB plug??

Best,

Karsten

Uses 4.0x1.7 mm 'locking' barrel (coaxial) type power plug, same as sony DAT decks.

[BlackCrowe]

Uses 4.0x1.7 mm 'locking' barrel (coaxial) type power plug, same as sony DAT decks.

So you mean you have to go with the power plug, no chance to power the unit over USB??

[Colin Liston]

Uses 4.0x1.7 mm 'locking' barrel (coaxial) type power plug, same as sony DAT decks.

So you mean you have to go with the power plug, no chance to power the unit over USB??

It will NOT power over USB

[guysonic]

Revised MR-1 review version now 4 posted and likely nearly finished.   

Found version 3 too technically obscure to be mostly unreadable (very sorry about that).   

  So maybe time to give this a read to see if understandable, and now no need to be kind about feedback/suggestions. 

  www.sonicstudios.com/mr-1revw.htm 

[landshark]

Nice write-up Guysonic!  One thing I've noticed, and it may be a problem with my deck, is if the internal battery gets low, I start losing volume on one channel (I think the right channel?).  I noticed in your write-up that the two channels have different self-noise levels - any theories as to why the channels should behave differently?

Thanks!

Mike

[guysonic]

Nice write-up Guysonic!  One thing I've noticed, and it may be a problem with my deck, is if the internal battery gets low, I start losing volume on one channel (I think the right channel?).  I noticed in your write-up that the two channels have different self-noise levels - any theories as to why the channels should behave differently?

Thanks!

Mike

Hard to tell cause without circuit schematic diagram to know how analog output (gain) is being handled.  From working the deck, forgot to mention LINE and PHONES output BOTH controlled by same volume up/down buttons simultaneously. 

So we commence pure speculation on what could be happening.

Volume control of these two linked outputs may determined by dual channel varying voltage, or more likely just one single mono channel voltage working into two or four voltage controlled LINE/PHONES amplifiers. 

While same voltage seems to control both line/phones output, phones voltage output is almost half that of line output if I remember correctly, so maybe line and phones do have their own amplifier (two stereo amps) controlled by the same control voltage. 

If this is the case, interesting to see if your LINE output also experiences unbalance with low battery voltage suggesting dual control voltages where one channel loses voltage regulation with low battery.  If both line/phones affected then problem is likely with component(s) generating control voltage losing function.   If just phones is losing balance, then likely problem with amplifier driving that output.

In any case, this should not be happening if deck continues to otherwise run OK (not shut down) at that lower battery level suggesting there is problem with sub-standard part, or less likely a design error.

It may be that MR-1 is not so different than R-09 in using just one master CODEC IC generating all or most analog input/output functions.  If this the case, then quality control tests on this IC may be lacking low voltage regulation tests affecting critical performance.

However, all supply voltages inside MR-1 should be regulated to work until the deck shuts itself down, and in this case also likely the problem with a voltage regulator powering certain circuits is dropping regulation too soon, before the deck is designed to know shut down point.