Topic: Tascam DR100mkii Review

[stevetoney]

Dear Jon and Rainer:

How does the issue you're debating help with the diagnosis of the early cut-out problem with the Tascam?  If it doesn't help and your discussion about flat vs. sloping discharge curve is tangential to diagnosing the root cause of the Tascam problem, could I request you start a new thread? 

It seems to me the concept of internal battery resistance (perhaps on old rechargeables and certain types of alkalines) and its effect on output voltage was the key concept that needed to be flushed out.

Thanks

Well, my main point was about high internal resistance of various types of alkaline AAs, which will contribute to the variance in observed runtimes with that option.  You would want to be sure to use the Duracell Coppertop/Energizer level and not the lower grades, and if you want maximum possible life, the primary (photo) lithium grades.

Also the point about recorders/phantom as constant power, not current, loads--as the battery voltage drops and internal resistance increases, the box will draw increasing amounts of current.  That will accelerate the battery towards death, and that effect is worse as power load increases (meaning high phantom draw).

 

[BMillz]

Well, I'm gonna give this recorder a chance.  Just put in a return for my DR-40.

PS. I got a decent deal over at JR.com.  It was $315 today with shipping.  You just have to use their end of year promo code (JR2012) and join their free "friends with benefits" email program for the free shipping.

[stevetoney]

This link on the Battery University site seems to describe what might be happening on the early cut-out.  The first graph seems like it would be a logical explanation for the experiences of dogmusic and Sebasian.

http://batteryuniversity.com/learn/article/how_does_internal_resistance_affect_performance

[kleiner Rainer]

Hi all,

in my first post I already discussed a possible cause of the short runtime of the DR100Mk II: high power consumption when using P48. I checked the manual and it lists a maximum power consumption of 4W.

Assuming 2 NiMH AAs with 2.5V, this amounts to 1.6A of current 

At this current range, AAs are a bit under-powered...

Since I want to share my hard gained experience of decades of engineering and outdoor recording, here a kind of "executive summary" about batteries and rechargeables:

- care for your batteries. Keep them clean and cool, recharge them regularly and as soon as possible after use. Do not drop them or leave them in the car in the summer.

- keep the battery contacts of your recorder and the contact areas of your batteries clean. Use denatured alcohol and q-tips. we want the lowest contact resistance possible.

- buy quality cells from well-known and reliable sources. Concert tickets and the gas needed to get there are much more expensive than even Lithium AAs.

- If available, choose cells optimized for high current applications (eg "photoflash").

- when building external battery packs, prefer ready-made packs with welded contacts and selected cells. I recommend asking the RC guys. Most battery holders I know are crap, except Bulgin and Keystone ($$$).
Build big. Bigger cells=less resistance and more runtime. P48 is a power hog.

-invest in a good charger. Again, ask the RC guys, there are very good universal (NiCD, NiMH, LiIon, LiPoly, Lead acid) chargers that also can cycle and condition batteries and show charge and discharge capacitances.
If your NiMH cells get hot during charging, it is not a good charger.

I hope this helps a little bit.

Greetings,

Rainer

[stevetoney]

This link on the Battery University site seems to describe what might be happening on the early cut-out.  The first graph seems like it would be a logical explanation for the experiences of dogmusic and Sebasian.

http://batteryuniversity.com/learn/article/how_does_internal_resistance_affect_performance

I don't think a recorder would be a pulsed-load the same way a computer is, especially given the evidence in this thread that the cause of AA death is closely associated with phantom load, which is constant.  The trouble is that DC converter efficiency is dependent upon a low-resistance supply.  So as the resistance increases the efficiency drops, which in turn demands more current, which is a nasty positive feedback loop.

^  Gotcha, Jon.  My point in linking the article wasn't to focus on pulsing being the cause of the voltage cut-out as much to link to another source that supports a more general concept that when there's a power strain on the battery, whether caused by pulsing or in our case when P48 is engaged, that batteries with high internal resistance will tend to challenge the low-voltage cut-out set point more than if the battery does not have high internal resistance.

[stevetoney]

0.06C / 0.1C
Initial voltage:  8.35V / 8.34V
1 hour: 8.15V / 8.11V
2 hour: 8.04V / 7.92V
3 hour: 7.94V / 7.76V
4 hour: 7.83V / 7.63V
5 hour: 7.71V / 7.53V
6 hour: 7.63V / 7.46V
7 hour: 7.56V / 7.43V
8 hour: 7.51V / 7.37V
9 hour: 7.48V / 7.21V
10 hour: 7.45V / 6.86V
11 hour: 7.43V
12 hour: 7.38V
13 hour: 7.29V
14 hour: 7.15V
15 hour: 6.76V

So, I was curious to see graphically what this looked like so I copied the data into Excel...

[stevetoney]

Wouldn't it be interesting to compare the above results under several differing conditions...

1)  With batteries of differing chemistries

2)  At each chemistry, effects of differing 'calendar' age and/or 'usage' age

3)  How differing the battery load affects the above results.


Then for each situation, the variables I'd be curious to analyze are...

a)  how steep is the slope of the curve initially until it flattens out, and

b)  at what voltage, as a percentage of the initial voltage, does the curve flatten at.

[Sebastian]

Here's an update on battery run times... After a few days of charge/discharge cycles I'm getting continuous runtimes of around 320 mins. with the Li-Ion and NiZn AAs together. The Li-Ion lasts for 180 to 190 mins. and the NiZn AAs last for 120 to 130 mins. This is enough for any concert I attend.

[flintstone]

Sebastian,  thanks for sharing.  Are you using the internal mics for your tests, or external using phantom power?

[spyder9]

Here's an update on battery run times... After a few days of charge/discharge cycles I'm getting continuous runtimes of around 320 mins. with the Li-Ion and NiZn AAs together. The Li-Ion lasts for 180 to 190 mins. and the NiZn AAs last for 120 to 130 mins. This is enough for any concert I attend.

Is this with Phantom turned on?

[hi and lo]

I would assume so. Sebastian's normal rig is MBHO 603a > MP2

[Sebastian]

My run time tests were all done with two phantom-powered MBHO 603a bodies and KA200N capsules. According to the specs they draw 4.5mA each, so that makes 9mA for both mics.

[manleyf]

I bought one from JR, got it in yesterday but I think I have an issue.

My input select switch will not move past the "uni" position so I'm unable to select omni or line in.

Has anyone experienced this?

[BMillz]

Hi Manley,
I literally just got mine in the mail today via JR and haven't had that issue.

[newplanet7]

Did anyone run straight in at a show yet with this deck?
I listened to your samples steve and the pres sound good but, we need to
know how they react in a high spl environment too.