PINT Problem

[amb]

Quote:

Originally Posted by SubRosa Sorry to double post but is this consistent with what other people are seeing? Could others with PINTs test this for me. As I stated, my DMM won't measure current draw and it looks like I'll be using one 9V now, so that would put me in the 180ma range if this info is universal, unless I buy a 9.6V NiMH.

No, my own observation is that the dual AD8397 config will draw a total of ~50mA between 15V-24V of supply voltage, dropping to around ~40mA around 9V, and then go up a bit to ~50mA-60mA at around 5V or 6V. All currents are subject to chip-to-chip tolerances and are thus a bit "hand-wavy", but 180mA is definitely not normal at any supply voltage.

 

[Heady]

Quote:

Originally Posted by cire depends on the voltage: ~4.5 to 24v = ~50ma ~3.2 to ~4.4v = ~180ma ~2.5 to ~3.1v = ~20ma

Hi cire, can you please tell us if these figures are what you measured with your PINT with AD8397 opamps. Or did you compile them from the results posted by others.

Thanks.

 

[The Monkey]

Quote:

Originally Posted by amb No, my own observation is that the dual AD8397 config will draw a total of ~50mA between 15V-24V of supply voltage, dropping to around ~40mA around 9V, and then go up a bit to ~50mA-60mA at around 5V or 6V. All currents are subject to chip-to-chip tolerances and are thus a bit "hand-wavy", but 180mA is definitely not normal at any supply voltage.

Based on very limited testing, my results with 9V are very similar to amb's.

 

[cire]

Quote:

Originally Posted by Heady Hi cire, can you please tell us if these figures are what you measured with your PINT with AD8397 opamps. Or did you compile them from the results posted by others.

its what i measured using my digital benchtop PSU

 

[Filburt]

Sorry, I didn't see the post where you said you were smoking C6. Did you make sure you oriented them correctly? C7 also?

 

[Heady]

Quote:

Originally Posted by cire its what i measured using my digital benchtop PSU

Thanks cire. I did get 160mA while using 4.5v but the amp was oscillating, could hear some odd sounds.

 

[SubRosa]

Quote:

Originally Posted by Filburt Sorry, I didn't see the post where you said you were smoking C6. Did you make sure you oriented them correctly? C7 also?

Yep, everything was oriented correctly; I don't know how, but it's cleared itself up. Just gotta' case it up now.

 

[FallenAngel]

Great news

, after hooking up a cheap mp3 source and some crappy headphones, I'm measuring 50mA - 55mA of current draw off 2 9V batteries, it kinda jumps around while playing music, but it does sound pretty damn good. DC offset is below 10mV at full blast.

Listening to it off my TREAD right now with MS-2s and it sounds really good, I really don't know whether I like it more than the Pimeta which cost me more than twice as much.

I declare this Mini^fied PINT complete. Just finished casing it in a mint which, with some creative positioning (I've got a huge 1000uF ELNA cap in there) actually fits everything including a big DC power jack with 2 9V's. Pictures soon.

Mini^fied version done, time to clean up the mess on the second, Tangent's Low Noise version, there's a headache in the making, and for those who see the time, yes it is 3AM

 

[amb]

Quote:

Originally Posted by FallenAngel Great news , after hooking up a cheap mp3 source and some crappy headphones, I'm measuring 50mA - 55mA of current draw off 2 9V batteries, it kinda jumps around while playing music, but it does sound pretty damn good. DC offset is below 10mV at full blast.

Yes, it's normal for the current draw to dynamically vary while playing music with a headphone (or dummy load) connected. The ~50mA figure is for quiescent (i.e., idle, no sound, volume control minimum) condition.

Congratulations for a successful build.

 

[Heady]

After getting a new analog multimeter, I am happy to announce that my second built, with AD8397 opamps, L/R opamp mini3-fied but ground opamp as per Tangent, now appears to be working normally. Current draw is about 50mA. This is with 9V battery. Could not get it to work with 3 or 4 AA batteries.

The first built is not resurrectable. RIP.

 

[mb3k]

I just built another.
Works fine, gain of 4, but aaround 70-80mA. But very very low dc offsets.
Hopefully it's alright

 

[cire]

just built a PINT with a pair of AD45048s and it works fine as far as i can tell. the only thing worth noting is that the offset is a bit higher than all the other 8397 PINTs i've built at 13mv. the 8397 ones were normally around 6-8mv

 

[Filburt]

Quote:

Originally Posted by mb3k I just built another. Works fine, gain of 4, but aaround 70-80mA. But very very low dc offsets. Hopefully it's alright

Probably mild oscillation. Try throwing C6 in.

 

[mb3k]

Quote:

Originally Posted by Filburt Probably mild oscillation. Try throwing C6 in.

It's already in.
It's running off of a STEPS at 24V.

 

[tangent]

Quote:

Originally Posted by mb3k It's already in. It's running off of a STEPS at 24V.

Try lowering the STEPS' output voltage.