sangram said:
Why would you not run it without a load?
And yes, without a heatsink. The offset voltages are very low (which you'd hope they were given the lack of input) .001v to .002v. Could be oscillating, it only ran for a few seconds and as Sangram said it didn't get any hotter. I will try it with an 8ohm speaker or two and see what happens.
Hi,
with the inputs correctly terminated and the output terminated but no speaker load connected, the chip should run in quiescent mode. This should be the quiescent current specified in the data sheet. That current times the rail to rail voltage gives the quiescent dissipation (Pq).
If the Pq is more than 500mW then you should connect the heatsink. Otherwise it will run warm. If the Pq>1W it will be damn hot.
A solid state amplifier does not need a load to be safe (a valve amp does).
with the inputs correctly terminated and the output terminated but no speaker load connected, the chip should run in quiescent mode. This should be the quiescent current specified in the data sheet. That current times the rail to rail voltage gives the quiescent dissipation (Pq).
If the Pq is more than 500mW then you should connect the heatsink. Otherwise it will run warm. If the Pq>1W it will be damn hot.
A solid state amplifier does not need a load to be safe (a valve amp does).
So interms of consumption - it would be something like:
50v by 110mA is something like 5.5W.
Though at low load my trafo is pumping out 2x29v (58v) and the max quiescent current is 170mA which would be 9.89W.
There are 3 nice tables on "Total Power Dissipation vs Output Power/Channel 1% THD (max), RL = 4Ω, 80kHz BW" which shows a +/- 25v input consuming 10W being just under 10W input.
So yeah close to 1W 🙂
50v by 110mA is something like 5.5W.
Though at low load my trafo is pumping out 2x29v (58v) and the max quiescent current is 170mA which would be 9.89W.
There are 3 nice tables on "Total Power Dissipation vs Output Power/Channel 1% THD (max), RL = 4Ω, 80kHz BW" which shows a +/- 25v input consuming 10W being just under 10W input.
So yeah close to 1W 🙂
Hi Raro,
the Pq is about 5W for +-25Vdc
Rth j-a is 30C/W.
without a sink the junction temperature (Tj) will rise quickly to about 180degC. when ambient temperature is about 30degC.
You cannot idle this chip without a sink.
!
can you ask the Moderator to change the link to the datasheet.
It includes "cache" in the address which confuses my PC and maybe others. I had to reboot, I could not cancel the pdf request.
the Pq is about 5W for +-25Vdc
Rth j-a is 30C/W.
without a sink the junction temperature (Tj) will rise quickly to about 180degC. when ambient temperature is about 30degC.
You cannot idle this chip without a sink.
!
can you ask the Moderator to change the link to the datasheet.
It includes "cache" in the address which confuses my PC and maybe others. I had to reboot, I could not cancel the pdf request.
Hi Pinky,
post 42 in this thread.
Can I report such a problem directly without cluttering the thread?
post 42 in this thread.
Can I report such a problem directly without cluttering the thread?
AndrewT said:
Exactly my point. I thought he was running with a sink, but then saw the picture...
Here's a picture of the carpet ... er gainclone with a heatsink.
Doesn't really get more than a little warm in the area on the back of the Alu 5mm plate.
I can see why people use those plates over the front of the chip, they can be a pain to hold in place and a nice little threaded plate would be perfect 🙂
Doesn't really get more than a little warm in the area on the back of the Alu 5mm plate.
I can see why people use those plates over the front of the chip, they can be a pain to hold in place and a nice little threaded plate would be perfect 🙂
Attachments
It is looking good 🙂
Beware the carpet on the static sensitive devices. (Sorry if this is starting to sound monotonous 🙁 )
Beware the carpet on the static sensitive devices. (Sorry if this is starting to sound monotonous 🙁 )
Thanks 🙂lndm said:
lndm said:
This is real wool, so I figured the risk was lower than if it were synthetic- but point taken.
Hrm,
I have hooked up the inputs and outputs, but don't seem to be getting as much as a speaker pop when I turn it all.
All the voltages appear to be present and correct, it is being fed from my PC (and not a pre-amp'd source, or a CD player).
Where do I start checking things?
I have hooked up the inputs and outputs, but don't seem to be getting as much as a speaker pop when I turn it all.
All the voltages appear to be present and correct, it is being fed from my PC (and not a pre-amp'd source, or a CD player).
Where do I start checking things?
Do I really need or want a gainclone?
YES. With a condition.
Only if you want to learn something and are willing to work for it...
YES. With a condition.
Only if you want to learn something and are willing to work for it...
Visit National Semi Site
By the way, the wholesale pricing on the chips has been greatly reduced to 3 bucks a piece.
By the way, the wholesale pricing on the chips has been greatly reduced to 3 bucks a piece.
Why the responses?
Because the newbies can only follow so much. I appreciated every tread myself in my search.
Because the newbies can only follow so much. I appreciated every tread myself in my search.
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