Quote:
Originally Posted by Henmyr  Great. I have the LT1469IN8 so it should probably work even better then. Will probably put it back in the dac.
|
Please do! I really enjoyed reading about your earlier opamp tests so I've been looking forward to your impressions of using the LT1469 in the DAC! I remember you wrote it was maybe the next one in line for trying.. Well, the LT1469 seems pretty hot for DAC duty so I say let it do it's thing!
I'm still new to opamps so starting to get the hang of it but please correct me if I'm wrong, anyway I was thinking about high temps:
The AMP board takes 2 dual chips for a total of 4 opamps. Assuming it only uses one opamp for each sound channel, then only 1/2 in the left chip and 1/2 in the right chip are used.
The DAC board takes 1 dual chip for a total of 2 opamps. Assuming it uses both opamps for both sound channels, then both opamps in the chip are used.
So I think a dual opamp chip should then consume twice as much power when inserted in the DAC socket, compared to an AMP socket, meaning twice the heat dissipation.
Somewhere back in the thread is was mentioned that high temp could be a sign of oscillating which I guess is true, but I don't think that's the case with the Zero and these opamps, they seem to work perfectly and I think it's just the huge power consumption difference. Looking at these numbers I understand the other seemed really hot after using the LT1057:
Supply Current Per Amplifier:
LT1057: 1.7mA typ - 2.8mA max
LT1361: 4.0mA typ - 5.0mA max
LT1469: 4.1mA typ - 5.2mA max
LT1364: 6.3mA typ - 7.5mA max
The LT1057 should come out coolest, LT1361 and LT1469 much warmer and LT1364 the hottest of these, and if my theory is correct, each of them run warmer in the DAC socket than in the AMP sockets.
Anyway, these LT chips seem capable of operating at very high temperatures, like Penchum posted they're apparently good for up to 150'C internally so should be no worries. I guess it's easy enough to put a VGA RAM sink on it or something but as long as it's within spec that's pretty useless. Temperature should not affect performance unless it goes out of spec (at which case you may be more concerned with permanent damage). Say the case would be 10'C warmer than the room temp, no let's say 20'C warmer. On top of that have a room temp of 35'C now that would be 55'C air temp inside! Even this 55'C condition would still not push it, it's well within the specified operating range from -40'C to 85'C. Think it's pretty safe to say there's Zero chance of overheating in this case
But, I can give you some info on the headphone amp. It's a dual mono design, has Opamps in sockets, so you can customize it's sound, and it is quite powerful. Many current owners (me included) are driving 300ohm headphones with ease.
)
The OPA267's should be mounted on the amp section, right?
