Owen,
Is it possible to run this off of +- 8.4v (NiMH batteries)?
I may want a PSU board if not....
I know the parts are optimized already, but could you recommend a replacement for C22 and the like that has a lower profile?
Silly questions, I know. Maybe I should just put it together like a normal board.
Thanks,
Nelson
Is it possible to run this off of +- 8.4v (NiMH batteries)?
I may want a PSU board if not....
I know the parts are optimized already, but could you recommend a replacement for C22 and the like that has a lower profile?
Silly questions, I know. Maybe I should just put it together like a normal board.
Thanks,
Nelson
nope, well yeah for about 5 minutes, nimh have crappy energy density and this amp, depending on the load can draw +/-300-400ma (higher into extreme loads)
depending on your Vin you can use 7343 size smd solid polymer caps such as the panasonic special polymer range, one soldered either side of the board, or kemet have a slightly lower performance but higher voltage polymer tantalum range in the same size
as with most all balanced amps, it will put double the swing into double the load impedance with double the psu, it doesnt make double the swing just because its balanced.
nope, i think i remember opc saying he has removed the onboard connectors altogether, we can then choose what we like, i think this is a great idea
Hi Guys,
A huge thanks to all those who helped get the list back up to date! Whether you confirmed your order, dropped off, or changed your order, I appreciate everyone's patience with this. There are only a handful I have not heard from.
Now to field a few questions:
N-Brock:
No worries about your free board, I didn't forget! I know qusp mentioned power density which may or may not be an issue, but +/-8.4V is more than enough voltage to get plenty of output, even into 600R phones. The SE-SE board would draw about 32mA at idle and that will increase if you're playing loud music into low impedance phones. I would say it's worth a try but you may not get a full day out of it, or even half a day for that matter.
As for the caps, qusp is exactly correct with the Panasonic SMD polymer parts. If you use those, the overall board height would be around 7mm, or closer to 10mm if you put them top and bottom as suggested.
I'm kinda rooting for anyone who does a portable setup since I'll probably be doing one myself later on. You guys blaze the trail and I'll follow along!
idjoel2000:
That really depends... it will have double the output voltage swing which will translate into 4 times the power into the same given load impedance. This will only be true however until you hit the current limit of the LME49600. Into lower impedance loads (say something like 8 ohms) you won't see any increase in output power. Into a 600 ohm load though, you'll get 4 times the power.
dggs:
Very good catch on the PSU confusion. I didnt' realize I had printed the schematic with both supplies on it.
CLARIFICATION: The PSU kit contains only one PCB and one +/- supply. It is NOT dual mono. I can see how this may have been confusing. If you want dual mono supplies you will need two PSU units.
One PSU is more than enough to power a stereo board, and I would call the dual mono option a pretty big luxury. I see no need to do it, but several people asked for it so I obliged.
QRikard:
I will definitely make common shipments with all parts ordered! It saves everyone trouble.
JBdV:
Sorta
... the connectors are gone completely from these boards. They took up a lot of board spade and very few people used them in the end. I not have convenient PTH pads for all connections and people can now choose their own connectors or wire the boards into an existing chassis.
Cheers,
Owen
A huge thanks to all those who helped get the list back up to date! Whether you confirmed your order, dropped off, or changed your order, I appreciate everyone's patience with this. There are only a handful I have not heard from.
Now to field a few questions:
N-Brock:
No worries about your free board, I didn't forget! I know qusp mentioned power density which may or may not be an issue, but +/-8.4V is more than enough voltage to get plenty of output, even into 600R phones. The SE-SE board would draw about 32mA at idle and that will increase if you're playing loud music into low impedance phones. I would say it's worth a try but you may not get a full day out of it, or even half a day for that matter.
As for the caps, qusp is exactly correct with the Panasonic SMD polymer parts. If you use those, the overall board height would be around 7mm, or closer to 10mm if you put them top and bottom as suggested.
I'm kinda rooting for anyone who does a portable setup since I'll probably be doing one myself later on. You guys blaze the trail and I'll follow along!
idjoel2000:
That really depends... it will have double the output voltage swing which will translate into 4 times the power into the same given load impedance. This will only be true however until you hit the current limit of the LME49600. Into lower impedance loads (say something like 8 ohms) you won't see any increase in output power. Into a 600 ohm load though, you'll get 4 times the power.
dggs:
Very good catch on the PSU confusion. I didnt' realize I had printed the schematic with both supplies on it.
CLARIFICATION: The PSU kit contains only one PCB and one +/- supply. It is NOT dual mono. I can see how this may have been confusing. If you want dual mono supplies you will need two PSU units.
One PSU is more than enough to power a stereo board, and I would call the dual mono option a pretty big luxury. I see no need to do it, but several people asked for it so I obliged.
QRikard:
I will definitely make common shipments with all parts ordered! It saves everyone trouble.
JBdV:
Sorta
... the connectors are gone completely from these boards. They took up a lot of board spade and very few people used them in the end. I not have convenient PTH pads for all connections and people can now choose their own connectors or wire the boards into an existing chassis.Cheers,
Owen
wont be waiting long to see a portable, i'll be dropping it into my dac/amp and using it as a kinda iv stage with buffer to see what runtime i get, but i'm running a lifepo4 +/-6.6vdc(13.6v) 2300mah battery, which is ~25mm x 110mm x 70mm and even i'm worried about runtime, with nimh to get that capacity battery you would be carrying a lunchbox. since i'm mostly running jh13 i only need the current gain so a center tapped regulated 13.2v psu will be fine.
Owen: do you have any suggestions on perhaps biasing the input to avcc/2? aside from perhaps changing the balance of the regulated voltages to be offset from the dac supply? i'm going to drop the resistance on the input to nothing and change the feedback R to ~180r, which is the value i've been using with opa1632dgn by itself
also, isnt the double the swing/4 x power into the same load only really true if you actually double the load? i always figured the impedance seen by a balanced amp is halved, even though its the same load, because its seen in parallel and thus the amount of swing you can put into the lower apparent impedance does not double
Owen: do you have any suggestions on perhaps biasing the input to avcc/2? aside from perhaps changing the balance of the regulated voltages to be offset from the dac supply? i'm going to drop the resistance on the input to nothing and change the feedback R to ~180r, which is the value i've been using with opa1632dgn by itself
also, isnt the double the swing/4 x power into the same load only really true if you actually double the load? i always figured the impedance seen by a balanced amp is halved, even though its the same load, because its seen in parallel and thus the amount of swing you can put into the lower apparent impedance does not double
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