wormyrocks
New member
Hi all,
I have a Teensy project which heretofore used an audio shield, which worked well for my purposes. But I'm now realizing that, since space is at a premium, the Prop Shield accomplishes the majority of my goals much better, so I ordered one. I'm just wondering what to expect through the transition. Specifically:
1. Currently, my project has a line in jack and a headphone out jack. The left channel of the line out from the audio board is fed into a LM386 amp circuit that drives an 8-ohm speaker. This amp circuit is made of bulky through-hole parts, which the Prop Shield circumvents.
However: is there still a way to have a line out from the Teensy as well as a speaker output? If I were to, say, connect a 3.5mm jack directly to the DAC pin of the Teensy (in parallel with the input to the prop shield amp) would I still be able to get a clean line out? Provided that I feed it into a high-impedance load like a speaker amp or a mixer, what can I expect that to do to my onboard speaker output? Would it be safe to use it to drive headphones?
2. My project also currently has a line in (from the SGTL5000 ADC). Is there any way to replicate that without the outboard sound module? Would it be possible to just feed a line-level signal from a 3.5mm jack directly into one of the Teensy ADC pins, or am I liable to fry something?
3. How does using the onboard DAC and ADC on the Teensy rather than an outboard SPI module affect CPU time?
4. I am currently running my project off a 5v boost regulator and lipo cannibalized from a cheapo USB phone charger. Would it be better to feed the Teensy + prop shield directly from that 5v output, or would it make more sense to use a 5v linear regulator to maybe get a cleaner signal, albeit at ~4V after dropout? I know that boost converters frequently introduce noise, but I'm also aware that it probably isn't smart to run a 5v regulator off 5v. Or will the decoupling caps on the prop shield filter out most of the noise? If there's an ideal solution here with regard to powering an audio project off something like this, which is what I have, please let me know!
5. I purchased a 128MBit flash chip in the same line as the 64MBit model currently on the prop shield with the intention of swapping it out. There shouldn't be any problems with that, should there?
Thanks everyone! Happy to be here!
I have a Teensy project which heretofore used an audio shield, which worked well for my purposes. But I'm now realizing that, since space is at a premium, the Prop Shield accomplishes the majority of my goals much better, so I ordered one. I'm just wondering what to expect through the transition. Specifically:
1. Currently, my project has a line in jack and a headphone out jack. The left channel of the line out from the audio board is fed into a LM386 amp circuit that drives an 8-ohm speaker. This amp circuit is made of bulky through-hole parts, which the Prop Shield circumvents.
However: is there still a way to have a line out from the Teensy as well as a speaker output? If I were to, say, connect a 3.5mm jack directly to the DAC pin of the Teensy (in parallel with the input to the prop shield amp) would I still be able to get a clean line out? Provided that I feed it into a high-impedance load like a speaker amp or a mixer, what can I expect that to do to my onboard speaker output? Would it be safe to use it to drive headphones?
2. My project also currently has a line in (from the SGTL5000 ADC). Is there any way to replicate that without the outboard sound module? Would it be possible to just feed a line-level signal from a 3.5mm jack directly into one of the Teensy ADC pins, or am I liable to fry something?
3. How does using the onboard DAC and ADC on the Teensy rather than an outboard SPI module affect CPU time?
4. I am currently running my project off a 5v boost regulator and lipo cannibalized from a cheapo USB phone charger. Would it be better to feed the Teensy + prop shield directly from that 5v output, or would it make more sense to use a 5v linear regulator to maybe get a cleaner signal, albeit at ~4V after dropout? I know that boost converters frequently introduce noise, but I'm also aware that it probably isn't smart to run a 5v regulator off 5v. Or will the decoupling caps on the prop shield filter out most of the noise? If there's an ideal solution here with regard to powering an audio project off something like this, which is what I have, please let me know!
5. I purchased a 128MBit flash chip in the same line as the 64MBit model currently on the prop shield with the intention of swapping it out. There shouldn't be any problems with that, should there?
Thanks everyone! Happy to be here!