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Arduino based LDR volume and source selection controller
Arduino based LDR volume and source selection controller
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Old 19th November 2017, 08:22 AM   #911
sorinv is offline sorinv  Romania
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I finally started building this, more than 1 year after I got my PCBs. In the meantime I figured I need more IOs than the 3 in x 1 out board I have on hand.

Anybody has any of these PCBs available:
- IO board - 4 in x 2 out
- IO board - 3 in
- all in one with 4 in x 2 out
- anything else that may apply

Thanks,
Sorin
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Old 22nd November 2017, 02:54 PM   #912
zdr is offline zdr  Belgium
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I have all-in-one boards with relays available.
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Neb. [LDR Volume Control OLED firmware:]
https://drive.google.com/open?id=0B7...ENmRXNYUEtySVE
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Old 27th November 2017, 04:15 AM   #913
obscurus is offline obscurus
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I want to make the left & right channel off balance with code! Is it possible to do so ?
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Old 27th November 2017, 06:16 AM   #914
obscurus is offline obscurus
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I found this line:

att = getAttFromStep(i + 2);

so if I need Vr = 1/2 Vl

then I can use smt like: att_r = att - 6;

and apply to below block?

I appreciate if any one can help me on this?
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Old 29th November 2017, 11:33 AM   #915
Fixmos is offline Fixmos
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Hey thank you for sharing you DIY project! I will solder off the ldr's from my lightspeed/lighter note attenuator and make this, hopefully the ldr's will survive another heat cycle from the soldering iron
Again, thank you
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Old 5th December 2017, 07:55 AM   #916
sorinv is offline sorinv  Romania
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Anybody tried to integrate a headphone amp in the same chassis as the LDR attenuator?

I am thinking of putting in a headphone amp connected to the secondary output (4 in / 2 out AIO version here). I'm planning on controlling it with the arduino and a separate relay, so it gets turned on only when I select the output to headphones.

I have seen that initially there was planned a delay relay for soft starting a tube preamp, and I am curious if anybody has more info on how to use this functionality to turn on the headphone amp instead.

So my questions would be:
1. Where exactly on the board to connect an additional relay for this
2. What kind of relay should I use? Latching / non latching? Assuming 5v / 220V?
3. Where exactly should I alter the code to support the functionality?

Hopefully some of you would have some answers. If not, I can try hacking it myself and post here the results, if I get any

Thanks,
Sorin
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Old 6th December 2017, 01:27 PM   #917
zdr is offline zdr  Belgium
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Quote:
Originally Posted by sorinv View Post
Anybody tried to integrate a headphone amp in the same chassis as the LDR attenuator?

I am thinking of putting in a headphone amp connected to the secondary output (4 in / 2 out AIO version here). I'm planning on controlling it with the arduino and a separate relay, so it gets turned on only when I select the output to headphones.

I have seen that initially there was planned a delay relay for soft starting a tube preamp, and I am curious if anybody has more info on how to use this functionality to turn on the headphone amp instead.

So my questions would be:
1. Where exactly on the board to connect an additional relay for this
2. What kind of relay should I use? Latching / non latching? Assuming 5v / 220V?
3. Where exactly should I alter the code to support the functionality?

Hopefully some of you would have some answers. If not, I can try hacking it myself and post here the results, if I get any

Thanks,
Sorin
I have the headphone amp in the same chassis, but is turned on along with the preamp. Not sure why you want to bother and fiddle with power pops while switching the output channels, unless you have a tube headamp.
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Neb. [LDR Volume Control OLED firmware:]
https://drive.google.com/open?id=0B7...ENmRXNYUEtySVE
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Old 6th December 2017, 01:35 PM   #918
sorinv is offline sorinv  Romania
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Quote:
Originally Posted by zdr View Post
Not sure why you want to bother and fiddle with power pops while switching the output channels, unless you have a tube headamp.
It's not tube. I thought I would not have the headamp turned on when not needed. Most of the times I'll listen through speakers, so headamp not needed most of the time.
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Old 6th January 2018, 10:41 AM   #919
zdr is offline zdr  Belgium
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Quote:
Originally Posted by sorinv View Post
It's not tube. I thought I would not have the headamp turned on when not needed. Most of the times I'll listen through speakers, so headamp not needed most of the time.
I don't think it's worth the effort. Consumption of the solid state headamp is negligible.
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Neb. [LDR Volume Control OLED firmware:]
https://drive.google.com/open?id=0B7...ENmRXNYUEtySVE
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Old 7th January 2018, 10:50 PM   #920
Monte McGuire is offline Monte McGuire
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Arduino based LDR volume and source selection controller
Quote:
Originally Posted by sorinv View Post
It's not tube. I thought I would not have the headamp turned on when not needed. Most of the times I'll listen through speakers, so headamp not needed most of the time.
I don't know the circuit details, but it's possible that having the headphone amp in the circuit, driven, and powered off could damage the headphone amp. Various semiconductors like op amps might have their input terminal voltages driven by the main output signal beyond the voltage at the power supply terminals (which are at 0V when powered down), and that can permanently damage them. The same goes for transistors - some junctions could be reverse biased, which may damage the device. It's also possible that the amp will place a nonlinear load on the main output when it's not powered up, injecting distortion into the main signal. This would be similar to loading the output with a diode - never a good idea.

I'd skip that idea entirely unless you can also make sure that the signal to the headphone stage is also disconnected. Overall, it seems excessively complicated for no benefit. Having the extra load on your power supply regulators will make them work better anyway, so just leave the headphone amp powered on.
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