5V DC voltage regulators.
Hi George,
I found two TI chips than can provide the required ±5V values:
1. Linear Regulators - Standard Voltage Regulators - UA7805 - TI.com
2. Linear Regulators - Standard Voltage Regulators - UA7905 - TI.com
Best regards,
Bins.
Hi George,
I found two TI chips than can provide the required ±5V values:
1. Linear Regulators - Standard Voltage Regulators - UA7805 - TI.com
2. Linear Regulators - Standard Voltage Regulators - UA7905 - TI.com
Best regards,
Bins.
The MkII is double regulated, it has a +12v regulated linear wall wart (you can use your 15vdc supply) that gets
re-regulated by a +5v regulated supply, which then goes to the 100kohm log pots then to the 100ohm resistors and then to the + led portion of the NSL-32SR2S.
All the 0's of the wall wart, the +5vdc supply and the cathode of the led go together, you can put them to chassis earth, I perfer not too.
Cheers George
re-regulated by a +5v regulated supply, which then goes to the 100kohm log pots then to the 100ohm resistors and then to the + led portion of the NSL-32SR2S.
All the 0's of the wall wart, the +5vdc supply and the cathode of the led go together, you can put them to chassis earth, I perfer not too.
Cheers George
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Binspaul,
This is a fine solution. You should consider using 3 of these in your circuit. If you want your volume to go down low you need to saturate those shunt resistors to get their lowest resistance. This takes about 10mA per LDR. The max output of the REF02 is 10mA so consider using one REF02 per LDR and one for series, or two for series. Either way is fine but both ways will change volume a little differently. If you use one single REF02 you wont have enough output to control the Lightspeed the way it should be. Almost your entire rotation of your control pot will work identically to a higher powered Lightspeed, but when you try to turn the volume down all the way it just wont happen.
However, I dont think it would be the same circuit anymore. There is really nothing wrong with dual regulating down to 5V with a few LM317 or other 3 pin regulator. Its going to be the easiest solution for you.
If you would like to be a bit different and do something else you might try LM4040-10. It will only give out 100mW max and split between the two LDRs sucking the most power at the time this will be fine. You can use more than 5V to control them but you have to be careful not to exceed about 100mW per LDR and its not necessary to use more than 50mW per device to get the lowest resistance. I should say its not necessary to use more than 50mW on a 'typical' device as some of them saturate only with a little higher power since the LDRs are not all identical to each other even though their specs say they are.
Uriah
This is a fine solution. You should consider using 3 of these in your circuit. If you want your volume to go down low you need to saturate those shunt resistors to get their lowest resistance. This takes about 10mA per LDR. The max output of the REF02 is 10mA so consider using one REF02 per LDR and one for series, or two for series. Either way is fine but both ways will change volume a little differently. If you use one single REF02 you wont have enough output to control the Lightspeed the way it should be. Almost your entire rotation of your control pot will work identically to a higher powered Lightspeed, but when you try to turn the volume down all the way it just wont happen.
However, I dont think it would be the same circuit anymore. There is really nothing wrong with dual regulating down to 5V with a few LM317 or other 3 pin regulator. Its going to be the easiest solution for you.
If you would like to be a bit different and do something else you might try LM4040-10. It will only give out 100mW max and split between the two LDRs sucking the most power at the time this will be fine. You can use more than 5V to control them but you have to be careful not to exceed about 100mW per LDR and its not necessary to use more than 50mW per device to get the lowest resistance. I should say its not necessary to use more than 50mW on a 'typical' device as some of them saturate only with a little higher power since the LDRs are not all identical to each other even though their specs say they are.
Uriah
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Hi Uriah,
If that is the case with REF02, then can I use the PTN78000W (http://focus.ti.com/lit/ds/symlink/ptn78000w.pdf) ? It is having an output current capability of 1.5A.
Please suggest...
Best regards,
Bins.
If that is the case with REF02, then can I use the PTN78000W (http://focus.ti.com/lit/ds/symlink/ptn78000w.pdf) ? It is having an output current capability of 1.5A.
Please suggest...
Best regards,
Bins.
Hi Bins,
Yeah that will work and probably do a great job. The only thing anyone might not like about it is that its a switching regulator. I have a switching regulator on my first Lightspeed and it DOES make a tiny amount of really high frequency noise that I only hear when my ear it directly on the speaker.
One other thing to consider is that this supply is not stable without a .1A load on it so you might pick a low value high wattage resistor to put across output and ground to load it so you get stable voltage regulation. If your output is 5V then you might use a </=50R resistor of a few watts as a load.
I say if this is something available to you it looks like a great solution.
Also, dont let its switching bother you much. Its at about .5MHz so you are NOT going to hear this at all. Mine was switching about 100 time slower which is definitely in our hearing range.
Uriah
Yeah that will work and probably do a great job. The only thing anyone might not like about it is that its a switching regulator. I have a switching regulator on my first Lightspeed and it DOES make a tiny amount of really high frequency noise that I only hear when my ear it directly on the speaker.
One other thing to consider is that this supply is not stable without a .1A load on it so you might pick a low value high wattage resistor to put across output and ground to load it so you get stable voltage regulation. If your output is 5V then you might use a </=50R resistor of a few watts as a load.
I say if this is something available to you it looks like a great solution.
Also, dont let its switching bother you much. Its at about .5MHz so you are NOT going to hear this at all. Mine was switching about 100 time slower which is definitely in our hearing range.
Uriah
Hi Uriah,
Thanks for your reply. I am having around 5 of them available with me. One feature of those regulators is that, it is having an INHIBIT pin that can be used to turn ON/OFF the supply. (See Page:19)
I am having some WELWYN 250mW 0.1% metal film resistors available with me. Will they suffice for the purpose of loading ?
Best regards,
Bins.
Thanks for your reply. I am having around 5 of them available with me. One feature of those regulators is that, it is having an INHIBIT pin that can be used to turn ON/OFF the supply. (See Page:19)
I am having some WELWYN 250mW 0.1% metal film resistors available with me. Will they suffice for the purpose of loading ?
Best regards,
Bins.
Bins. You would have to use several of them. You dont want to run them at max and they only handle a quarter watt but you need at 5V at least a load of a half watt to keep stable voltage going to the LDRs. Its not a real big deal to have stable voltage but if you want it to be right, to be the best it can with your supply, then you need a min of .5W on a load and you dont want only .25W worth of resistance loading it. Plus it has to be the right value of resistor meaning it has to be 50R or less and the lower it goes the higher the wattage must be.
Uriah
Uriah
50mA and 5V comes out at 250mW. That's the rating of your resistors.
If you reduce the current to ~20mA then the resistor will run much cooler dissipating only 100mW (~40% of maximum rating).
5V and 20mA requires a 250r resistor. You can use 240r (20.8mA) or 270r (18.5mA). Decide how many of those 250mW resistors, run in parallel, you need/want to use to get your total current load on the PSU.
If you reduce the current to ~20mA then the resistor will run much cooler dissipating only 100mW (~40% of maximum rating).
5V and 20mA requires a 250r resistor. You can use 240r (20.8mA) or 270r (18.5mA). Decide how many of those 250mW resistors, run in parallel, you need/want to use to get your total current load on the PSU.
Power supply...
Hi,
The power supply with PTN78000W seems too complex without much added benefits. It needs more components than a very simple 5V supply using LM7805 IC's.
I am going for a much simple supply, but with a 3 stage model ( 15V -> 10V -> 5V) (Adapter Out -> UA7810 -> UA7805). All IC's are readily available with me and just waiting for my 15V adapter to arrive....
@George/Uriah: What is your suggestion ?
Best regards,
Bins.
Hi,
The power supply with PTN78000W seems too complex without much added benefits. It needs more components than a very simple 5V supply using LM7805 IC's.
I am going for a much simple supply, but with a 3 stage model ( 15V -> 10V -> 5V) (Adapter Out -> UA7810 -> UA7805). All IC's are readily available with me and just waiting for my 15V adapter to arrive....
@George/Uriah: What is your suggestion ?
Best regards,
Bins.
Never mind.. Scrolling through the WHOLE thread I find them... Repost for others...
http://www.diyaudio.com/forums/anal...uator-new-passive-preamp-188.html#post1788083
Hi,
The power supply with PTN78000W seems too complex without much added benefits. It needs more components than a very simple 5V supply using LM7805 IC's.
I am going for a much simple supply, but with a 3 stage model ( 15V -> 10V -> 5V) (Adapter Out -> UA7810 -> UA7805). All IC's are readily available with me and just waiting for my 15V adapter to arrive....
@George/Uriah: What is your suggestion ?
Best regards,
Bins.
Bins,
This is your best option
It is easy, it works, the parts are easily found.Uriah