Thanks for the answers. I did a few measurements:
V across CCS resistor = 1.20
CCS resistor = 4.2 ohms
CCS current = 284mA
Vgs of CCS Tr = 4.55
Voltage across 3 green LED's = 5.75
Current through 3 green LED's = 2.7mA (27mV across R108 which is 10 ohms)
DC Input Voltage after all R/C filtering = 22.3 V
DC Output Voltage = 14.8 V
I think that all is fine. I am using the regulator for the active crossover to my Orion speakers. I need the modify the crossover to add a notch filter and want to increase to current of the regulator while I have the crossover disassembled. I have plenty of heatsink capacity and transformer reserve current. While I work on the crossover it will be easy to modify the regulator. So the question is do I go the easy route and lower the CCS resistor value (add another resistor in parallel) or should I be more radical and add an additional LED to my string of 3.
Then I would reset the resistor value of the CCS resistor to around 7.5 ohms assuming a voltage drop of 3.1V across the CCS resistor yielding 410mA. If the input voltage drops below 22V I can easily change the input R/C filter to adjust that.
I guess that my real question is am I compromising the regulators performance by having just over 1V across the CCS resistor.
Thanks guys for the advice.
Bill
V across CCS resistor = 1.20
CCS resistor = 4.2 ohms
CCS current = 284mA
Vgs of CCS Tr = 4.55
Voltage across 3 green LED's = 5.75
Current through 3 green LED's = 2.7mA (27mV across R108 which is 10 ohms)
DC Input Voltage after all R/C filtering = 22.3 V
DC Output Voltage = 14.8 V
I think that all is fine. I am using the regulator for the active crossover to my Orion speakers. I need the modify the crossover to add a notch filter and want to increase to current of the regulator while I have the crossover disassembled. I have plenty of heatsink capacity and transformer reserve current. While I work on the crossover it will be easy to modify the regulator. So the question is do I go the easy route and lower the CCS resistor value (add another resistor in parallel) or should I be more radical and add an additional LED to my string of 3.
Then I would reset the resistor value of the CCS resistor to around 7.5 ohms assuming a voltage drop of 3.1V across the CCS resistor yielding 410mA. If the input voltage drops below 22V I can easily change the input R/C filter to adjust that.
I guess that my real question is am I compromising the regulators performance by having just over 1V across the CCS resistor.
Thanks guys for the advice.
Bill
I added a series resistor to bring my CCS resistor value up to 8.6 ohms.
The Vgs drops to 4.35V. The LED's have the same 5.75V. The CCS R (now 8.6ohms) has a 1.4V drop.
The input voltage has gone up a volt and 160mA of the CCS is not enough current to supply the load.
I'm out of time for today but plan to do the crossover mods tomorrow.
Thanks,
Bill
The Vgs drops to 4.35V. The LED's have the same 5.75V. The CCS R (now 8.6ohms) has a 1.4V drop.
The input voltage has gone up a volt and 160mA of the CCS is not enough current to supply the load.
I'm out of time for today but plan to do the crossover mods tomorrow.
Thanks,
Bill
No, you don't compromise it as long there is enough Vin-Vo. You just save on Rset dissipation.
It looks like the 200mVgs change is telling you that the 610 does not like what you are asking.
Add in mains voltage changes and the 610 is going to struggle to maintain CCS current constancy.
Basically, I am still disagreeing with Salas.
Your Input voltage rejection ratio is going to suffer, because the Vgs is approaching the Vds of the pass device.
Add in mains voltage changes and the 610 is going to struggle to maintain CCS current constancy.
Basically, I am still disagreeing with Salas.
Your Input voltage rejection ratio is going to suffer, because the Vgs is approaching the Vds of the pass device.
So it's a MKT, not a MKP. Makes sense you got better results with the Auricaps.
Hi
have started the build of a single positive bjt reg ( i have a IRF reg to but am building the BJT first).
I am feeding it with a 50va 18v trans. and need 210ma to feed my Dynavector P-075mk2 RIIA, i have used a 6 AH led battery with great success (even when it drains fast)
I built the reg with 4 green leds and a 10ohm R301 that gives me 300ma ccs
it worked smooth with my 240ma dummy load.
But when hooking up my RIIA it refuses to bring it up to 12 v it stops at about 2.5v, when "helping" it whit a battery it starts and works well.
Raising the CCS to 400ma 6,6ohm the RIIA starts if the regulator is powered up and running without load and hooking up the load later.
Raising the CCS again to 536ma 5ohm it starts both hooked up at the 12V side when plugging in the A/C and when hooking up the 12V
So here comes the essence:
-Can i run above 500ma CCS when i only need 210ma? (meaning is it conductive to sound quality)
-Would a different setup work better? am running 4,7uf MKT C304 and BJT
-Would it be wise to use good (Dale maybe) 1ohm r307 in the Zobel ? (and other resitors as well)
Thanks
Per
have started the build of a single positive bjt reg ( i have a IRF reg to but am building the BJT first).
I am feeding it with a 50va 18v trans. and need 210ma to feed my Dynavector P-075mk2 RIIA, i have used a 6 AH led battery with great success (even when it drains fast)
I built the reg with 4 green leds and a 10ohm R301 that gives me 300ma ccs
it worked smooth with my 240ma dummy load.
But when hooking up my RIIA it refuses to bring it up to 12 v it stops at about 2.5v, when "helping" it whit a battery it starts and works well.
Raising the CCS to 400ma 6,6ohm the RIIA starts if the regulator is powered up and running without load and hooking up the load later.
Raising the CCS again to 536ma 5ohm it starts both hooked up at the 12V side when plugging in the A/C and when hooking up the 12V
So here comes the essence:
-Can i run above 500ma CCS when i only need 210ma? (meaning is it conductive to sound quality)
-Would a different setup work better? am running 4,7uf MKT C304 and BJT
-Would it be wise to use good (Dale maybe) 1ohm r307 in the Zobel ? (and other resitors as well)
Thanks
Per
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Is it a high start up current need from the Riaa, or some instability between the reg and Riaa? It takes to watch it with ameter and oscope to really know. If its a matter of needing more current, using >500mA is no constraint if your sinks are still under 60C. And it is conductive to SQ, though anti energy star. 
Are there any high value electrolytics on the Riaa +V that they try charge up and demand much instant current? Maybe a good idea to delete them. Don't know if 1R R107 can be picked up quality wise. But it should be present with MKT Zobel. What do you mean helping it with the battery? Touching the battery between V+ & GND Riaa and then it kickstarts?
Are there any high value electrolytics on the Riaa +V that they try charge up and demand much instant current? Maybe a good idea to delete them. Don't know if 1R R107 can be picked up quality wise. But it should be present with MKT Zobel. What do you mean helping it with the battery? Touching the battery between V+ & GND Riaa and then it kickstarts?
Thanks
Thanks gain
Per
yes i guess its a high startup current, when using a battery i see a spark when connecting power.
i dont know i will investigate later i suppose so
Yes
Thanks gain
Per