Using the HYPNOTIZE as a general shunt reg PCB

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#41
Salas,
Can you please post the updated schematic refer to build as per your thread #1, so we don't have to go to the other thread.
And there are quite some different circuit in different page in the other thread that is hard to follow.
Thank you.
 
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#46
Salas said:
Theoretically yes, but it will be very difficult to match the sides with the LED references and 0.3x resistors. I would use a Vbe controlled source for that. How much more is the 6A than the bias needed per side? You better be economic, so the dissipation is mainly kept at the load.
Click to expand...

A Vbe controlled source in place of the resistors/led's/IRFP9240? Is matching the current drawn by each side necessary? Also, you recommended earlier that the regulator be set up for twice the current drawn by the load, but for an F5 is this still necessary for best sonics? Perhaps give it only an amp headroom above the F5's bias?

Thanks for sitting around in this thread answering our questions ;P
 
#47
The Vbe is steady 0.66V and helps in projecting the set resistor value. Then there is Vgs. If you match Vgs of CCS 240/9240 (unlikely, else you got many) then there will be no reason for the currents not to be matched also. But not necessary, especially when in Ampere count.

Twice I recommend in relatively low consumptions, so to have the MOSFETS working warm enough. Its a benefit, some members have found out too. When you have those MOSFETS at 1.5A vicinity and over, their Ygfs has picked up a lot though and I would not consider waste as a benefit anymore, especially at such power range heatwise.

Class A amps are the best shunt's customers as I have wrote before. Just because the juice is burning steadily on their sinks already. Set +20% on the shunts and it will keep their own sinks heat logical. Only don't test without the planned draw.
 
#48
derwhalfisch said:
you recommended earlier that the regulator be set up for twice the current drawn by the load, but for an F5 is this still necessary for best sonics? Perhaps give it only an amp headroom above the F5's bias?
Click to expand...
the F5 is a push/pull ClassA amplifier.
At quiescent condition the two supply rails draw constant current, equal to the bias current plus the current to the front end.

At power output, when we are listening to music the supply rails draw variable current.
In the extreme when the F5 is sending 27W of ClassA power to the load, the supply rails are alternately drawing zero amps and twice the bias current.
If the amp goes into ClassAB because the load has demanded more than twice the bias current then the regulator that supplies that rail at that instant must supply this worst case current load.
 
#51
derwhalfisch said:
AndrewT and Salas;

Thanks for the clarification ;P I have so many different ideas and schems competing for attention in my head, as I try to determine where best to spend my dollars, I'm getting confused. Might stick with KISS principle in the mean time and just use loads of caps ;P
Click to expand...

A shunt reg would be heroic for an F5 in full tilt indeed. T-Amps fly with it as far as I know from experience. Depending on the actual load demand you could end up spending enough for sinking the shunts for an F5, that is true. OTOH if your speakers are sensitive and you don't use much power in practice it can be conservative enough. A middle of the road solution could be a series reg non the less.
 
#52
Hi Salas

I have build +-12 vdc (CCS Is ~100 mA) hypno reg - It really sounds great, thank you for this great project
however I would like to ask about current running through 10 R - this Is current which only runs through shunt, right ?
I have different currents (voltages) at 10 R for both rails 54 mV and 77 mV
Is this because of the properties of fets
are these values correct ?
 
#53
If you mean the 10R under the 5xLEDS Jfets, yes the numbers are OK. Those are the Vref leg currents. Not the whole shunt's. Is it the larger number on the positive side? If yes and for a DCB1, all swell. It is down to properties of Jfets and the way I use them to introduce a little ''thing'' for DCB1 or just differences of not being matched if with the general guide change with the ''off board'' leg twist. What you supply with it?
 
#54
yes that 10R Is the one that you show at your first post to be measured
54 mV I get on positive side and 77 mV at negative
do you recommend using jfets with specific Ids
I power audio LM4562 of DAC which has only +-10 mA current draw (I will lower CCS current to 50 mA not 100 mA which I use now)
do you have min recommends about transformer current rates with shunt (you recommend CCS to be 3 times load current but what about transformer AC current)
 
#55
1. If you put the positive Jfet side leg as I show on the photo, the differences can only be down to using different Idss Jfets. If it does not upset much your final positive and negative Vout voltages, you may leave them as they are. 5.4mA and 7.7mA are certainly handled by the leds. If you feel like matching Idss, BLs around 8mA which are coming up common in batches are perfetcly OK.

2. Do not get the CCS down more if you don't mind the heat that the Mosfets put out now, maybe less is still sufficient for your application but those Mosfets work better with as much current as you can spare.

3. In your case a 50VA Tx is luxuriously adequate.
 
#60
Help regs. +-24V 100mA

Please help, I need to power an I/V DAC +-24V & 100mA, so if I understand well all resistors must be 1W, I have also the TX 24V x 1,41 = 33,84V / 50VA but due to mine limited electronic knowing, please be so kind to let me know the correct values for resistors, capacitors & leds assuming that I can use the Hypnotize pcb. Also I need a negative reg. so how can I do to use the Hypnotize for +- reg.

Thanks in advance.
 
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