Will do, thanks
The Arcol HS50 will handle 14 watts without an additional heatsink, but it will be extremely hot
I installed an ARCOL HSD150 without extra heatsink in a Pass F5Turbo choke input psu.
without external heatsink it´t rated at 45 watts
with 19watts over it, its temp skyrocketed and when it reached 118 degrees C, I realised it need a dedicated heatsink after all
delivery will take place within this week
best
Leif
dwjames layout is as good as it gets.
The LUNDAHLs are things of beauty. Nothing short of bespoke comes close to them, but I will put off giving them a try. I am jealous dwjames and look forward to hearing your report.
"Small" value bleeder/pull down resistors were the first, if crude, shunt regulators. Very wasteful, it is true, but the brute force way to smooth a supply and add a measure of voltage stability.
Being a tubes guy I have always thought the choke input was the best way - it certainly is for power amplifiers. But over the years many have found the choke input is not always the best way. I know quite a few people who have tried them for filament supplies and found they preferred the chokes later in the filter. Many feel the same for phono and line amps. I do wonder with a really wasteful bleeder this might not be the case but I have never tried.
Yes, the resistor value I suggested for using after the BELLESON is much too large. I got my decimal point too far to the right. 900R is more like it.
I am surmising that the current demands of the digital side of the chip might prefer a faster, less stable, supply. Speaking from no experience, just pondering. I like the idea of starting with an RC filter instead of a simple input capacitor. I figure the resistor might offer a measure of diode spike reduction.
I wonder if the choke might be slower to charge and discharge, which would be useful for linear circuits but not so much with digital. I have no idea what dynamic current demands a DAC chip has.
The LUNDAHLs are things of beauty. Nothing short of bespoke comes close to them, but I will put off giving them a try. I am jealous dwjames and look forward to hearing your report.
"Small" value bleeder/pull down resistors were the first, if crude, shunt regulators. Very wasteful, it is true, but the brute force way to smooth a supply and add a measure of voltage stability.
Being a tubes guy I have always thought the choke input was the best way - it certainly is for power amplifiers. But over the years many have found the choke input is not always the best way. I know quite a few people who have tried them for filament supplies and found they preferred the chokes later in the filter. Many feel the same for phono and line amps. I do wonder with a really wasteful bleeder this might not be the case but I have never tried.
Yes, the resistor value I suggested for using after the BELLESON is much too large. I got my decimal point too far to the right. 900R is more like it.
I am surmising that the current demands of the digital side of the chip might prefer a faster, less stable, supply. Speaking from no experience, just pondering. I like the idea of starting with an RC filter instead of a simple input capacitor. I figure the resistor might offer a measure of diode spike reduction.
I wonder if the choke might be slower to charge and discharge, which would be useful for linear circuits but not so much with digital. I have no idea what dynamic current demands a DAC chip has.
Hello,
With choke input transformer, rectifiers and caps all will have an easier life and perform better. Allen did write that the choke will function as a kind of electronic flywheel.
So far adding a choke input always did make my devices sound more powerfull, less electronic.
With my tripath amp however the battery approach was much better. I cannot explain why.all parts were good quality. Maybe because using battries will stop pollution from the circuit going into your power system and into your other gear.
Going from normal grade choke to Tango choke input ones was aldo a big step.
The lundahl choke can be used for choke input just add a bleeder to assure the circuit to function as a true choke input and you are done.
Sincere greetings, Edward
With choke input transformer, rectifiers and caps all will have an easier life and perform better. Allen did write that the choke will function as a kind of electronic flywheel.
So far adding a choke input always did make my devices sound more powerfull, less electronic.
With my tripath amp however the battery approach was much better. I cannot explain why.all parts were good quality. Maybe because using battries will stop pollution from the circuit going into your power system and into your other gear.
Going from normal grade choke to Tango choke input ones was aldo a big step.
The lundahl choke can be used for choke input just add a bleeder to assure the circuit to function as a true choke input and you are done.
Sincere greetings, Edward
Hi Rick,
You are right a regulator just as any other component is not perfect, it has no flat output impedance. Different regulators all have their merits, I look for a regulator that can cource AND sink current and has a low as possible output impedance in a high as possible frequency range.
The resistor has a steady value that is never very low; otherwise you would short circuit the output of your regulator. A shunt regulator however will lower its impedance if current demand of the circuit lowers, in order to keep the total current draw steady.
What I mean with "fast" is that the regulator can sink current fast by lowering it's impedance. A resistor howerver will maintain it's (rather high) impedance at any time, and than it will take more time to dissipate the power that returning current will bring.
I don't mind if you favour other regulators, each his own
I also agree with you that all regulators have their own sound, But this is also valid for resistors, capacitors and such.
For me its most fun to try to find the best sounding combination of components.
This is also the reason why I find a regulating power supply for a locally regulated circuit overkill, this power supply can be heard.
Regards,
RIP Allen Wright. I learned a lot from his books! I only hated his super regulators they sound nice but some of the IC components kept blowing up on me.
I have never liked full choke input power supplies im my amps (maybe because I already use nice tube rectifiers) you just need to try both and decide for yourself what sounds best in your situation.
With some rectifiers a choke input can smoothen the high frequency pulses of the rectifiers.
You can also make a choke input supply with a small capacitor (like 1-2uf) behind the rectifiers. This can bring you a nice balance between cap and choke input filters.
they sound nice but some of the IC components kept blowing up on me.I have never liked full choke input power supplies im my amps (maybe because I already use nice tube rectifiers
) you just need to try both and decide for yourself what sounds best in your situation.With some rectifiers a choke input can smoothen the high frequency pulses of the rectifiers.
You can also make a choke input supply with a small capacitor (like 1-2uf) behind the rectifiers. This can bring you a nice balance between cap and choke input filters.
Hello Supersurfer,
I have been using 5T4, 5R4GYB and 5U4 with Tango chokes designed for choke input and Allen Wright shunt reg always did work for me.
If i will build the dac i will use the Tent shunt when the new dac board comes available and i will copy your power supply with lundahl or some 100mh 1A French '' vintage '' chokes that i have in stock.
Soon we will have some impressions about the lundahls here from another member.
Sincere greetings, Edward
I have been using 5T4, 5R4GYB and 5U4 with Tango chokes designed for choke input and Allen Wright shunt reg always did work for me.
If i will build the dac i will use the Tent shunt when the new dac board comes available and i will copy your power supply with lundahl or some 100mh 1A French '' vintage '' chokes that i have in stock.
Soon we will have some impressions about the lundahls here from another member.
Sincere greetings, Edward
Hi Marcus,
A zener diode will introduce a lot of noise in your power supply. If you want to use a voltage reference a led is a better choice. You only need to use an array of leds for a higher voltage.
Hi Eduard,
Tango is nice, I use Tamura in my amps. If the superreg works for you you are lucky.
I think I have fiddled around too much with my amp design when using the superregs, they are quite sensitive. I got fed up with changing the fets for new ones.
Regards,
A zener diode will introduce a lot of noise in your power supply. If you want to use a voltage reference a led is a better choice. You only need to use an array of leds for a higher voltage.
Hi Eduard,
Tango is nice, I use Tamura in my amps. If the superreg works for you you are lucky.
I think I have fiddled around too much with my amp design when using the superregs, they are quite sensitive. I got fed up with changing the fets for new ones.
Regards,
Evening all!
So I've thrown my choke power supply together quickly on the kitchen table,
but I have a couple of issues..
My 2x12v Transformer is actually putting out 2x13.5v ac. This is getting rectified into 17.7v dc. Each choke is dropping 1v, so I end up with 15.7v dc, which is a bit much for feeding 3.3v regulators..
Also, my 24ohm 50w bleeder resistor is really kicking out some heat...
Without the bleeder resistor, I get 13.9v ac and 19.6v dc out with no drop across the chokes. Hmmmm...
So I've thrown my choke power supply together quickly on the kitchen table,
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
but I have a couple of issues..
My 2x12v Transformer is actually putting out 2x13.5v ac. This is getting rectified into 17.7v dc. Each choke is dropping 1v, so I end up with 15.7v dc, which is a bit much for feeding 3.3v regulators..
Also, my 24ohm 50w bleeder resistor is really kicking out some heat...
An externally hosted image should be here but it was not working when we last tested it.
116 degrees Celsius after 5 minutes of being powered up and still climbing... I clearly need a big heatsink there... 
Without the bleeder resistor, I get 13.9v ac and 19.6v dc out with no drop across the chokes. Hmmmm...
Your voltage output will depend on whether you have a capacitor input or choke input. Assuming a full wave bridge rectifier, with capacitor input the voltage before any dropping resistors/chokes is 1.4xVAC and with choke input it is 0.9xVAC. Also, if your transformer is oversized for the current that you are drawing, the output voltage will be higher. If your supply is not supplying current, as when you have no load and also with your bleeder resistor removed, the measured voltage will be higher.
To test your supply, you should determine the current that you need from it and connect a dummy resistor load sized to draw that current.
Your 24 ohm bleed resistor has 15.7 volts across it so the current through it is 15.7/24=.654A, and power dissipated is 15.7v x .654A = 10.3 watts.
To test your supply, you should determine the current that you need from it and connect a dummy resistor load sized to draw that current.
Your 24 ohm bleed resistor has 15.7 volts across it so the current through it is 15.7/24=.654A, and power dissipated is 15.7v x .654A = 10.3 watts.
Hello,
Still early morning here but to me it looks like the choke is corrected to wrong way if i compare to the drawing of the pdf file from Lundahl.
The yellow lead is connected to the input side. Then there is a bridge between connect 3 and 4 and at the bottom there is connector nr 6 which you use as an output.
In their drawing at the bottom the bridge is between 3 and 6 and they use 4 as the output.
YES, in the power supply you are copying the same is done.
In the pdf file you see a small dot ( probably the start of the winding) at one end of each coil. That is used as the input.From thje other end you will have to go the dot side from the other coil.
Any ideas?
Ben Mah did explain it very precisely. If you want 12 volts out with choke input you need a higher tension.
For digital gear EI transformers seem to be better and usually easier to find in surplus stores.
Once it is working you can try this:
Jimmy’s Junkyard Blog Archive Potting the Lundahl Choke [Part 1]
Sincere greetings, Edward
Still early morning here but to me it looks like the choke is corrected to wrong way if i compare to the drawing of the pdf file from Lundahl.
The yellow lead is connected to the input side. Then there is a bridge between connect 3 and 4 and at the bottom there is connector nr 6 which you use as an output.
In their drawing at the bottom the bridge is between 3 and 6 and they use 4 as the output.
YES, in the power supply you are copying the same is done.
In the pdf file you see a small dot ( probably the start of the winding) at one end of each coil. That is used as the input.From thje other end you will have to go the dot side from the other coil.
Any ideas?
Ben Mah did explain it very precisely. If you want 12 volts out with choke input you need a higher tension.
For digital gear EI transformers seem to be better and usually easier to find in surplus stores.
Once it is working you can try this:
Jimmy’s Junkyard Blog Archive Potting the Lundahl Choke [Part 1]
Sincere greetings, Edward
Hi James,
Ben Mah explained it nicely. You can try choke input to lower the voltage. If that is not enough you can extend the supply with an extra RC step. This will make the impedance higher, but makes for better smoothing. Both have their merits.
Eduard is correct that I have connected the chokes different from the Lundahl datasheet. This is done with a reason; I find that connecting the input of the rough, unregulated DC is most effectively when connected at the core of the choke. This is where the induction is highest.
You can use it the other way around but that will not influence the DC voltage level.
In my setup I draw 1,3A this lowers the output voltage to 11,6V. Now I think about it, the solution is clear: just stack up to 4 boards and your done
Regards,
Ben Mah explained it nicely. You can try choke input to lower the voltage. If that is not enough you can extend the supply with an extra RC step. This will make the impedance higher, but makes for better smoothing. Both have their merits.
Eduard is correct that I have connected the chokes different from the Lundahl datasheet. This is done with a reason; I find that connecting the input of the rough, unregulated DC is most effectively when connected at the core of the choke. This is where the induction is highest.
You can use it the other way around but that will not influence the DC voltage level.
In my setup I draw 1,3A this lowers the output voltage to 11,6V. Now I think about it, the solution is clear: just stack up to 4 boards and your done
Regards,
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Thanks guys. I suspect that the current draw isn't going to be quite enough even with a 24ohm bleeder resistor, as I only have 1 dac deck with shunts, it's only using 0.27A so even with the bleeder resistor, I'm still going to be pulling approx half of the 1.5A that's recommend in the specs from Lundahl...
Is a bleeder resistor the only practical way of putting extra load across the power supply?
Edward, yes, you're right, I don't have it wired as per the data sheet from Lundahl.. I'll get that changed. Thanks.
Is a bleeder resistor the only practical way of putting extra load across the power supply?
Edward, yes, you're right, I don't have it wired as per the data sheet from Lundahl.. I'll get that changed. Thanks.
Cool, thanks. I'll give a go without the first caps and see how it looks.
Interesting about the choke wiring
I'll see if I can find a heatsink around here for the bleeder resistor.
Now I know I should have a different resistor value for testing ideally so I can see what voltage will be output with the proper load.
Thanks again for taking the time to explain guys