Type of Choke for CLC?

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I believe Mr Tho got all those facilities. Why don’t you ask him to measure the ripple and look at the spectrum with any soundcard freebie software, 100/120 and 200/240 Hz are crucial for linear PS.
Then with all results at hand, you may convinced me and others in this forum to adopt your Lundahl topo.
For your VN friends or customers, such approach does need to be lubricated with snake oils, they love it, their way of life.
Wish you luck in VN with Lundahl products, don’t forget your reserve parachute, business there is a deal with commies feudal gangland.

Bye for now
Pascal
 
I believe Mr Tho got all those facilities. Why don’t you ask him to measure the ripple and look at the spectrum with any soundcard freebie software, 100/120 and 200/240 Hz are crucial for linear PS.
Then with all results at hand, you may convinced me and others in this forum to adopt your Lundahl topo.
For your VN friends or customers, such approach does need to be lubricated with snake oils, they love it, their way of life.
Wish you luck in VN with Lundahl products, don’t forget your reserve parachute, business there is a deal with commies feudal gangland.

Bye for now
Pascal
Haha,
You must be the new Groucho Marx.
I am not doing any business in Vietnam. No need doing that while on holidays.
My friend being an engineer at On Semiconductor has access to loads of equipment to do testing.
But we don't need to convince anyone to use this or that product. Yes, it may looks like that sometimes. We don't have any stock of things we need to sell.
Selling these kind of things will not make you a rich man. I know in Europe most online sellers not even keep these products in stock. After you order at their place they will order at Lundahl. If you wanna make money selling chokes you must organize a group buy and find a company in India or China to make it for you. Like someone said a two coil 20mh 5A would be nice, put it in a nice steel box and have it vacuum impregnated.
I don't need such a choke because I don't need that much current but it could be very nice for lots of the Nelson Pass power amps.
Greetings Eduard
 
... In Vietnam people are more biased towards Tango/Tamara than to Lundahl who only recently established a dealership in Hcmc. I have some Tango chokes in stock because they have been replaced by Lundahl. Why the Lundahl were better I don't know. They were connected in differential mode, they had higher number of Henries ( which all9ws a much lower blender current).. The tango chokes were the ones designed especially for choke input and all of then were used in choke input power supplies....
Then you only met second and third tier, first tier diyer dismiss anything less than custom Finemet Noguchi or HiB Hashimoto.:yes:
 
What type of inductor is preferred in this case? Air core? Iron core (sledgehammer), or P-core? There is a big difference in price and if there is not much difference in performance, I'd rather go for the cheaper ones.

Thanks!

get your local winder and you'll save a lot of money. i paid around $35 for 4 air core 3mH 18awg (or 16awg, forgot it) 0.5Rdc
 

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...The highest current finimet was 1A.
I see you never heard of Finemet DC filament choke for the 211/845.
But the original poster is on a budget so he will probably use some crossover coils.
Original poster defined what he wants on #8 and #32.
... I presume the Rdc is high....
... I'm looking for a minimum of 5-10A current rating. ...
I find the LL2733 you repeatedly mention lack 5-10A current rating and low DCR he wants. Perhaps you can suggest a different Lundahl or other choke more relevant.
 
First of all, so sorry because my English is not good. My first amp in my life is a solid state amp but unfortunately so many my close friends is a fan of vaccum tube amp. I really impressive with the sound of tube amp of my friends and I tried to build some tube preamp and combine with my solid state class A amp and hope I can find a better sound between solid state and tube (hybrid system) but after some tried I can't find my favourite.
When Nelson Pass and Mike introduce VFET transistors, I tried to build some VFET amp as: Sony VFET P2, Iron Amp, VFETRON. With VFET transistors, I can find some tube sound in the solid state amp and I can say: this is the correct way that I can go.... Because of that, I tried to build my SIT Nemesis with a topology as: single ended class A, choke input in the power supply, output transformer and specially is Pass SIT 1 transistor. My SIT Nemesis is not finish now but I can believe absolutely my amp will have a half sound of solid state amp and a half sound of tube amp, that is my favourite for myself!
About the choke, I really a fan of Tango choke but unfortunately I can not find any Tango choke coil with high inductance and current enough for my choke input design so I must use LL2733 from Lundahl and hope in the future Lundahl will make some bigger choke for solid state amp.
I and some my friends in Viet Nam tried to modify from capacitor input to choke input because we are can hear the sound is better after modify, we just measure the sound quality by ear, not by electric machine, so everything I wrote here about choke input just apply for myself and my some friends, not for all. If someone trust me, you can try for yourself, and if you tried and don't like choke input, it's is normal:wave2:
Have fun....
 
Thank you Nagini for sharing your experience. I fully agree a proper choke input power supply does perform very well. Which seems to satisfy your intended use.

However, I think both you and Eduard fail to see the problem on the use of LL2733 for a generic Firstwatt PSU. Consider an F5 which is rated to deliver 50W RMS into a 2 ohm load. It means 7.1A peak current draw for a single channel, 14.2A for stereo. How do you propose the LL7233 to be connected to avoid saturation?

I think a choke input Firstwatt PSU will require a custom wound choke, no less.

A choke for CLC on the other hand has different requirement that can be met with off the shelf parts.
 
I have some Tango chokes in stock because they have been replaced by Lundahl. Why the Lundahl were better I don't know.

We share the same experience. Perhaps the chief difference between Lundahl and the other mainstream chokes is the winding geometry: to the best of my knowledge only the Lundahl chokes are properly layered and achieve low parasitic capacitance, whereas the Tango are just old school PS chokes. The screened Tango version sounds particularly bad to my ears.

Having said this, all Lundahl chokes are wound on miniature cores. Not really suitable for high current amps.
 
Hello,
The Hammond seems ok but choosing one that is closer to the current rating needed will give you more mH which will be an advantage I think.
Once I was told that using an output transformer with a MUCH higher current rating than the actual current running is not the best thing to do. I wonder if this the same for power chokes.
There seems to be two groups. One that will go for low dcr and less mH and the other going for more mH which will result in a higher dcr.
So far I did go for my between 100mH and 562mH. All were electronics with currents between 1 and 1,5A . The latest one was the dddac which has shunts that keep the current drawn at a constant level. The first one was Le Classe A by Jean Hiraga in 1985 so no need to tell me I am trying yo promote Lundahl because back then Lundahl was just a local brand operating in the margin.
There just are not to many high current chokes available to the general public. The ones which sometimes pop up in surplus stores usually come from army supplies where higher frequencies are used to reduce dimensions.
Our member in Indonesia got some air coils. Which can be easy to source. But I think in his country you could walk into a local store and when they are not busy they will just do it. In the western world they will not be interested to much if you just walk in to a company with such s simple request.
I remember asking a company to make 50 coils for a lcr riaa filter they just won't do it.
Maybe the diy store from this site could decide to organise a group buy of a 2 coil 20mH 6A rated choke. I once did ask a company if they could not make a choke using the bigger core they use for one of their power transformer. Just to get the same mH but with a higher current rating and less dcr. I know that changing the seize of the air gap will allow them to make 3 different current/ mH ratings using that bigger core!
I think there will be people interested. I think going from crc to CLC is an easy way to improve your gear. Much easier than just throw in a bigger power transformer ( WITH SOFT START) and more caps.
Switching to choke input will reduce the importance of getting a bigger transformer because the choke will form an easier "load" to both transformer and rectifier.
It was the late Allen Wright who taught us that the input choke should be bigger than the power transformer.
Greetings, Eduard
 
How about the Hammond 196G12 wired in series for the choke input power supply? http://www.hammondmfg.com/pdf/EDB196g12.pdf
As Eduard says, it will work but not optimum, the inductance is simply too small, something like 20-100mH is needed for each supply rail. You should verify your need by using PSUD2.
...There just are not to many high current chokes available to the general public. ...
Yes, I was hoping you know something other than custom orders.
...Our member in Indonesia got some air coils. Which can be easy to source. But I think in his country you could walk into a local store and when they are not busy they will just do it. In the western world they will not be interested to much if you just walk in to a company with such s simple request. ...
Problem in Indonesia is lack of local availability of decent quality cores and magnet wires. Small transformer makers are hampered in making audio grade parts by the lack of demand and high initial investment of decent material. We highly appreciate any info you can share on sources of good core and wire material that will supply in small quantity.
...Maybe the diy store from this site could decide to organise a group buy ...
...It was the late Allen Wright who taught us that the input choke should be bigger than the power transformer.
I think you can safely predict that for most PassDiy builds, demand for choke input is very low due to cost and weight factor. Most choose to make do with the CRC PSU topology Mr. Pass developed for his commercial Firstwatt offering. And just like you and Tho, those with lesser peak current requirement find the LL2733 and other off the shelf chokes like Hammond is within price bracket and adequate.

However, if one is uncompromising, proper iron core inductor for choke input psu is one of the most difficult part to manufacture due to wide frequency band requirement and magnetostriction vibration of the core. Customarily, a tedious process of split bobbin winding and vacuum varnish impregnation followed by baking and potting in flexible compound is employed. Many find choke input is less than satisfying if someone attempt to scrimp on the material or process.
 
Hello,
BUT there are loads of Nelson Pass builders who will use BIG transformers like 1000VA which needs in rush current limiter. Most of the day crowd like their amps to be big and heavy so throw in a few chokes might help.
The chokes I use for choke input in my dddac are used very close to their current limit ( like I said before because a.c. ripple is well below the maximum rated 120 volts an engineer in Germany told me that they can be used with higher current than specified in the pdf)
BUT still there is no mechanical noise at all and radiation towards near by components is very low. Measured with induced voltage across another choke nearby..
There are some other companies like Sowter who can make made to measure chokes.
Like Allen Wright said in the past using a smaller power transformer a bigger choke could be the way to go.
Of course people like to brag about the seize of the power transformer not that they did install a choke input which isn't that expensive.....
Greetings, Eduard
 
Hope that I'm not going to find myself swimming in shark infested waters but here goes...

...The box will contain my power transformer, rectifiers, a few caps, and a choke on each rail. This will connect to a power jack in the back for the umbilical to the amp. Each amp will have a few more caps, forming a CLC power supply.

What type of inductor is preferred in this case? Air core? Iron core (sledgehammer), or P-core? There is a big difference in price and if there is not much difference in performance, I'd rather go for the cheaper ones...

Hi Eric
Here is a shark repellent for you.
Download holes template from spec sheet of all chokes from your wish list.
1. Trace and drill those holes to your PS chassis.
2. Buy 3 x 1 Ohm 100W gold resistor (1$ each eBay)
3. Replace L with R = 0.3 or 0.5 or 1...
4. Input shorted to ground via small non polar cap 1-2 uF..., bias IDQ within safety margin (FBSOA spec sheet of your 3 legged device) and listen for any 120 Hz hum.
5. No hum, you are done. Read this before going to your next step
6. Remove R and replace it with L.

Cheers
 
First of all, so sorry because my English is not good...
...I tried to build my SIT Nemesis with a topology as: single ended class A, choke input in the power supply, output transformer and specially is Pass SIT 1 transistor. My SIT Nemesis is not finish ...
Hi Nag,
Your English is for sure far much better than my Vietnamese
It was a pity that my journey in VN is too short, would love to meet your diyaudio community, for sure there is a lot of things to learn from you and your friends (excluding Dutchman).
Talking about the Nemesis, I am building the one for all “THF-51S amplifier” with heaps of Wieland pcb connectors for a quick change from single ended to double balanced and from common source to common drain (Zeus). Will take a rest until my jet lag is over then be courageous enough to tackle an output transformer.

Cheers from Pascal
 
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Hello,
...
Our member in Indonesia got some air coils. Which can be easy to source. But I think in his country you could walk into a local store and when they are not busy they will just do it. In the western world they will not be interested to much if you just walk in to a company with such s simple request.
I remember asking a company to make 50 coils for a lcr riaa filter they just won't do it.
Maybe the diy store from this site could decide to organise a group buy of a 2 coil 20mH 6A rated choke.
Greetings, Eduard



Your input in this thread reminds me of the 16-17 century about tulips and nutmeg.
 
... BUT there are loads of Nelson Pass builders who will use BIG transformers like 1000VA which needs in rush current limiter. Most of the day crowd like their amps to be big and heavy so throw in a few chokes might help ...
... Of course people like to brag about the seize of the power transformer not that they did install a choke input which isn't that expensive.....
True enough. Many people here also make PassDiy designs and use huge transformers. A good custom wound 500VA EI power transformer is about US$50-100, decent off the shelf 200VA is around $15-25. No local made choke I am aware of is decent enough for choke input PSU duty, sounds dead and vibrates like crazy. Chokes for CLC are adequate. Regarding price of transformers and chokes, I do not think Indonesian idea of expensive is similar to EU's. You'll meet more of us and confirm. But, as in anywhere else, there are some of us with cost no object attitude.:D
 
Hello,
There are people who say that a nice Ei core transformer can be better than the often used doughnut. The bigger band with will let lots of mains noise just pass through.
The EI core with some shields works better they say ( ask Rod Coleman)
An input choke for high current is indeed hard to make. The ones I use are quiet. The ones i had made were also not all quiet. Thicker wire will create more space between the windings and often not carefully windings will make it rattle.
There are not many cores available in small quantities. Maybe Google can help.
Greetings, Eduard
 
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