Hammond 159zl as clc choke

So...I just tried a pair of Hammond 159zl chokes in my f5. 23v rails, dual pair of mosfets. Replaced crc setup. Whoa. Iam liking what I am hearing. It's not placebo.

Do these things (Hammond chokes) break in?

What's the best place or position in the chassis to put them? I could mount the further away from the boards with farther leads or closer to the caps with shorter leads.

Is it advisable to twist the in/out wires on the chokes?
 

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So...I just tried a pair of Hammond 159zl chokes in my f5. 23v rails, dual pair of mosfets. Replaced crc setup. Whoa. Iam liking what I am hearing. It's not placebo.

Do these things (Hammond chokes) break in?

What's the best place or position in the chassis to put them? I could mount the further away from the boards with farther leads or closer to the caps with shorter leads.

Is it advisable to twist the in/out wires on the chokes?

they will break if they fall from enough distance from ground

away from pcbs is better

twist every pair of wire with slightest amount of AC across them ; so - twist those too

;)
 

wdecho

Member
2014-10-28 11:45 am
I have thought about putting some chokes in my PS so this is good news. I did not think it would effect the sound too much is the reason I have not. Chokes are pretty common in Tube amps.

Nothing to settle in or break in. It's just coils of wire making an electromagnet. Being an electromagnet it does, as Zen says, have a field around it.
 
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Hello,
I have been using Hammond and Lundahl chokes in both high and low current circuits.
Take a look at the following link.
Lundahl Transformers - Tube amplifier transformers
Greetings, Edward
P.s on his website there is also some info about higher admissable current to the lundahl filament chokes when the voltage is lower> Because Pass amps use very moderate dc voltages it can possible to use a choke with high mH rating. I would not worry to much about dc serie resistance
 
I have thought about putting some chokes in my PS so this is good news. I did not think it would effect the sound too much is the reason I have not. Chokes are pretty common in Tube amps.

Nothing to settle in or break in. It's just coils of wire making an electromagnet. Being an electromagnet it does, as Zen says, have a field around it.

I have a pair that are currently not being used. If you're interested in experimenting, and would like to borrow them, let me know. - Pat
 

wdecho

Member
2014-10-28 11:45 am
I have a pair that are currently not being used. If you're interested in experimenting, and would like to borrow them, let me know. - Pat

Thanks for the offer. I am starting on another tube amp next week so I am going to be busy with it. As for a good reasonable priced choke, I have used these extensively in tube builds with good results even when 10hy was specified.

C-14X Triad Magnetics | Mouser
 
lundahl filament chokes

Hello,
In the past i had the a modified Hiraga 30 watt amp which used the chokes developped for another amp designed by the French team.
The french choke was 200mH, 2,5A and 0,8 ohm. I dasked the shop in Paris if i could use the choke in my Hiraga and they said sure!
Now there are some lundahl filament chokes that could be used in some solid state amp designs but nobody seems to try it!!
With the lundahl which has 2 windings you only need one choke. Per Lundahl did assure me if the current in the negative and positive lead are equal current the Lundahl can be used.
Because the ac voltage across the choke is low the current going through the choke can be much higher. See the following link.
Lundahl Plate chokes, Lundhal Anodendrossel
There is one more '' dealer '' in Germany who sells Lundahl chokes with reduced mH but extra current capability if i am right.
People should not worry to much about ohmic value of the choke.
So far i only see people using very low mH chokes. I would like to encourage people to try a filament choke in their Pass or other class A amps.
Greetings, Edward
 
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People should not worry to much about ohmic value of the choke..........

being proponent of LC and CLC filters , I agree with most things you wrote , but not with quote above ; as everything else , that part of equation must be optimised

I wouldn't go above 1Rdc per winding , in any case

in recent years , NEM AI150 ( thread in Solid State forum) is nice specimen of amp using differential choke in CL filter
 
Hello,
I had a quick look at the amp you mentioned. They are using choke input filter. That is what i do with all my devices but then the Pass people will need to buy another transformer because there will be a big voltage drop across the choke.
People could start by just adding a lundahl choke with two windings and see what happens!
If they like they could try to find a higher voltage transformer and go for choke input. The theory is well explained in a 6moons review of that NEM amp.
Of course 1 ohm or lower would be better but you need at least 100mH or more to get some good filtering. AND for choke input you need to know about the critical inductance to make it work like a true choke input.
Greetings, Eduard
 
After spending some time with the chokes in my f5 I would say it's an improvement. Detail and little decays are more pronounced. It seems brighter, but not in a bad way. Perhaps delicate sounds have a bit more detail and body.

It's not a night and day difference. Keep in mind this is a 2.5mh choke. Are they worth the money? I think so, assuming you have the space. Again, I could probably live without them but Iam happy. Next step, rectifier upgrade. Anyone have a recommendation on fast/soft rectifiers preferably in a block-type package and preferably with screw or push on connections? I have seen the ixys hexfred blocks but they are solder pin connected. I don't want to wire my transformer's solid 12g secondary to that little pin on the ixys bridge.
 
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Hello,
Of course using the using the Lundahl will give you more mH. It is easy to get more than 2,5 mH.
And the lundahl are constructed in such a way that filtering will be better and they will have less influence on parts surrounding them.
NO No i am not related to Lundahl and will not write any n\more posts in this thread untill someone actually tries them ONE ( yes you need just one because of the two coils)
Greetings, Edward
 
After spending some time with the chokes in my f5 I would say it's an improvement. Detail and little decays are more pronounced. It seems brighter, but not in a bad way. Perhaps delicate sounds have a bit more detail and body.

It's not a night and day difference. Keep in mind this is a 2.5mh choke. Are they worth the money? I think so, assuming you have the space. Again, I could probably live without them but Iam happy. Next step, rectifier upgrade. Anyone have a recommendation on fast/soft rectifiers preferably in a block-type package and preferably with screw or push on connections? I have seen the ixys hexfred blocks but they are solder pin connected. I don't want to wire my transformer's solid 12g secondary to that little pin on the ixys bridge.
Replacing the R of a CRC to become C{R+L}C improves the high frequency attenuation of the filter.
I suspect some of the "sound quality" difference could be the reduction in HF passing into the amplifier via the power inputs.
 
Well, since I still have the resistors is there any benefit or rational reason to go CRCLC vs CLCC (Iam working with 3x33,000f per rail)? If using resistors and an inductor as a filter I am assuming it would be better to have the resistors first, then the inductor closest to the load. But I am often wrong.
 
Out of interest i tried modeling one half of my F4 supply and replaced the .1r resistor (four .47r in parallel), with a Hammond 159ZJ (10mh, 5A, 0.16r). Only real difference i see is a reduction in ripple from 161mv to 71mv. Might pick a couple up and give them a try.

On a related note, anybody know of a good Hammond supplier in the EU or UK? I used to use tubes.it on ebay but seems they are no longer in business.
 

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