I'm a beginner and at the recommendation of another DIY member I want to build an SSE. I already have the board and I'm reading though the instructions. I read that the choke and power supply cap would be discussed elsewhere in the upgrades section but I can't seem to find recommendations.
I'm going with Edcor transformers and I'd like to stick with the same brand for the choke. I'm going to get the more robust transformers so I'd rather go,the same route for the choke. I'd like the CXC series. Can someone educate me on choke selection?
My friend did recommend the power supply cap I should choose but I figured any help here would maybe help others.
Thanks.
I'm going with Edcor transformers and I'd like to stick with the same brand for the choke. I'm going to get the more robust transformers so I'd rather go,the same route for the choke. I'd like the CXC series. Can someone educate me on choke selection?
My friend did recommend the power supply cap I should choose but I figured any help here would maybe help others.
Thanks.
It is a good idea to get all your transformers and choke from one source. I got all of mine from Edcor. I have two SSE's,
one for high power tubes like KT88 and the other for low power tubes like 6V6. For the one with high power tubes I used
the Edcor CXC125-10H-200mA choke and for the low power tubes one I used CXC100-7H-150mA.
Power caps - for C1, DO NOT go over 47uF and for C2 it should be at least 100uF and you can go much higher as long as
it will fit in that position on the board, these must be rated for 500V. For an auxilliary motor run cap, 50uF to 100uF will be fine.
one for high power tubes like KT88 and the other for low power tubes like 6V6. For the one with high power tubes I used
the Edcor CXC125-10H-200mA choke and for the low power tubes one I used CXC100-7H-150mA.
Power caps - for C1, DO NOT go over 47uF and for C2 it should be at least 100uF and you can go much higher as long as
it will fit in that position on the board, these must be rated for 500V. For an auxilliary motor run cap, 50uF to 100uF will be fine.
I assume you've read Tubelab's documentation on the SSE. Here's a thread with comments on the choke including comments by George Anderson the designer.
http://www.diyaudio.com/forums/tubes-valves/187813-tubelab-simple-se.html
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Thanks but I'm going to use an Edcor choke. Mainly because to me I like the consistency of using one source, second to save on shipping and third because I like the way they look.
I read through a few articles on the web for choke selection since there is no 'upgrade' page as specified on the TubeLab.com web site for SSE amps.
This time I did read through everything carefully thinking maybe I missed something but now I'm positive there isn't an explanation on choke selection on the TubeLab.com site.
I read through a few articles on the web for choke selection since there is no 'upgrade' page as specified on the TubeLab.com web site for SSE amps.
This time I did read through everything carefully thinking maybe I missed something but now I'm positive there isn't an explanation on choke selection on the TubeLab.com site.
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There is an explanation, but it is found with the TSE board, which was developed first. The principle is the same for both amps. A forum search will also turn up plenty of information about choice of chokes.
"People have asked ” what kind of choke do I use?” I use the Triad C-14X because it has 150 ohms of DC resistance. It is UGLY, so you will want to hide it under the chassis. If you need a better looking choke, use one that has nearly 150 ohms of resistance, and has the same or higher current rating as the power transformer. The Hammond 193J will work, but you will gain a few volts of B+ because it is only 82 ohms."
In addition to DC resistance, you also need to consider the inductance.
A choke needs a certain amount of minimum current to work properly. In choke input supplies, the minimum current is V/L. So, more inductance may be better in some instances.
This is why I used a 10H choke on my child resistant low power SSE - to make sure that even with small tubes, there would always be enough current through the choke.
Win W5JAG
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Actually there was already an answer. In my post #6 in this thread I included a link to another thread about chokes where George Anderson of Tubelab posted this.........
"Just about any choke that can handle 150 mA or more will work. Aim for 5 to 10 Hy and a DC resistance between 100 and 250 ohms. I used a 1 Hy choke with 60 ohms of DC resistance in one of my amps because I didn't have space for a bigger choke. It still works better than a resistor.
The aux cap should be a motor run (NOT motor start) cap. Motor run caps are made for a very low ESR and work synergistically with the electrolytic to form a very good low cost solution. These are usually rated in AC volts and should be 370 VAC or higher. Any capacitance value from 40 uF to 100 uF will work. I usually shop for 80 or 100 uF motor runs on Ebay and have found them for $15 to $20. "
As you can see he gave suggested values for current rating, inductance, and DC resistance of the choke plus recommendations for the auxilliary cap.
So is a choke with a higher Inductance rating or a higher Current rating the better choice?
Edcor has two chokes. One is the CXC125-10H-200mA and the other is the CXC125-8H-250mA. According to what's been written so far either of these 2 would satisfy what has been recommended...but which one is the best choice and why? And cost not being a factor wouldn't the CXC125-10H-300mA be a better choke choice since it is at the highest Inductance rating recommended and it exceeds the current rating?
I'm asking to have a better understanding. Thank you.
Sprags,
My own understanding is limited, but from what I know, the resistance also needs to be considered. The Triad C-14X choke which George mentions on his website has been used in many builds and it has a rating of 6H, 150 ohms, 200mA.
The Edcor chokes you mention have a lower resistance rating (75 ohms, 60 ohms)... lower than 100 ohms, but still they should work...
You can check out this Transcendar choke: 10 Henry, 180 mA, DC Resistance: 145 ohms, Part Number: TT-410-CH
Not as pretty as the Edcors, but better looking than the Triad.
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Time For School....
Here are two links to help the OP learn a little about using chokes in a power supply... A little knowledge helps figure things out. It's easier to post links rather than explain myself because 1)I'm too lazy; 2)It's been almost 50 years since I went to electronics school and it would hurt the brain trying to remember everything...
Power Supply Chokes
Chokes Explained
Here are two links to help the OP learn a little about using chokes in a power supply... A little knowledge helps figure things out. It's easier to post links rather than explain myself because 1)I'm too lazy; 2)It's been almost 50 years since I went to electronics school and it would hurt the brain trying to remember everything...
Power Supply Chokes
Chokes Explained
George designed the power supply as a CRC type with 150 ohms for R. The cheap Triad choke happens to have the same DCR, so the drop across the filter will be about the same that the design expects. It is a drop in replacement for the resistor. The inductance of the choke is a bonus to reduce ripple compared to the original design.
That said, you can use a different choke as long as you continue observe the voltage ratings of the other filters in the amp. You can use PSUD to play around with different values.
That said, you can use a different choke as long as you continue observe the voltage ratings of the other filters in the amp. You can use PSUD to play around with different values.
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