Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Cree on October 05, 2020, 02:48:42 pm
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I am in the "winter time Project" build. Radial cap's will save me some room inside my chassis, standing the capacitors up instead of laying them down. Where can I get good quality redial cap's, or should I use standard cap's and stand them up and glue them to the board???. Any input will be greatly appreciated. Ether way.
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AES has them...
https://www.tubesandmore.com/products/capacitors?filters=Termination%20Style%3DRadial%20Leads%2CType%3DElectrolytic
All the big suppliers like Mouser, Allied, etc, have huge selections.
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Mouser.com has a great selection of radial caps. I buy lots from them, mostly 500V Nichicons. They also have a ton of axial and radial film caps (Panasonic, Mallory, etc) and every resistor you could ever need. Great parts site.
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But would you use them for a quality build? I may have two more builds in me,, these last two need to be my best. Which means you might laugh, cuz you guy's do great work with any part(s).
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Quality doesn't care if the leads come out each end or one
if you glue them all over the amp and run cheap multi-color wires, that might effect quality :icon_biggrin:
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Nichicon, is this a good radial cap manufacturer? Found a supplier in South Carolina.
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I discovered that the radial 47uf-500 volt caps that I tried to use in one of my builds were not capable of handling the draw put upon them by the tubes, they were physically too small. Replacing them with larger axial caps solved the problem that I had with the amp. My recommendation would be to get the largest diameter radial caps that you can find for your build.
Just my personal 2 cents...
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> Nichicon, is this a good radial cap manufacturer?
Nichicon is one of the world's largest cap makers. You probably have hundreds of Nichicons in your life, not causing trouble. You sure do not have to go to South Carolina.
DigiKey lists 24,733 Nichicons. 15,000 are radial leads. https://www.digikey.com/short/zwr0t2
> save me some room inside my chassis
IMHE, this is usually a mistake.
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Nichicon, is this a good radial cap manufacturer? Found a supplier in South Carolina.
I can only speak from my experience. I've never had problems with one, and Nichicon his a very respected name in caps from what I have read.
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I also have no concerns about Nichicon.
But when I want to save room in the chassis I do so two ways - a cap can (s) - usually the F&T 2x32 and/or the F&T axial dual caps - available 2x16 and 2x33. But thinking of your desire "these last two need to be my best." I'd suggest using a chassis big enough for the job. I think gluing caps to the board is hack.
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I discovered that the radial 47uf-500 volt caps that I tried to use in one of my builds were not capable of handling the draw put upon them by the tubes, they were physically too small...
How did you come to those conclusions, ie that the HT cap couldn’t handle the current draw, and that its small size was the cause?
Have you got a link for the cap in question? As a proper manufacturer will issue info for that product line, which should note typical ripple current capability and ESR.
Even then, it could just have been an individual instance of dodgy cap.
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Crazy question but since we're talking power filter caps, HT means "high voltage" what does the "T" stand for...? Why not HV...?
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I believe those "designations" go to the way back days, some us just get used to those days :icon_biggrin:
High Tension = High Volts
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Thanks Shooter, makes sense.
Like B+ from the old days.
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Crazy question but since we're talking power filter caps, HT means "high voltage" what does the "T" stand for...? Why not HV...?
It’s for ‘high tension’, old school Brit term for any kind of high voltage. Might still be used to refer to overhead power lines.
I use it as many here might be familiar with Marshalls, in that many of their valve :icon_biggrin: models have a HT fuse, perhaps labelled up on the back panel, which acts to kill the high voltage supply, one way or another.
Equivalent North American term would be A, B+ and C-, to refer to the 3 batteries in early tube radios etc, to supply the heater, high voltage and bias circuits respectively.
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A) a cap can (s) - usually the F&T 2x32 and/or the F&T axial dual caps - available 2x16 and 2x33.
Cap can's do not come in the needed values for the design.
B) I'd suggest using a chassis big enough for the job. I think gluing caps to the board is hack.
I am now going to move into a larger chassis, BUT, I may have used the wrong word when I said "glue", I meant silicone bead around them. To help hold them for the shock of moving the thing around once built. Instead of them flopping on the leads. I have seen many done this way, and did not think it was a hack, just another way to solve a problem.
Moving on to new frontiers, has anybody here ever watched Emmerdale? Had to through that in, where it will never read.lol
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My grammar, what was I thinking. Throw not through. Sorry, Mrs. England, You taught me better.
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I discovered that the radial 47uf-500 volt caps that I tried to use in one of my builds were not capable of handling the draw put upon them by the tubes, they were physically too small...
How did you come to those conclusions, ie that the HT cap couldn’t handle the current draw, and that its small size was the cause?
Have you got a link for the cap in question? As a proper manufacturer will issue info for that product line, which should note typical ripple current capability and ESR.
Even then, it could just have been an individual instance of dodgy cap.
I had to search my memory to answer your questions...This is from 2 years ago...
The caps in question were actually 47uf-400 volt capacitors. I used them to replace the bad caps in the voltage doubler that makes up the first stage in the power supply of a Bogan CHB35A that I was converting to guitar use.
I think that they worked fine with no load, but when I put a load on the amp by playing it fairly loud, the primary voltage drop was quite excessive. Once I replaced them with the axial caps that I used, the amp worked fine.
This is a picture of the inside of the amp with the radial caps in it, on the left side of the picture. I had wanted to use radial caps because it was easy to put them in.
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Those don't look like any Nichicons I have used.
KMG?
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I discovered that the radial 47uf-500 volt caps that I tried to use in one of my builds were not capable of handling the draw put upon them by the tubes, they were physically too small...
How did you come to those conclusions, ie that the HT cap couldn’t handle the current draw, and that its small size was the cause?
Have you got a link for the cap in question? As a proper manufacturer will issue info for that product line, which should note typical ripple current capability and ESR.
Even then, it could just have been an individual instance of dodgy cap.
I had to search my memory to answer your questions...This is from 2 years ago...
The caps in question were actually 47uf-400 volt capacitors. I used them to replace the bad caps in the voltage doubler that makes up the first stage in the power supply of a Bogan CHB35A that I was converting to guitar use.
I think that they worked fine with no load, but when I put a load on the amp by playing it fairly loud, the primary voltage drop was quite excessive. Once I replaced them with the axial caps that I used, the amp worked fine.
This is a picture of the inside of the amp with the radial caps in it, on the left side of the picture. I had wanted to use radial caps because it was easy to put them in.
It sounds like you had some bad caps. Also, voltage doublers will show a drop in B+, especially under excessive load such as an amp flat out, when compared to a bridge rectifier or full wave rectifier. This is normal for a voltage doubler circuit. Your final cap value for that stage ends up being half the value you used btw. So for your 47uF, you really had the equivalent of a 23.5uF cap. You probably could have got away with using 200V caps in that section also. Each leg of the doubler is lower than for a normal circuit.
Radial caps are usually better quality these days than axials because they have to be. Many more things use radial caps nowadays than axials so the companies have to make sure they are good quality.
Greg
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Those don't look like any Nichicons I have used. KMG?
I think AmberB's remarks (https://el34world.com/Forum/index.php?topic=26527.msg290499#msg290499) were in reference to radial caps, not Nichicon caps.
However a cap, radial axial cubical or tesseract, should do what it says on the label. While the DCR is not on the label, we have some expectation what a cap that value and size "should" be. Of course there are crap caps, on the market and also in our drawers. At this late date it may be hard to know what AmberB's trouble was.
"KMG" is Nippon Chemi-con's line of Standard, Downsized, 105C caps.
http://www.chemi-con.com/upload/files/9/1/133529179952d6c3126cc66.pdf
47u 400V is rated 250mA ripple, which may be borderline in a large Bogen doubler.
EDIT: yes, PSUD says 255mA rms in these caps.
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Thanks! My point was that I generally trust Nichicon. I've never used KMGs. I use a fair number of cap cans, a form of radial caps, with never a problem.
But, have now learned something new (for me) -- to look at the data sheet more closely. Never occurred to me to look at ripple current specs, and of course that is important in power supply smoothing filter caps!