m15mk2: question about 350v 100µF caps

  • Be careful when poking around in it.

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    Writing about music is like dancing about architecture.

  • >Do you think,you are ready now for build this Amp?

    Thanks for your answer.

    Maybe not, in fact I bought it already built ... (and I'm studying it !) :)

    So I ask another stupid question: in the picture below they are not parallel ?

    You'll not get the answer here in this forum, and unfortunately the only thing you get is that you shouldn't build the amp, it happen the same with me the same people, there is not one else replying back. Anyway the comment was there without even knowing if you built it or not, in this scenario you had it built :) on the Schematics they are in series. If you ask other questions you will not get the answer you looking for, but redirections to some link telling you to study. Don't waste time asking here unfortunately the Forum would or should be a nice place to gently talk about Amps even when someone beginner ask a simple or silly question, as we all need to start some how somewhere.

    Davide Violante

    Rockers&&Rocks

    http://www.rockers.rocks

    Schoonenburgsingel 176

    2135GE Hooffdorp

    Netherlands

  • You'll not get the answer here in this forum, and unfortunately the only thing you get is that you shouldn't build the amp, it happen the same with me the same people, there is not one else replying back. Anyway the comment was there without even knowing if you built it or not, in this scenario you had it built :) on the Schematics they are in series. If you ask other questions you will not get the answer you looking for, but redirections to some link telling you to study. Don't waste time asking here unfortunately the Forum would or should be a nice place to gently talk about Amps even when someone beginner ask a simple or silly question, as we all need to start some how somewhere.

    Actually let me add, it is true the fundamentals in Electronics should be a must, and beginners cannot have that. however being gentle and nicely explain something out is a different story. Being direct and telling people to study or are you ready to build is not the exact way to go. I would say that everything else is true there is requirement for an understanding of what we are doing, and the Forum should help on that. I am member of 18watts never had a single issues with any of the member in there however, I still trust Madamp and I must admit I had also some very good advises like buying a great book on how to build Amps.

    Davide Violante

    Rockers&&Rocks

    http://www.rockers.rocks

    Schoonenburgsingel 176

    2135GE Hooffdorp

    Netherlands

  • Hello, Enbi (or what´s the name actually? I couldn´t know...)

    Welcome to the Forum. You can ask questions, whatever You would like to know. But please don´t hear to Davide. Sorry, but the only thing he shows is, that he don´t understand anything about the Forum and it´s members.

    Read between the lines, hear what Max, Micha an the older member here say to You (or why someone don´t answer to your question either!) and You will get the Problems quit.

    And please - be kind! Then You´ll be really welcome.

    Michel (that´s MY name!)

    By the way: I don´t answer questions like this, even ´cause I don´t know it... Sorry.

    I might look like I´m listening to You, but in my head I´m playing my guitar!

  • And Davide (and at this point I mean ONLY Davide!)

    If You start to diss this fine Forum: Please leave us alone! Then You are not welcome anymore... :(

    The effect of You´re writung is, that the best and helful members here feel sad and confused. That´s YOUR fault. Not ours! Please, go. Or learn something...

    To all the fine others here: Sorry, but I can`t help...

    I might look like I´m listening to You, but in my head I´m playing my guitar!

  • enbi in the schematic they are somewhat parallel. But they have a resistor in between.

    The part you are looking at is the powersupply. Directly after the rectifier, the DC still has ripples. The Caps act even the ripples out and the resistors help that the capcitancy is not directly connected to the input ripples... hmm, hard to explain. There was a very good graphic showing exactly this only a few days ago by Moonshine

    Edit: its the first post here: Hilfe bei der Auslegung der PSU für Röhrenprojekte

    The third graphic shows the ripple directly after the rectifier (in green) and then blue and later red is how they are evened out after resistor/cap...

    Edit2: the graph also shows the actual voltage. More than 300V... the (already deadly) voltage at power outlets is 'only' 230V or less.

    Edit3: And I wish we wouldn't have to waste so much time to violanted - he could simply have blown himself up without ever writing anything here

    Edit4: Last but not least another answer to the original question: In series you add the capacitance. With a higher capacitance you can buffer higher voltage ripples, but once the capacitance is enough, it won't get better. Instead - and this is what you see here - you have a resistor and another stage that is somewhat parallel. It evens out more ripples... as you can see in the diagram by Max

    3 Mal editiert, zuletzt von simon.bethke (19. November 2021 um 09:25)

  • Hi enbi and welcome to our forum,

    if you're really interested in learning how amps work I can highly recommend this site: http://www.valvewizard.co.uk.

    Regarding your specific question you can read the chapter dealing with the power supply, the arrangement of reservoir cap and the filter chain is explained very well right here: http://www.valvewizard.co.uk/smoothing.html

    Best regards,
    Max <3

    "Perfektion ist nicht dann erreicht, wenn es nichts mehr hinzuzufügen gibt, sondern wenn man nichts mehr weglassen kann."
    - Antoine de Saint-Exupéry

  • Thank you all. Sorry for my scandalous incompetence!

    My interest in those caps stems from the fact that a small upgrade :) from 6v6 to 6l6 has been done on the amp, it sounds very good but the first cap (c29) disagrees, it gets really hot (there are about 450v)

    What can I do ?

  • Hi there,

    no, please don't get us wrong! There is no such thing as "scandalous incompetence"! Everyone has started being a beginner some day, nobody was born knowing everything about electronics and no, you do not have to have a PhD in electronics to build or modify tube amps.

    BUT

    Tube amps are highly dangerous and operate at lethal voltages. They are by no means the right topic to start learning or practicing DIY or electronic stuff. The problem is that you cannot see the danger as voltage and current is invisible. Have you actually touched the caps during operation or shortly after? Then you have - unknowingly - made the first mistake that could have cost you your life without even realising it. The caps you asked about store the energy for the entire amp and can hold charge (large enough to kill you!!!) even after you have switched off the amp or even pulled the plug. They need to be discharged first to be safe. Anything you do with an amplifier like that is extremely dangerous if you don't have any experience or theoretical knowledge.

    And that is why we always suggest getting some basics before even opening, touching or staring too long at tube circuits. It's no rocket science, but you definitely need at least some knowledge about electronics or you put your life at risk!

    Cheers and best regards,

    Max <3

    "Perfektion ist nicht dann erreicht, wenn es nichts mehr hinzuzufügen gibt, sondern wenn man nichts mehr weglassen kann."
    - Antoine de Saint-Exupéry

  • Here I am not discussing the knowledge of the expert guys responding but the manners and way how things are handled. If I ask a question that may appear super silly for someone that has built amps all his life or someone that is an Electronic expert and studied electronics, I would simply expect the answer, yes is in "parallel yes isn't" explaining the reasons and maybe point out to resources to study. Instead what I often noticed is the direct rude approach, such "are you sure you can build this Amp? "Can you read schematics?" there is not needs to highlight or remark those things since it is obvious that if someone is asking the question and if the question is a very basic one it is obvious that is someone that doesn't know exactly what is doing.

    Building a Kit can be done with correct step by step instructions and with explanations of those steps and someone can learn that way too.

    It is not possible or it can't always be a must that you need to study Electronics if you simply want to build one or 2 Amps for personal use and for the pleasure.

    Anyway I am loosing my time here too since my complain is not the expertise that you guys have, I have super top respect for that. I bought the book for electronics how to build an amp, and I will read it all, for personal interest. My coming in play here was simply the manners used to approach new people coming that all. I am also free to openly express my opinion I am not insulting anyone just freely expressing my opinions

    Davide Violante

    Rockers&&Rocks

    http://www.rockers.rocks

    Schoonenburgsingel 176

    2135GE Hooffdorp

    Netherlands

  • Hi,

    What Voltage rating did the Cap have?,I think,them are under rated,choose ones with Higher Voltage ratings,500V or so.

    regards,

    Micha

    But think of,to discharge them!!! before touch anything in the Amp.

    Ok

    The original cap is 350v 100uf

    I can't find a 500v 100uf radial cap

  • enbi check out this first before go on

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