What every part does in a Fender Champ 5F1 vacuum tube guitar amplifier

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  • เผยแพร่เมื่อ 6 ม.ค. 2025

ความคิดเห็น • 41

  • @julesl6910
    @julesl6910 8 หลายเดือนก่อน +12

    I know you don't have a huge number of views and comments but believe me, it's coming to the right people. I really appreciate you making this as it has cleared up many questions for me. It's literally us or nothing, these amplifiers exist on the community that support them. Please keep doing what you're doing, I'd love you to get into the nitty gritty as you said and share your knowledge with us.

    • @mearslab
      @mearslab  8 หลายเดือนก่อน +2

      Thank You :)

  • @-dazz-
    @-dazz- 11 หลายเดือนก่อน +20

    I have a couple comments if you don't mind. You probably know these already, I understand you're trying to keep things simple here.
    -The grid leak resistors' job is mainly to reference the grids, to ground in this case. Because the input impedance of the grids is very high, there's going to be very little voltage drop in the grid leak resistors, meaning the grids are going to be at close to 0V with no signal.
    -The cathode bypass caps actually form high pass filters, so they boost "high" frequencies. The thing is, if the bypass cap is large enough in capacitance, the cutoff frequency of the high pass filter may include bass frequencies as well. IOW, with a large bypass cap you're boosting the whole spectrum of frequencies, not just the lower end, while a small bypass cap will only boost the high end. Again, the larger the cap, the lower the frequency cutoff.
    -Push Pull power stages can be class A as well (not necessarilly always class AB), depending on the operating point, plate and screen voltages and OT primary impedance. If those are set so that both tubes conduct at all times, that's class A. If the tubes reach a point where one of them stops conducting when the input signal reaches a certain amplitud, that's class AB.
    -I believe another reason why they picked lower values for the filter and reservoir caps back then is because rectifier tubes have their limitations with regards to the current spikes they can withstand. When you switch on the amp with the caps discharged, theres a big current spike until those caps get to 300V or 400V or whatever. If the caps were much larger in capacity, it would take longer to charge them and the current spike may destroy the rectifier. The datasheet of that 5Y3GT specifies an input cap of 20uF. That's probably why Leo picked 16uF for the reservoir cap.

    • @mearslab
      @mearslab  11 หลายเดือนก่อน +6

      Wow, thank you for this comment. I was aware of a bit, but not all of the info you mentioned. That's the beauty of social media, different perspectives allow for better understanding. My filter theory has a long way to go and that makes a lot of sense what you mentioned about the cathode bypass cap in particular. Fascinating insight into the filter cap sizes too. Thank you again for the comment, this is great!

    • @dannap8831
      @dannap8831 8 หลายเดือนก่อน +2

      ahhh this was a cool comment to read. I ALWAYS find myself wondering just exactly WHY certain values were chosen. It's great to hear reasoning like this. cheers

  • @michaelinglis567
    @michaelinglis567 หลายเดือนก่อน

    My first tube amp build was a Champ style amp that I built to have a switchable output section. So it can be the stock 6V6 or an EL84 and to switch between them I just added a ground lift switch and made sure each tube has its own grid resistor and proper bias resistors. Plus I added a bright switch on the treble pot, a mid boost on the bass pot and an input level low/high on the volume. And lastly a negative feedback loop bypass switch. That amp is fantastic and I couldn't possibly be happier with it. I'll use it for the rest of my life. The champ circuit is dead simple but so so good. I think every guitar player could benefit from and enjoy a champ in their arsenal. I can even get some great higher gain tones when it's paired with the Klon clones I build that have two channels (one for using the Klon as a clean boost and another to use the Klon as a higher gain overdrive. That's how everyone uses them anyways so I figured I might as well start building some that allow you to switch between those settings with a foot switch. And the channel two/boost has its own gain and level pot). Anyways they are great amps!

  • @thatampguy
    @thatampguy 10 หลายเดือนก่อน +4

    Dude this video has been sorely needed. Perfect for the greenhorns out there. Ty

    • @mearslab
      @mearslab  10 หลายเดือนก่อน

      Thank you

  • @forestyogin2218
    @forestyogin2218 2 หลายเดือนก่อน

    From a Caper to a Red Islander, thanks. Even though my father was an electrician, I do not generally relate to this type of stuff. I easily quadrupled my 57 year old awareness. I just want to be able to have a language and functional understanding for circuits like this (and I have this exact amp as well). And by the way . . . parasitic oscillations are very desirable when I drive my Kingsley Harlet into a Tone Bender (Soul Bender), that is some of the magic. So thanks again from across the Northumberland Straight.

  • @stevenwolfson8699
    @stevenwolfson8699 8 หลายเดือนก่อน +1

    Really enjoyed this video. Brings back memories from HS electronics class ... a very long time ago.

    • @mearslab
      @mearslab  8 หลายเดือนก่อน

      Thank You!

  • @-dazz-
    @-dazz- 11 หลายเดือนก่อน +5

    The youtube algo has been recomending some great small channels like yours lately. Great content, mate. Subbed.

    • @mearslab
      @mearslab  11 หลายเดือนก่อน +2

      Thank You!

  • @phillphall
    @phillphall 5 หลายเดือนก่อน

    I appreciate this video a lot. Thanks for being so clear and just talking like a normal person😂

  • @goodknight37
    @goodknight37 7 วันที่ผ่านมา

    Great video👍

  • @jamesbowskill2067
    @jamesbowskill2067 หลายเดือนก่อน

    Wonderful content. Many thanks

  • @karensmith5510
    @karensmith5510 5 หลายเดือนก่อน +1

    Great video. If someone wanted to build this amp. How would the correct transformers for the power input and for the speaker. What is the ohms for the primary input of the speaker transformer. Interesting that the high voltage from the output going to the heater of the 5y3gt doesn't burn out the 5 volt winding of the output transformer. I know some stuff about electronics, but more then some beginners do. Do you have any information or numbers as to what transformers would work for this amp Thanks for your time.

  • @waynegram8907
    @waynegram8907 2 หลายเดือนก่อน

    What does B+ stand for? Are you going to make a video lesson about biasing, because I'm not sure why the crossover distortion gets worse when the plate voltage is higher and the cathode current is low. To get less crossover distortion you lower the plate voltage and increase the cathode current which I'm not sure why it makes the crossover distortion less and less. This is about biasing the output tubes or output transistors

  • @mt-nv4jd
    @mt-nv4jd 7 หลายเดือนก่อน +1

    Excellent discussion. Thanks.

    • @mearslab
      @mearslab  7 หลายเดือนก่อน

      Glad you enjoyed it!

  • @McSlobo
    @McSlobo 6 วันที่ผ่านมา

    This is great content but I wish that instead of having these all old schematics so prominently and easily available there was schematics that were safe on top of the pile. But safe schematics are more difficult to find and regulation between continents also varies. Also, these old schematics should always read with big red letters warning and what's wrong with them. There's nowadays X and Y capacitors for the mains connection, they fail differently when they fail. Also, does the output transformer act as a choke suppressing a lot of the AC hum?

  • @skullheadwater9839
    @skullheadwater9839 10 หลายเดือนก่อน +2

    Quite a bit oversimplified but, this would be good for someone who was thinking of getting into tube guitar amps and had no idea what anything was except that guitar amps have tubes. I won't break down everything and explain as that would be a page of info that no one would read anyway but rest assured there is more to it.

    • @thatampguy
      @thatampguy 10 หลายเดือนก่อน +2

      Yes, so your video would be like this. To the point and a perfect primer. We are dealing with a matrix of rc networks directing electron traffic. It can get so much more granular, but that's not the purpose of this video. A deeper dive would be great, so please get to it.

    • @mearslab
      @mearslab  10 หลายเดือนก่อน +1

      Thank you, you’re exactly right!

  • @dexterj5615
    @dexterj5615 4 หลายเดือนก่อน

    Youre a sage thank you for the knowledge

  • @HOLOCULT
    @HOLOCULT 2 หลายเดือนก่อน

    Great video!!! Subbed!

  • @LPCustom3
    @LPCustom3 หลายเดือนก่อน

    Thanks!

  • @timburle4980
    @timburle4980 8 หลายเดือนก่อน +2

    I think you should have explained how the current through the tube gets amplified. If I was a beginner, I would find this very confusing.

    • @mearslab
      @mearslab  8 หลายเดือนก่อน

      Great suggestion!

  • @good.citizen
    @good.citizen 11 หลายเดือนก่อน +1

    nat
    atbot GPT-3 (:|] 49:03 "... thank you. i drew schematics for sun amp out a community college. finally i can figure what i was drawing " [BEEP]

  • @dasistthomsen9
    @dasistthomsen9 7 หลายเดือนก่อน

    What I dont get is with what kind of physics tubes can get dc power from same cable that our instrument signal is going on , I know I can put effort and find it online and I will , just sharing what I think most newbies like me will ask too
    Thx for the awesome video

  • @addisonpaygestone4206
    @addisonpaygestone4206 10 หลายเดือนก่อน +1

    Hey I made a schematic based off of a class a amp I was wondering if you could help me out to see if I would get proper signal flow and right placement of the tone stack and getting as much gain as I can

    • @mearslab
      @mearslab  10 หลายเดือนก่อน +2

      Sure thing, I'll try my best

    • @joerivera3222
      @joerivera3222 9 หลายเดือนก่อน +1

      Can I reach you through a email you may have or anything?

  • @superflysoulbrother
    @superflysoulbrother 10 หลายเดือนก่อน +2

    Are the 10k and 22k the screen grid resistors?

    • @mearslab
      @mearslab  10 หลายเดือนก่อน +1

      Good question, the 10k is but the 22k isn't. The 10k drops the b+ voltage a little bit for the screen grid of the 6V6 power tube. The 22k drops the b+ voltage so it's in a suitable range for the 100k plate resistors for the 12AX7 preamp tube.

  • @Steve-wz5pz
    @Steve-wz5pz 7 หลายเดือนก่อน +1

    "Yeah!"

  • @crisdunbar4753
    @crisdunbar4753 8 หลายเดือนก่อน +2

    Wow, Nardwuar knows all about tube amps. Who knew??

    • @mearslab
      @mearslab  8 หลายเดือนก่อน

      Keep on rockin' in the free world!

    • @pattonsghost520
      @pattonsghost520 8 หลายเดือนก่อน +1

      😂

  • @sempercompellis
    @sempercompellis 2 หลายเดือนก่อน

    nice vid- speakers tip-- before you sit down for a video, drink a nice healthy glass of water- great for cotton mouth