Yet another 5F1 build into a Champion 600 chassis

Discussion in 'Amp Tech Center' started by tibrocks, Feb 4, 2015.

  1. tibrocks

    tibrocks TDPRI Member

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    Hi everyone,

    I've seen here some great builds and very well documented so I will definitely need your help as I found this forum to be a great resource.

    After modding my champ 600 as described here I've been using it without problems

    (well I couldn't get rid of a low, ~70-120Hz hum that was not volume-dependent - getting DC heaters and replacing catode resistor from 470 to 560 ohms did bring an improvement though) but in the past two weeks the amp started making noises, crackling and humming - quite sudden and I can't find the cause - I tried playing at both low and high volumes and from time to time it starts making crackling noises that can get quite loud.

    To be hones this crackling sound is chasing me as 4 years ago I have build a Deluxe Reverb clone from a Weber amp Kit - and still has this problem although I didn't bring the amp with me in London.
    At that time I replaced the caps with orange drops, installed Allen Bradley resistors and got the big Output Transformer from Classic tone with the extra iron. The amp is amazing but it does have this issue

    Now my Champ 600 has it and I decided to rebuild the whole circuit to a 5F1 specs, keeping the Classic Tone 18031 OT, DC heaters, will use SS rectifier and I would like to have a Tonestack bypass switch, negative feedback modes and an Lpad attenuator plus the catode resistor which is much better for the UK's 240v line.


    Will try to document the build but at the moment I am sourcing parts and checking other builds to get an idea of what I need to consider.
    Any suggestions welcome

    Cheers
     
  2. bparnell57

    bparnell57 Poster Extraordinaire

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    I think a cool mod would be having a bright input or perhaps using a push pull pot for either a bass cut/treble boost bright tone, or perhaps bypassing the negative feedback at the output. If you wanted to get really fancy, go get an old stacked pot and some vintage stacked knobs and put either a control for level of negative feedback, or a tone control. Cutting out negative feedback can really increase the gain and grit of the amp.
     
  3. muchxs

    muchxs Doctor of Teleocity

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    Going your own way by converting a Champion 600 to a mutant 5F1 layout creates as many problems as it solves. Been there, done that. It's a hard way to go and this ain't my first rodeo. There are some unavoidable compromises in a Champion 600 conversion that can be a challenge to overcome.

    Start with an aftermarket 5F1 chassis and circuit board or better yet a 5F2. There's plenty of room in a 5F2 chassis.

    "The easy way is hard enough!"

    .
     

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  4. bparnell57

    bparnell57 Poster Extraordinaire

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    Why use a turret board in a champ 600 at all. Use good old true PTP wiring with terminal strips and you can use a chopstick to attempt to lower the noise. I guess this shows my fondness (or rather wanting to share the frustration) of antique radios and test equipment. PTP is a real pain to work on, but it's easier to me at least than trying to use an existing board in a different chassis. PTP 5F1's have been done in Champ 600 chassis with good success. So have turret boards. It's all in how you want to do it. You could even use perf board if you wanted. Use DIYLC (do it yourself layout creator, it's free online) to work out what will work.

    Edit: I will agree with Muchxs that the issues are all possible to exist in any new unknown layout. It's not easy. I just want to emphasize that.
     
  5. MadJack

    MadJack Friend of Leo's

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    Dave/hackworth1/Boothill Amps has done a few 5F1 conversions and had a turret board with components to do the conversion. IIRC, there is a thread on that conversion also.
     
  6. tibrocks

    tibrocks TDPRI Member

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    Thanks guys for your input

    @bparnell57 Yes, I am planning to do some of these mods, will have the negative feedback one and was also thinking to install a 3 way switch that will go Pentode-Standby-Triode - has anyone tried this? to me it sounds like a good idea but not sure how to implement it..

    also I did consider PTP but it appears to be more complicated and I thought a turret board gives a cleaner layout - have ordered the turret board couple days ago..

    and @muchxs, the idea is to use as many parts as I already have, that's why I want to build it inside the Champion 600 chassis, and I thought the 5F1 is a simple circuit to start with (am I wrong?)

    All I need is a functional amplifier, to eliminate the low hum and more important, the crackling noise which is very annoying and ruins the recordings..
    Sounds like hitting a reverb tank.. (although I wish it had one..)

    >What problems could I bump into, what should I pay attention to, and what could cause the crackling noise??


    Thanks
     
  7. bparnell57

    bparnell57 Poster Extraordinaire

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    Make sure your solder joints are nice and clean and well flowed, and also make sure that all wire and component lead lengths are kept as short as possible. Tightly twist heater wiring as well as all AC wiring if you'd like to avoid hum, or even do DC heaters. Don't bundle wires together in long runs, let them have some space to avoid hum and noise. Use metal film resistors for the lowest noise. Use good sockets, even NOS or good vintage ones if you can get them. Good old used or NOS tubes and you should be good to go.
     
  8. Lunchie

    Lunchie Poster Extraordinaire

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    Hey! That amp looks familiar! :D

    Yep, I didn't do it myself I let the pros do it. I sent my chassis off to Hacksworth1 aka Dave aka boothill amps and he did the initial 5F1 conversion. My suggestion is replace the stock Transformer! I cheaped out and had dave reuse my Tranny. It blew a couple months later with modest use.

    After it was toast I sent it off to Much who repaired it, built me a kick butt cab and threw a 6x9 in it that is absolutely killer.

    I thought the 5F1 was killer in the little C600 cab, its 10x killerer in a more normal size cab.

    Here are some additional pics. No gut shots for respect to the builders involved.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
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  9. boredguy6060

    boredguy6060 Friend of Leo's

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    I did a Champ 600 to 5F1 conversion.
    I used Classictone PT and OT and it turned out rather nice.
    It's quite and using a 12ax7 and 6v6 and 5Y3 it is straight up Layla sounding, starts breaking up about 3-4 on the dial.
    With a 5751 and a 6L6GC and a SS rec it gets considerably more headroom, breaks up at about 7 on the dial
    You got to do a lot of planning, one way the tube sockets go under the board, the other way not.
    If you drill any more tube sockets watch out for the mounting rails inside the cab.
     
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  10. Lunchie

    Lunchie Poster Extraordinaire

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    Thats probably right about the breakup with the SS rec. I would assume that the old 6x9 is pretty inefficient but I could be wrong. I'd say about 6-7 o'clock I start getting into that classic tweed break up. 10-12 I got to hold onto my socks because I'm full blown Tweed crunch and its surprisingly loud.

    I don't want to say what I have into the conversion total, its slightly less then what you would pay for a Muchxs straight up 5F1 build. That was probably ludicrous by a financial sense. However, its not going anywhere and what I ended up with was seriously the best sounding 5F1 I've ever plugged into. It kills the Fender EC Champ and that thing is pretty dang good itself.

    Whats great about it, its still a different beast then my Morpheus on Tweed setting. The C600 build has more hair on the crunch where as the Morpheus stays tighter and more articulate. The C600 has more treble where the Much is fuller with boomy low ends. So even though I have essentially two of the same, they are still different beasts. Very cool in my book! :cool:

    Anyway, not trying to hijack your thread. I just really think the C600 conversions are a cool beast.
     
  11. boredguy6060

    boredguy6060 Friend of Leo's

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    It ain't cheap that's for sure.
    I agree that by the time it's all said and done, You could probably buy a 5F1 kit and build it that way.
    I know that I got close to 500$ in mine, but it wasn't about being the cheapest way to go, I liked the looks of it.

    I would change many things if I were to do another one, but I'll never sell it so I can live with my errors, like I said it sounds great.
     
  12. tweeddeluxe

    tweeddeluxe Tele-Afflicted

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    I'm very happy with the conversion I did a few months ago. I too used a Classictone OT, but kept the stock PT with a SS rectifier. I already had a 8" alnico Web sig in it.

    As boredguy mentioned, planning is key. The build turned out well, imo. It's quiet and sounds much better than the original. It's currently plugged into a 12" cab loaded with an Eminence Red White and Blues and sounds fantastic.

    The speaker is tight, but fits.
    [​IMG]

    Had to swing one end of the OT over just a smidge to clear the speaker magnet. Relocated the speaker jack and put the fuseholder in the old hole..
    [​IMG]

    A little tight but easier than a 5e3.
    [​IMG]

    Go for it. It's a fun build.
    tom
     
  13. boredguy6060

    boredguy6060 Friend of Leo's

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    TD, your layout and construction are far cleaner than mine.
    I didn't want to have a tube socket under the board because I didn't trust my layout, and if it had problems I didn't want to have to remove the board.
    At least that was my thinking at the time.
    I moved the 12ax7 right under the inputs and hooked the grid stoppers right to the grid. I used a terminal strip for the 1.5k and bypass cap.
    That allowed me to cut the board down and save some real estate. However if I had to do another one I doubt I'd take that approach.
    I wanted to avoid having too much going on that I couldn't easily get to in case I had wired something wrong. I think that wouldn't be my main concern the second time around.
    Dave/Hackworth1 had a nice layout and I've seen several since, which includes yours, that are done very nice and clean.
    I have a decent gutshot of someones PTP layout which is done very clean, that I picked up on the internet somewhere, that's an interesting looking project.
    150$ bucks is the going rate right now for a C600RI, which isn't bad for a cab and chassis....It's tempting.
     
  14. tibrocks

    tibrocks TDPRI Member

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    Hi guys and really sorry for the delay, I've been outside UK for a while.

    Now I'm back and found some new parts.
    First off, thanks @bparnell57 for the tips, very good advice!

    Second.. @tweeddeluxe I was surprised to see your amp.. mine's incredibly similar!! Will attach a picture;)
    [​IMG]

    [​IMG]


    While I was away I managed to find some parts left from the Deluxe Reverb build:
    [​IMG]

    I have found a choke transformer that was supplied with the kit, rated 9H 120mA that I would like to use - but I don't know how, any suggestion welcome


    Also there was a Weber Copper Cap rectifier and I thought it might be a good idea to use it since I only have the stock PT which doesn't have filament winding for Rectifier (would be 5V)

    Let me know what you think!

    Cheers
     

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  15. bparnell57

    bparnell57 Poster Extraordinaire

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    I'd say use the copper cap for now and wire in a tiny 2 amp 5 volt filament transformer later if you want to try tubes for voltage drop. Otherwise I'd say stick to a set of diodes inside. The choke is excessive for this kind of build as in push pull amps it's used to lower levels of sag, but single ended amps don't sag. It's also over sized.
     
  16. tibrocks

    tibrocks TDPRI Member

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    Thanks!
    I thought the choke would also reduce hum? if I am to use it that would replace the 10k resistor in the power filtering section, is that correct?

    Also, thinking of removing indicator lamp that draws from the heathers and use a simple, Neon Lamp as a power-on idicator - does anyone know how to wire that?

    Cheers
     
  17. tibrocks

    tibrocks TDPRI Member

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    Guys,

    I am almost done with the main board, however I ran into a problem - and unfortunately realised much later.. :oops:
    The center pins were misplaced and components didn't align properly.. :eek:

    This is what I got:
    [​IMG]

    The main concern is the Cathode resistor which goes under the 22k resistor, is this a problem that it overlaps?
     

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  18. tibrocks

    tibrocks TDPRI Member

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    Anyone? :)
     
  19. bparnell57

    bparnell57 Poster Extraordinaire

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    Cathode resistors get pretty hot. Put a tiny bit of air space between them and it'll be fine. Also, for a neon lamp, just put it across the power input after the switch. Very simple, like adding a lightbulb to a lamp.
     
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