Mini Toggle Switch placement for 5F1 Mods?

Discussion in 'Shock Brother's DIY Amps' started by James Knox, Jun 5, 2020.

  1. James Knox

    James Knox Tele-Meister

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    I want to use Mini Toggle switches to switch on/off NFB and Bypass Cap.

    1. Which Mini Toggle do I want - SPST? SPDT?

    2. Where do I drill holes in my chassis? I have seen pic’s where they are mounted on the bottom, near the preamp tube socket, and I saw one that was mounted in one of the 2 guitar input jacks. Why does a guy need 2 input jacks right, lol?
     
  2. muchxs

    muchxs Doctor of Teleocity

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    Two input jacks are super handy for a hot / not so hot input. One input gives expedient access to your overdrive tone, the other input gives you "instant clean".

    ...if you set it up that way.
     
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  3. tessting1two

    tessting1two Tele-Holic

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    You can certainly move the fuse holder to the bottom of the chassis next to the power cord.
     
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  4. King Fan

    King Fan Poster Extraordinaire

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    Besides the usefulness of the 'Lo' input and questions about control-panel labels, logic, and looks, also check out wiring run length. Here's a suggestion: wire 'em up in the back and see how often you end up using 'em. I use a *small* NFB cut all the time on my 5F2a -- doesn't require volume re-setting, just nicely pushes the tone across the edge of breakup. It's so useful I put it on a footswitch -- kind of thing you might use several times in a single song.

    OTOH Rob's 3-way NFB/bypass mod on my 5E3 is on a mini-toggle between tubes, in one of the vents of the back panel, where your fingers find it without thinking. It's perfect there; I like it, but I don't use it all that often, and it's a big enough change I often adjust amp volume, guitar volume, and maybe add a pedal when I engage it. Perfect location for that with short wiring runs.

    Switch type? Depends on how many wires you're interrupting, redirecting, or combining. A single, simple NFB cut (or separate bypass cut) needs a simple SPST. But look at Rob's combi NFB+bypass mod and see why it needs a SPDT ON-OFF-ON.
     
  5. James Knox

    James Knox Tele-Meister

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    Nice! (How do I set it up that way?)
     
  6. James Knox

    James Knox Tele-Meister

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    Thank you Sir! Lots of food for thought there...
     
  7. James Knox

    James Knox Tele-Meister

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    @King Fan Just read through RobRobs NFB/Bypass mod. Wow! Don’t know how I missed that. Probably cuz it’s 5E3 related and I’m still in the 5F1 learning stages, lol. So..... would that exact mod work in the 5F1 circuit?
     
  8. King Fan

    King Fan Poster Extraordinaire

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    Others will know more if it'd *work.* But.... Rob was introducing NFB where there wasn't any and found he needed to lift the bypass cap to hear its effect. You'd be trying to reduce existing NFB (maybe not all the way and maybe with a pot -- good idea).

    Then, separate idea, you'd be thinking to lift the bypass cap (and lessen gain) to match early-production Champs (and the original schematic) -- but be aware most Champs actually had the bypass cap.

    So I think I'd use two separate switches and separate wiring. I may be wrong.

    This has all been done by other 5F1 builders -- see if you can hunt up those threads and steal baby steal. And I hope some of them will chime in here.
     
  9. muchxs

    muchxs Doctor of Teleocity

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    That's the way Fender set it up with the two 68k grid stoppers. Genius! Perhaps Fender's best idea ever.

    In theory you can use a single input with a 33k grid stopper. But... you can add distortion, you can't add clean. Also in theory if you have a single input with a 33k grid stopper you can back your guitar volume off a touch. Except I'm a basher. I never touch that volume knob except to assure it's absolutely pinned.

    I'm not going to give up that extra input on something like a Vibro Champ or a Princeton Reverb, both amps I've made play clean all the way up. Maybe not as clean as a mini- Twin but still clean.

    It's a matter of understanding that Leo designed '60s Fender to play clean but he also went for everything he could get. That means '60s Fender amps are a lot closer to breakup than you might think. The trick is to go through the circuit from one end to the other and pick up a fraction of a decibel where you can. That makes it play clean. Then add a little more gain than you took away. That makes it play dirty.

    Using NFB to knock the gain back is one way to do it.

    I look at the inside of an amp as if it's the faders on a mixing console. I don't have as much range as a console but even in something like a tweed Champ there are parameters I can push one way or the other.


    So far I haven't built a 5F1 with a switch aside from its power switch. That's not counting my Morpheus types. I originally designed Morpheus as a modification package for '60s Fenders. I eventually built it on a 5F2 chassis. Neat little amp! It's tiny. It's as loud as a Princeton Reverb clean and even louder, dirty.

    Morpheus Junior is trapped in my Mad Scientist brain. Next trick is a 5F1 that plays clean 'n' tight all the way up. I already built a (few) 5E3 (s) that plays clean all the way up. Next time I'll do it smaller.

    My 5E3 has 12AX7s in both preamp slots. I like a 12AX7 for V1 in a 5E3. It gives me a little more note definition.
     
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  10. James Knox

    James Knox Tele-Meister

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    Yes, I was thinking 2 different switches, but Robs on/off/on switch is so inspiring! I think I've just decided - use 2 switches for the 5F1 and make my next build a 5E3, lol!
     
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  11. cgharrison

    cgharrison TDPRI Member

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    I just finished an octal single ended amp based off the Supro spectator (6SL7-6V6-5Y3). I tried a bunch of mods, and ended up sticking with a couple. First, hi and lo inputs (a la Fender) are great with a simple circuit. The stock spectator has both inputs wired the same, but having two options there really gives a nice range of clean and crunch tones. Second, I put a cathode bypass cap (25uf/50v) for the 6V6 power tube on an SPST on-off switch on the front panel, between the volume knobs and inputs, in line with the silk screen numbers of the inputs. I toyed with putting the switch on the under side of the chassis, but the thing is so useful, I just decided to bite the bullet and put an additional hole on top. The output, gain, and presence of the amp are vastly different with and without this cap, and all the available sounds are really nice. The lo input with no bypass cap is very soft and jazzy - 40’s Charlie Christian style. Lo with bypass cap gets into an early Muddy Waters Can’t Be Satisfied (the recording with just bass and guitar) sound. The hi input with no bypass cap is clean and bright, and with the bypass cap engaged gets into those familiar 5F1 type tones. I’ve messed with power tube bypass caps on push pull amps, and the difference is extremely subtle. On a single ended amp, though, the change is amazing. Compared to a switch for the preamp cathode bypass cap, it’s much more valuable IMO. Negative feedback is another really effective thing to switch, but I personally like the amp with no negative feedback at all. My 2 cents...
     
  12. James Knox

    James Knox Tele-Meister

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    I have just read through this 3 times cuz I really want to absorb it. As I read, I realized that about 15 years ago I was in my Need 4 Tweed Phase. Buying and selling Clark and Victoria Tweed Amps. Went through their Champ, Deluxe, Regal, and Tyger (310) models. Discovered in that journey that I liked a tighter low end, lighter smaller cabs, etc,.

    Segued into the Fender Princeton Rabbit hole - Silverface, Blackface, 10”, 12”, Reverb, non Reverb, Vibro Champs, etc. and discovered that I prefer the OD/Distortion of my pedals. That Ted Weber makes phenomenal speakers and that sometimes I like the punch and immediacy of Ceramic over Alnico.

    Played nothing but a non-rev Silverface Princeton for years after that. So, I totally get your “build em clean” ethos! Morpheus Junior? THAT sounds amazing!

    Recently returned to an interest in Tweed, mostly because I want to learn more about building, understanding “under the hood”, reading schematics, etc,.
     
  13. Lowerleftcoast

    Lowerleftcoast Tele-Afflicted

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    There is another option other than a toggle switch.

    I like Bourns pots with a push pull switch. No extra hole to be drilled. The tone and/or volume pot can serve dual duty. The switch is with the other controls. Win win.
     
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  14. James Knox

    James Knox Tele-Meister

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    Those insights are worth much more than 2 cents my friend! Man, I would love to hear some octal preamp tube examples. I’m a huge Muddy fan, one of my fav albums being the Folk Singer album. Muddy bringing the blues to the “Folk Movement”, lol. Great tones there. Was your build in a 5F1 or 5F2A chassis?
     
  15. muchxs

    muchxs Doctor of Teleocity

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    Wow. Talk about the high price of education.

    It's funny. I've bot schematics IO drew in the '80s all high powered high gain stuff. Lately I've been making everything as small and light as I can make it and still keep my tubes.


    bill-the-cat.jpg
    In my era... I'm stuck in the '70s and '80s. Distortion pedals kinds sucked and besides that, I didn't have to take my socks off to count my choices. Some of 'em sound o.k. when someone else plays through them. We had a choice of the old Big Muff, perhaps a '70s premonition of Friedmans to come. I have a couple Distortion + pedals. Later we could get the aptly named Rat.

    I've worked my way into better tighter versions of classic circuits. Can't beat a 5F1 for instant rock 'n' roll tone.

    After gradually tightening the nuts on 5E3 types I finally have one I'm going to keep.

    "Just because I can" I have a '69 (or so) Vibro Champ chassis I'm going to load with non- reverb Princeton guts. I'm debating whether I want to use an 820H or a Copperhead. Seems to me it should be a handy little monster.

    The (currently conceptual) Morpheus Junior... one knob. Some people complain about the "tight" 5F1 chassis. I figure you could pack about ten cell phones in there. Ten cell phones gives you enough computing power to pilot the Space Shuttle or land a 747. Making it do tube tricks is simple by comparison.

    We're lucky we have all the parts available. It's easier to get tube amp parts now than it was in the 1980s.
     
  16. muchxs

    muchxs Doctor of Teleocity

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    I did the two switch thing on my original Morpheus. Initially the design brief was a Boston pedal builder wanted an "interesting" clean tone to demo his boutique distortion pedals. So I gave him his clean voice. I added tweed and boosted tweed as reference tones to his silicon or germanium based distortion.

    PM me if you build a 5E3. I can save you a couple decades of wandering around in the dark otherwise known as "research and design".

    :cool: :cool: :cool:

    Not directed towards me but my Morpheus amp is built on a tweed Princeton chassis. It's been a while since I had a Morpheus and a 5F1 side by side. The Morpheus is loud enough to gig with. It has been proven to be loud enough to gig with. It sounds big and tight compared to a 5F1 without being substantially larger.
     
  17. James Knox

    James Knox Tele-Meister

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    Thank you so much for your kind offer! I will definitely take you up on that if I go down the 5E3 road. Right now I’m in the middle of a 5F1 and hoping to do some “mod experimenting” to learn more about the capacity of the 5F1 circuit. Been thinking about coming up with a BOM and sourcing some cherry pick in’ parts and build a 5F2A, rather than just buying a 5E3 “kit”. I’ve owned Clark and Victoria 5E3’s and not sure if I really want another one, though it would be fun to build and experiment with.

    With that in mind, I kinda got a charge when you wrote this:

    Is your Morpheus a proprietary design, or is there info available? I like the idea of a “maximized” circuit in a “minimal” footprint.
     
  18. muchxs

    muchxs Doctor of Teleocity

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    The definition of insanity is trying the same thing over and over and expecting different results.

    You heard one 5E3, you heard 'em all. I fall down laughing when I hear claims that one nearly stock 5E3 is substantially better or worse than others.

    It's like all sorts of fruity flavors of tubes. Dude! They don't sound as different as some people claim. Further, who is to say that Holy Grail tube you just bought is going to be anything like the one right next to it in the same batch.

    :rolleyes:

    Morpheus is my own design. I didn't document it. Anything good will be bootlegged in seconds after it is posted on the internet.
     
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  19. ArcticWhite

    ArcticWhite Tele-Holic

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    Anyone else just love to read muchxs's posts? Hell half the time I'm not even that interested in the OP topic but then in comes a writer like much, or RobRob, and its like hearing a super tasty solo in an otherwise unremarkable song.
     
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  20. James Knox

    James Knox Tele-Meister

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    Love the metaphor!

    And yes, I agree...
     
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