5F1 'Champ' variations - a 'better' version..... or not?

Wharfcreek

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So just curious; how do you all feel about Rob Robinette's use of 'micro-champ'? If you put something in FRONT of the word 'Champ', and about the only thing left of the 'original' design is the 12AX7, is that an 'OK' use of 'Champ'..... or not? I mean REALLY!!! I think we all know that this amp design has been pretty well 'accepted' and 'respected'. Maybe I should go with 'Nitro-Champ'...... ha ha ha! Seriously though, it's pretty obvious that this is really going to boil down what I simply decide I'm going to do.......and then the individuals who follow along will decide if they like my nomenclature or not. Either way, I figure this will boil down to the words of Abraham Lincoln: "You can please some of the people all the time, and all the people some of the time, but you can't please all the people all the time!" How True!!!

In the immortal words of Eric Cartman: I do what I want, or I'm takin' my ball and I'm goin' home!!!

When done I will try to post a schematic along with a build list of parts. Sadly the Hammond prices are going up, up, up! But, right now the little 154M Choke is still available for about $15, the 269GX power transformer is about $65, and the P-T31 output transformer available at Antique Electronics Supply is still under $20. So, for about $100 in 'iron' costs (plus what ever your shipping costs are) you can 'clone' a Champ on what ever platform you want..... a Hammond Aluminum chassis like I'm using, or your own versions....what ever.....and for another maybe $75 in switches, jacks, passive parts, sockets, and a volume control, you can pretty much complete a 'new' build for under $200 less tubes. The 269GX PT will deliver 75ma of Rectified current at roughly 300VDC, and it has 2.5 Amps of 6V available.....so, enough to run a 6V6, a 12AX7, and a 6CA4 rectifier. Again, not 'exactly' the same, since no 5V winding for a 5Y3 rectifier. But, in my book, (like the 6BQ5 vs the 6V6) I think the rectifier choice makes no real difference. Hence my choice to go with the 6CA4, the 6BQ5, and the 12AX7. Hey, I might end up with a 12AT7 in the front end....and what a travesty that would be!
(just kidding)

Anyway, I think anyone who's been around 'amp' building for a while would probably agree....using the above 3 pieces of Iron and following the 5F1 schematic and only varying where necessary to accommodate the above, a 'respectable' 'Champ' clone can be built, and it will perform very much like an 'authentic' version..... assuming use of properly chosen speaker and enclosure. And, if you don't agree........well........you're entitled to your opinion! I've made up my mind!!
 
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ahiddentableau

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I think you're overthinking it. Call it what you want. If anybody gets that out of shape about you changing the speaker size they have way too much time on their hands.
 

printer2

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Randall RD5H Details
Tube-driven metal machine made for practice and recording.
Please note - Photos may not depict current design of front panel. No change to functions, however Randall has removed the symbol of a Devil on all amps due to market research - new photos are coming soon.
Single Channel all tube5 watt (12AX7/6V6) head with Gain, Tone, Master Volume, 3 way ToneStackShift for midrange contour with Class A Discrete instrument level FX loop and Speaker emulated XLR direct output with with Dummy load for Silent operation and ground lift.

Features:
  • Power: 5W tube
  • Single channel
  • Tubes: two 12AX7 (preamp); one 6V6 (power)
  • FX loop
  • Speaker-Emulated XLR output
  • Dimensions: 12.4" x 8.6" x 8.4"
  • Weight: 14.3 lbs.

  • Wattage / Power: 5w @ 1% Distortion
  • Channels: 1
  • Speaker: n/a
  • Impedance: 8O Minimum + External Jack
  • FX/GATE/REVERB: Class A Discrete Instrument Level Loop
  • FOOTSWITCH: n/a
  • Dimensions (LxWxH in mm): 316x220x215
  • Weight (kg): 6.5

The Randall RD1H Diavlo 5W amp head gives you real high-gain tube tone made for the most face-melting metal, and presents it in a portable size and practice-friendly volume.


But really it is just a Champ.
 

Wharfcreek

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....on steroids! Wasn't all that 'high-gain' stuff what Randall was famous for. I think I'm wrong about this, and maybe having a brain-fart, but wasn't it Randall who worked as an engineer at Fender and did all those pull-pot mods to a lot of the existing line of Fender amps before going out on his own? If not him, maybe someone can refresh my memory on that one!!
 

printer2

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....on steroids! Wasn't all that 'high-gain' stuff what Randall was famous for. I think I'm wrong about this, and maybe having a brain-fart, but wasn't it Randall who worked as an engineer at Fender and did all those pull-pot mods to a lot of the existing line of Fender amps before going out on his own? If not him, maybe someone can refresh my memory on that one!!
Will the answer make you happier?
 

loopfinding

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for me if i was going to do a champ i'd do either:

5f2-a - better filtering, you get an unobtrusive tone control that is more or less 5f1 all the way open. i would add a bypass cap blend or switch on the first triode as a bass control, to prevent woofiness with HB guitars.

BF champ (don't need the trem) - probably just leave it alone besides adding a considerable lift switch for the mid resistor to get tweed-enough sounds when i needed.

and then i would probably use a vibrochamp chassis and take advantage of the extra tube slot to run at least the input triode in parallel for a better noise floor. i think having the two separate pres in one amp could be cool too, but personally one "close-enough" solution above is worth the lower noise floor to me. i might also change the input triode to look more like the 6G3.

that’s what i like anyway. i’m not a purist.
 
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TequilaCaster

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Randall RD5H Details
Tube-driven metal machine made for practice and recording.
Please note - Photos may not depict current design of front panel. No change to functions, however Randall has removed the symbol of a Devil on all amps due to market research - new photos are coming soon.
Oooooo... a Metal Champ.
Perhaps the marketing change 👿 is to penetrate the 'Prays and Warship' market segment.

The Epiphone Valve Junior is a 12AX7 / EL84 'champ' amp. $150 used at guitar center....
https://media.guitarcenter.com/is/image/MMGS7/000000118052190-00-720x720.jpg
 

printer2

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What kills me is there is a old radio cabinet being sold here, originally the guy had it listed for $160, I emailed and said that it might be a little much and explained what had to happen to get it going again (and no it is not, "It probably needs a new tube.". He thanked me wand then listed it for $60, then 40, then 30 and it is now $20. Would have jumped at it years ago but I have too much stuff at it is. A 6K6 output tube (3.5W ans a 12" speaker. I am looking for one with a 10", was disappointment by the 12". Could be easily made into whatever flavor of Champ you want (even a Princeton).
 

Wharfcreek

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Those 'conversions' are some of the best versions of this old amp! BTW, I'd guess that Leo, being a 'radio guy' to start with, might well have built an early proto type of a Champ from some old radio and a WesternElectric circuit diagram. So, you're following in hallowed footsteps!
 

Peegoo

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Is it still a Champ if it's a tweed twin Champ?

This is a homebrew 5F1 in a homebrew cab about the size of a vintage Fender Deluxe. I covered it in tweed linen to match the original model that never existed :cool:

The baffle has a pair of 8" Quams I reconed. The Torque Amplifier badge is from a 1940s-era International Harvester tractor's transmission, because it seemed like the thing to do. It looks a bit goofy being a large cab with a small cutout for the control panel, but it gets pretty stinkin' loud and sounds great when dimed.

Peegoo-Tweed-Twin-Champ-Montage.jpg
 

Peegoo

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IMO, 'Fender Champ' means a single-ended amp with one 12AX7, and one 6V6 tube complement.
It does not need to have tube-rectified power, but can have zero-to-N number of tone controls.

What if it has diode rectification, a 12AX7 pre and a 6N1P power tube, and volume and tone controls? Is it a Champ?

No: it's a half-watt Nova SS Champlifier. The badge is from a '66 Chevy muscle car.

Can you tell I'm a fan of small amps?

Peegoo-Nova-SS-Champlifier.jpg
 




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