Trouble with Fender Champ 5F1 clone.

[labb]

Travis, here is what I would do if I were you..First change those resistors to the higher wattage ones as recommended..That is very important..Then decide where you want your B1 (plate) voltage to be. First go to the nos 5y3. That is going to drop you about 20 volts from where you are. Next get about 6 10 volt, 5 watt zener diodes. If you want to drop your voltage 10 volts, put one of the zeners in the center tap to ground of the HT lead of the PT. Banded end goes towards the transformer. each zener you put in series will drop the voltage another 10 volts. Then, after you reach the voltage you want to be at, you will have to re-bias. Around 12 watts is a good place to bias to..All of that being said, I would re-bias, as is, to the 12 watts as discussed before (820 ohms should just about get you there) and just play the heck out of it.

As for the OT you are using, that is the replacement OT for the Fender Champ and you are ok with it. You can go to a larger, say 10 or 15 watt rated OT and most will say it will increase your bass and make the amp break up later..Take a look at the Hammond 125 DSE or 125 ESE. Lots of folks like them.

And as Phil said "Good Job"

[FunkyE9th]

Here is my OT
Specifications
Audio Watts (RMS): 8
Primary Impedance (Ohms): 7,000
Secondary Impedance (Ohms): 3.2
Mounting centers: 2-3/8"
Weight: 0.6 lbs

What kind of OT do I need to be looking at for running a 6L6?

Travis,

Are you looking into a 6l6 because you are concerned about the high voltage or because you want to have the flexibility of being able to try different tubes?

If you are concerned about the high voltage, one very good suggestion jjman made above is to use a dropping resistor. That will cost $1. You can play with different values to get to voltage you want. You just have to make sure the power rating of the resistor is high enough. And you might even be able to go back to the 470 Ohm if you bring it down enough.

Just as a point of reference, with my SE amp, when I'm using a 6v6, I'm getting about 351V on the plates with a 500 Ohm cathode resistor, NOS 5Y3 and plate dissipation of 13.5W. I like it hot. You were at 377 when you originally had the 470 ohm resistor.

If you just want the flexiblity of being able to use different tubes, then yes I would go ahead and change the OT. I like the Hammond 125ESE or the Weber WSE15. These are big OT's make sure they fit you chassis.

Anyway, IMO you should just work on getting the voltage down and stick withe 6v6 for now and just play it. Have fun with it. Later on, maybe switch the OT.

-FunkyE9th

[rfgordon]

If you want another suggestion for a new OT, try Matt's iron at
www.musicalpowersupplies.com

He has three SE PTs: 8, 10 and 20 watts. I just build the amp pictured with one of his prototype 10 watt OTs, and it sounds absolutely killer! I've done about a dozen amps with his stuff, all very nice. Best deals going, particularly on low power PTs.

And I heartily second filtering the screen grid. I'd add an extra 22 mF cap after a 15k 3watt resistor and connect that node to a 1K5 3 watter on the screen.

And, as for high voltage SE amps, I just build one using a KT88. With a 5AR4, there's 486 VDC on the plate, and man, does it roar!

[Travis]

If you want another suggestion for a new OT, try Matt's iron at
www.musicalpowersupplies.com

He has three SE PTs: 8, 10 and 20 watts. I just build the amp pictured with one of his prototype 10 watt OTs, and it sounds absolutely killer! I've done about a dozen amps with his stuff, all very nice. Best deals going, particularly on low power PTs.

And I heartily second filtering the screen grid. I'd add an extra 22 mF cap after a 15k 3watt resistor and connect that node to a 1K5 3 watter on the screen.

And, as for high voltage SE amps, I just build one using a KT88. With a 5AR4, there's 486 VDC on the plate, and man, does it roar!

send some sound clips man!

[Travis]

I added 2 2k 1 watt resistors to the cathode. I like the tone much better now. I also went ahead and bought a NOS 5Y3. I really wanted to keep this cheap for now. I do plan on building a Fender Bassman 5F6 Clone. Does anyone have any recommendations on this project?

[Cygnus X1]

Travis,
Great job!
Congrats on the build. You mentioned something about EVH early "brown sound". I also built the SEL (go to AX84.com) and it has great versatility and tone. Lots of drive!
I also ended up running a 6V6 in it.

It is SS rectified, I am using a Weber power tranny with a fullwave bridge recto setup. I have two of these amps, one with the Weber 15 watt SE output tranny, the other amp has a Hammond 125 ESE. I have noticed little difference in those transformers.

The amp does give off a nice cranked Marshall tone...you might think about building one.

[Phil_S]

I added 2 2k 1 watt resistors to the cathode. I like the tone much better now. I also went ahead and bought a NOS 5Y3. I really wanted to keep this cheap for now. I do plan on building a Fender Bassman 5F6 Clone. Does anyone have any recommendations on this project?

You might consider the AA165 or AB165 over the 5F6. In any case, I'd find a different rectifier than the 83 tube. Have you looked for an 83?

[Travis]

I added 2 2k 1 watt resistors to the cathode. I like the tone much better now. I also went ahead and bought a NOS 5Y3. I really wanted to keep this cheap for now. I do plan on building a Fender Bassman 5F6 Clone. Does anyone have any recommendations on this project?

You might consider the AA165 or AB165 over the 5F6. In any case, I'd find a different rectifier than the 83 tube. Have you looked for an 83?

I'm not sure what you mean by 83 tube. What amp is the aa165 or ab165?

[Cygnus X1]

AB165 is an SS rectified Bassman.
3 12AX7's, one 12 AT7 for the pi, two 6L6 power tubes.

And likely pricey for the iron in it.

Still, check out the SEL for low volume/high gain.
You can get the tranny's for less than 100 dollars.

[Travis]

I put a 2k resistor on the cathode. This has me at 5 watts. The amp does not break up as early, slightly cleaner sounding.

[jjman]

I put a 2k resistor on the cathode. This has me at 5 watts. The amp does not break up as early, slightly cleaner sounding.

Your plate voltage is probably pretty high now. I would target a result that yields about 11watts or so at idle.

[Travis]

I put a 2k resistor on the cathode. This has me at 5 watts. The amp does not break up as early, slightly cleaner sounding.

Your plate voltage is probably pretty high now. I would target a result that yields about 11watts or so at idle.

it's 440 volts with a 35 volt drop. Doing the math it puts me at 5 watts. Is this not where I need to be?

[Travis]

nevermind the last posting.

[jimmy74]

Just finished a "mega" champ kit with a cathode biased 6L6WC power tube, 5Y3 rect and a 12AX7 pre. I'm getting 297vDC on pin 3 of the 6L6 and 19v bias at 41mA, seems a little on the cool side? what sort of bias resistor would you suggest using? Currently a 20W 470r.

thanks
J.

[martin manning]

I don't recognize 6L6WC... is it 6L6GC? 6L6WGC?