Well I just got it on Friday and I'm really excited! I can't wait to start building it. Not to worry, there will be plenty of (no doubt) dumb questions from me!!!Actually, now that I think about it I have the first dumb question! I'm slightly confused on how to properly ground everything. Does it ground to the metal chassis and does everything go to the same spot? I remember reading something about 'star grounding' or something like that but I don't remember where. Someone enlighten me please!
Here is more than you would ever need to know.
It's part of my bible...I have made many missteps, but at least my builds are as quiet as a church mouse by following these guidelines.
http://www.aikenamps.com/StarGround.html
I recently did a 5E3P (40W 5E3) from Weber for someone and followed the grounding points on the layout using the brass plate and all.
Worked great and it was a quiet amp...no hum.
The 5F2A ought to be similar...it will help to have the brass plate separate from the amp when making the ground solder points so the whole chassis doesn't act as a heat sink.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
Yep, just use the brass plate. I've never had a problem with any old-school Fender style amp build where I used the original grounding scheme.
I mean, ever hear of anyone fitting a star ground to a 1958 Princeton?! Star grounds are for things with Gain controls (and 18 watters).
What cab did you go for?
Ooops. (I guess).
I used a star ground on the 5E3 build.
It is quieter (in background noise) than the two vintage TD's I played recently. But still way too loud!
NTBLUESGUITAR...Just curious, What did you bias your 6L6's at? I built my own similar amp and would love to hear others experiences.
Mine was not a Weber kit...Mojo Cab and Chassis, the rest are from my own sources.
Not trying to side track the thread of course. Congrats on the 5F2A, Thog!
Mandopicker
Ahh...well, I built it out with cathode bias.Originally Posted by Mandopicker
In fixed bias 6L6 amps, I personally like them around 69% max plate dissipation.
I have a 5F2A on my list of projects, too, BTW.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
I completed a 5F2A myself a bit ago. Feel free to hit me up with questions. Although TJ is probably a better bet as he's the one I ask anyway.
"Oh, Mister D.J.,
I keep wondering why you don't play much blues anymore
I don't know what you got against me
Whatever it is, I sure would like to know"
Still haven't seen yours yet!
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
Mine is also cathode biased (adjustable). As a result, I have set it up running the tubes at a number of levels and actually found that conservative settings seem to sound best as well.
Thanks, NTBluesGuitar.
Mandopicker
I want to say I used a 250ohm/10W resistor in there in it's final version. The owner loves it, and I agreed that it sounded best that way.
YMMV.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
You guys should here the 5F2A x 2 we built for our drummer. It's has 2 x 6V6 in parallel, a GZ34 recto and an old Jensen P12P recently reconed amd remagnetized. speaker. It is a frickin MONSTER! (and it's dead quiet). People's jaws really drop when we I say "I'll just play this little 'Princeton'" and then crank it. It's the loudest 12+ watts I've ever heard. Think AC15 ... :-)
Man, I'm still torn between 5F2A standard or the 5F2Ax2, Gris. I've seen lots of schematics on the paralleled SE power stage, but can't settle on one.
Which was yours again?
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
Started off as a std GA-8 (6V6 parallel) schem, but ended up 'off chart.' I've even forgotten what value bypass caps are in it cause i played around with em before i figured it was really the cathode resistor that needed fixin and i never put the bypass caps back to 'stock.' IIRC PT was a big Weber SE model and the OT was switched from Weber's monster one to an Allen model a tiny bit smaller (but still big). Of course, the beauty of building an amp like this is because the board is so spartan you can experiment with diff values til you hear what you like... :-)
That's interesting NTBlues...
That size resitor ran my tubes a lot hotter that I felt they should, so I ended up using a 200 ohm bias pot connected to a 330 ohm 5 watt resistor and at its lowest setting (530 ohm) its roughly 30-35ma per tube, while at the other end (330 ohm) it can be closer to 45 to 50 ma per tube.
I know that there is more to the equation in deciding what is correct, but it is just good to hear others experiences. Certainly more material for experimentation.
Thanks again for indulging. Now back to the 5F2A...
Mandopicker
Thanks for all the responses guys! I just got the regular cab with the 10" alnico signature series 10s speaker.
Thanks! You will no doubt hear me!I completed a 5F2A myself a bit ago. Feel free to hit me up with questions. Although TJ is probably a better bet as he's the one I ask anyway.
By the way, is it just me or can we not use private messages?
Here are some pics of my build. I am actually going to open it up today to troubleshoot some "rustling" noise that cropped up - so let me know if you want a picture of a specific part or area...
My wire colors are screwy - Weber doesn't ship with instructions, so I just used what I felt was appropriate - I later found something on the Weber site that told me that I was all wrong. Oh well.
EDIT: I also sourced all of the caps, resistors, pots, jacks, and switches from mouser - so things may look a little different...
http://www.thebluesatemyhomework.com/5F2A/IMG_0043.JPG
http://www.thebluesatemyhomework.com/5F2A/IMG_0044.JPG
http://www.thebluesatemyhomework.com/5F2A/IMG_0046.JPG
http://www.thebluesatemyhomework.com/5F2A/IMG_0054.JPG
"Oh, Mister D.J.,
I keep wondering why you don't play much blues anymore
I don't know what you got against me
Whatever it is, I sure would like to know"
Nice work Sting!
Looks great,Stingerman!
"My flesh and my heart fail...but God is the strength of my heart and my portion forever."
PS. 73:26
MY JAMS--
http://www.soundclick.com/bands/defa...&content=music
Very cool...I source all my parts for these, too, but then, I make my own boards as well.
Nice work, man! I hope to get my 5F2 cab re-covered here soon.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
Awesome thanks!
Just to muddy the waters. I've only built two amps, a 5e3x2 and a 5f4. I found the brass plate a hassle to deal with (didn't have an iron big enough to heat it properly) and best used as a template for wiring the pots. As far as grounding, I followed the Hoffman instructions and the 5e3x2, with Weber's included metal-film resistors, was absolutely dead quiet. With no input and the volumes at 12 only a very slight hiss was perceptible and absolutely no hum.
I went "authentic" with the 5f4 and used Carbon Comp resistors and have a bit of vintage hiss.
http://www.el34world.com/charts/grounds.htm
Here's signal flow
http://www.el34world.com/charts/currentflow.htm
Here's how I got the ground buss on the pots and jacks.
Once finished the entire assembly just dropped into the chassis and I flew the leads to the preamp stages.
I know the brass plate is the proper way but I've had no issues not using it.
Good luck!
TT
On SmartPhones:
"Once men turned their thinking over to machines in the hope that this would set them free. But That only permitted other men with machines to enslave them." Frank Herbert.
The pots are part of the ground so using the back of the pot casing and having the pots all touching the brass plate means that its very similar to soldering each lead or component to the plate... just looks a bit cleaner.
"Oh, Mister D.J.,
I keep wondering why you don't play much blues anymore
I don't know what you got against me
Whatever it is, I sure would like to know"
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