#1
Allrgiht ive been considering making an amp, the jcm 800 2203 because it looks rather easy compared to the others, but i need help on the tube part.

http://www.freeinfosociety.com/electronics/schemview.php?id=483

http://www.freeinfosociety.com/electronics/schemview.php?id=484

what is the numbering of the tube signs?

is it

123
456
789?
#2
What numbering on the tube signs?

I wouldn't recommend that for a first build. You might try building a simpler amp with a good layout before that...maybe a Marshall 18 watt. That would make a good punk amp cranked. There are also versions of the Fender Champ circuit that have been tweeked to give great distorted tone similar to a Marshall.

That's a hard first project.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#3
Quote by That_Pink_Queen
What numbering on the tube signs?

I wouldn't recommend that for a first build. You might try building a simpler amp with a good layout before that...maybe a Marshall 18 watt. That would make a good punk amp cranked. There are also versions of the Fender Champ circuit that have been tweeked to give great distorted tone similar to a Marshall.

That's a hard first project.



seriously? it looks like it would take 2 hours to build, but ok ill take your advice, the only problem is that i truly wouldnt think it would be loud enough.

i know theres 9 spots for the poweramp tube, but ive never actaully seen one of those (things you place the tube on). does it looks literally like it shows in teh schem? I thought they were circular

EDIT: nevermind on the 18 watt marshall it shows how to do it, thanks


BUT

http://www.drtube.com/schematics/marshall/18wr.gif

those letters on the tube part dont mean anything right? (where it shows the numbers under where it says Marshall 18 watt)
Last edited by llanafreak44 at Aug 21, 2006,
#4
Thats showing the physical layout of pins on the tubes - what they look like in real life. The pin's arrangement on the schematic is often changed to make it easier to lay out.
As said, the first one is definately not a first project, and would take me longer than 2 hours to lay out and solder, before I even checked it over and tested it. Often, schematics like that are reverse-engineered by looking into an original head and following the wires/leads/traces. They are meant for repairs, so it is easier to identify a broken component and replace it. If you build them as they are shown, they may sound different or may not sound at all alike. I remember one of the earlier Mesa Boogie amps used spaces between PCB tracks as capacitors, and it won't work without them.
The 18 watt project, on the other hand, has been worked on by lots of people and is known to work very well.
#5
The letters are just codes for what the pin does, (Heater, Plate, etc Grid, etc)
I'm too lazy to look up the codes right now, but H = Heater, I think K is the Cathode, P = Plate, G1/G2 = Control and/or Screen Grid (I forget which one's which), etc.
#6
Quote by greenbox
The letters are just codes for what the pin does, (Heater, Plate, etc Grid, etc)
I'm too lazy to look up the codes right now, but H = Heater, I think K is the Cathode, P = Plate, G1/G2 = Control and/or Screen Grid (I forget which one's which), etc.



thanks man

its ok if i just use 24 wire right?
Last edited by llanafreak44 at Aug 21, 2006,
#7
Quote by Wyld Stallyn
Thats showing the physical layout of pins on the tubes - what they look like in real life. The pin's arrangement on the schematic is often changed to make it easier to lay out.
As said, the first one is definately not a first project, and would take me longer than 2 hours to lay out and solder, before I even checked it over and tested it. Often, schematics like that are reverse-engineered by looking into an original head and following the wires/leads/traces. They are meant for repairs, so it is easier to identify a broken component and replace it. If you build them as they are shown, they may sound different or may not sound at all alike. I remember one of the earlier Mesa Boogie amps used spaces between PCB tracks as capacitors, and it won't work without them.
The 18 watt project, on the other hand, has been worked on by lots of people and is known to work very well.


]
Truly? So if i want to build a JCM 800 if i actaulyl do build this 18 watt, i would have to buy the schematic?
#8
I like using a bit thicker wire.
18 guage for the heaters, 20 for the rest

I recommend using 600 volt rated wire too.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#9
Wyld Stallyn is talking about the layout.
The JCM was built on a PCB board. The 18watt was a hand wired layout. You'll need to come up with your own layout for the JCM, but with the 18watt there are heaps of premade layouts for you to use.

To be honest, I don't think you're at all ready for anything near that JCM.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#10
Quote by That_Pink_Queen
Wyld Stallyn is talking about the layout.
The JCM was built on a PCB board. The 18watt was a hand wired layout. You'll need to come up with your own layout for the JCM, but with the 18watt there are heaps of premade layouts for you to use.

To be honest, I don't think you're at all ready for anything near that JCM.



Allright im going to try to buld the 18 watt