AN Wonderland/JM 100w layout

[rccolgan]

That means running the ground up to the furthest point away from the chassis which is right at the send/receive jacks. Attaching my layout as another way of looking at this.

The reason to separate the grounds instead of one single ground point for all of your filter caps is to reduce ground loops by isolating sections of the preamp which would correspond to the preamp filter caps too. Sometimes this makes a difference, other times it does not. I tend to follow best practices that I've learned here from Dumble & the clones. I know some folks will revise layouts and ground schemes until the very end of the battle.

[caesparza]

Hi Ryan,

Thanks for the answer, I'm checking your thread on the amp, nice information over there!. I'll replicate the specified ground points.

Cheers mate.
CE

[caesparza]

Hi,

A couple of weeks back I finished the build. Completely surprised with the sound of the amp. Had a lot of expectations about it, and it definitely doesn't disappoint at all.
Right now I'm running at 50W with 2 output tubes. (I'll be ordering a matched quad next month). Haven't connected a Strat type guitar to it yet.

I'm thinking about the half power switch on the back, to put the 4 output tubes in triode mode. rccolgan what are your impressions about the sound? As I understand, this is supposed to lower the output to about 60%, that would be 60W. Am I right about that?

The other thing I was considering on adding is a negative feedback loop lift switch. I have done this on every fender amp I have disabled the ground switch on the back and I like the extra tweed flavor I get on those amps. Could I expect the same kind of reaction from this amp design?

Now I have to build the cab for the head and the front and back plates, but first I need to decide about the extra features I want. I would like to make it leaving the wood naked (I'm thinking on a Walnut cab). Is there any other wood I should consider?

Thanks everybody and specially Taylor for this thread, this is my second build and so far both of them have ended up being great. Its a great learning experience to build from scratch.

[jazzbass]

"I'm thinking about the half power switch on the back, to put the 4 output tubes in triode mode. rccolgan what are your impressions about the sound? As I understand, this is supposed to lower the output to about 60%, that would be 60W. Am I right about that?"

Hi Caesparza, I have built some JM's for friends, a couple of 50watts and some 100watts and I can say that I prefer the 100watt without the switch that halves the power. I find that it makes no sense to add it because it complicates the project a lot and the result is not satisfactory.

Franco

[James_rc]

Is there a particular reason for the ground points marked as Ground at Send/Receive? Where is located that ground point?

I was thinking on grounding all filter caps at the same point.

That means running the ground up to the furthest point away from the chassis which is right at the send/receive jacks. Attaching my layout as another way of looking at this.

The reason to separate the grounds instead of one single ground point for all of your filter caps is to reduce ground loops by isolating sections of the preamp which would correspond to the preamp filter caps too. Sometimes this makes a difference, other times it does not. I tend to follow best practices that I've learned here from Dumble & the clones. I know some folks will revise layouts and ground schemes until the very end of the battle.

I was working on the send/receive tonight and started wondering if I can just omit it? I personally won’t ever use an effects loop, and it seems like it would get rid of two long co-ax runs that could introduce noise?

I’m using Taylor’s chassis with Ryan’s boards. I would (1) delete the long co-ax run from the middle pin of Master to the send/receive tip, (2) delete the co-ax run from Return to the board, and (3) ground the two points that ground at the send/receive appropriately somewhere else in the chassis.

Just thinking out loud. I’m most concerned about introducing noise with those two long co-ax runs.

[ijedouglas]

Is there a particular reason for the ground points marked as Ground at Send/Receive? Where is located that ground point?

I was thinking on grounding all filter caps at the same point.

That means running the ground up to the furthest point away from the chassis which is right at the send/receive jacks. Attaching my layout as another way of looking at this.

The reason to separate the grounds instead of one single ground point for all of your filter caps is to reduce ground loops by isolating sections of the preamp which would correspond to the preamp filter caps too. Sometimes this makes a difference, other times it does not. I tend to follow best practices that I've learned here from Dumble & the clones. I know some folks will revise layouts and ground schemes until the very end of the battle.

I was working on the send/receive tonight and started wondering if I can just omit it? I personally won’t ever use an effects loop, and it seems like it would get rid of two long co-ax runs that could introduce noise?

I’m using Taylor’s chassis with Ryan’s boards. I would (1) delete the long co-ax run from the middle pin of Master to the send/receive tip, (2) delete the co-ax run from Return to the board, and (3) ground the two points that ground at the send/receive appropriately somewhere else in the chassis.

Just thinking out loud. I’m most concerned about introducing noise with those two long co-ax runs.

You can certainly omit it but the amp is really quiet even with the EFX loop. If you are using coax I think you'll be just fine

[dorrisant]

You can certainly omit it but the amp is really quiet even with the EFX loop. If you are using coax I think you'll be just fine

I totally agree. Not too difficult to put it in while building and this amp makes your modulation effects sound spectacular. Seriously, El Cap is amazing in this circuit's loop.

[mgotoo03]

Hi all,

Just finished my build. Sounds great! I had troubles getting it to bias properly and finally realized the layout on page one seems to be missing a connection between the two 220uF caps in the power supply to place them in series (see attached where I've added it in red). Once that connection was there everything fell into place.

Wonderland 100w jan2017.jpg

[James_rc]

You can certainly omit it but the amp is really quiet even with the EFX loop. If you are using coax I think you'll be just fine

I totally agree. Not too difficult to put it in while building and this amp makes your modulation effects sound spectacular. Seriously, El Cap is amazing in this circuit's loop.

Thanks, guys. I left it in since I’d already run the master to send/return co-ax, but I had a grounding puzzle to work through.

I oversized the chassis hole for the return jack and used an isolation washer there (can’t remember why!). Then I realized later that I couldn’t ground there because of it. I was able to ground the shield for the Return to .02 on board coax to the send jack, but needed to find a new home for the other two wires that ground there. I ended up grounding them at the speaker jacks. Hopefully that works out. (Fingers crossed).

And also, maybe I shouldn’t try to re-work the circuit if I’m still trying to figure out where to ground things.

[award70]

What would be the appropriate spot to put the effects loop send/return if I want to put the loop before the reverb instead of after it? I think just before the the 220k grid resistor resistor on V4a would work but I want to get some other opinions.

[award70]

On second thought, if I put it there it would cause issues because that 68k resistor is acting as the grid leak for V4a....

[dorrisant]

Best to follow the schematic there. Don't forget to experiment with the mixer values once you are familiar with the values from the schematic and layout you have.

[award70]

Yeah maybe I'll build it as shown and then experiment.

[dorrisant]

Yeah maybe I'll build it as shown and then experiment.

Do you have any room for an extra socket?

[award70]

Do you have any room for an extra socket?

Yes I have 6 “preamp” or 9 pin sockets. I was going to use the spare for a dumbleator, which prompted my original question. I’m definitely open to ideas though.