EF86 TMB Modern Classic (New Project)

[foreverstrung]

So I've just begun this new build/project. Thx Josh for the schematics and layout.
I'll post pics as I go.

[JMPGuitars]

This is your turret board: https://www.instagram.com/p/Croc9pyOzRi/

I didn't solder any of it, that's on you.

[foreverstrung]

Need some help here. Suggestions. I purchased this chassis and plate(s) from Mojo Tone. Not surprisingly the plate layout is not the same as this amps "proposed" layout. The plate from MT has 2 seperate Master ports, stacked, where I would want primarily a single port. And it only gives me 2 input jacks where's as the EF86 has and optional 4 total. With 2 volume pots for 2 diff channels.....IDK if I should have a custom plate made for this EF86 or just wire it up with 2 input jacks total, with 2 volumes, for 2 channels and just use a grommet

pic 1.jpg

/plug thing for the extra port in the master location, but this seems kind of ghetto......Appreciate your thoughts. Pics enclosed. Apologies amp is upside down,

pic 2.jpg

[JMPGuitars]

Typically, it's 1 Master volume over the input jack for that channel. It's not for 2 master volumes.
Usually looks like this:

18W-master-volume.png

You can do that, or you can be "different" and use a dual concentric knob for gain/volume and then you can use your 4 inputs from the project and ignore the master label. Or scratch it off. Or put a sticker over it. It doesn't really matter, do what you think you'll find useful.

[Bieworm]

I don’t know your options, but I make my own plexi faceplates. It’s pretty easy if you have access to a laser cutter or know someone who does. The fun part is that you get to make your own logo and stuff. But I recently noticed the laser guy edited my layout on the back panel and mistakenly engraved TREMELO instead of TREMOLO

IMG_6818.jpeg

[JMPGuitars]

I don’t know your options, but I make my own plexi faceplates. It’s pretty easy if you have access to a laser cutter or know someone who does. The fun part is that you get to make your own logo and stuff. But I recently noticed the laser guy edited my layout on the back panel and mistakenly engraved TREMELO instead of TREMOLO
IMG_6818.jpeg

You gotta work on symmetry there. 2A Slo Blo should be two lines, centered under the hole. "Tremelo" isn't centered under the hole either.

Unfortunately, my laser's max width is 12ish inches. I plan to eventually get one big enough for faceplates. But faceplates would take a long time to pay for a $3000 laser.

[Bieworm]

I don’t know your options, but I make my own plexi faceplates. It’s pretty easy if you have access to a laser cutter or know someone who does. The fun part is that you get to make your own logo and stuff. But I recently noticed the laser guy edited my layout on the back panel and mistakenly engraved TREMELO instead of TREMOLO
IMG_6818.jpeg

You gotta work on symmetry there. 2A Slo Blo should be two lines, centered under the hole. "Tremelo" isn't centered under the hole either.

Unfortunately, my laser's max width is 12ish inches. I plan to eventually get one big enough for faceplates. But faceplates would take a long time to pay for a $3000 laser.

LOL you’re right!

[foreverstrung]

This is the status so far. I'm realizing the parts I still need, as I need them. Impedance switch is coming later today. Missing pots next week.
I think the 120v input jack wires need to be swapped. hot/neutral. Appreciate some clarification if so. In fact I'd appreciate a review of the fuse/power wiring as I've done it diff than the schematic with this Modern Classic laid it out. I did an older version with input and fuse as separate.

EF86 pic 1 status.jpg

Thx

[JMPGuitars]

It's a little hard to tell from the photo angle, but here's how an IEC inlet works:

iec-inlet.png

Look closely, and you'll see letters N, E, and L printed next to the spades. N = Neutral, E = Earth (ground), and L = Load (or line, or hot).

If your red wire is connected to Load, then fuse, then power switch, it's correct. The fused IEC inlet on your previous amp build works the same way, but the L -> fuse -> spade out to switch is all built in.

[foreverstrung]

So far. Still waiting on a couple things to be shipped.
Still need to dress it out some, but it's getting there.

[JMPGuitars]

You need to work on you AC section. All AC wires should be twisted together (like your switch wires, or the pilot). The pilot wires are longer than they should be. Either splice the wires together directly and twist them, or place a terminal strip much closer to the pilot lamp. Running them as far as they are going is just asking for trouble.

You should also shorten your CT to ground wires.

Take a look at the AC section in this post for reference.

[foreverstrung]

Better?

pic3.jpg

The grounding issue you pointed out, shortening CT to ground wires I still need to address

[foreverstrung]

Finished assembly.
Next itemized cap/resistor check and highlighter check.

new build 1.jpg

new build 2.jpg

new build 3.jpg

new build 4.jpg

new build 5.jpg

[JMPGuitars]

A few spots I'm not so sure about, but I'd say in general your soldering is looking much improved. Nice work!

From the looks of it, you may have some noise issues to be resolved with some chopsticks and lead dress adjustment, but that shouldn't be a big deal.

Looks good.

[foreverstrung]

So attached is the voltage chart. Obviously I've got some issues to work thru. I've been meticulously going thru all my connections and layout. Found and repaired 1 mistake.
I'll just start with this for now. I'll go over scope stuff shortly, but note V5 P7. What's up here? Is this an issue with the OT or the EL84? I hate to admit it, but IDK what to make of this.
Appreciate the feedback

Modern classic voltage chart 1.pdf

[JMPGuitars]

Check your wiring. Make sure you're measuring DC voltage. And use the correct voltage chart: files/JMPGuitars_18W_EF86_TMB_Modern_Cl ... ltages.pdf

Also, you oriented your power tube sockets reverse of how I would have. It may not matter, but it means you have to be extra careful checking your wiring.

Thanks,
Josh

[Daviedawg]

Simplest thing to go wrong are the power valves themselves. Swap them first and see if the readings follow. If you do not find any wiring issues which are going to be localised to the valve connections since the other one is reading ok, you could try swapping the OT connections over and see if the issue follows.

Dd

[foreverstrung]

Simplest thing to go wrong are the power valves themselves. Swap them first and see if the readings follow. If you do not find any wiring issues which are going to be localised to the valve connections since the other one is reading ok, you could try swapping the OT connections over and see if the issue follows.

Also, you oriented your power tube sockets reverse of how I would have. It may not matter, but it means you have to be extra careful checking your wiring.

I reversed the EL84's and still the same readings and location.
Switched the blue/brown wires from the OT and pin7 @ V4/5. Voltage issued followed the wires
All wiring at the sockets and elsewhere are connected as itis in the layout. Triple checked.
Talked to Gradyon at GDS and he said to disconnect the blue and brown wires from the tube sockets and measure the ohms. Should be 600 ohms blue to brown. 300 ohms blue to red (center tap at 32/32 cap) and 300 ohms brown to red.......I got 366 ohms blue to red. OL brown to red and OL blue to brown........Graydon sent me a replacement.
Of course I thought It might be my fault the OT was faulty, but I checked everything multiple times and see nothing. Upon first power up I used a dim bulb with no issue. It never blinked.

The chassis came with the power tube sockets oriented differently. I really should have just drilled them out. In fact, I'm real happy with how this amp is dressed out, except for the heaters. There done right, I've really made sure of that with the oriented issue, but the wiring and shrink wrap just looks sad compared to the rest of the amp. I might just redo them while I wait for the new OT

[foreverstrung]

Attached is the voltage chart. I'm still getting some high voltage. Appreciate any thoughts
Thx

voltage chart 5.25.jpg

[Bieworm]

The plate voltage on V1a looks like the 100k resistor is shorted. Overal voltages are pretty high. Start with lowering the voltage at node A and work your way down from there. But FIRST check that plate resistor on pin 1 of V1!!!!