18Watt.com

This thread is for any questions specifically related to the Tremolo TMB circuits, both for turret builds and the PCBs.

The BOM, schematics, and layouts are in the downloads section here: viewtopic.php?f=25&t=25550

Prior to building / attempting to build this circuit, please review the soldering and grounding threads in my signature.

Thanks,
Josh

Here's a link to the Tremolo TMB Reverb PCB: https://reverb.com/item/40259316-jmpgui ... v1-36-2021

Here's a link to the footswitch PCB: https://reverb.com/item/40466873-jmpgui ... switch-pcb

Thanks,
Josh

First question: how about a 1 watt version?

Bieworm wrote: ↑

Thu 05/06/21 2:01 pm

First question: how about a 1 watt version?

I could do that, but not sure how quickly I'll have time.

LED 3PDT switches for the 2 button footswitch (single color LED versions only):
https://www.amplifiedparts.com/products ... t-led-ring

Amp side TRS jack: Cliff CL12207 or similar
Pedal side TRS jack: Neutrik NMJ6HFD2-AU or similar

Filtered IEC inlet: Schaffner FN9260. Use a 10A ceramic fuse for Neutral (because we don't actually want this fused), and a 2A Slow Blow for Line (US voltages).

In tighter spaces (height), Nichicon URS2G220MHD1TN 22µF 400V will work for the preamp filter caps.

The pcbs have arrived. My plan is to solder components I have onto the board. Dumb question #1 do you solder the leads on both sides? There are 2 68K resistors on the BOM and Schematic - I only see one on the board and it seems to have " * " next to it. The schematic shows it going to pin 2 of V4 - on the layout I don't see any 68Ks- make me think I've got the wrong layout..(2.15 3/13/21)
All resistors are called out to be 1 watt - is there any wiggle room?...maybe 1/2 watt...

lavrgs wrote: ↑

Wed 06/09/21 5:57 pm

The pcbs have arrived. My plan is to solder components I have onto the board. Dumb question #1 do you solder the leads on both sides? There are 2 68K resistors on the BOM and Schematic - I only see one on the board and it seems to have " * " next to it. The schematic shows it going to pin 2 of V4 - on the layout I don't see any 68Ks- make me think I've got the wrong layout..(2.15 3/13/21)
All resistors are called out to be 1 watt - is there any wiggle room?...maybe 1/2 watt...

Always look at the schematic. If you look next to the letter Y with a blue circle, you'll see both 68Ks are actually for the FX loop, one is on the board, one is not. There's a * next to it because if you're not using an FX loop, you can skip both 68Ks and jump X to Y. I should put a note on the docs about this, thanks for bringing it to my attention.

I don't recommend lower wattage, but in some spots it's okay. You also need to consider voltage, and most 1/2watt resistors are typically only 250V, which is not enough. The schematic also shows voltages, so you can see where some of them are more important than others.

I'm not sure what you're asking about the soldering leads on both sides thing?

Thanks,
Josh

JMPGuitars wrote: ↑

Wed 06/09/21 7:36 pm

I don't recommend lower wattage, but in some spots it's okay. You also need to consider voltage, and most 1/2watt resistors are typically only 250V, which is not enough. The schematic also shows voltages, so you can see where some of them are more important than others.

I'm not sure what you're asking about the soldering leads on both sides thing?

Thanks,
Josh

-
I need to order a bunch of resistors so a few extra won't hurt.
I see the 2nd 68K connected to the FX Return - got it
Quick question on the foot switch board - it looks like the distance between switches is pretty close to the switch box that came with my mojotone - did you design it to fit? I assume the LED switches you recommended eliminate the need for the resistor and led. I don't understand how power comes in but I haven't looked closely

Soldering the components on 1 side of the board is enough. I did my soldering on the bottom side of the PCB

lavrgs wrote: ↑

Wed 06/09/21 11:24 pm

I need to order a bunch of resistors so a few extra won't hurt.
I see the 2nd 68K connected to the FX Return - got it
Quick question on the foot switch board - it looks like the distance between switches is pretty close to the switch box that came with my mojotone - did you design it to fit? I assume the LED switches you recommended eliminate the need for the resistor and led. I don't understand how power comes in but I haven't looked closely

CMF60 are the resistors I use, they're great.

I don't know anything about the switch box from mojotone, but if it fits, it fits. I think I was looking at a 1590B size box.

You still need a resistor with the built in LED switches. The LEDs and battery are completely optional, but if using an LED, then the resistor is required either way.

Thanks,
Josh

JMPGuitars wrote: ↑

Fri 05/07/21 7:14 pm

Filtered IEC inlet: Schaffner FN9260. Use a 10A ceramic fuse for Neutral (because we don't actually want this fused), and a 2A Slow Blow for Line (US voltages).

The FN9260 is a base number there are a bunch of modifiers. Not all have 2 fuses the biggest question is amperage rating since you say you're using a 10 amp fuse should I be looking for an IEC rated at 10 amps?

lavrgs wrote: ↑

Fri 08/06/21 9:35 am

JMPGuitars wrote: ↑

Fri 05/07/21 7:14 pm

Filtered IEC inlet: Schaffner FN9260. Use a 10A ceramic fuse for Neutral (because we don't actually want this fused), and a 2A Slow Blow for Line (US voltages).

The FN9260 is a base number there are a bunch of modifiers. Not all have 2 fuses the biggest question is amperage rating since you say you're using a 10 amp fuse should I be looking for an IEC rated at 10 amps?
IEC.JPG

This is the exact model I'm currently using: https://www.mouser.com/ProductDetail/631-FN9262-10-06

I've also used the FN9260-10-06.

The mains fuse will blow above 2A. The point of the 10A ceramic for Neutral is because we don't actually want a Neutral fuse. If you find a model number with the same filtering, and only a single fuse, let me know the part number, and I'll start using that instead.

Thanks,
Josh

On my 2 last builds I followed Matec's schematic of the Jtm145. That's a standard IEC socket and the filtering circuit wired on the board. I'm pretty happy with that approach.

Bieworm wrote: ↑

Fri 08/06/21 11:20 am

On my 2 last builds I followed Matec's schematic of the Jtm145. That's a standard IEC socket and the filtering circuit wired on the board. I'm pretty happy with that approach.

My chassis is designed to use a fused or filtered & fused IEC inlet. It's better to keep it on the inlet if you have the space.

JMPGuitars wrote: ↑

Fri 08/06/21 12:27 pm

Bieworm wrote: ↑

Fri 08/06/21 11:20 am

On my 2 last builds I followed Matec's schematic of the Jtm145. That's a standard IEC socket and the filtering circuit wired on the board. I'm pretty happy with that approach.

My chassis is designed to use a fused or filtered & fused IEC inlet. It's better to keep it on the inlet if you have the space.

I know.. I'm aware of that benefit. But for my own amps I use large chassis' like you. The people I built these 2 amps for wanted a smaller package

I originally wasn't going to install turrets into the board but I'm considering it, although it may have been better when I had a bare board. Are turrets soldered into this board? I ask because the ones I have are definitely not a press fit...are there different turrets for pressing and for soldering?

lavrgs wrote: ↑

Sat 04/23/22 5:04 pm

I originally wasn't going to install turrets into the board but I'm considering it, although it may have been better when I had a bare board. Are turrets soldered into this board? I ask because the ones I have are definitely not a press fit...are there different turrets for pressing and for soldering?

I press and solder the Keystone 1509-4 turrets. Anything that fits can be placed and soldered too. Turrets aren't necessary though, that's up to you.

I'm just beginning this build. Reviewing other threads, I'm assuming 20g wire for the heaters (stranded) and 22g for the rest? I found a thread on here explaining the diff between PVC and PTFE wire. I picked up PVC.
I'm assuming 20/22g wire works for this amp because it's an 18w with EL84's. Were as a bigger amp the wiring might be 18/20g.
These are questions. Not statements. Appreciate any input

foreverstrung wrote: ↑

Sat 10/22/22 9:51 am

I'm just beginning this build. Reviewing other threads, I'm assuming 20g wire for the heaters (stranded) and 22g for the rest? I found a thread on here explaining the diff between PVC and PTFE wire. I picked up PVC.
I'm assuming 20/22g wire works for this amp because it's an 18w with EL84's. Were as a bigger amp the wiring might be 18/20g.
These are questions. Not statements. Appreciate any input

I use 20AWG across the board, except for 18AWG for the power connections to the transformer.
My shielded signal wire is usually 22AWG. I prefer the PTFE because it's thinner, and holds its shape better, but high-temp PVC is fine. If I didn't mention this in the build guide, I probably should.

Thanks,
Josh

Ya, it's not in the guide. As well, where the "shielded signal wire with 22AWG" is used. Same with the 20AWG "across the board" and 18AWG for power connections......please excuse my ignorance, I'm just not sure of these little things and where exactly each is supposed to be used as I refer to the build guide.