Tremolo TMB Questions

[JMPGuitars]

Another quick question. My power jack is not the same as in the TMB manual. I suspect the power input jack in the manual has a slow blow fuse contained. I have none. But as this pic shows, I've got a hole in the chassis, (but not the plate. easy enough to drill). I'm sure this is the spot for a solo slow blow fuse. But it's not in any layout I have, nor could I find anything in this forum. I see it in the schematic and I'm getting better reading and deciphering them, but I sure would appreciate some direction on this fuse holder. I'd like to have something to compare it too if I install one using the schematic as I see it.
To clarify, it appears to be real simple, but I wanted to run it by you guys.
Which kind/type specifically. Does it matter? Suggestions on where to pick one up and best of all, a pic or something of the layout with it in.
Thx

I sent you a fused socket. There's a 2A slow-blow fuse in a sliding drawer, accessible from the outside of the chassis.

https://www.mouser.com/ProductDetail/562-719W-00-02

If you're not familiar with them, they're sneaky. Look closer at the front:

fused-iec-inlet.jpg

EDIT: A guy that I made one of these amps brought it in for me to check out and replace the tubes (his power tubes were dead, he played the hell out of them for a year), and he didn't know there's a fuse in that IEC socket either. I guess I should tell people.

Thanks,
Josh

[foreverstrung]

This shielded wire applications, I'm assuming that I'm only connecting the inner wire. The exterior braided wire is clipped back and then shrink wrapped to keep the ends clean and tidy. Correct? That's how it "appears" to me from the TMB manual.
Also, you guys, I don't want to hijack this thread with these questions. If it's more "politically correct", I'll start a new thread......Please advise.

That's correct for only one end of the shielded wire. The opposite end gets the outer braid connected to ground (that's what creates the shield).

Don't worry about it, that's what this thread is for. ...but you are welcome to start your own thread if you want to post your progress separately.

Thanks,
Josh

Question about this shielding wire. In the layout drawings it shows none of these shielded wires outer braided wire grounded except for the input jack and that's only through a resistor. Is the braided part of the shielded wire being grounded "implied" and always just how you roll?
Can you guys help me to understand this application/installation?

[foreverstrung]

Besides the shielding wire question, there's this. Which is it? 220 0r 500

[Bieworm]

I use 300 or 330 there
I advise you to put in a 220p, but with enough clearance between the board and the cap. That way you can parallel another cap to tweak to the desired treble response. The tremolo TMB can be a bright bugger.
I also use a 25k mid pot instead of the 50k. I like it a lot more... but that's my personal preference.

[JMPGuitars]

The shielding wire is only implied on the layouts, no ground connections are shown. That's up to you, and the resistor you're talking about has nothing to do with it. Look at the schematic, you'll see that 1M resistor is between hot and ground.

I'm with Bieworm, I usually use a 25K pot, and a 220pF cap there. That's for brightness. A higher value will be brigher. 220pF not as bright as 500pF, 25K pot not as bright as 50K pot. You can use the tonestack calculator app to compare if you want.

Check which cap values I sent you before soldering.

Thanks,
Josh

[foreverstrung]

Referring to the manual and then the "layout" drawing regarding the effects loop, The picture in the manual shows the "recieve" jack connecting to the PCB board one way and the the layout drawing showing it another way. The schematic, as I understand it, is the same as the picture in the manual, so I suspect the "Layout" drawing is incorrect, but I'd appreciate clarification if possible. If for nothing else then confirmation
Thx

[Bieworm]

To be honest I was confused about that too. But it appears to me Josh has the Reverb Send jack closer to the speaker jack, and the Return jack further from the speaker jack.
I do it the other way around.

Josh, could you post a pic from the backplate? Thanks

[JMPGuitars]

Not reverb, effects loop.

_JMP3350.jpg

Anyway, the only thing that matters is that the send/receive jacks line up to the correct words. The amp in the manual lines up correctly.

Thanks,
Josh

[Bieworm]

Not reverb, effects loop.

_JMP3350.jpg


Anyway, the only thing that matters is that the send/receive jacks line up to the correct words. The amp in the manual lines up correctly.

Thanks,
Josh

Correct! That's what I was thinking...
I was checking out the FX loop earlier this week for some other project. That was what I noticed then. And now it came up in this thread.. I had to respond

[marygross]

Thanks for sharing

[Quokka42]

Not sure if this is the right place to ask, but I am building an amp with this same tremolo circuit at the moment, but I can't get a 2M pot for the speed. I did see a description of how this circuit works but can't find it. I am wondering what effect using a 1M pot will have and how to compensate for it?

[JMPGuitars]

Not sure if this is the right place to ask, but I am building an amp with this same tremolo circuit at the moment, but I can't get a 2M pot for the speed. I did see a description of how this circuit works but can't find it. I am wondering what effect using a 1M pot will have and how to compensate for it?

Since a pot is a variable resistor, and 1M is half of 2M, you could expect the maximum level (speed) to be lower if using a lower pot, maybe about half being that it's linear.

B2M pots are readily available, probably even down undah. The only question is the best source with shipping charges considered. Alpha makes a good 2M linear pot, and you can get them from most of the popular sources including Mouser.

[Bieworm]

I use these: https://www.tube-town.net/ttstore/compo ... 2_50_10666

[Quokka42]

Not sure if this is the right place to ask, but I am building an amp with this same tremolo circuit at the moment, but I can't get a 2M pot for the speed. I did see a description of how this circuit works but can't find it. I am wondering what effect using a 1M pot will have and how to compensate for it?

Since a pot is a variable resistor, and 1M is half of 2M, you could expect the maximum level (speed) to be lower if using a lower pot, maybe about half being that it's linear.

B2M pots are readily available, probably even down undah. The only question is the best source with shipping charges considered. Alpha makes a good 2M linear pot, and you can get them from most of the popular sources including Mouser.

Thanks for that - exactly what I was looking for. I am sure I will source a 2M pot eventually, but I'm kind of housebound with a broken foot ATM and my usual suppliers don't have them. I will build it with a 1M for now and I suspect it will be fine at the lower speeds. I would expect with the series resistor it is probably more like 60% and from memory the higher speeds are pretty ridiculous. I eventually want to modify it to take a string reverb tank anyway. The tremelo wasn't bad, but reverb sounds better on guitar IMHO.

[JMPGuitars]

Thanks for that - exactly what I was looking for. I am sure I will source a 2M pot eventually, but I'm kind of housebound with a broken foot ATM and my usual suppliers don't have them. I will build it with a 1M for now and I suspect it will be fine at the lower speeds. I would expect with the series resistor it is probably more like 60% and from memory the higher speeds are pretty ridiculous. I eventually want to modify it to take a string reverb tank anyway. The tremelo wasn't bad, but reverb sounds better on guitar IMHO.

If you don't like the speed range, you could add a series resistor too.

However, if you prefer reverb, you should build the Tremolo TMB Reverb and have both.

[Rvaughan68]

New to the forum. This looks like an amp I would love to build. Where can I source the chassis and face plates? Also, will the chassis fit in a standard 18W 1x12 combo cabinet with controls oriented on top?

[JMPGuitars]

New to the forum. This looks like an amp I would love to build. Where can I source the chassis and face plates? Also, will the chassis fit in a standard 18W 1x12 combo cabinet with controls oriented on top?

Hi,

Welcome to the forum!

I can get you the chassis, faceplates, and a board (either PCB or turret board). I could also do a full kit (no cabinet) if that's something you want. The custom chassis should fit the width, but you will want a deeper cabinet. If you're having the cabinet made for you, 10" depth is usually good.

For more info you can email me directly via support at jmpguitars dot com.

Thanks,
Josh

[Rvaughan68]

Awesome. Thanks for the quick response.

[Rvaughan68]

Josh thanks for getting me started with chassis and transformers. I'm sourcing all the parts and had a few questions. Are the 220pf in the treble circuit and .01uf caps in the tremolo circuit Wima style film caps? Can you recommend voltage and the lead spacing to fit the PCB. Link to Mouser or other would be great. Also what type of switches do i need for the reverb and tremolo circuits. One more, what type of tube sockets are best to use with the chassis. Remember, you said the need paitience is just beginning. Thanks

[Rvaughan68]

Sorry about the bad grammar/spelling at the end there.