18 watt tmb tremolo build question

[Bieworm]

Josh

What can I expect from your design on that amp...is it more gainy that the classic 18 watt? Is there A fair account of cleanish headroom on tap or is it a crunch-only amp?
I am building the board , but I would like to know if there is some clean to be obtained.
Also, the regular TMB has a MV/gain knob..is it possible to adapt that one on your design?

[JMPGuitars]

I dunno, maybe. The extra gain stage to drive the preamp will likely give it a little more punch, but you're the first person building it, so you'll have to let us know.

Headroom can be adjusted with the B+. Build it first and see how it sounds.

[Bieworm]

I dunno, maybe. The extra gain stage to drive the preamp will likely give it a little more punch, but you're the first person building it, so you'll have to let us know.

Headroom can be adjusted with the B+. Build it first and see how it sounds.

Well..the board is in progress...
It's pretty crowded btw..the right side isn't finished yet, but on the left it's New York City .
I wonder if it's going to give me trouble. The 8k2 resistors are going to be connected directly to the EL84's. That's the blue wiring..

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And damn Wima's with their short legs...there is nothing else available. Even the .0042uf caps are out of stock. I guess a .01uf as a substitute will alter things too much huh?

[JMPGuitars]

Well..the board is in progress...
It's pretty crowded btw..the right side isn't finished yet, but on the left it's New York City .
I wonder if it's going to give me trouble. The 8k2 resistors are going to be connected directly to the EL84's. That's the blue wiring..
And damn Wima's with their short legs...there is nothing else available. Even the .0042uf caps are out of stock. I guess a .01uf as a substitute will alter things too much huh?

Yeah, I custom make all my boards, so I can space them out however I like. Those holy boards are cool for small circuits, but they do get crowded fast.

Not all WIMAs have short legs. Pay attention when you order, or google the model number to see. My WIMA caps mostly have long leads, except for some of the smaller/lower voltage ones I have.

I don't know where you're ordering from, but I just checked Mouser and they have many thousands of 4700pF WIMA caps in the 400 to 630 volt range (as well as their other ranges).

Thanks,
Josh

[Bieworm]

I buy mostly at a local electronic components store. Usually they have everything I need, but not now clearly.
I am going to order online. Taking a few days off of building.. the family is starting to complain

[zaphod_phil]

Even the .0042uf caps are out of stock. I guess a .01uf as a substitute will alter things too much huh?

It depends on where it's being used. I've searched through the TMB Tremolo schematic and don't see any .0042uf caps :-/

[Bieworm]

Even the .0042uf caps are out of stock. I guess a .01uf as a substitute will alter things too much huh?

It depends on where it's being used. I'm searching through the TMB Tremolo schematic and don't see any .0042uf caps :-/

Oh yes there are 4... but I seem to have written .0042..should have been .0047!! But I have them now.. the board is ready, except the groundwiring

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[JMPGuitars]

For future reference you should do the ground bus wires before putting anything on the board. The grounds buses generate a lot of heat soldering them in, and you don't want that on the components. I'd use heatsinks while soldering it in for your current build.

For me, the process is:
1. Build the board, including the bus wires
2. Solder the wire connections to the board
3. Solder the components to the board

That way the least amount of heat is applied to the components in the process of building the amp.

Thanks,
Josh

PS. I'm looking forward to hearing this when you're done.

[zaphod_phil]

Oh yes there are 4... but I seem to have written .0042..should have been .0047!!

So that's what they are! I thought I must be going crazy

[Bieworm]

For future reference you should do the ground bus wires before putting anything on the board. The grounds buses generate a lot of heat soldering them in, and you don't want that on the components. I'd use heatsinks while soldering it in for your current build.

For me, the process is:
1. Build the board, including the bus wires
2. Solder the wire connections to the board
3. Solder the components to the board

That way the least amount of heat is applied to the components in the process of building the amp.

Thanks,
Josh

PS. I'm looking forward to hearing this when you're done.

Thx for the tips. Will learn from that a lot!
Step by step... becoming an addict. Got the classic 18W to work with all the right voltages yesterday. That was a quest on itself, but I learned a lot along the way.
The TMB tremolo is really itching... it is not going to be long now before it wil run. Already plan to rip the guts out of my newlywed classic an go for the JMP design. You'll get a well deserved mention on a proper place on the amp,Josh!

[pacealot]

Just wanted to crash your thread to say that I just registered here specifically because I'm incredibly interested in this specific circuit, so I'm following your build closely (and anxiously!). Trying to work up both the nerve and the finances to follow suit and build it myself as well.

I did have a question/observation: I noticed that one of those .0047µF caps shown on the layout is listed as .047µF (actually .05µF) in the schematic. It's the one going to ground from the run of three .01µF caps in the tremolo speed section of V1 (the rightmost of the ones on the layout). Curious as to which value is meant to be correct...

[Bieworm]

Just wanted to crash your thread to say that I just registered here specifically because I'm incredibly interested in this specific circuit, so I'm following your build closely (and anxiously!). Trying to work up both the nerve and the finances to follow suit and build it myself as well.

I did have a question/observation: I noticed that one of those .0047µF caps shown on the layout is listed as .047µF (actually .05µF) in the schematic. It's the one going to ground from the run of three .01µF caps in the tremolo speed section of V1 (the rightmost of the ones on the layout). Curious as to which value is meant to be correct...

Welcome on 18W !!!
Well the build is in progress.. the board is ready for implanting and the wiring at the PT is finished just now.
Shoot! That is a good question. I put in a .0047, but you're right I think. In the classic tremolo that is a .047 in that spot.
This calls for Josh? Phil? .0047 or .047? Wouldn't the .0047 make it a very slow trem?
Thanks in advance for the bright answers

[JMPGuitars]

Whoops. Nice catch with the typo. Please download the corrected layout: files/JMPGuitars_18_Watt_Tremolo_TMB_Layout.pdf

I would correct the cap in your build.

Also, .05 and .047 or .005 and .0047 are respectively effectively the same. I wrote them as .05 in the schematic to match the original for highlighter verification testing, and left them because I was too lazy to change them to the values I use since it makes no difference.

Thanks,
Josh

[Bieworm]

[quote=JMPGuitars post_id=245022 time=1583717518 user_id=2]
Whoops. Nice catch with the typo. Please download the corrected layout: files/JMPGuitars_18_Watt_Tremolo_TMB_Layout.pdf

I would correct the cap in your build.

Also, .05 and .047 or .005 and .0047 are respectively effectively the same. I wrote them as .05 in the schematic to match the original for highlighter verification testing, and left them because I was too lazy to change them to the values I use since it makes no difference.

Thanks,
Josh
[/quote]
I find you far from lazy Josh!
Will change the cap in a few hours, when I come home from work.
Just have to put in the pots for trem int + speed and I can wire the thing up.
Also redid the wiring for the heaters. Now they're even more properly twisted all over.
Is there any harm in tiewrapping all wires at the PT in a few strands to keep things neat and tidy? I already did, but I don't know if there are wires in that area that absolutely need to be separated?
I know that preampwires and heaterwires need to be apart..
Any other stuff I need to know to avoid hum and oscillation?

[Bieworm]

20200309_224052.jpg

Tubes are wired now. Tomorrow the pots

[colossal]

Although the "arrow" indicating the direction to ground printed on the sleeve is pointing towards your ground, that G-Luxon 1000uF cathode bypass cap looks like it's in backwards (polarity reversed). Usually the tapered/fluted end indicates the (+) terminal. Might be something to check.

[Bieworm]

Although the "arrow" indicating the direction to ground printed on the sleeve is pointing towards your ground, that G-Luxon 1000uF cathode bypass cap looks like it's in backwards (polarity reversed). Usually the tapered/fluted end indicates the (+) terminal. Might be something to check.

You're right! That might be wrongly printed or wrapped. Can I check that somehow?

[Bieworm]

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Appears I have various electrolytics like that of which I know they operate correctly. Even though the waist is on the negative side. They are radial types. I think the general rule only appplies for axial types

[JMPGuitars]

They are radial types. I think the general rule only appplies for axial types

That's correct, that rule only applies to axial style. Radials have the negative stripe next to the negative terminal rather than pointing at it. The fluted waist is next to both terminals in that case. Your photos make it look confusing because you have the radials disguised as axials the way they're laying down.

[Bieworm]

Cooked my Power Transformer. The leg from the rectifier resistor was broken at the diode side. It sparked and then the tranny was starting to melt and gave smoke. The cables from the filament wires. Makes sense?