18W TMB build

[dkochan]

Done, for now. Just a kit build (BYOC) of an 18W TMB, no trem.

I have learned a few things around here reading through the archives and will want to change a couple of things about this, (like the incoming mains grounding, and grounding to the PT mounts) but it is a fun little amp and runs nice and quiet.

Dave

[xtian]

Nice work. Looks very tidy.

[dkochan]

Thank you!!!

[The Ballzz]

Agreed on the tidy, nice work! Good thoughts on the grounding issues. Just curious, whose kit? Not a big fan of the impedance selector switch, but..... nicely executed.
Enjoy,
Gene

[dkochan]

Thank you! It was from the Build Your Own Clone folks, byocelectronics.com.

Just curious about the impedance switch dislike... You don't like putting a selector there, or you don't like that particular switch, or ? Opinions on these things are good and the more the merrier. I am always looking for whys.

Thanks much,
Dave

[The Ballzz]

It's the particular switch I'm not fond of, simply from a mechanical/construction standpoint. I prefer:

https://www.tubesandmore.com/products/P-H600

http://www.mojotone.com/Mojotone-Impeda ... -image.jpg

Just appears more sturdy/durable/etc!
My $.02 & Likely Worth Even Less,
Gene

[dkochan]

Gotcha. Yeah, I think they put this together to hit a price point. There were some things I would have been willing to spend a bit more on.

Thanks for the link to the other switch. I agree that it looks better in every way.

That is the fun of building from a kit, unless it comes from someone like RJ... I am starting to see the light here as far as sourcing parts and planning.

Thanks again, Gene.

Dave

[RockinRocket]

Are the pots grounded to the chassis? If so you have the pots grounded to the power transformer mount as well. If you amp I pretty quiet I don't know if regrounding it will make any difference, mine didn't and my 18 watt lite is dead quiet using the original grounding schem.

[Structo]

The ground on the IEC should go to it's own point on the chassis. (earth ground)

You have it going to the filter cap.

Also if you have any heat shrink tubing, I would put that on the end of the wire rather than wire nuts that can come loose.

That impedance switch that Ballz showed is the one I have used on several amps.
Very robust!

[pdf64]

You've made a really nice job there.
There are a few things there would be better done differently, eg Structo's points.
It's a shame that the instructions http://byocelectronics.com/TMB18instructions.pdf contain several such examples of poor practice.
I don't like that they've decided to add standby, especially such a poor arrangement, that facilitates hot switching of the reservoir on to the rectifier.
I don't understand the mindset that puts more value on standby than, say, adding a B+ fuse?

[dkochan]

Thanks for the kind words.

Yes, as I hinted above, the more I have learned here the less I have been impressed with the instructions and kit. It filled a need for me - a "paint by numbers" build while I have been laid up due to an accident, (being able to work on it for only a few minutes at a time, having instructions to follow and kind of "placehold" for me was a real help) but I almost want to label this thing "For Amusement Only."

I have built a few of their pedals - solid kits and there are a couple I absolutely love - but they need help in the amp department. Super great company to deal with, too. Figures.

I am thankful to have a site like this where I can "learn to know better." You guys are the best.

Dave

[The Ballzz]

dkochan,
Hey, don't feel too beat up by us "picky" folks! With the neat and tidy construction, addressing any of the mentioned issues should be quite easy, if and when you feel compelled.

A) The switch I mentioned should be just fine for personal use. My comment was simply inspired by the fact that I would not use that one for something I was "planning" to sell.
B) The "Mains" grounding issues should be be addressed eventually, but should not pose much trouble until/unless you become a road dog plugging it into multiple, unknown quality power sources.
C) The standby issue can be avoided completely by simply leaving the switch in "run" position all the time and just letting the amp fully warm up (30-60 seconds) before applying signal.
D) Replacing the wire nuts with doubled up shrink tube "should" be addressed sooner rather than later. I typically make the first piece 1/2" or so extra long, shrink it, then fold it back onto itself and then put another over it. You could even "triple" it, if that better floats your boat.

All in all, a very nice build that likely sounds fantastic! You should be proud! Even more so if this is you first amp build and I'm guessing it is, given the cleanliness of your nicely built cradle!

Nice Job,
Gene

[pdf64]

I suggest moving the hot line wire between the IEC socket and fuseholder to the back terminal of the fuseholder.
As it is, if someone is careless when replacing the fuse and doesn't pull the line cord out of the wall socket or amp, they may get shocked as they fit a good fuse.

[dkochan]

dkochan,
Hey, don't feel too beat up by us "picky" folks! With the neat and tidy construction, addressing any of the mentioned issues should be quite easy, if and when you feel compelled.

A) The switch I mentioned should be just fine for personal use. My comment was simply inspired by the fact that I would not use that one for something I was "planning" to sell.
B) The "Mains" grounding issues should be be addressed eventually, but should not pose much trouble until/unless you become a road dog plugging it into multiple, unknown quality power sources.
C) The standby issue can be avoided completely by simply leaving the switch in "run" position all the time and just letting the amp fully warm up (30-60 seconds) before applying signal.
D) Replacing the wire nuts with doubled up shrink tube "should" be addressed sooner rather than later. I typically make the first piece 1/2" or so extra long, shrink it, then fold it back onto itself and then put another over it. You could even "triple" it, if that better floats your boat.

All in all, a very nice build that likely sounds fantastic! You should be proud! Even more so if this is you first amp build and I'm guessing it is, given the cleanliness of your nicely built cradle!

Nice Job,
Gene

Thank you!!

Actually the cradle is new. I finally gave in on that. This was my third build. First one was a scratch-built Champ-ish "thing" from the Marshallized Champ layout in KOC's TUT3. The schematic and layout are not perfect. DAMHIKT. That was maybe 12 years ago.

The second was an Egnater seminar amp, maybe 8 years ago.

Then this one. So I am sort of going backward on the difficulty curve. :oopsd:

Next up is either a 5E3 that I have most of the parts for or an Express that I have parts coming from RJ for. A D-style is on the "medium term" list. That one is in the planning phase. Once I am smart enough to ask dumb questions I will be asking dumb questions over in the D area.

It is good to be back doing this stuff and I think the addiction is really sticking this time.

[dkochan]

I suggest moving the hot line wire between the IEC socket and fuseholder to the back terminal of the fuseholder.
As it is, if someone is careless when replacing the fuse and doesn't pull the line cord out of the wall socket or amp, they may get shocked as they fit a good fuse.

I thought I had done that! I should have double-checked with the meter.

Thanks for the catch!!!