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Hi All,

Just arrived home in Cape Town (South Africa) with my new Tweed kit in my luggage. I'm very excited to start building the amp, it will be my first F-style amp too ;-)

Here it is:


I'm also going to build a cabinet for the Tweed, it will be the first woodwork I do since school (about 15 years ago) so that will likely be trickier. I decided to make my Tweed not a tweed covered amp but to cover it with red tolex and tan + black grill cloth, but I'll use the standard Tweed cabinet design and just substitute the covering material. I've ordered the tweed kit with the VRM module which scales the whole amp I believe. I'm hoping that that will give decent tone to fairly low volumes. The PA/PI scaling on my 18 watt is great in that regard.

I've built an 18 watt amp before so this isn't my first build, I'm hoping this build will go smoothly too (The 18 watt fired up without a hitch first time round). I'm currently also building another 18 watt amp for a friend so that I'll build before I build this kit (I should be done with that in about a week if I get off my butt and do something).

Here's my 18 watt with my two guitars, both are Tokai from Japan. Cabinet contains 2x Celestion G12H30s.


Any hints and tips on how to do a proper sounding 5E3 cabinet will be much appreciated and hints about good looking tolexing around corners will also help me greatly

Cheers

Welcome to the brotherhood of Trinity! I sent you cabinet plans and when it comes to tolexing, I can help you as well. Check out the resource section though. A tweed style cab is not the easiest to cover.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

You wont be disappointed .. i turned mine on with a speaker .. finely .. just a few hours ago im hooked .. wife shut me down something called sleep
it going to be a great Friday . Trinity rocks !!!

I have not started yet but I have ordered a BBQ 12A125A, 8ohm, light dope, 30 Watt with a gold basket

Keep us posted of your progress; attempting my first build right now (Tweed).

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Muddy
Calgary,AB

I've recently completed an 18watt build but it has a little problem which I'm trying to remedy before I start my Tweed. Hopefully that will get sorted out soon, I'm itching to start the Tweed.

Maybe we can help you out there too. We do build 18s too!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I found the issue on the 18 watt. I used a cap rated for 25V between the unused input on the PI to ground. That cap sees more than 50V and the cap didn't like it. Now I must just clean up the mess I made looking for the issue because in the haste I did some bad soldering and there's a really dodgy connection on another coupling cap now. Sigh....


OK back to Tweed stuff. I see there is an old layout and a new layout. Also, I see it is recommended to use the old layout with the VRM. Why is this? I'd like to use the best layout (read minimum hum) because I don't play my amps clean and I don't want hum (not too much at any rate).

I see the VRM came with a little silicon washer. (I haven't read the instructions much, I think I know what to do LOL). I use heatsink paste with a mica washer on the other amps and that works fine. Is this silicon pad a good enough heat conductor to let the MOSFET cool through the chassis?

Do I use the silicon (maybe its not silicon) pad instead of the mica washer + heatsink paste?

Use the layout provided in the kit. If you have a black board, use the new; a red board; use the old.


Use the grey sil pad - use NO paste. it is an electrical insulating, conductive pad..

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

OK so I found someone else to make my cabinet. They're not charging an arm and a leg and do real good work (played on his JTM45 O_o)

Here's what I've done so far..







More to follow soon...

Looks good, nice clean work on the board.

Snowy

Did I post pics of a tweed with VRM? IF not, I have some that will Help you.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I wouldn't mind seeing a very neat VRM installation onto the pot as well as the interconnecting wires so I can figure out a clean layout for that part.

I assume I snip the pot's little solder holes off and solder the legs into the VRM board? (I must get the orientation right, the first two amps I built had the VVR going from loud to soft from 0-10 3rd time lucky I hope)

viewtopic.php?f=12&t=1176

Near the bottom of the page. Note this is the old layout so the 0.1uF caps are pot on a terminal strip near the tube socket.

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http://pdfelectronics.com

Thanks

BTW, the little brown 820 ohm resistor measured 930 Ohm so I replaced it with another one I had lying around. Are those brown ones the carbon composition resistors? They seemed to show gold lines which means 5% but they varied a lot more than the others (more like 10%). Unless I just need a better lamp so I can see in the dark

Question:

I see the VRM module does not contain a plastic insert for the mosfet which means the mosfet's casing will be attached to the chassis via the screw. I thought one should isolate the mosfet from the chassis entirely.

Do not bolt the MOSFET directly to the chassis. This will create shorts, sparks and general pain when the amp is started up.

Your VRM kit should have come with a grey silica pad that goes between the MOSFET and chassis.

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http://pdfelectronics.com

That part is clear. Usually I also put a little plastic insert into the screw hole of the mosfet. This keeps the bolt you use to fasten the mosfet with isolated from the mosfet itself (and hence from the chassis/heatsink) It is this plastic insert I do not have.

More pics!

Heaters, before I soldered them.


The VVR board now attached to the On/Off Switch / VVR pot



Power Transformer mostly wired, must still install the Mains power to complete this section of the amp.



Rectifier

OK so I still want some clarification on the mosfet issue. Here's a photo of the mosfet in my 18 watt. It is attached to the chassis, with heatsink paste and a mica washer. There's a little plastic insert that you insert into the mosfet before you insert the bolt. It keeps the bolt electrically isolated from the mosfet and hence the chassis. I did not receive this with my 5E3 kit. My question is, do I need to go and get one or is the mosfet casing supposed to be attached to the chassis?