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Hi, I've just started the build of the 5E3.

It's first amp build. My only experience is the build of a headphone preamp (a Crack from Bottlehead with the speedball option. I found it an easy build).
I think for this build I'm going to have few questions and will need some help despite the documentation..


So here's my 1st question about the tubes sockets orientation and numbers.

*** Are they well oriented like this ?
Page 31 (version 3.) it says to orient the pin #1 away from the board (which is what I did I think) but in the coloured layout/diagram (not sure how to call it), the orintation seems to be on the opposite direction (#1 in the direction of the bottom of the metallic box).




*** On the picture, is the #1 pin the one with the black point I put with a marker ?
Page 28, it's said the pins are numbered clockwise when seen from the bottom. But on the coloured layout/diagram they seems to be viewed from the top (in my understanding) but are numered clockwise as well which make no sense. So obviously, there's something I don't understand well here as well.


Thanks for your answer !



*** Btw, do I have to open a new topic for each question I will have (not to many hopefully) or should I put them within this thread ?
*** Would some of you share the links of topic/forums thread (etc.) of builds full of pictures, if you have some in your bookmarks ? That would be helpfull

Thanks againlot for your time and help. Very appreciated !

1) OK, here's the trick. Fold the layout along the dotted line (where top and back of chassis drawing meet) as if you were looking from inside the chassis. You'll see that the octal (8) pin tube key way points to the top of the chassis and the gap between pins on the noval (9) pin socket points towards the bottom back edge of chassis. Simply put, rotate sockets 180 degrees from what you have. Also, the sockets have the (barely readable) numbers stamped on them. I always do what you did and mark the number one (1) pin on octal sockets, but on the inside. 2) Continue this post for your build, it will be easier to follow. 3) Sorry don't have any bookmarks to share, but you can maybe use the search function for Tweed Builds.

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"The only problem with being retired is you never get a day off"

Oops, noval socket mounted correctly. Also, I always suggest reading JoeyVelour's post "Of Soldering and Solderability" Backstage>Resources, page 3, in addition to Stephen's soldering guidance in the Tweed build manual. And double check under board jumper wiring, on my first Tramp made an error on a jumper that drove me nuts trying to find

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"The only problem with being retired is you never get a day off"

sockets have the (barely readable) numbers stamped on them.

Thanks a lot Hankules. It helps a lot. I didn't pay attention it was written on the socket (it's barely visible indeed). It appears I've put the marker on the #8 (that I thought was #1) -also did inside, on the outside was only for the purpose of the picture-. I've misinterpreted the clockwise direction of the number viewed from the bottom in the doc. I was confused about this and didn't want to go on without being sure..

Ok, so 1st (and hopefully last) major error avoided !

EDIT // I've found the answer in the meantime.


Hi again ! Quick question...

About the installation of the Heater wires, can someone confirm me it's ok to attach the black wires to the 5th and then the 4th socket pin (instead of the 4th and then the 5th) ?

Thanks !



(It may seem a silly question for most of you. My guess is that it makes no difference but I don't want to trust a guess and need to be 100% sure. )
Also, I'm not sure if it's linked to the mention Don't switch the heater wire polarity.

It makes no difference as long as pin 4 and 5 are connected. Polarity refers to making sure one color of wire is connected to the same pins, if you follow the layout, you're golden. Tip: It's is easier and neater (for me at least), to wire backwards from V1>V2>V3>etc. and end up at the terminal strip. Try and keep the wires twisted as much as possible and close to the chassis. Heater wires are AC current and and can introduce 60 cycle hum; keeping the heater wires close to chassis helps prevent this. Same applies to transformer wires. Twisted and close to chassis.

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"The only problem with being retired is you never get a day off"

Looks good so far I like to keep the heaters twisted as close to pins as possible, but that's me being OCD. You should be good.

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"The only problem with being retired is you never get a day off"

Thanks (again ! ) Hankules !!

I've installed this afternoon the power transformer. I think it's doing well (except I was wondering afterwards if I had to twist the yellow wires and red wires toegther by color like the greens)
Pictures below...

I'm now have to test the power transformer as required and I have to say I'm just stuck there..

- AC MAIN voltage : where do I put the two pins of my multimeter ?
- AC Voltage across the indicator lug : where do I put the two pins of my multimeter ?
- AC Voltage across pin 2-8 : where do I put the second pin of my multimeter ?
- AC Voltage across pin 4-6 : where do I put the second pin of my multimeter ?


Also, I don't get what I'm supposed to do at this step : Connect to the center tap of the Output Transformer to the same side of the stand by switch.
Any thoughts ?


Thanks !!! (Hankules maybe ? Since you seems to be my dedicated saver !!!

The heater wiring looks good.

Yes, ideally you should twist the two yellow wires from the power transformer together right up to the tube socket. Same with the two red wires. As Hank said, it's all AC coming out of the transformer so the wires should be twisted to minimize hum. The red-yellow and green-yellow go to ground so they can run separately.

I'm not sure about that line mentioning the center tap for the output transformer. As shown on the layout drawing, it connects to the board along with the long red wire you have on the Standby switch. Your output transformer isn't even installed yet, so don't worry about it. But you should put some tape on the end of that long red wire on the Standby switch so it can't contact anything during your testing.

AC MAIN voltage: where do I put the two pins of my multimeter?
On the power connector. One probe on the live terminal and the other on the neutral terminal.

AC Voltage across the indicator lug: where do I put the two pins of my multimeter?
One probe on one of the green wires that connect to the pilot light and the heaters, the other probe on the other green wire.
If you connect one probe to the chassis and the other to either of the green wires you should read half the voltage you got measuring across the two green wires.

AC Voltage across pin 2-8: where do I put the second pin of my multimeter?
One probe on pin 2, the other probe on pin 8.

AC Voltage across pin 4-6: where do I put the second pin of my multimeter?
One probe on pin 4, the other probe on pin 6. Also if you connect one probe to the chassis and the other to either pin 4 or pin 6 you should read half the voltage you got measuring across the two pins.

This is high voltage, so be very careful! If your meter has alligator clips for the probes, use them. Also, keep one hand in your pocket when probing around high voltage. This will keep your heart from being in the middle of the path if you accidentally touch something you shouldn't.

It's all AC voltage at this stage, so make sure your meter isn't set to DC. You won't get any meaningful readings that way.

1) Wall Outlet- both probes , it may vary slightly from 120, 115 or whatever your wall voltage should be. 120VAC in USA. You are measuring AC (VAC) using BOTH probes of multimeter on the respective pins for 2, 3 and 4. RE: Xfmr wires: I didn't twist mine, didn't make any difference on my Tweed, but probably wouldn't hurt. BE careful, but confident and steady, you're measuring high voltage.

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"The only problem with being retired is you never get a day off"

Dang it, beat me again. And in depth, too I would suggest maybe making red wire from standby to rectifier socket longer and route along corner of chassis to the socket. The Tweed was my first build and I see things I would change now, but it's quiet and Stephen's design is very forgiving.

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"The only problem with being retired is you never get a day off"

Thanks a lot Mitch and Hank for your time and this complete answers. It's very appreciated and very usefull !! They may seem very basic questions but with high voltages I want to do it perfectly. And as you can see I'm not familiar with electronics that much. I've missed the twist of the yellow and red wires of the transformer indeed. Unfortunately, I think they are now too short to make the correction. I'll see how it goes at the end and will think about it at that time.


So, I'll probably do the measurements this evening, in the safest envirronement as possible.


I've assembled the eyelet board in the meantime (not soldered yet). I have quick questions about it and the resitors. But I'll post about them later...

No problem. We all had to learn this stuff sometime. The ony dumb questions are the ones you don't ask!

Ideally, those red and yellow wires should be twisted together, but it's not mandatory. Just being very close together is OK, too. Yours isn't bad. You could use some cable ties to keep them together if you want.

The layout drawing is the key to the assembly. Just follow it and you should be good. There are lots of posts here about neat and successful Tweed builds you can look at for reference, too.

Here are some pictures of the Tweed I built.

Thanks for the pictures !

I was a little impatient so I've made the measurements already...

Everything looks fine. I think I've read that since there's no tube plugged, it's normal to get values a little higher than expected.. (?)
- AC MAIN voltage: 120
- AC Voltage across the indicator lug: 8 // (one probe to the chassis : 3)
- AC Voltage across pin 2-8: between 8 and 9
- AC Voltage across pin 4-6: between 723 and 730[ (it kept changing a little within this range) // (One probe to the chassis : 362)

Next step, later...

Looks good. The voltages will be higher than normal until you get the tubes installed.

True. Heater voltage (which is what you measured at indicator) will drop to 6.3 (+/-) with tubes in. You can also check the heater wiring by checking pins 4-5 and 9 of V1 socket.

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"The only problem with being retired is you never get a day off"

Hi all ! Little followup and a batch of questions... I saw that a resitor was missing so I had to wait to get it to continue. In the meantime I've started the build of the cabinet (cf. last pictures below). So as I said I have few questions. I've tried to find answers on my own but still I'd need some explaination. Hopefully it will be ok for you guys. I realize I have many...


- Resitors : the one missing was a 56K. I've received it today and checked with my multimeter and it appears it's 52.4 (instead of 56k +/-5% it should be between 53,4 and 58,8). Is it still acceptable even it's above the 5% tolerance ? The other ones seem to be ok (with the +/-5%) except the 220K. One is 211 and the other one 233.


- Signal wires : it is said in the first step that "it's imperative that where possible, the signal wires run close to the chassis, while the heater wires run as far away from the signal wires". I recognize now what's the heater wires but what are the signal wires exactly : all the others that are not heater wires or few of them (and if so wich ones ?) I wondering because I want to know for the installation of the flying leads... (if they are signal wires, I will install them as close to the chassis as possible, otherwise I won't care).


- Yellow wires (twisted from the board) : (cf. pciture below..) Do I use the big heat shrink for this wires ? I may have missed the info but I don't see the use of it anywhere in the documentation. The 2 others (the small and medium ones are for the co-axial cable, aren't they ?)



- Optionnal 470K cathodyne : Is the 470K resistor optionnal or also the yellow wire itself is also optionnal ? +it's optionnal, ok... but what the difference with or without ??



- Co-axial calbe : from the points 3 to 5 of the following pic, I'm completely lost about what I'm supposed to do... I don't know if it's because english is not my first language but I cannot figure out this part. Also I don't understand why there's this mention "be sure to ground only at this end of the cable". The other end of the co-axial cable is not connected to anything, right ?



- Last one (sorry... sigh...) VRM : with the installation of the VRM, the yellow wires have to be connected only to the eyelet I marked as 1 on the picture (not to the one I marked as 2, isn't it ?)



Also, If someone can provide a picture of his/her VRM installation (this current version), it would be appreciated. Obviously, there's something I definitely don't get here... If I follow the instructions as I see them, there's no way it would fit as is. The mosfet is supposed to be located on the side of the green paper I've put (I don't want to use it for now and risk to damage it since I've no clue how to use/place the potentiometer yet).




So here are my questions, Hopefully there're not to many at a time... After this batch I think I'll be all good to finish the build.
THANKS A LOT !!!


In the meantime, I've converted some solid raw pine shelves I use at home and started to build the cabinet (get the right thickness, dimension then find a way to do the 1/4 inches fingerjoints). So here I am...

1) Don't know for sure on the resistors
2) Signal wires are the co-ax cable (from V2 to Normal Volume)
3) You can, but you don't have to use the heat shrink on the yellow wires. It does help keep them twisted until you solder them on the pins.
4) Optional cathodyne resistor: Not required unless you decide to. If you do, solder one lead to V2, pin7 and the other to yellow wire. See Trouble Shooting/Tone Tweaking section of Build Guide.
5) Only one end of the shield on the co-ax is grounded . On the layout it is indicated by a thin gray line on the Normal Volume control (along with two other ground wires). Be careful soldering the shield and conductor (signal) wires. You can melt the insulation between the shield and conductor and ground out the signal. There's a photo tutorial somewhere on how to prepare the co-ax, will post when I find it.
6) If you are installing a VRM, connect yellow wires and one end of the capacitor to eyelet 1 and the other end of capacitor to eyelet 2 (x2) and leave out the dotted section. If not installing VRM, leave out caps and wire as shown with the dotted lines.
7) Yes that's where it goes. Don't forget the to put the gray sil-pad between MOSFET and chassis.
That took a while, I'm a slow typist.

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"The only problem with being retired is you never get a day off"

Check out the support page on main site. Find and open Triwatt Builders Guide, pages 45 and 46. Has a pictorial on shielded cable prep.

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"The only problem with being retired is you never get a day off"

Finally found the original tutorial. Here is the link: viewtopic.php?f=2&t=1144 You can find a lot of information on Board Index >Back Stage> Resources

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"The only problem with being retired is you never get a day off"