5E3 for 6V6/6L6

[tubeswell]

Here's the start of my next DIY. About 5 1/2 hours furiously measuring, scribing, cutting, drilling, filing, punching, bending, more drilling, riveting, more filing, and the chassis is ready for the engraver. Cost of the Aluminim (about $5), rivets (less than $5). I thought I'd get the underbelly engraved also this time.(I wonder if Mr Minute's prices have gone up. I think he charged me $26 last time - Its always the most expensive bit). I got Carbon Comp resistors this time - curious to see what the mojo is all about. It'll be configured to run either 2 x 6V6s + 5Y3GT, or 2 x 6L6s + 5U4GB or 5AR4 whichever.

[tubeswell]

Iron-on

FYI Put the iron on today

PT = 325-0-325 180mA, 6.3V CT 4A, 5V 3A = NZ$98.75 +GST
OT = 8K CT, 4R, 8R, 16R ~ 30W = NZ$58.75 + GST
Choke = 4H 50mA 110R = about NZ$20

I decided to lie the PT on its side this time to save some space (which means I had to cut a little hole. Result was better than I expected) - Maybe I'm going to do this from now on

Got the chassis engraving done on Thursday = NZ$31 including the underbelly (Still covered in film).

[Bruce / Mission Amps]

For what it's worth... I never put the transformers on first.
When you go to install the sockets, filament wiring and all the other misc parts to the chassis you might find out why.
With a choke and an X mount OT like yours you'll have to do it before the eyelet board.

[tubeswell]

Hi Bruce

I've done my previous two builds this method. Iron first, then sockets and top panel stuff, then eyelet board. With a bit of planning I usually manage to get it all in okay.

However, I'm curious as to why you mentioned it (I can always learn new tricks)

[Bruce / Mission Amps]

Hi Bruce

I've done my previous two builds this method. Iron first, then sockets and top panel stuff, then eyelet board. With a bit of planning I usually manage to get it all in okay.

However, I'm curious as to why you mentioned it (I can always learn new tricks)

Because with no transformers it is much easier to maneuver the chassis around and that big hole (where the PT goes) is a good place to insert a block of wood in to hold the chassis on an angle while wiring up the sockets and filament strings from right to left... all the way to the first 6V6 socket.
Tweed Fender type chassis can give a novice builder an acute case of sausage fingers and any trick to make it easier is welcome relief.

[tubeswell]

DIY Eyelet Board

Bit of electrical switchboard (NZ$5), cut, filed and drilled to any shape U want. 4mm holes drilled in for 4mm tin eyelets ($NZ2) which are tapped in tight. Secured with 4 spacer nuts (~NZ$2), and 2 hours swearing and cursing. (The input signal wires are going to be shielded cable direct from each pair of input sockets to the grid pins of V1, hence no eyelets for the 68k resistors). Job done now - good enough for me. It is wide enough for Sprague Atoms, and yes I can get in in and out of the chassis with the sockets and everything fitted in. 8-)

[cat]

Good work, youre doing ok in the budget department I reckon too. I might have to bring my soldering iron and my Aussie dollars to NZ

Cat

[tubeswell]

Progress slowed a bit while the 'site was down. 3 x beldon octal @ ~NZ$7 ea. and 2 beldon noval at ~NZ$4 ea. Fender bayonet lamp holder and blue Biezel NZ$31, two switches NZ$2.50 ea. fuse holder $NZ3. Bit of tag terminal for the common ground wires NZ$2. 1 x 15ft power cord NZ$5 (from the warehouse). Got some output sockets NZ$3 ea. I put a cutaway in the eyelet board just where the input sockets are to make it a bit easier getting it in and out.

[tubeswell]

Inching along

Well yesterday I dallied and delayed modding my C30 for the umpteen-trillionth time while it rained. (FWIW I think it sounds better with quasi SLO100 style preamp, but what the hey!? on past performance, I might re-do everything again in 6 months time :-)

Today I woke up late (daylight saving), it was supposed to rain but it was a cracker of a day (dang - that meant I had to go get some lawnmower gas, mow the lawns, take the kids to karate, make a raised spring vege-garden in backyard for Mrs tubeswell (she's very happy) but by the time I finished the sun was already low in the sky - see pic) and so the bottom line is I had only a few measley hours to work on this this evening. ;-)

I nearly forgot to add - the alpha pots were NZ$2.50 each, the input sockets were NZ$5 ea. and the output sockets were ~NZ$2 ea. Miscellaneous wire NZ$0.20/m, 2 x 1N4007 NZ$1 ea. 1 5-tag terminal strip (for the diodes) NZ$1.

So I wired the recto tube socket (including buffer diodes) and the lamp and the heaters, and had time to trim the shafts on the pots and try out the remaining sockets for size. Whew! what a day!

[Alby]

Nice job tubeswell, those transformers look MaSSIVE!. I agree with Bruce in regard to trannys last, thats how I do it too, I hate wrestling with all the extra weight.
In regard to your faceplate engraving, I use a product called Letraset. You just rub on the letters and cover it with a clear coat product and your good. It's made in the UK so you may be able to find some as NZ is in the club too. I am told they don't make it anymore but if your interested I could send you enough to do an amp or two.

I will find a link to a picture of the Bassman I used it on and post later, I am also going to use it on my current amp, it's a 5G9 Tremolux.

Alby.

[Alby]

Here ya go.....


http://photoshare.shaw.ca/view/29904...74-94510/29904

[tubeswell]

Nice job tubeswell, those transformers look MaSSIVE!. I agree with Bruce in regard to trannys last, thats how I do it too, I hate wrestling with all the extra weight.
In regard to your faceplate engraving, I use a product called Letraset. You just rub on the letters and cover it with a clear coat product and your good. It's made in the UK so you may be able to find some as NZ is in the club too. I am told they don't make it anymore but if your interested I could send you enough to do an amp or two.

I will find a link to a picture of the Bassman I used it on and post later, I am also going to use it on my current amp, it's a 5G9 Tremolux.

Alby.

That Bassman looks nice - nice deep chassis must be easy to work around - I've got to do a 5F6a next (after my 6G15) - I don't think this current project will be as authentic looking (none of mine have been to-date).

Yeah I remember Letraset, not sure where I could get some now - why didn't I think of that before? Anyway a 5G9 is an absolute killer - I love my one

[tubeswell]

Input sockets wired in

Input resistors mounted at the sockets

6 inches shielded cable (NZ$0.20) grounded at input socket end, and going straight from 68k resistors at socket input lug to grid pins of V1.

6 inches copper wire (NZ$0.05) for the ground bus

4 x 68k ish CC and 2 x 1M CC - (NZ$9 all up)

plus 2.5 hours toil

[tubeswell]

Chassis almost done

Got a good 1/2-day in today - bad weather, more bad weather forecast tomorrow - I might get the cabinet built - we'll see :-)

Managed to knock-off the eyelet board and get the pots mostly wired up. Now almost ready to wire the eyelet board in and finish the tube sockets.

I decided to drop the choke for now and go with a screen supply node resistor as this is more traditional. When I get the 6L6 s in there I might re-evaluate.

2 x 22uF 25V bypass caps ~ NZ$1.50 ea
1 x 22uF 63V bypass cap $ditto
2 x 22nF 400V mustard caps ~ NZ$6 ea (I think? maybe a bit more - can't recall exactly) - I thought I'd try these for the coupling caps from v1, going by a plethora of opinions on the subject. Anyway I'll see.
2 x .1uF 630V film caps ~ NZ$3.50 ea
1 x .022uF 630V film cap ~ NZ$3 (I could've put another 22nF mustard cap in here but the schematic called for 630V - overkill? - probaby)
1 x 500pF 500V silver mica NZ$2.50
1 x .0047uF 600V 716P NZ$4.50
3 x Sprague Atom 20uF 500V ~ NZ$20 ea (I think? can't remember exactly - I must check it out)
9 x assorted CC resistors (plus 2-more that I overcooked and had to dump - that'll teach me) - NZ$1.50 ea (in addition to the ones on the input sockets)
3 x metal film resistors (cos I haven't got any 56k or 820R CC at the mo') - too cheap to mention
1 x 22k 1W carbon film resistor ~NZ$0.10

1 x 10W 270R wire-wound resistor ~NZ$5
1 x 5W 4k7 wire-wound resistor ~NZ$3
~1m wire assorted gauges ~NZ$2

[tubeswell]

Cabinet almost done

Well it rained again today and after 12 hours of cutting, drilling, glueing etc, there ya go. Still can't do finger joints, which is why I put dowels in the sides. (Maybe if I've acquired a table saw by the next build I'll do finger joints).

When the glue is dry, I'll cut and sand it all square, then rout the angles, then cover it with some of that gingham tweed that I've still got a few metres of.

This cab is same size as the one I built for my 5F2A in Feb (o.a. 21&1/2" x 16" x 9"), and everything fits in snugly. I will finish it similar to my 5G9. The only further refinement with this is I've recessed the baffle back 1/8" from the front of the cab. It is floating - mounted top and bottom in the corners. I have some steel corner pieces, but I might just cover it it fabric and leave those off.

72" x 9" x 3/4" white pine ~NZ$80
20" x 16" x 3/4" marine ply ~NZ$10
84" x 1" x 1" square cleating ~NZ$20
36" x 1/8" diam dowel ~NZ$3
1 carry hande NZ$20
screws and polyurethane glue ~NZ$10