Fender 5e3p from Wurlitzer organ amp

[Zombie_stomp]

I found a stepped down drill bit that would fit the chuck on the 3/8 drill I have which is big enough to drill the power and standby switches. I was then able to drill those holes and fit the switches and fuse holder. I fitted a grounded 3-conductor power cord and soldered it to the fuse holder, hot wire first, and ground wire to the chassis, then the hot wire from the fuse holder to the PT. The ground wire joint is a little lumpy, so I may re-solder it using more flux from a tin of flux I have on hand, just because that would be best. Calling it a night for now. After installing the switches, I may not have access to one of the holes I drilled intended for instrument jack, oh well. I may have to find a way to creatively cap it off since it is so close to the switches. I drilled so many holes for pots I intended to use with an add-on standalone reverb unit I hoped to fit inside this chassis, but I may end up cutting off and shortening this chassis and making the reverb unit inside a separate chassis.

[Phil_S]

I've been back for a couple of days and am glad to see both progress and others getting involved.

You've committed a near crime on the mains green ground wire. That one requires the following treatment: attach a ring lug (not a spade lug) to the wire. It can be a crimp lug or a solder lug; don't solder AND crimp. Drill a hole (or use an existing; plenty of them on the side panel) near the point of entry into the chassis for a #10 or #8 bolt (depends on ring lug size). Place the ring lug over the bolt, then an inside toothed washer, and finally the nut. Some people use two nuts to make sure it is locked in place. Make the length of the green wire the longest of the three mains wires. This is a safety consideration. In a catastrophic fall while the amp is powered on, the ground wire will be the last one to have tension applied. The mains ground is not used for any other ground wires. Please fix this properly.

On to the amp. I have always found it pays big dividends to make a layout drawing before plunging into the work. Doing this can be very time consuming and often results in many discards. It can be particularly frustrating when you are chomping at the bit to start soldering. That is the price of thinking it through. Being able to visualize all the things that need to be done can be hard for a beginner. Sure, you'll miss things, but those can be dealt with. In the end, the planning is likely to give you a better result than doing it on the fly. You've got to think this through, right down to the best rotation of the tube sockets, all the wire runs, and the placement of components. This includes some amount of "dry fitting" to make sure your caps and resistors aren't 1/4" too short and things like that.

You've got a really nice project coming together here. Make it the best you can.

One thing to do is to decide on the style of heater lead dress. There are two you'll see commonly used. One is to run the heaters up in the air and signal wires down on the chassis. The other is to lay the heater wires on the floor at the chassis fold. The idea is to keep heater wires away from signal wires. In general, heater wires are the first thing to be wired. There are lots of build pictures on this site. Look around.

Remember, slow and steady wins the race. Be the turtle, not the hare.

One more thing...I do not think I'd look to cut that chassis. You are going to need all of the space. You will be surprised how quickly the open spots get used.

[Zombie_stomp]

Well, there's all that space off to the right side far from everything else. I thought about putting a reverb unit in there. Not sure if it's enough room.

I'll correct the ground wire. The transformers both have 4 bolts I can use.

I'll map everything out and draw the locations and make a few copies. I might have to relocate the preamp tubes. But besides heater wires and signal wires, is there nothing else that needs to be kept separate?

[Firestorm]

The safety ground really should be on its very own bolt; nothing else there. The code is fussy. A small quibble on the fuse holder: the leads should be reversed. You don't want the hot lead connected to the end closest to your fingers.

Although it looks like the chassis is solderable, I wouldn't count on being able to make good ground connections to the chassis unless you have a large iron with a lot of surface area. Toothed ring connectors and Nylok nuts turn out to easier most times.

[Zombie_stomp]

There are several spot welded ground lugs on the chassis. As long as I don!'to have anything else grounded there I should be able to use that, but with all the emphasis on it, I will have to crimp a ring terminal on and bolt it on using a star washer.

[Phil_S]

+1 on all of what Firestorm says. I'm sorry I missed the fuse holder. I'm fussy about that, too. When you remove the cap, you want the fuse to pop out and break the connection to the mains so you can safely remove the fuse if it is still intact.

I'm not sure you understand about the nut and bolt for the mains ground. The nut and bolt assure a good mechanical connection to the chassis.

On the chassis ground lugs, these can be used, but it often takes a 100W gun to get enough heat for a good workman-like solder joint. You might try using two irons at the same time. It is far easier to find a place to run another bolt through the chassis and use solder locking terminals, example: http://www.digikey.com/product-detail/e ... -ND/317278 You can often put 2-3 wires in the hole and solder. You can stack 2 or 3 on a bolt.

There is much to learn for a first-timer. Much of it quickly becomes second nature...stuff we don't even think much about until you see it isn't done right.

[Zombie_stomp]

I got the area tidied up tonight. Hot line-fuse-switch-transformer. I extended and ran the output tranny center tap up to the standby switch. Solid ground ring terminal lug snug with lock washer.

[Zombie_stomp]

I have finished the power transformer and standby switch section of the layout. I'm not 100% sure how to start laying out all the other components, but I will try to work out a new point-to-point layout this week after an intensive resistor identification session, and printing of the color stripe code chart.

[M Fowler]

Wire up the rectifier and power tubes an input jack and test it as a power amp before figuring out the preamp section. At least then you know the power section is working proper then.

[Zombie_stomp]

As in running a preamplified signal through it to test it's output through a speaker?

[M Fowler]

As in running a preamplified signal through it to test it's output through a speaker?

Yes. It's a good idea to test the amp in various stages, something I don't do and wish I had when having to trouble shoot it when finished.

[Zombie_stomp]

What should I use to get the right level of amplification into the power amp? I have an EL84 powered 15 watt ampeg jet reissue amp, but maybe tapping into it's preamp section would be difficult because of the circuit board stuff it has.

Please advise a straightforward method.

Also, my original hope was just to somehow add an additional optional power amp to the ampeg so I could have it louder. I wonder if that is still possible!

[Phil_S]

Make a cable for your computer, ipad, mp3 player. You can probably do it with an inexpensive adapter that converts to 1/4" input. Alternatively, if you have an old cable you don't need, like broken earbuds, clip the end and use gator clips and wire.

[Zombie_stomp]

There is something with the rectifier tube I'm not sure about. What appears on the new layout as the filament pins for the 6L6s are tied together with a bias pot labed "hum balance". This is because they didn't really separate the signal and filament wires. So the part that differs between the new layout and the existing design is the use of pin#1. The fender design doesn't use it, the existing design has one of the filament wires going to pin 1 of the rectifier. I'm just curious why that pin is used on one design and not the other. I notice no filament wires going to the rectifier. I that must mean that tube works differently. Notice the squiggly brown wire going across to the recto in one photo, and the 'hum balance' bias system in place in the other.

[Phil_S]

I don't think that Proluxe layout is entirely correct, or else you have mis-read it.

Rectifier: Assuming a GZ34 for which the Weber Copper cap is a direct replacement. If using the copper cap, you don't need any filament supply. If using a real tube, you need a 5V supply connected to pins 2 & 8. Traditionally, B+ is taken from pin 8. I don't know why. I'd say follow the prevailing practice of using pin 8. Pin 8 of the rectifier gets connected to the center tap of the output transformer primary. The wire run from pin 8 to the OT CT is interrupted by the standby switch. (You don't really need the standby. Nothing bad will happen if you omit it.)

6L6. The outer legs of the OT primary get connected to pin 3 (one to each socket.)

I'm not sure about a balance pot. Can you elaborate? Hum balance is usually a "humdinger" which is a ~200 ohm pot between the legs of the 6.3V filament supply and the wiper grounded. It allows you to balance the filament supply to eliminate 60Hz hum. Bias should be totally separate. If this is a 6L6 based 5E3 Deluxe, it would be cathode biased, so there'd be no need for a bias pot.