My parts bin/salvage build

[leewongfei]

I got into building amps over the years fixing amp builds for people. Im not an electrician by trade or anything, but I used to fix arcade machines and pinball games for a living when I was in school. Ive acquired parts over the years and decided to see if I could use some of those parts to rebuild a 5e3 for my buddy or kid. I used what I had on hand only, and did not need to order anything to finish this build. Unfortunately something is off but Ill figure it out in the morning. Please be gentle, I know its not perfect, but all transformers, pots, sockets, switches, chassis, and some of the wire are from amplifiers that I fixed for other people or from upgrades I did for people. While I dont typically charge cash, my fee is usually keeping the parts that the person upgraded, which is how I got both of the transformers for this build. I couldnt get it any cleaner than it is at my skill level. The goal of this build was to be as economical as possible without making it cheap (if that makes sense).

The first 2 pictures are of a board that I stripped to use again.

 

[NTC]

That looks very nice. Especially compared to my now 20 year old 5E3 homebrew. Did you make the eyelet board or buy it?

What kind of problem are you having? I am sure some of the smart folks around here could help if you need it.

 

[leewongfei]

That looks very nice. Especially compared to my now 20 year old 5E3 homebrew. Did you make the eyelet board or buy it?

What kind of problem are you having? I am sure some of the smart folks around here could help if you need it.

The eyelet is a used Mojotone eyelet board. I like the material and build quality of the Mojotone eyelet boards, but the eyelets are rather small.

The amp has some sound on the extension speaker, but its weak. The tubes are new as well. Im thinking its a grounding issue.

 

[NTC]

You DO have something plugged into the normal output, right? If not, and if the normal output is wired as a shorting jack, you will get little or no output and could damage the amp (I blew up a JJ 6V6 this way).

 

[King Fan]

Nice job. I like the frugal, practical, and planet-friendly reuse of parts.

You know you have our whole busload of problem-solving crazies standing by, but on a 5e3 there are some extra-high-yield first steps some of our big-brains have shared. Gimme a minute…

 

[King Fan]

If all your tubes are glowing, here are some high-yield "5E3" things you can do power-off, even before voltages: First, the Dr. @D'tar input resistances...

Next, the @andrewRneumann amp-wide resistances:

And last but not least, @2L man recently reminded us that though wiring and function of the speaker and extension jack are critical (as @NTC points out), they're hard to test with an ohmmeter (basically cuz the OT leads come from a single long wire), so some up-close inspection of wiring plus switch-to-tip opening and closing may be needed. IIRC he said he'd tack solder a couple wires to bypass the jacks and connect the speaker straight to the OT leads; I'm lazy and have just used alligators, but he pointed out you'd need to be super careful to avoid one coming loose.

Oh, and then seldom a month goes by without someone finding their guitar cable or speaker cable was faulty...

 

[D'tar]

Im not 100% certain but it appears your main speaker jack tip connects to the extension speaker jack ground?

Maybe 99%

 

[leewongfei]

Im not 100% certain but it appears your main speaker jack tip connects to the extension speaker jack ground?

View attachment 1089940

Maybe 99%

If all your tubes are glowing, here are some high-yield "5E3" things you can do power-off, even before voltages: First, the Dr. @D'tar input resistances...

View attachment 1089892

Next, the @andrewRneumann amp-wide resistances:

View attachment 1089894

And last but not least, @2L man recently reminded us that though wiring and function of the speaker and extension jack are critical (as @NTC points out), they're hard to test with an ohmmeter (basically cuz the OT leads come from a single long wire), so some up-close inspection of wiring plus switch-to-tip opening and closing may be needed. IIRC he said he'd tack solder a couple wires to bypass the jacks and connect the speaker straight to the OT leads; I'm lazy and have just used alligators, but he pointed out you'd need to be super careful to avoid one coming loose.

Oh, and then seldom a month goes by without someone finding their guitar cable or speaker cable was faulty...

Thank you King Fan! I will take a look during my lunch break, its a crazy Monday at work. I know im not too far from getting it right, hopefully it goes faster when im not working lol.

 

[leewongfei]

Im not 100% certain but it appears your main speaker jack tip connects to the extension speaker jack ground?

View attachment 1089940

Maybe 99%

Here is a different angle of how the output transformer is wired up. Sorry for the late reply. I am working today and for some reason, its crazy today at work lol.

 

[D'tar]

Not sure if it has been mentioned but if you are only using one speaker it should be plugged into the main speaker jack. Only use the extension speaker jack when using a second speaker along with the primary speaker.

 

[King Fan]

Whoa, Nelly. I now see why @NTC and @D'tar are asking if you had your speaker plugged into the 'wrong' output jack...

 

[leewongfei]

Whoa, Nelly. I now see why @NTC and @D'tar are asking if you had your speaker plugged into the 'wrong' output jack...

View attachment 1090178

I took that picture while testing the shorting jack for debris before I posted last night, since it was a used jack. I thought that maybe a ball of solder got in there that I couldnt see, so I took an unused plug and pushed them through just to "clear the chamber" for lack of a better term. The amp was not on. That was actually the problem with the amp. The primary jack was defective and not connecting. I added a picture to this message since i probably said that wrong. The plug has been replaced and the amp is perfect now! Thank you everyone for looking at this with me!

*D-Tar, your message is what put me onto the problem. I took another look today and that when I noticed that the jack was all jacked up (sorry!).

 

[NTC]

Moral: don't use cheap jacks. One of my early builds used jacks from Radio Shack - they ALL had to come out they were so bad. They would bend and not make contact even after being bent into proper shape. Looks like that is what happened here.

 

[2L man]

I use insulated plastic jacks for loudspeaker output and they are quite cheap but look sturdy agains cheap steel jacks. Insulation means that chassis cannot be used as a circuit but that is essential feature for me as well.

I often use a stereo jack especially for higher power amps and then connecting also "the middle" lug with Cold signal it doubles the area what output power use when a mono plug is inserted. The tip connection is constructed so that it make contact both side of the plug tip groove so there already come better contact for the Hot and now stereo jack improve the Cold contact

 

[leewongfei]

Wow, I will never reuse a jack plug again. The bright-low plug doesnt work either. Bright low is my favorite 5e3 channel too! While it could be a lot worse, I am just glad it was an easy fix lol. I placed order with Tube Depot for a few more jacks and other items I am low on. This should be good to go by Friday!

One final about the amp. I really dont like aluminum as a chassis material. Grounding is a little more specific if that makes sense. While its very quiet, tghe process to get it there was strange. At one point, I almost considered soldering directly to the chassis. I ended up finding the right washer with more aggressive teeth that dug in more. Once I did that, it finally quieted down.

**Please pardon any grammatical mistakes. I used my voice to type this while trying to walk my dog in a snow storm.