5E3 Amp Build

Barnezy

RaymondLin said:

Nicely done sir!

Thanks!

vanlooy1

First class!! Amazing for a first build!!! I reckon it’ll fire up fine..

UnclePsychosis

Looks good. Have you got a chassis to stick it in? I think if I ever get round to building an amp I'm going to finish it extravagantly. 

Barnezy

UnclePsychosis said:

Looks good. Have you got a chassis to stick it in? I think if I ever get round to building an amp I'm going to finish it extravagantly. 

Do you mean cabinet? 

No waiting for it to arrive. It's being built. I've gone for standard Fender tweed for this. I will be lacquering it though with shellac. I was thinking of doing a light relic, abit like this.... not sure yet. 

https://guitar.com/guides/diy-workshop/workshop-59-fender-bassman/

UnclePsychosis

Chassis/Cabinet yeah I guess so. Box?  

Tweed is cool as feck, but is it pink paisley cool? 

https://www.thefretboard.co.uk/discussion/162862/nad-or-new-cab-day-really-pink-paisley-amplifier-build-now-completed

Barnezy

UnclePsychosis said:

Chassis/Cabinet yeah I guess so. Box?  

Tweed is cool as feck, but is it pink paisley cool? 

https://www.thefretboard.co.uk/discussion/162862/nad-or-new-cab-day-really-pink-paisley-amplifier-build-now-completed

The chassis is the metal part the wiring sits in, that's all. 

No, deffinately not pink paisley. I was going to get fudge Tolex, but went Tweed this time. Next one maybe. 

Vinylfan

Very good work! It’s inspiring as I have no soldering experience and that’s the part putting me off. 

Enjoying your updates and it looks like it is progressing well. 

Good choice of cabinet too. Where are you sourcing the cabinet from?

Barnezy

So, as I wait for my speaker, multimeter, and cab to arrive, I've not done much to the amp. However on the suggestion given, I made a Dim Bulb Current Limiter today, for the first test of the amp. Pretty straight forward, parts cost £5 and took about 20 minutes. Should limit any damage to the amp if there is an error in the circuit. 

 

springhead

Lamp limiter is a good idea for first power up. Hope the remaining items arrive soon.

Barnezy

Advice needed please. 

I started doing my circuit and voltage testing today. 

Firstly when the amp was on the desk at an angle, i.e. with nothing supporting the non-trasformer side, the transformer was making a loud buzzing sound. See video below. When I leveled the chassis with a box, the sound stopped. Is this normal? 

Buzz. 

Modulus_Amps

 No, definitely not normal, and the lamp is lit up too?

Is that a 100w filament lamp you are using?

Also it does not look like you have the PT bolted down properly?

Barnezy

Modulus_Amps said:

 No, definitely not normal, and the lamp is lit up too?

Is that a 100w filament lamp you are using?

Also it does not look like you have the PT bolted down properly?

60w bulb. The dim bulb tester, isn't lit up anymore than if I plugged another device in. It's not lighting up as if there is a short. 

One nut is missing as I moved the earth across one. All others are tight. Put the last one back now. 

As mentioned, when I placed a box under it and leveled it the noise stopped. Voltages are being delivered as they should be. 

Barnezy

Just tried it at an angle with the final PT bolt attached and it's no longer doing it, so perhaps it was just the vibration of the transformer on that one point? 

springhead

Is the cover tight on the transformer?  My 5E3 build had a ringing transformer, the cover vibrating at a high pitch.

The bulb will be dropping your voltages a bit but measure all the windings and see if you're getting roughly the right results.

Barnezy

springhead said:

Is the cover tight on the transformer?  My 5E3 build had a ringing transformer, the cover vibrating at a high pitch.

The bulb will be dropping your voltages a bit but measure all the windings and see if you're getting roughly the right results.

Thanks. 

It seems it was that one nut missing that was causing it. I swapped the earth position previously and given they are so fiddly to install, thought I'd leave that one until I'd done the checks. 

Anyway, I've run the amp with no tubes and voltages are even in the positions they need to be. Run it stortly with the rectifier and pre-amp tubes and voltages are all there. 

My speaker arrives today, so will do the final test with the power tubes, but so far all looks good. 

hotpickups

Blimey this is why I'd never undertake an amp build without some kind of supervision. I wouldn't even know how to build the lamp tester

Keefy

hotpickups said:

Blimey this is why I'd never undertake an amp build without some kind of supervision. I wouldn't even know how to build the lamp tester

Here you go:

https://www.youtube.com/watch?v=wRFRwOnLsZI&t=6s

RiftAmps

Barnezy said:

Modulus_Amps said:

 No, definitely not normal, and the lamp is lit up too?

Is that a 100w filament lamp you are using?

Also it does not look like you have the PT bolted down properly?

60w bulb. The dim bulb tester, isn't lit up anymore than if I plugged another device in. It's not lighting up as if there is a short. 

One nut is missing as I moved the earth across one. All others are tight. Put the last one back now. 

As mentioned, when I placed a box under it and leveled it the noise stopped. Voltages are being delivered as they should be. 

A 100w bulb is better in this application. It'll allow up to 416mA of current (see Ohms law) at 240v which still is lower than the consumption of nearly every guitar amp >5w but crucially, it won't glow in a non-fault condition such as powering up with no valves installed. A 60w bulb will emit a slight glow, which may confuse the user into thinking there is a fault when there's not.

Nice build BTW!

RaymondLin

RiftAmps said:

Barnezy said:

Modulus_Amps said:

 No, definitely not normal, and the lamp is lit up too?

Is that a 100w filament lamp you are using?

Also it does not look like you have the PT bolted down properly?

60w bulb. The dim bulb tester, isn't lit up anymore than if I plugged another device in. It's not lighting up as if there is a short. 

One nut is missing as I moved the earth across one. All others are tight. Put the last one back now. 

As mentioned, when I placed a box under it and leveled it the noise stopped. Voltages are being delivered as they should be. 

A 100w bulb is better in this application. It'll allow up to 416mA of current (see Ohms law) at 240v which still is lower than the consumption of nearly every guitar amp >5w but crucially, it won't glow in a non-fault condition such as powering up with no valves installed. A 60w bulb will emit a slight glow, which may confuse the user into thinking there is a fault when there's not.

Nice build BTW!

You learn something new every day.

Modulus_Amps

Barnezy said:

Just tried it at an angle with the final PT bolt attached and it's no longer doing it, so perhaps it was just the vibration of the transformer on that one point? 

Thats good, Transformer bolts beed to be tight, the laminations in a transformer actually move under magnostriction, thats why when you run a valve amp without a speaker attached you can hear the output transformer emmiting the guitar signal...

.... but of course we would never run the amp without a speaker attached!!