Amp tinkerers and people who aren't afraid of 700 volts or so in here....

Moderators: Slowy, Capt. Black

BY Marshmallow
Hi All,

A few weeks ago, I decided to build an amp with the help of an awesome guy named Rhys. note* 2 cameras are used in this process (Home + phone cam). I decided to make one here as I'm going to Japan. Rather have an amp made in nz for when I head there.

I started a thread for my own reference. feel free to comment. FIrst post is from 14-30 dec.

It will be based on Steve Luckey 5e3 but completely ditching the diagram but rather, read off the schematic as it could be made simpler.. + twin preamp later on.

Black board bought from Mable Audio. Turrets, sockets, fuse holder etc..Filter caps from USA.

Let's start:
Main turret:


Wiring strapped around turrets. allow to heat turrets for 20s before soldering. Do not move wiring otherwise it will cause dry joint. Note: Complete all flying leads before installing components.


3 pcs aluminium folded chassis etc. won't provide too many photos as I don't want to flood the page.



Mount componets: Filter caps installed later on the date


fit on chassis (will be taken off when output transformer arrives)

I have split the 12AY7 cathodes for the robrobinette "5E3 Lead channel mod"
at a later stage. It will also be easy to change this 1st stage into a fender twin pre-amp on V1
again at a later stage.

two more of robinette's Mods,

1 = Master Volume in place of R15 referring to Steve Luckey 5E3 schematic.

2 = 3 way switched feedback--normal/no cathode bypass/feedback. again referring
to the same drawings centered around V2-A pin 3--C5--R13.
Cathode Bias + LED PILOT LIGHT

Other changes done, C2 and C3 are .047uf. In the wires going to each 6V6 pin 4 are now 470 ohm 3 watt resistors.

Last edited by Marshmallow on Thu Jan 04, 2018 6:45 pm, edited 3 times in total.
BY Marshmallow
From Today:
Now that holiday is finished I am now working on the amp in my bedroom in the City. Output transformer arrived. Still don't have a power transformer. Most parts mounted. Labels are for when I install the Japanese or NZ transformer.

More mods - external bias testing.

Where do you guys get those bottle type valves? Does anyone have a cheap 5e3 POWER transformer for sale?


Power Section


Most bits have been wired up. Just literally need a power transformer and hook up the rest of the output transformer wires to the valve sockets, power supply and the speaker. I also need to wire the switch and input jacks.


Will do more work tomorrow!
BY Marshmallow
jvpp wrote:Cool, looks tidy with good solder joints. Do you have a circuit diagram of your build?

Hey man. Thanks! I practised soldering before I started. No diagram as the build is straight off steve luckey's schematic but I am documenting everything as I go.. where the wires go, measurements, and every step etc... It's 24 turrets each side. Earth bus is copper wire. pots are A1M
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BY jeremyb
Awesome work man!
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BY Molly
As ever, blown away with this stuff. If I had these skills (and the time) I'd rip out the PCB from my Bluesbreaker and just make something cool too.
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BY Mini Forklift Ⓥ
Super jealous. Damn that is great, props to you. What an accomplishment once it's finished!
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That looks awesome.! The master and feed back switches sound like a really good idea too
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BY Olderama
It's upside down doh............

Nice work :)
BY Marshmallow
Olderama wrote:It's upside down doh............

Nice work :)

Haha cheers! I don't know why but I always prefer the valves facing up than a reversed or top mounted chassis.

Won't be doing any work today. Probably over the weekend! Will keep you guys updated. any old 5e3 transformers for sale? or any 5e3 transformers at all?