I'm feeling brave ... building an AmpMaker kit

Sporky · June 2023

I didn't find tolex particularly tricky when I made a cab. Though you may be avoiding it for other reasons, of course.

TTony · August 2023

Thread has lain unloved for a couple of months - I received the package of bits, but had some other workshop jobs to clear first, plus I wanted to know that I had some decent spare time, rather than rushing it in spare half-hours.

Today was the grand kit un-packing day!

Ready for action ...

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/40d079a8a1fe657f16ff5b608046206f82756b4f67b2743017

Bits unpacked and sorted

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/f649aaec5f92cff6f91b22e905868082d13147379d6cfd6391

And contents all present and correct (which is always a good start).

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/c07b3916925ca4da956bdcb37276a6c5ca2f020a50f79561d6

I ended up double-checking all the resistors before noticing that the little slip of paper that told me there was a minor spec change in a couple of the components. D'oh.

Still, the multi-meter has had a good workout today.

So, basically, half way there now ...

TTony · August 2023

TBH, my electricals knowledge is limited, but a couple of things persuaded me to have a go at this.

Mrs TT encourages the kit-building thing, but isn't quite so supportive of amp buying. So here's a way of getting a new amp into the house!
I've built some pedals which have - largely - worked, so now know the difference between the main components and am reasonably happy soldering stuff. The last kit included a surface-mounted chip which was challenging, but done. There's nothing anything like as delicate in the amp build.
The construction guide is quality. I read through that a couple of times before placing the order with AmpMaker. The guide looks to be pretty comprehensive, is clearly laid out with plenty of diagrams. I reckon I can follow that!

Time will tell.

PeteC · August 2023

Nice one Tony - the great thing about building valve amps is that its a very tactile experience and the kind of circuits and components you work with mean you can teally tweak a lots of things and experiment to your hearts content.

If you get the bug then i would really recommend getting hold
of a copy of Aspen Pitmans Tube Amp book. If uou can get past the Grooves Tubes sales pitch ( which isnt too bad tbh ) the rest of the book is an absolute goodmine of classic amp circuits and Layouts ( especially classic Fenders )

i built my first few amps simply by following the Fender layouts in that book

i really miss the Fender ProAmp circuit I built from the book - it was one of the best amps I have owned, period.

Next stop a Trainwreck or Dumble ODS build Tony !

Good luck with the build - you cant beat playing your own handmade guitars through your own handmade amps

jaymenon · August 2023

elstoof said:

Would definitely recommend a light bulb limiter, safety first and all that

Please explain...

stickyfiddle · August 2023

Brill! I missed this when first posted. I really enjoyed the Trinity 5e3 build I did a few years back. Looks like Ampmaker has made some improvements to old designs since I last went on his site, which is great.

Looking forward to seeing the progress.

Just don't die - I got just one jolt from mine, ironically when almost finished and installing valves. Not pleasant and that was just through my thumb...! I recall a great mind once said "Electricity is ouchy if you get it up you" - wise words...!

TTony · August 2023

jaymenon said:
Please explain...

@jaymenon ;;

PeteC · August 2023

When your building with valve gear its always worth making a simple discharge line from a couple of decent crockodile clips and a 3-5w 100k or 220k power resistor in between them ( all shrinked and well insulated !)

use thisnto drain the power capacitors in the filter supply ever time you have had the amp powered up and you next work on it. Power supply caps can hold a very powerful charge for a long time

Whatever you do dont work inside a live amp with a guitar that your holding plugged into it - I would never do that myself (ahem….)

i always measure the residual voltage on the B+ and make sure its super low/gone before doung any work on the amp.

elstoof · August 2023

Here’s a good video on the cap draining process

https://youtu.be/_ATLTizLbDU

digitalkettle · August 2023

elstoof said:

Sporky said:

TTony said:

^^^
That's my first task @elstoof and I like your practical build

The ice-cream tub used affects the tone.

Viennetta gives a more layered sound, but Kelly's is a lot creamier.

I was going for the Wall’s of sound

If I quote all these ^ together it'll be like a Magnum opus!

TTony · August 2023

This build is definitely slow & steady.

At least, I *hope* it's steady (I'm definitely taking my time).

First stage, the main chassis bits, is done.

I would have saved myself a bit of time if I'd taken the protective cover OFF the chassis before I screwed all the screws in place, but I thought I'd leave it on to protect against damage, scratches, etc. That valve seat on the left was the only real awkward bit.

So with that moved aside, on to the first turret board ..

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/10fc4e6ab96052cc982fc6f5979b32c823d36f555713b8156b

The only soldering done so far is the bare wire that connects the top 5 and bottom 3 turrets. Everything else is just placed into position (with legs cut to size apart from the couple of diodes towards the RHS (which are deliberately *not* in the turret holes).

Thought I'd do that rather than start soldering and then realise that something didn't fit, or I'd put a resistor between the wrong turrets, or put a capacitor in the wrong way round.

All resistors checked in the DMM (again) before placing in position and all capacitors deliberately placed so that the polarity is clear to see.

Would any of the more experienced amp builders do anything differently?

elstoof · August 2023

Looks tidy to me, as long as it matches the schematic, values are correct, caps are pointing the right way then I’d be happy with how it looks. It’s always good practice to put any printed values on components facing up and visible.

I’ve yet to start my P1800, it’s in the box taunting me. I need to fix the 5e3 I made first, and somehow managed to start 5 guitar builds this week

TTony · August 2023

I think I’ve quadruple checked the resistor values now, so they’d better be right!!

elstoof said:

and somehow managed to start 5 guitar builds this week

Start them this week, finish them next week.

But 5 ???

elstoof · August 2023

I don’t have any big machines so I book days at a workshop when I need to use bandsaw, thicknesser etc. It made sense to start a bunch at a time to not pay for a whole day, drive down there, just to thickness one body and cut one neck… starting to doubt that logic now!

TTony · August 2023

Got the soldering iron out this morning and did another hour's work on the amp build.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/179d56a0e5f79a1f2dde48e713015df31af5f288d24c9edd39

Some of the wires could probably be cut shorter, but I'm wary of finding out that I've soldered them incorrectly and need to move them later, and then find that they're too short.

Also, I need to get better at soldering left-handed. There's not quite as much access to some of the solder-spots as it appears from the photo!

All good practice and learning for next time ....

A couple more bits of soldering to do, then I can test the power stage of the build.

TTony · August 2023

And I think we can say that the Power Stage test is successfully passed.

Capacitors discharged correctly within a minute of power-off too.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/397ecf731c5897ea6449ddc66149d4afdbbbb20fa5b3d8c01f

Stick the valves in, switch on, and they glow a comforting dim amber

So far, so good ...

Got the main turret board to put together next, then wiring all the front panel controls in. It takes a while, but then I'm definitely not rushing anything (no need to) and checking everything a few times before cutting/soldering anything in place.

TTony · August 2023

Done another hour of soldering this morning, and got the second board done and in place.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/6273d6a39c633997399bc330d85fcbe2c6f06d6bf16dcd0bd0

Next stage is to wire the valve sockets and front controls into the boards. That's going to be a lot of wire cutting, tinning and soldering!

I'm deliberately stopping myself from rushing ahead to get it all done, and taking it slowly and checking everything as I go.

elstoof · August 2023

Shaping up nicely

SteveF · August 2023

Looking good Tony very neat and tidy

TTony · August 2023

This took a bit of soldering, and a bit of tweezering to get wires in place, or out of the way of the hot end of the soldering iron!

But, into place they all went eventually.

I then ticked off every single connection against the diagram in the build guide ... and found one wire that I'd completely missed. So, it was worth checking.

Wire added, and it was time to run through all the tests.

I admit to feeling a little nervous, poking around inside a switched on valve amp with my multimeter probes, but I seem to have avoided any nasty accidents.

And also seem to have soldered everything in the right place. All results, I believe, within acceptable tolerances.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/f7e3edc165933395cc729fc44330055274916edcef778dad04

And so .... let's switch the damn thing ON

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/9509620ab4bf301d63404ed5102b723efdb6661abbf53ff3da

Yup, it works.

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I'm feeling brave ... building an AmpMaker kit

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