Q418C - Mike builds an amp and tries not to die // 5E3 build now in progress!

stickyfiddle

Everything seems present and correct, and I've marked up all the resistors with the values so I can crack through that part when I get there. I forgot to take a picture of that step. I also bought the VRM kit, which is a simple B+ voltage control for basic power scaling. I'm planning to get the thing built properly without VRM first, then I'll open up and again and add the VRM circuit.

The transformers are by Heyboer, which are meant to be great. They have really great writing on the packaging. 



After a couple of hours of reading and checking I set about on the chassis, between bouts of fishing the other cat out of the cabinet.... All very straightforward so far. Tomorrow I'll start soldering

Modulus_Amps

stickyfiddle said:

and that is the reason amp builders have to stick metal cages around hot valves

good luck with the build!

stickyfiddle

 

Yeah, I'll need to be very careful who is wandering around once I start getting high voltages involved! 

stickyfiddle

More progress yesterday. Couldn't sleep so got up at 6 and did a good 6 hours or so on it. 

First I populated the chassis.



Then wired up the heater wiring. Straightforward so far...



Power transformer in and wired. Some slight confusion when I forgot the instructions were written primarily for 110V and I needed to use the 240V colour code, which was on the next page. But all good and sorted *before* I powered anything on.



Quick test of that wiring to confirm the right voltages were getting to the right places. All good so far - no electrocutions and no fire!

stickyfiddle

Next up is the board wiring. This is easy. In theory. When you don't have insomnia and don't get complacent. This was the point where, having been very happy with how easy it was, I remembered I needed to add all the flying leads at the same time, otherwise connecting this with the rest of the amp would be all-but-impossible...



I got there in the end.. 


Tidied-up board in-situ. You'll note I *still* forgot the main connection from the OT (red wire attached to the left-most filter cap at the bottom). That's been spliced onto the capacitor's leg, and should be robust enough, but I'm annoyed I didn't get it perfect first time.



Anyway, next up is the other half of the wiring, then testing. 

I've already checked and rechecked the wiring as I've been going, but will do another careful once-over of everything before I switch the mains back on. 

Speaker should be arriving tomorrow, so I'm hoping to get the soldering finished tonight, then tomorrow is testing and (hopefully) finishing the build without dying! 

stickyfiddle

In other news, I have run out of 60/40 solder and the lead-free stuff I have in reserve is eating iron tips like nobody's business. Need to get some more leaded before I go mad.

skippy76

Looking good mate (thumbs up)

roberty

Looks like a shed load of wires coming out of the transformer - what do they all do?

That's a lot of progress in one day!

Rocker

Well done but your pics are not showing on my iPad. Just small square boxes. 


*Edit: pics work fine on my PC running Windows 10.

stickyfiddle

roberty said:

Looks like a shed load of wires coming out of the transformer - what do they all do?

That's a lot of progress in one day!

A combination of grounds, neutrals and live AC feeds at a couple of different voltages, plus the input 240V feed. There's also a couple of wires for 110V input, which are insulated and tucked away in case I ever want to convert for that voltage. 

I'd never really read anything about all this stuff before this build, aside from a basic knowledge of what transformers do and how from A-level physics. It's actually all relatively simple in an amp this size, but there's still lots of different parts doing different things. 

stickyfiddle

Rocker said:

Well done but your pics are not showing on my iPad. Just small square boxes. 

Strange. They're imgur-hosted and working on a couple of different machines here. 

Are they broken for anyone else?

not_the_dj

Photos look fine to me. Insides of amps scare me so well done. 

stickyfiddle

not_the_dj said:

Photos look fine to me. Insides of amps scare me so well done. 

Hey, there's still plenty of time for me to mess it up!!

King85

Looking really good so far! How are the instructions? Step by step or just wiring diagrams and schematics?

roberty

stickyfiddle said:

roberty said:

Looks like a shed load of wires coming out of the transformer - what do they all do?

That's a lot of progress in one day!

A combination of grounds, neutrals and live AC feeds at a couple of different voltages, plus the input 240V feed. There's also a couple of wires for 110V input, which are insulated and tucked away in case I ever want to convert for that voltage. 

I'd never really read anything about all this stuff before this build, aside from a basic knowledge of what transformers do and how from A-level physics. It's actually all relatively simple in an amp this size, but there's still lots of different parts doing different things. 

I get it, thanks

stickyfiddle

King85 said:

Looking really good so far! How are the instructions? Step by step or just wiring diagrams and schematics?

You get a layout and circuit diagram, as well as some really detailed step by step instructions. It's not completely paint-by-numbers, but gives you enough hand-holding to improve chances of getting it right. 

I've had a copy next to me on an iPad, crossing out each stage as I go, and marking off the components and solder joints on the major diagrams to keep myself clear on what has been done and what hasn't. I don't *think* I've missed anything yet.

http://www.trinityamps.com/docs/TweedBuildersGuide32.pdf

grappagreen

@stickyfiddle ;

Looks like a solid job so far mate. One piece of advice.. don't rush to get it over the finish line

I really enjoyed building mine and I'm still living to tell the tale - if I can do it, anyone with a brain, some basic skills and a quality work ethic can do the same. 

Can wait to hear it (I just broke the piece of advice above already!)

Si

stickyfiddle

grappagreen said:

@stickyfiddle ;

Looks like a solid job so far mate. One piece of advice.. don't rush to get it over the finish line

I really enjoyed building mine and I'm still living to tell the tale - if I can do it, anyone with a brain, some basic skills and a quality work ethic can do the same. 

Can wait to hear it (I just broke the piece of advice above already!)

Si

Cheers

I didn't do any last night as it happens, as I felt a bit shit. Still not feeling great but the speaker should be delivered within the hour, so it'd be nice to get sound out of it today if possible. I actually have very little wiring left at this point, but I need to test properly before I give it any beans! 

Speaking of which, what's the best way to test? Dummy load in the form of appropriate ohm & wattage resistors, or just a speaker with the volumes turned down? @ICBM?

Kalimna

Im reading this thread with much interest, as I have a Tweedle-Dee Modulus kit waiting to be started. And, like you, I'd rather not fry myself in the process!

Adam

stickyfiddle

Speaker is here and it's blue  

I do need to crack on a fair bit, as both MrsF and I would quite like to reclaim the kitchen table at some point...!