Modulus Amps Princetown Kit Build

Dave_Mc · May 31

Wow excellent work so far.

spev11 · June 1

More soldering before work this morning, pics later.
And a revelation, you may have noticed the power transformer was giving me much stress and headaches (all my own doing) because its a dedicated 240v that Modulus have made for the amp(and the tweed deluxe etc).

As the cable colours didn't match up with any of the instructions (some of them anyway) I got myself in a right state stressing about it. If only there was somewhere with a written list of the colours and what they are (such as brown/blue 240v, red HV6.3 etc etc), a quick google and a link to the bloody transformer on the Modulus web page and there it was. face palm for me and some relief, if only i'd thought of that earlier, spev11=dull as a brush

Anyway , off to do some work, might solder some more later.

Airmiles · June 1

spev11 said:

more Pinewood studios perhaps

Baltic Pinewood I hope

Respect for taking it on - I have the desire but not the courage.

spev11 · June 2

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/466b78711563683f5f6b95220a77e94bd91b41f5bf34b35f38

little bit more wiring done today, all the board to socket wiring is done, I've tested continuity on all the connections so far and its all good. Upper wiring next then the heater wiring. I'm still stressed out about the transformer wiring (I know what the black wire coming out from the secondary side between the twin red and twin yellow is but I'm just not convinced I'm gonna put it in the right place).

I really should have gone for a simpler kit but money is tight and I reckon I can only afford to do this once under current circumstances (and I certainly can't afford a new Princeton)

spev11 · June 6

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/6d1de4acec34b917bba1ddb222bf6bf4634aebda4772830a41

Not as much progress as I'd have liked since the last update, I've finished thea heater wiring (almost, got the two leads from the lamp to the first of the 6v6's to go as well), capcan is wired up and the pots are also now attached. Continuity check passed (at least it shows the wiring is complete so far anyway). Couple of wires for the rectifier and the 6v6's to go on (and some resistors).
I've not done any of the suggested mods yet, will get it working as standard and see how it goes.

Michael has been brilliant with advice and checking stuff over, the kit is brilliant (so much so that i've started saving for the next project for the end of the year)

spev11 · June 6

if anyone is wondering what that rogue black wire just floating behind the 2nd pot from the left, it's a bit of cut wire that I hadn't pulled out yet, just cleaning it all out and spotted it after I'd taken the photo.
I will add this, despite enjoying myself thoroughly so far the bloody twisted heater wiring did try my patience somewhat, I'm sure there is a proper way to do it but I haven't found it so it was just get it done

nick79 · June 9

Great stuff, I’m enjoying reading this.

I’m hoping to do something similar, I’ve been hankering after a 6g2 Princeton for a while but don’t want to pay £2000+ to Fender. So I’m hoping Micheal at Modulus could put together a kit for me if I ask him nicely..

yours is looking good, all the stress will be worth it when you finally fire it up!

spev11 · June 9

Unless it explodes taking out the back room with

it’s great fun amongst the stress, only trouble is wanting to build another
also I’m having a cabinet dilemma, I’ve got enough pine to build either a 1x12 or go for a head as originally planned. If i go for the 1x12 I was thinking of making a Velcro grill on a frame and then a quick release baffle for the speaker so I can try out any of the four I have here ( a 1x12 greenback, 1x10 vt jr, orange 1x12 something and a 70/80 1x10) or just set up a cab to do the same.

gdculley · June 9

I'm also enjoying this, it looks like quite a step up from the 5f2a kit I built and will be very rewarding I'm sure! I'm looking forward to you documenting the cab build too! :-)

thermionic · June 9

spev11 said:

I will add this, despite enjoying myself thoroughly so far the bloody twisted heater wiring did try my patience somewhat, I'm sure there is a proper way to do it but I haven't found it so it was just get it done

This is how:

https://youtu.be/9_ceJzH3RmE?si=dhI1PS_ES7aPNh80

springhead · June 9

thermionic said:

spev11 said:

I will add this, despite enjoying myself thoroughly so far the bloody twisted heater wiring did try my patience somewhat, I'm sure there is a proper way to do it but I haven't found it so it was just get it done

This is how:

https://youtu.be/9_ceJzH3RmE?si=dhI1PS_ES7aPNh80

I’ve always used a hand drill with the other ends of the wires in a vice. I then let the drill hang on the wires for a while (hour or so) for them to settle. Otherwise they can start untwisting when you release them from the chuck and vice.

Using a drill gives you an even twist rather than one wire wrapped around the other which is important for hum cancellation, as well as looking neat.

TTony · June 9

Just caught up with this thread.

Total respect to you for taking on the challenge. It's a great buzz (

) when you finally get to plug it in and switch on and enjoy the results.

(After years of deliberating I finally dared myself to take on a build last summer, but wouldn't have done so without excellently detailed instructions - too chicken to do what you're doing!).

spev11 · June 11

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/4c5cc4ade01d725f9a44148a2037b95ad57d99dc77659bc796

kn

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/dfa15626ad9b06777a21a9c99d72e77130264b5be606d5edbb

Knocked up a quick and dirty amp stand when i had a quiet five minutes this morning in work. Finished the wiring this afternoon, added the grid stop and the screen, decided not to fit the adjustable bias yet (if at all).
then the nerve racking (that's an understatement) first power on, as you might be able to see the power lamp lit, left in on for 5-10 mins and no smoke. I've got the power up instructions from stewmacs build manual so i'm following that.
Like a dick I didn't bring the tubes so I could only check voltage on the V1 12ax7 pins 9 to 4/5 which shows 6.8v 9stewmac say between 5-7v so i'm reasonable happy)
i'll check all the caps are drained next and home for more startup procedure.

TTony · June 11

That looks very neat and tidy.

Chris.B · June 11

Well done on not letting any of the magic smoke out during your initial power on tests - that's very promising.

Looking forward to hearing how you get on with the final stages.

spev11 · June 11

TTony said:

That looks very neat and tidy.

thats very kind of you, i'm a little disappointed that some of the wiring is crossing where I'd prefer it didnt but i'll live with it for my first one.

hopefully adding valves doesnt descend into chaos

spev11 · June 11

ah balls, I need to make a footswitch with phono connections on it , arse

nero1701 · June 11

thats a really tidy looking build mate, well done

robinbowes · June 11

spev11 said:

ah balls, I need to make a footswitch with phono connections on it , arse

There's your first mod: relay-based switching, with both local and remote options

Dave_Mc · June 11

Wow that looks awesome so far

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Modulus Amps Princetown Kit Build

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