Journey of my Bassman Micro build

Paul-T

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Looking good. Can't you export straight to PDF? Worked for me . I need to find a new panel maker with the gold option.

Might be just as easy to switch both live and neutral with your power switch.
 

joulupukki

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Looking good. Can't you export straight to PDF? Worked for me . I need to find a new panel maker with the gold option.
Not sure. The person I'm thinking of having them create the panels requires EPS or Corel Draw.
Might be just as easy to switch both live and neutral with your power switch.
I'm not sure I follow. What do you mean?
 

KeithDavies 100

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Burning the midnight oil today to wrap up the Bassman Micro amp head cabinet. I’ve gotta find some black screws for the handles and maybe some black screws for the back, but other than that it’s ready for whenever I can get the chassis put together.

Also, part of the electronics came today … and the rest should arrive tomorrow.

I documented most today’s steps in that Volley thread I linked to earlier in case you wanna see more details. But, here are a bunch of pics from today…

View attachment 984252 View attachment 984254 View attachment 984255 View attachment 984256 View attachment 984257 View attachment 984258 View attachment 984259 View attachment 984260

Here’s the two amp head cabs I’ve built. This one for the Bassman Micro and the British style 18w. I hope I can get the actual amps put together soon!

View attachment 984261

Oh, and the metal mesh is now installed on my 18w head as well (finally got some and took care of stapling it into both amps tonight).
View attachment 984262
I feel woefully inadequate when I read these threads! These are just gorgeous. If I tried this it would have wonky corners and bits of sticky tape at the edges. We're in a rental house at the moment - just moved back to the UK - and I told my wife I want a workshop at our new place. I thought I'd have a go at some kit builds - guitar and amp. My wife thinks that's hilarious, which is not unreasonable! Anyway - following this with interest.
 

wangdaning

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I'm not sure I follow. What do you mean?
He means using a DPDT for the power switch and connecting both PT lines to it so neutral and hot switch at the same time.

Good work, I have been bashing my head over here to get a decent setup to do some cabinets. It has been really hard to get things delivered recently where I am and they do not have hardware supply places you can just go buy a power tools. Hopefully, by summer I can glue some stuff up and the two amps I have built can get a home.
 

joulupukki

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He means using a DPDT for the power switch and connecting both PT lines to it so neutral and hot switch at the same time.
Ah, I see. I would if I had one of those switches, but don't, so I'll go with just switching the load line.
Good work, I have been bashing my head over here to get a decent setup to do some cabinets. It has been really hard to get things delivered recently where I am and they do not have hardware supply places you can just go buy a power tools. Hopefully, by summer I can glue some stuff up and the two amps I have built can get a home.
Thanks. Yeah, I initially was going to build my cabs with just some biscuit joints and not bother with the finger joints but then a friend offered to let me borrow his router jig. I couldn't resist ... and went a little crazy building all these cabs. Good luck with your cab builds. Hopefully you'll be able to figure out something that'll suit them well. What amps did you build?
 

joulupukki

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Alright. I think my panel designs are about ready for etching. The front panel I've gone over and triple-checked the measurements. The back panel I'm not sure about the spacing of everything, but I think it'll work. Does anyone spot any issues? I'm not planning to sell this commercially or anything, just want it to look good. It'll be etched on gold with black lettering. The red-colored lines will be cutouts.

BHT-JTM45-ML-Front-Master.jpg

BHT-JTM45-ML-Back-Master.jpg
 

Hyakuya

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Alright. I think my panel designs are about ready for etching. The front panel I've gone over and triple-checked the measurements. The back panel I'm not sure about the spacing of everything, but I think it'll work. Does anyone spot any issues? I'm not planning to sell this commercially or anything, just want it to look good. It'll be etched on gold with black lettering. The red-colored lines will be cutouts.

View attachment 985279
View attachment 985281
Your NFB switch says BF6A... Shouldn't that be 5F6A.
 

joulupukki

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@Hyakuya great catch! I don't know what I was thinking. :) Glad I didn't hit that submit button yet. I'll get it fixed up. I've tried to triple/quadruple check everything, but here goes...

BHT-JTM45-ML-Front-Master.jpg

BHT-JTM45-ML-Back-Master.jpg


The contents of both panels are slid down a bit from what they'd normally be because the front and back panels of the amp head overlaps the top about 1/4". I'm not sure if this is how it's normally done, but that's how I built it. Hopefully the panels will work out well.
 

joulupukki

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I decided to go for a Marshall-style square pilot light. Is there any advantage one way or another 120V vs 6V?

120V:

6V:
 

Nicko_Lps

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I decided to go for a Marshall-style square pilot light. Is there any advantage one way or another 120V vs 6V?
Your amp is Marshall style so... The Marshall style light suits better aesthetically in your case 😁

A small suggestion: I would place presence and Tonestack Grnd+NFB switches next to that pilot light and keep "Master" as far away possible from 120V light and On/Off switch plus have effects loop away from output jacks! Something like this:

1653118473973.jpeg

1653118448485.jpeg
 

joulupukki

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A small suggestion: I would place presence and Tonestack Grnd+NFB switches next to that pilot light and keep "Master" as far away possible from 120V light and On/Off switch plus have effects loop away from output jacks! Something like this:
Ah, interesting. Noise reduction strategy?
 

Nicko_Lps

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Ah, interesting. Noise reduction strategy?
They are AC sources so i guess that you will introduce hum to sensitive preamp-parts like your MASTER pot.

Is this change messing alot with your layout plan or potentially drilled chassis/faceplate? If it doesn't, id say don't risk having MASTER close to AC sources.
Alternatively you can wait until someone debunks this theory of mine!

In a modification ive made on my amp(PCB) when i added a pre-PI Master volume, to play it EXTRA safe i used Mogami 2330 to send signal to the pot and return it to the PI.
https://tubedepot.com/products/mogami-w2330-interconnect-wire


Your work is insane so far, hope ill see it till the end!
 

joulupukki

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Gotcha. Well, the panels are made already so I will hope for the best. I do plan on using a number of RG174 shielded lines and I’ll experiment and see what happens. Thanks for the explanation.
 

joulupukki

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What do most people do with the unused secondary wires of the 125B output transformer? Cover the ends with heat shrink tube and maybe zip tie them to the other wires so they don’t dangle around?
 

sds1

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Does anyone spot any issues?
These are nitpicks:

- remove the "Indicator" label (obvious)
- change "Preamp" to "Normal" (preamp describes both channels really)

Speaking of Bright/Normal -- with only one instrument input and no switch how do you select between them?
 

King Fan

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Nitpicking = brainstorming seems useful; a Bassman Micro is a bit tricky. So I'm just thinking out loud, not suggesting. For sure Indicator is redundant but does Marshall do it? Still, despite my long posts I'm not a fan of pointless ink. ;)

For obvious reasons Rob has made the single input the original 'hi bright', but as the only channel, it might just be called Input or In. Likewise, I think Rob calls that pot 'Bright Volume' just to show how it came over from the full version; 'Volume' might work on the label.

As a detail, Rob's writeup has the option for a bright switch, but IIRC Rob also notes the stock bright cap value is pretty puny. Even more to the point, I don't know how attractive/useful the non-bright 'normal' channel would be, so how much a switch helps.

The amp also has two masters; one Rob labels on the pots as Preamp MV, the other as PI MV. I'm not sure what the most accurate and informative frontside labels would be.
 




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