Next Build

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TriodeLuvr
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Re: Next Build

Post by TriodeLuvr »

lavrgs wrote:
Sat 06/05/21 5:15 pm
TriodeLuvr wrote:
Sat 06/05/21 4:14 pm
lavrgs wrote:
Sat 06/05/21 11:15 am
I am considering making a chassis, that I will call a composite; it would be constructed of machined side walls and use flat aluminum panels for front back and top.
How would you attach the pieces to each other? Angle aluminum? Or would you weld it together? I've been making chassis for hi-fi gear from rectangular aluminum extrusions. They're 1/8" thick, sized 10" X 2", 8" X 3", etc. I cut them to length, cut out the bottoms for working inside the chassis, then add front and rear panels that are anodized and engraved. It's a huge amount of time and work cutting all the pieces, and I probably won't continue this process when my current small inventory is used up.

I think there are more off-the-shelf solutions for instrument amps than for hi-fi. And they're cheaper, too. A pre-made chassis for the type of gear I frequently build would cost upwards of $400 if the shop did everything (anodized and/or painted and engraved/silkscreened).

It's a never-ending problem.

Jack
My design started yesterday but when I get to a point that it's ready for review I'll post it. With a 19+ inch run I may need some center braces. The cosmetics will probably be some kind of engraved plastic - last time I sent it out and it was too expensive- since I am doing a retrofit on my mill I would like to see if I can make something. That's a ways out - later this summer. I'm at a point where I should sell an amp before I make any more but I like what I have. The Mojotone clone may be used as a donor for transformers or may be sell it.
Please post a pic when the work is at the point where you're comfortable showing it. I'm also using a mill, but its a bench-top model with limited movement. That really eats a lot of time when larger pieces are involved. On the upside, it's CNC, so I can engrave and fill panels without sending them out. Here are a couple photos of a subchassis I'm building for my current project. All of this is my own work, including setting the PEMs and anodizing the bias panel. It's nice to have this capability, but the work is tedious at times. I often wish I could concentrate on design and leave the mechanical stuff for someone else.

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Image

Jack
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lavrgs
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Re: Next Build

Post by lavrgs »

TriodeLuvr wrote:
Sat 06/05/21 8:05 pm


Please post a pic when the work is at the point where you're comfortable showing it. I'm also using a mill, but its a bench-top model with limited movement. That really eats a lot of time when larger pieces are involved. On the upside, it's CNC, so I can engrave and fill panels without sending them out. Here are a couple photos of a subchassis I'm building for my current project. All of this is my own work, including setting the PEMs and anodizing the bias panel. It's nice to have this capability, but the work is tedious at times. I often wish I could concentrate on design and leave the mechanical stuff for someone else.

Image
Image

Jack
Beautiful work!
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lavrgs
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Re: Next Build

Post by lavrgs »

Here is the general concept for the composite chassis. Placement of items should be considered "rough" outline, but suggestions are welcome.
Front has 7 holes for pots 1 for input 2 for toggle switches and 1 for a F*nd*er style pilot
Back has IEC hole 5 cliff jack hole 1 switch hole
The side panels are 3/8 thk all sheet metal is 0.06 - may change the top if transformers need more support.
The front and back panels support the top panel but I may add a bracket in the middle with a couple extra screws. While this would not be a production chassis the bare metal is around $20 for the sheet metal and just over $15 for a 24" rectangular bar... most shops would cut to size. Drilling and cutting shapes is up to you...hard ones are PT and IEC...files and nibblers... Bottom line don't start yet 9-)
EDIT UPDATED PDF to include EIGHT volume holes , Cap Can hole, threw in some 9 pin sockets
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Last edited by lavrgs on Thu 06/10/21 4:43 pm, edited 1 time in total.
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JMPGuitars
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Re: Next Build

Post by JMPGuitars »

Steel or aluminum? .06 is fairly thin, but you can use fender washers to strengthen/reinforce the transformer mounts.

Why only 7 knobs? Are you not using reverb or something?

Thanks,
Josh
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Re: Next Build

Post by lavrgs »

JMPGuitars wrote:
Thu 06/10/21 3:27 pm
Steel or aluminum? .06 is fairly thin, but you can use fender washers to strengthen/reinforce the transformer mounts.

Why only 7 knobs? Are you not using reverb or something?

Thanks,
Josh
Aluminum for all items.
Hmmm did I count wrong...dang? easy fix...
my first pass uses a spacing of 1.5 inches for the holes. 2 inches for the tubes but is not based on any particular criteria. On the rear I grouped the cliff jacks and offset the switch from that group.
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lavrgs
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Re: Next Build

Post by lavrgs »

Updated the pdf in the post above
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TriodeLuvr
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Re: Next Build

Post by TriodeLuvr »

JMPGuitars wrote:
Thu 06/10/21 3:27 pm
...you can use fender washers to strengthen/reinforce the transformer mounts.
I used Marshall washers in mine. :lol:
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Re: Next Build

Post by JMPGuitars »

TriodeLuvr wrote:
Thu 06/10/21 8:17 pm
JMPGuitars wrote:
Thu 06/10/21 3:27 pm
...you can use fender washers to strengthen/reinforce the transformer mounts.
I used Marshall washers in mine. :lol:
😂😂😂 Did it look like this?
marshall-washer.jpg
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TriodeLuvr
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Re: Next Build

Post by TriodeLuvr »

JMPGuitars wrote:
Fri 06/11/21 6:02 am
TriodeLuvr wrote:
Thu 06/10/21 8:17 pm
JMPGuitars wrote:
Thu 06/10/21 3:27 pm
...you can use fender washers to strengthen/reinforce the transformer mounts.
I used Marshall washers in mine. :lol:
😂😂😂 Did it look like this?

marshall-washer.jpg
I use that at amplifier shootouts. :lol: :lol: :lol:
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Re: Next Build

Post by JMPGuitars »

TriodeLuvr wrote:
Fri 06/11/21 9:17 am
JMPGuitars wrote:
Fri 06/11/21 6:02 am
TriodeLuvr wrote:
Thu 06/10/21 8:17 pm


I used Marshall washers in mine. :lol:
😂😂😂 Did it look like this?

marshall-washer.jpg
I use that at amplifier shootouts. :lol: :lol: :lol:
Ha!
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Re: Next Build

Post by zaphod_phil »

JMPGuitars wrote:
Thu 06/10/21 3:27 pm
...you can use fender washers to strengthen/reinforce the transformer mounts.
That's a desecration of a Marshall amp! :evil:
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Re: Next Build

Post by JMPGuitars »

zaphod_phil wrote:
Wed 06/16/21 3:00 pm
JMPGuitars wrote:
Thu 06/10/21 3:27 pm
...you can use fender washers to strengthen/reinforce the transformer mounts.
That's a desecration of a Marshall amp! :evil:
lol! Should I call it a metal automotive washer instead? ;)
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Re: Next Build

Post by JMPGuitars »

lavrgs wrote:
Thu 06/10/21 4:44 pm
Hey Everybody,

I wanted to post a HUGE THANK YOU to Bill for helping me out with my chassis design!

He took my visio dxf drawing and made it into a proper CAD file, and helped improve it on the way. Check it out:
JMPGuitars-Noval-Chassis.jpg
If anybody needs help in this area, I highly recommend hiring him.

Thanks,
Josh
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lavrgs
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Re: Next Build

Post by lavrgs »

All the items for the pcb are on order plus the reverb driver & a few pots. I'll be using Josh's pcb and man is it hefty- He did an excellent job. I may revise my plan of tearing up the Mojotone to get parts and just buy all new. The mojotone works really well in spite of all the negative things that many have said. For me it was a great learning experience. I had built an Allen amp but the instructions were so good that all I did was follow them turn it on and play for five years, not a bad thing but I didn't learn anything other than I can follow directions...

I also got a Joshuwah, my first wah but I've wanted a wah for a long time. It is fantastic - my problems is that there are so many to choose from - I think Cr* B*by make 10 different versions If you feel compelled to support the work Josh does on this site check out the JMP Guitar site and view his offerings. I hope plugging for the admins is not considered bad form. I know he wouldn't do it for himself
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Re: Next Build

Post by lavrgs »

After a long hiatus I am back to amp building...my primary distraction for the last year has been retrofiiting a Tree J325 milling machine https://photos.app.goo.gl/LLHf8M84eQYwP3ph6 I had put all other activities on hold until it was complete...complete is just a concept, but it is working and making parts for amplifiers (indirect 18 watt content) I routed a board the other day for another amp project.
OK I need to include direct 18 Watt content. I purchased a board from Josh about a year ago. He rewarded my assistance with his chassis design, by comping a chassis for this project. I haven't been on board much but Josh is working on a few other projects and I have provided chassis designs for that effort along with a head cab concept.
I am committed to focusing on amp builds for the next week or so and I am excited to try bringing up the 18 watt single input TMB reverb soon. Today I lay the board in the chassis as I was checking the spacer heights to ensure clearance above the reverb connectors. I thought a progress photo was in order.
IMG_2646.jpg
. I will wire up pots tomorrow and be close to ready to mount the board.
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lavrgs
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Re: Next Build

Post by lavrgs »

In case you're wondering what the clamps are for from the picture above; my universal chassis stand 9-)
IMG_2647.jpg
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lavrgs
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Re: Next Build

Post by lavrgs »

I have 26 ga shielded wire - it seems a little small. What is recommended?
shield.JPG
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Re: Next Build

Post by JMPGuitars »

lavrgs wrote:
Sat 04/23/22 10:52 am
I have 26 ga shielded wire - it seems a little small. What is recommended?shield.JPG
I use 22 or 20 AWG depending on what I have available.
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Re: Next Build

Post by lavrgs »

Almost four years later and I'm back to it; what's the hurry...My big cnc lathe project is on hold for a month so I'm trying to clean up the projects in the corner ncluding tube tester, Champ radio and and and.
Going through everything to figure out what is there and what is not will take a few days. I already found an error; mis-wired the impedance switch, simple fix; I only use 8 Ohms but I broke out the soldering iron.
Printed out a big schematic to redline; and figure out what's next. The wiring in between pots is done but none that go to the board. Same with tube wiring; all wires that go tube to tube are in place and checked.
It's better to find all the problems before I lay the board into place...
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