I have started and stopped this project too many times over the last 6 months. Figured if I made a thread it would help motivate me. I wanted a second Dumbleator for my Wonderland amp. Also wanted to build an amp top version so it is easier to grab and go when needed versus the one in my rack.
I populated most of the boards a while back with parts on hand. When I made my rack version, I made a mess of trying to cut the IEC hole. This chassis is much thinner aluminum. I also made a router jig of MDF and then used the Dremel router. It cut like butter. My jig was definitely not perfect but good enough for a device just for me.
Then drilled out the rest of the holes. I'm using the same boards I designed for the 1U rack.
Next, I need to call around town for a powder coating shop.
-Dan
Another Dumbleator
Moderators: pompeiisneaks, Colossal
Another Dumbleator
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Re: Another Dumbleator
I finished the boards while the chassis is off being powder coated. Not sure what jobs like that normally run but this shop charged me
$100 for acid wash and powder coating with 4 holes being masked for grounds. Hopefully I get that back this week and can work on the graphics soon.
Mix of old and new parts here. Only thing I'm not sure about is that NTE cap. I think it's MPP and I could not discern an outer foil when testing on my scope? It was the only 0.47u I had on hand.
On my rack d'lator I find the first bright switch to be over the top at 1000p. On this one I am going to use an on/off/on switch with either 500p or 150p selectable. Keeping the second one the same.
-Dan
$100 for acid wash and powder coating with 4 holes being masked for grounds. Hopefully I get that back this week and can work on the graphics soon.
Mix of old and new parts here. Only thing I'm not sure about is that NTE cap. I think it's MPP and I could not discern an outer foil when testing on my scope? It was the only 0.47u I had on hand.
On my rack d'lator I find the first bright switch to be over the top at 1000p. On this one I am going to use an on/off/on switch with either 500p or 150p selectable. Keeping the second one the same.
-Dan
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Re: Another Dumbleator
Back from powder coating. The shop did a great job. I went with white and a light texture, it's technically a gloss finish but not too shiny.
-Dan
-Dan
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Raoul Duke
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- Location: S.E. Mass.
Re: Another Dumbleator
Interesting project Dan!
Been thinking about building one of these, but haven’t done my research yet regarding boards, transformer etc.
What did you use for those and what’s the chassis? Looks like a BUD maybe?
Thanks!
Been thinking about building one of these, but haven’t done my research yet regarding boards, transformer etc.
What did you use for those and what’s the chassis? Looks like a BUD maybe?
Thanks!
Marc
Re: Another Dumbleator
Hi Marc,Raoul Duke wrote: ↑Sun Feb 09, 2025 12:54 am Interesting project Dan!
Been thinking about building one of these, but haven’t done my research yet regarding boards, transformer etc.
What did you use for those and what’s the chassis? Looks like a BUD maybe?
Thanks!
It is this Hammond chassis:https://www.amplifiedparts.com/products ... 13-x-7-x-2
I designed the boards and ordered the minimum quantity a while back. I tried to make the design follow the layout in the files section but allowing for the updated design changes Martin posted as well as radial or axial caps. It is optimized for a 1U rack build the PCBs are not that compact. I'm sure I could find the PCB files and share them if you would like.
-Dan
Re: Another Dumbleator
Nice work with the Dremel.
I used the same chassis to make mine yrs ago except I used the Hammond black powder coated steel chassis and it was a lot harder to cut the steel.
Nice thing about the powder coating is that nowadays with the cheaper fiber lasers you can laser off the powder to label the chassis!
Cheers
G
I used the same chassis to make mine yrs ago except I used the Hammond black powder coated steel chassis and it was a lot harder to cut the steel.
Nice thing about the powder coating is that nowadays with the cheaper fiber lasers you can laser off the powder to label the chassis!
Cheers
G
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Raoul Duke
- Posts: 759
- Joined: Sun Apr 17, 2022 1:00 am
- Location: S.E. Mass.
Re: Another Dumbleator
Thanks Dan!dbharris wrote: ↑Sun Feb 09, 2025 2:53 pmHi Marc,Raoul Duke wrote: ↑Sun Feb 09, 2025 12:54 am Interesting project Dan!
Been thinking about building one of these, but haven’t done my research yet regarding boards, transformer etc.
What did you use for those and what’s the chassis? Looks like a BUD maybe?
Thanks!
It is this Hammond chassis:https://www.amplifiedparts.com/products ... 13-x-7-x-2
I designed the boards and ordered the minimum quantity a while back. I tried to make the design follow the layout in the files section but allowing for the updated design changes Martin posted as well as radial or axial caps. It is optimized for a 1U rack build the PCBs are not that compact. I'm sure I could find the PCB files and share them if you would like.
-Dan
If they’re the same as what’s in the files section I’ll just grab them from there. I actually like building the boards oddly enough. Mine are never perfectly symmetrical and sometimes just plain ugly - but they work (so far anyway) lol.
I appreciate the info and will watch how this build for sure.
Marc
Re: Another Dumbleator
Posting some process shots of labeling the controls in case it is helpful to anyone. For whatever reason I've had a terrible time with my vinyl cutter on this project. I think the manufacturer may have changed the thickness of their standard vinyl because it kept cutting through the backing no matter my settings. I think I am also hitting the limits of cutting small font. Some of the negative spaces in letters like B and R, I will need to go back over with white enamel.
-Dan
-Dan
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Re: Another Dumbleator
Been awhile...I couldn't get the enamel to transfer cleanly. I got frustrated and set this aside. Decided to make some aluminum faceplates from hardware store sheet metal, cut to size, round the corners, drill out the holes, brush finish, and finally apply some inkjet sticker graphics over them. Because I was limited by the 12 inch length on the sticker sheets, I had to do multiple face plates.
Also realized I had not been paying very close attention when building the power pcb. I had a 220K instead of a 2k2 for my first dropper and I had included the artificial center tap resistors even though this PT does not require them. Got those issues sorted out and then finished wiring up the build. Loaded with a TAD 7025.
Voltages are pretty much in line, maybe a hair on the low side, but within 5% of what is noted in the files section. It sounds good to me, so I'm not going to roll tubes.
Wall Voltage: 121.4 VAC
B+ 351.8
B+1 347.1
Pin 6 215.6
B+2/pin 1 243.6
Pin 3 29.7
-Dan
Also realized I had not been paying very close attention when building the power pcb. I had a 220K instead of a 2k2 for my first dropper and I had included the artificial center tap resistors even though this PT does not require them. Got those issues sorted out and then finished wiring up the build. Loaded with a TAD 7025.
Voltages are pretty much in line, maybe a hair on the low side, but within 5% of what is noted in the files section. It sounds good to me, so I'm not going to roll tubes.
Wall Voltage: 121.4 VAC
B+ 351.8
B+1 347.1
Pin 6 215.6
B+2/pin 1 243.6
Pin 3 29.7
-Dan
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Raoul Duke
- Posts: 759
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- Location: S.E. Mass.
Re: Another Dumbleator
Nice and neat Dan; looks good!
How did the bright cap change work out?
I’ll get to one of these eventually…
How did the bright cap change work out?
I’ll get to one of these eventually…
Marc
Re: Another Dumbleator
Thanks Marc!
I like these values better. If I was doing this again, I would probably go with something like 270pf and 680pf for the drive side of the circuit. I sorted through my NOS 390pf X5f caps for the one that measured lowest, it came in around 335pf if I remember correctly. That is a little larger than the standard 270pf for the recovery section.
All of the positions are usable depending on the guitar, amp, and speaker cab combo. This one will get most usage with my Wonderland amp, running pedals into the front of the amp, and the loop to give it a different character. It's also a lot easier to grab thank my rack unit if I need a loop outside of the house.
-Dan
I like these values better. If I was doing this again, I would probably go with something like 270pf and 680pf for the drive side of the circuit. I sorted through my NOS 390pf X5f caps for the one that measured lowest, it came in around 335pf if I remember correctly. That is a little larger than the standard 270pf for the recovery section.
All of the positions are usable depending on the guitar, amp, and speaker cab combo. This one will get most usage with my Wonderland amp, running pedals into the front of the amp, and the loop to give it a different character. It's also a lot easier to grab thank my rack unit if I need a loop outside of the house.
-Dan