Completed JohnH Attenuators?

Dblgun

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This is a great project, I sorted one out and works well. Thanks
 
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Gene Ballzz

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Wow...excellent work, excellent work, all of you!! Thank you for sharing!

^^^^^^^ What he said, times 10! ^^^^^^^

@Dblgun

That's quite similar to what I'm planning for a future build! Simply GO-JUS! Looks like you followed my layout diagram, almost to the letter! A couple questions/comments:
A> Did you drill and tap the case for the resistor mounting screws?
B> How did you do the cutouts in the lid? Did you use a router, or simply a jig saw and file?
C> Depending on your amp wattage (and how hot the unit gets), you may want to consider drilling a few holes in the bottom, especially around the largest resistors for a bit of flow thru/convection cooling.
D> Pics of the bottom of both the lid and the unit would be nice to see?

Great Work All!
Gene
 

Dblgun

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^^^^^^^ What he said, times 10! ^^^^^^^

@Dblgun

That's quite similar to what I'm planning for a future build! Simply GO-JUS! Looks like you followed my layout diagram, almost to the letter! A couple questions/comments:
A> Did you drill and tap the case for the resistor mounting screws?
B> How did you do the cutouts in the lid? Did you use a router, or simply a jig saw and file?
C> Depending on your amp wattage (and how hot the unit gets), you may want to consider drilling a few holes in the bottom, especially around the largest resistors for a bit of flow thru/convection cooling.
D> Pics of the bottom of both the lid and the unit would be nice to see?

Great Work All!
Gene
Hey Gene,
Yeah I tapped all of the holes for the resistors 4/40 with the exception of the large 100w which are 6/32.

As for the lid, I just built a new shop but haven't moved in yet so most my metal tools are packed. I used a die grinder with a small thin cutoff blade. I laid out the squares and then drilled the corners and then cut to them. From there I just ran a file and some sand paper over it to roll the edges. Super quick and dirty! I'm going to build another version in the future so I look forward to changing a few things.

It works well, we put it through the paces this weekend with a 4x10 30w "Dirty Shirleyish" circuit and had no issues with it getting too warm. It won't be used for amps with much more power than this, so should be good.

The underside of the lid.. 522.jpg
 
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RJB

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I have build 2, both in the cabinet. For both I added a by-pass switch, but in practice they are standard 'on' in the lowest setting.

The first is in my Fender Blues Junior IV. The circuit really is SUPER for this amp, now I can finally get all tones out of it I want at 'room volume'. I often use the maximum setting if I crack up the amp. For this I added even an extra -14db circuit.

BJ4.png

Secondly I build a 'low power' version for my DSL5. Turning the DSL5 more open does not change the tone very much, but it makes it a lot less 'sensitive' at the volume pots at low volumes. So also a 'standard on'.



DSL5.png

Very happy with both of them!
 

Lancer X

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My M2 build in project. I know - request for finished builds only. But this sinus infection said "take a night off". More wiring complete I don't have pics of yet. One resistor mistakenly ordered with big dorky leads attached. Taking stock:

IMG_4574.JPEG

Planning resistor layout, based on @JohnH layout with some tweaks. Note I decided to use a 1590D chassis per @Gene Ballzz. Not building in a 16 ohm option at this point, but think there would still be room if I want to mod it later:

IMG_4575.JPEG

Re-installing resistors, this second time with the thermal compound... @Gene Ballzz I decided not to tap case holes, instead installing w/ nuts. Since my install will be stuffed into the back of an amp chassis, I wasn't too precious with aesthetics.

IMG_4577.JPEG

When step drill bits attack - oh, the humanity!

(PS - plan out your ventilation before installing resistors... Playing it a little too fast and loose with this build.)

IMG_4578.JPEG

Dayton Audio inductor coil install on the chassis lid. Two extra wire ties used to support/level the unit beyond those it shipped with. Three more used to mount to case lid. Plenty of clearance for components below. Could have mounted deeper into case to mitigate interaction with aluminum chassis. Again with the lack of planning.


IMG_4580.JPEG

Coil mount:

IMG_4581 25.jpg

IMG_4582 25.jpg

Dry fit. Ready for wiring:

IMG_4583 25.jpg


Lower tier of wiring completed:

BE2B44F8-8EDE-420E-9D65-367122FA6515.jpeg


Ready for higher and final tier of wiring:

2336134C-A1AC-42E5-BF43-64469F880EC5.jpeg
 
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JohnO9

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Thanks @Barnsley Boy . I created the enclosure from pieces of L shaped aluminum (Online Metals). The heat sink and switches are from Parts Express. Lots of drilling and tapping for M3 screws to put it all together.
 

Mjh36

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Great pics everybody and tidy work!

Built this 8 Ohm M2 50 watt some months back and still haven't used it. Why not? Because I was building a tube amp and I ruined it. I'm a novice and I don't know how to troubleshoot/fix what I did. So now I'm waiting for a fully built Ceriatone AH-50 Deluxe, and that's still 6 months out.

Other than that it's a Hammond 1590F enclosure. Holes on bottom and sides. Big 15 amp switches. Line Out on front. I get a constant 7-10 Ohm reading on all outputs and switch positions, so it should work fine. Blue LED was just battery powered for the picture, haven't installed it. Umbrellas to help with cooling.


20210618_020519.jpg 20210619_004942.jpg 20210619_004901.jpg 20210619_004928.jpg 20210619_005126.jpg
 

Barnsley Boy

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@Mjh36 I love this!
The umbrellas look like an absolutely essential mod. If you could let @JohnH know the specification like fire rating (30/60/90 minute)
opening radius, which colour canopy gives the best cooling curve etc. I'm sure that he will upgrade the latest schematic to include
this!! I'm liking the lighting too. On a slightly more serious note and following on from temperature related switches, if you could work out a way
of lighting up the interior and switching the colours as the unit heats up, with red being danger level, that would be really cool (or hot!)

Good work fella,
 

JohnH

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@Mjh36 I love this!
The umbrellas look like an absolutely essential mod. If you could let @JohnH know the specification like fire rating (30/60/90 minute)
opening radius, which colour canopy gives the best cooling curve etc. I'm sure that he will upgrade the latest schematic to include
this!! I'm liking the lighting too. On a slightly more serious note and following on from temperature related switches, if you could work out a way
of lighting up the interior and switching the colours as the unit heats up, with red being danger level, that would be really cool (or hot!)

Good work fella,
That is a nice build. And down here at an outdoor gig in high summer, those 'brollies could be just the right thing. Otherwise in full sun, the box could collect more heat from solar radiation than from the amp power!
 

Lancer X

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My M2 build (continued) - part 1 is here

Used 18 gauge solid core wire throughout except for the runs to the coil on the lid. Don't recommend using solid core wire for microswitches such as these. It was a PITA to thread it through these little terminals.


IMG_4604.JPEG


Completed the upper tier of wiring:

IMG_4607.JPEG

Completed build with open lid:

IMG_4608.JPEG


Resistance testing with speaker load:

IMG_4611.JPEG


Front side. I will add some feet to the right side of the box from this angle. The box will stand up inside the cab of my RobRob 5E3 Deluxe Micro Mod 10" combo:

IMG_4616.JPEG


Rear side. Input, line out volume, line out, and (2) 4- or 8-ohm outputs:

IMG_4613.JPEG


Underside ventilation:

IMG_4614.JPEG
 

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