Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: EL34 on February 10, 2015, 11:05:42 am
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I finished my plexi 6V6 build and it is a really cool amp
This thing is whisper quiet. No hum at all
I made a few changes here and there as the build progressed
The 330uf cap on pin V1 pin 3 was replaced by a 22uf bypass cap
That channel now seems to have a more useable tone and less mud.
The 40x20x20x20 multi cap plus a 16uf cap for the power supply worked out great
Pete might notice in the pics that I moved my rotary impedance selector switch down top the last hole and this is a way better way to go. Thanks Pete
Lots of stuff to cram into the stout Chassis but it all fit
The exact build sequence of how I added parts is on the build page here
http://el34world.com/projects/Plexi6V6.htm (http://el34world.com/projects/Plexi6V6.htm)
The parts list is here
http://hoffmanamps.com/MyStore/catalog/PartsListIndex.htm (http://hoffmanamps.com/MyStore/catalog/PartsListIndex.htm)
The PDF schematic and layout are here
http://el34world.com/Hoffman/files/Hoffman_Plexi_6V6-V2.pdf (http://el34world.com/Hoffman/files/Hoffman_Plexi_6V6-V2.pdf)
The info on the library is here
http://el34world.com/schematics.htm#Plexi_6V6_build (http://el34world.com/schematics.htm#Plexi_6V6_build)
The PDF BOM is here
http://el34world.com/Hoffman/files/Hoffman_Plexi6V6_BOM.pdf (http://el34world.com/Hoffman/files/Hoffman_Plexi6V6_BOM.pdf)
This amp sings with humbuckers really nice but it also cleans up with single coils really nice
Here's a couple sound clips
Lead parts with a humbucker
The chord comping is two single coils, the middle position on the guitar
http://el34world.com/Misc/Music/files/Plexi6V6Demo1.mp3 (http://el34world.com/Misc/Music/files/Plexi6V6Demo1.mp3)
Sound clip #2
Some clean chord picking and then some soloing over the top of that
http://el34world.com/Misc/Music/files/Plexi6V6Demo2.mp3 (http://el34world.com/Misc/Music/files/Plexi6V6Demo2.mp3)
(http://el34world.com/projects/images/Img_9107_small.jpg)
(http://el34world.com/projects/images/Img_9095_small.jpg)
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Looks good Doug. It's also nice to see you building so much stuff lately.
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Thanks
Got to do it to make sure the build goes together properly for my customers
I make a parts list of all nuts and bolts, ring terminals, etc as I build and that all goes into the BOM
These Stout chassis builds are really fun
Such a great compact size
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beautiful build and it sounds marvelous!
--pete
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Thanks Pete
Hope to do some other clips soon
That rotary switch at the tail end worked out great
I just had to enlarge the .375 inch hole to .38 to get it to fit
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i like the layout. very compact yet serviceable.
are you going to add a pilot light?
--pete
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It's a really nice looking amp Doug. Is there a chance to hear it? Would like to hear how this amp sounds.
BTW I just got done drilling a 17x9x2 chassis for a single channel DR and that was not the funnest thing I have ever done. What would be cool for the SCDR is a marshall style chassis and the board reversed so it read in English and not Chinese.. :-)
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click the play button on the media player in the opening post.
--pete
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i like the layout. very compact yet serviceable.
are you going to add a pilot light?
--pete
yes, but I am going to make a face plate for it and so I would have to un-solder it
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It's a really nice looking amp Doug. Is there a chance to hear it? Would like to hear how this amp sounds.
see post #1
There is a sound clip link there
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Hate to show my ignorance, but what do the titles "Stout" , and "Plexi" mean ? Models of amps ? :w2:
I lead a sheltered life ya know.... :icon_biggrin:
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wow! How did I miss that clip? this little amp sounds pretty good. Nice bluesy sound. Great guitar playin' too.
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Hate to show my ignorance, but what do the titles "Stout" , and "Plexi" mean ? Models of amps ? :w2:
I lead a sheltered life ya know.... :icon_biggrin:
Hi Bill,
Stout refers to Doug's stripped down hot rodded 18W Marshall that he had several variations of and now sells a custom chassis for.
Plexi refers to a family of Marshall amps that featured a Plexiglas face plate.
Ray
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Hate to show my ignorance, but what do the titles "Stout" , and "Plexi" mean ? Models of amps ? :w2:
I lead a sheltered life ya know.... :icon_biggrin:
Good explanation by stingray above
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wow! How did I miss that clip? this little amp sounds pretty good. Nice bluesy sound. Great guitar playin' too.
Thanks, I only did a quickie demo from an existing backing track
I have been busy since then and hope to get back and explore the amp some more
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Thanks
Got to do it to make sure the build goes together properly for my customers
I make a parts list of all nuts and bolts, rig terminals, etc as I build and that all goes into the BOM
These Stout chassis builds are really fun
Such a great compact size
perfect for so many builds
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Very impressive work DH. That is a rockin' beast in a small package. :icon_biggrin:
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Thanks guys
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The PDF BOM is done and here
http://el34world.com/Hoffman/files/Hoffman_Plexi6V6_BOM.pdf (http://el34world.com/Hoffman/files/Hoffman_Plexi6V6_BOM.pdf)
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Sound clip #1http://el34world.com/Misc/Music/files/Plexi6V6Demo1.mp3 (http://el34world.com/Misc/Music/files/Plexi6V6Demo1.mp3)
Sound clip #2
Some clean chord picking and then some soloing over the top of that
http://el34world.com/Misc/Music/files/Plexi6V6Demo2.mp3 (http://el34world.com/Misc/Music/files/Plexi6V6Demo2.mp3)
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Some clean chord picking and then some soloing over the top of that
WOW!! That sounded incredibly good!! Very transparent tone. I loved the smooth transparent musically sweet overdrive on the soloing.
I'm quite impressed. Thanks for sharing it! Great build. :thumbsup: :thumbsup:
With respect, Tubenit
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That little package really sounds outstanding ! :icon_biggrin: I don't play that kind of music, because I don't know how ! I just listen !
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ME TOO :sad2:
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Thanks guys
I am not sure which amp I like best now
The 18 watt stout is pretty cool but the Plexi 6V6 may be even cooler
Have to do a side by side test and see
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The 18 watt stout is pretty cool but the Plexi 6V6 may be even cooler
Both great amps. My vote is for the Plexi 6V6 because of the transparency of the OD tone and how smooth the overdrive is.
With respect, Tubenit
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I posted a comment over on TAG on just how different the amp sounds in person compared to what got recorded.
Mic placement and other recording diddy's can make the amp sound completely different.
In person it has that Marshall cut that just gets in your face
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The 18 watt stout is pretty cool but the Plexi 6V6 may be even cooler
Both great amps. My vote is for the Plexi 6V6 because of the transparency of the OD tone and how smooth the overdrive is.
With respect, Tubenit
I could take the same exact backing track and record with the Stout TMB since I have not moved the mic yet
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I could take the same exact backing track and record with the Stout TMB since I have not moved the mic yet
That would be an interesting comparison, IMO.
With respect, Tubenit
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What is the wattage output on a 6V6 plexi?
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Got me?
I know that it is loud :)
I don't know if Steve measured his Plexi 6V6
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The Plexi 6V6 (mine was cathode biased) I built many years ago was louder than the original Princeton Reverb I had.
I am guessing it was maybe 14-15 watts?
With respect, Tubenit
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I just did the same clip with the Stout TMB
I'll post it in a bit
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What is the wattage output on a 6V6 plexi?
Mine uses JJ 6V6s and is idling at 19.7W (9.5+10.2). Never measured actual power. I believe it can hang with a Deluxe Reverb.
My plate voltage is 394V. Doug's should be less because of his PT.
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I have mine biased at 25ma per tube and I have 401 on the plates with the Solid state rectifier
I may have to check it again
that was when i first fired it up
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Your amp is actually slightly hotter than mine. I'm running 24/26mA @ 394V.
I used that same PT in my EL84 cat biased 18W amp with EZ81 recto. Plates were only 324. The EL84s were idling hotter than my 6V6s. Guess the combined recto drop and higher load sucked the PT down more than the Plexi 6V6.
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I will be measuring again so I can add all the voltages to the PDF documents
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Here's the same tune done with the Plexi 6V6 and then the stout TMB
I don't think I got the chord tone setup the same way in both clips because I had moved the mic for the Plexi 6V6 demo clip
I like the chord tone on the Plexi clip better but that is more mic placement in the recording
For the lead tone on both amps the mic is in the same spot
Plexi 6V6
http://el34world.com/Misc/Music/files/Plexi6V6Demo2.mp3 (http://el34world.com/Misc/Music/files/Plexi6V6Demo2.mp3)
Stout TMB
http://el34world.com/Misc/Music/files/StoutTMBDemo3.mp3 (http://el34world.com/Misc/Music/files/StoutTMBDemo3.mp3)
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Well, I honestly think I like the Stout rhythm tone more. It's fuller sounding with more mids (I think?) than the Plexi which has almost a glassy tone to it.
However, I like the Plexi 6V6 overdrive tone much better. It's just a lot more transparent to my ears than the Stout. The Plexi sounds more of a pushed clearer overdriven tone and the Stout sounds more distorted to me.
Having said that, I would be pretty happy with either amp tone.
With respect, Tubenit
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The cool part about having two players on the same page is you can start both of them at the same time
Then you can pause each player one at a time to go back and forth for a good comparison
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I think both sound fantastic in different ways- I could see switching it up between them all the time. Since they are so small they could fit in one cabinet easy enough and would bring twice the goodness to the party :)
I think I have to build both now.
Regan
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Ok, it's a Stout Chassis party
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I just uploaded a new Plexi 6V6 PDF file
The voltages are now on the schematic
http://el34world.com/Hoffman/files/Hoffman_Plexi_6V6-V2.pdf (http://el34world.com/Hoffman/files/Hoffman_Plexi_6V6-V2.pdf)
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I forgot to mention yesterday that the Stout TMB in the clip had a solid state rectifier plugged into the socket
So the voltages were much higher
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I finished up the Plexi 6V6 this morning by installing the face plate and the indicator lamp
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Here's my Plexi 6V6 is SG's cabinet
The stain is Vermont maple color
I sprayed Satin finish polyurethane over the flat stain
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Here's a few 3D renderings of what I could do to the front panel on my CNC machine
I kind of like the Top one with the circle in the middle
One design could have a depression with a Reversed engraved Faceplate or a backlit logo sunk down into a depression
The one with the small slots is nice also
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I really like Panel 5.
Have you seen EL panels? One of those would look really neat behind the slots!
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Have you seen EL panels? One of those would look really neat behind the slots!
What are they?
Brad :dontknow:
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I like #4 and #5, but #2 and #3 are good too.
Brad :icon_biggrin:
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I really like Panel 5.
Have you seen EL panels? One of those would look really neat behind the slots!
Not sure what that is?
I am leaning towards #5, but I have another idea based on that design
Instead of a circle, it would be an oval and slots on either side
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I think I am done with the front panel CAD work
It's down to panel 5 or panel 6
I like the oval panel 6 design but I also like the circle in panel 5
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I like the oval better.
Brad :icon_biggrin:
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Yeah, me too
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It's softer looking and makes the slots look better by moving them into more of an ark on their ends.
Brad :icon_biggrin:
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Here's a straight on view
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That looks great!
Kinda reminds me of an antique radio look
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yeah, that's back when things had real styling
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Yeah, I like it.
Brad :icon_biggrin:
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It's on the CNC machine right now being cut
I'll have pics in a while
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Yeeehaaaa.
It's done and it came out great
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Sure did!!!!!! :blob8:
What size and type of bit did you use? Spiral cut?
Did you cut it before or after you stained it?
Brad :icon_biggrin:
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Bravo! That looks fantastic!
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EL panels are flexible plastic panels that are coated with electroluminescent material that emit a soft glow when electrically charged.
Follow this link for examples of EL panels, tape, wire, etc...
http://www.adafruit.com/category/50 (http://www.adafruit.com/category/50)
Oh wow... they even have EL piping! Didn't see that before...
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Sure did!!!!!! :blob8:
What size and type of bit did you use? Spiral cut?
Did you cut it before or after you stained it?
Brad :icon_biggrin:
1/4 inch two flute end mill at 15,000 rpm
Straight down plunge at a very slow speed
Then a faster speed for the cuts
I under cut in two depth passes by .003" and then did a final pass at full depth for a super clean finish cut
It was already stained and clear coated when I did the cuts. All I did was take a small brush and brush some stain inside the cuts to get rid of the blond wood
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EL panels are flexible plastic panels that are coated with electroluminescent material that emit a soft glow when electrically charged.
Follow this link for examples of EL panels, tape, wire, etc...
http://www.adafruit.com/category/50 (http://www.adafruit.com/category/50)
Oh wow... they even have EL piping! Didn't see that before...
That's some cool stuff
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1/4 inch two flute end mill at 15,000 rpm
Straight down plunge at a very slow speed
Then a faster speed for the cuts
I under cut in two depth passes by .003" and then did a final pass at full depth for a super clean finish cut
It was already stained and clear coated when I did the cuts. All I did was take a small brush and brush some stain inside the cuts to get rid of the blond wood
Well your method and machine did a great job!
Brad :icon_biggrin:
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EL panels are flexible plastic panels that are coated with electroluminescent material that emit a soft glow when electrically charged.
Follow this link for examples of EL panels, tape, wire, etc...
http://www.adafruit.com/category/50 (http://www.adafruit.com/category/50)
Oh wow... they even have EL piping! Didn't see that before...
That's some cool stuff
that's a cool site for open source hackers. it's owned by limor fried, she's an MIT grad who ventured off into her own biz. check the whole site out, she sells some cool stuff.
--pete
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Sure did!!!!!! :blob8:
What size and type of bit did you use? Spiral cut?
Did you cut it before or after you stained it?
Brad :icon_biggrin:
1/4 inch two flute end mill at 15,000 rpm
Straight down plunge at a very slow speed
Then a faster speed for the cuts
I under cut in two depth passes by .003" and then did a final pass at full depth for a super clean finish cut
It was already stained and clear coated when I did the cuts. All I did was take a small brush and brush some stain inside the cuts to get rid of the blond wood
i'm assuming your cut job was an inside contour: do you recall what the feed rate on your X & Y axis? how many passes and what cut depth did you use? it'd be nice to have a staring point since i've never cut wood on my CNC, just aluminum and Garolite... :icon_biggrin:
thanks,
--pete
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EL panels are flexible plastic panels that are coated with electroluminescent material that emit a soft glow when electrically charged.
Follow this link for examples of EL panels, tape, wire, etc...
http://www.adafruit.com/category/50 (http://www.adafruit.com/category/50)
Oh wow... they even have EL piping! Didn't see that before...
That's some cool stuff
that's a cool site for open source hackers. it's owned by limor fried, she's an MIT grad who ventured off into her own biz. check the whole site out, she sells some cool stuff.
--pete
Yep. I've ordered a fair amount of stuff from them. Us "makers" love that site. She's come up with some very innovative stuff.
Another very cool lighting product there are the Neopixels - Individually addressable RGB LED strips, arrays, rings, etc. controllable with any microcontroller (like Arduino.) I've seen people make these into large video displays (think stadium Jumbo Tron but on a smaller scale.)
I'd like to do a "neon retro jukebox" sort of design for a tubes-up combo. Done well I think it would look really neat on stage.
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I love that front panel!
I am working on using some light blue EL wire in my latest build.
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i'm assuming your cut job was an inside contour: do you recall what the feed rate on your X & Y axis? how many passes and what cut depth did you use? it'd be nice to have a staring point since i've never cut wood on my CNC, just aluminum and Garolite... :icon_biggrin:
thanks, --pete
see my screen short for all the settings I used
Inside contour?
In CamBam the MOP is called profiling which is probably the same thing?
The tool is following a shape.
In this case I have it set for profiling the inside of all the shapes
I used real slow speeds because I did not want to splinter the wood.
3 for plunge and 10 for cutting, shown in screen shot
Two rough cut passes
-0.23 inches down, then -0.47 inches down
Cutting -0.002 back from the lines as a roughing clearance
One final pass at -0.47 with the roughing clearance pass set to zero so it does one final clean pass following the lines
I set the tool width to 0.245 inches wide to fool CamBam because my parallel lines were exactly 0.25 inches apart
It has a problem doing that if the tool bit is set to 0.25 inches wide
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i'm assuming your cut job was an inside contour: do you recall what the feed rate on your X & Y axis? how many passes and what cut depth did you use? it'd be nice to have a staring point since i've never cut wood on my CNC, just aluminum and Garolite... :icon_biggrin:
thanks, --pete
see my screen short for all the settings I used
Inside contour?
In CamBam the MOP is called profiling which is probably the same thing?
The tool is following a shape.
In this case I have it set for profiling the inside of all the shapes
I used real slow speeds because I did not want to splinter the wood.
3 for plunge and 10 for cutting, shown in screen shot
Two rough cut passes
-0.23 inches down, then -0.47 inches down
Cutting -0.002 back from the lines as a roughing clearance
One final pass at -0.47 with the roughing clearance pass set to zero so it does one final clean pass following the lines
I set the tool width to 0.245 inches wide to fool CamBam because my parallel lines were exactly 0.25 inches apart
It has a problem doing that if the tool bit is set to 0.25 inches wide
thank you so much! :icon_biggrin:
i was estimating about 13-14 IPM with my machine running @ 22K RMP on the spindle. my machine's spindle is a porter-cable router.
--pete
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I run a Bosch router motor but I use a super PID motor control
You mount a sensor that reads the rpm of the motor shaft
The motor speed stays constant, even under heavy loads
See the wire coming out of the end of the Router motor?
Big pic here
http://el34world.com/Misc/Cnc/CNC19.htm (http://el34world.com/Misc/Cnc/CNC19.htm)
It's so much nicer with an electronic control unit
http://el34world.com/Misc/Cnc/CNC19.htm (http://el34world.com/Misc/Cnc/CNC19.htm)
(http://el34world.com/Misc/Cnc/images/Img_7055_small.jpg)
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I run a Bosch router motor but I use a super PID motor control
You mount a sensor that reads the rpm of the motor shaft
The motor speed stays constant, even under heavy loads
See the wire coming out of the end of the Router motor?
Big pic here
http://el34world.com/Misc/Cnc/CNC19.htm (http://el34world.com/Misc/Cnc/CNC19.htm)
It's so much nicer with an electronic control unit
http://el34world.com/Misc/Cnc/CNC19.htm (http://el34world.com/Misc/Cnc/CNC19.htm)
thanks for sharing. i'm hoping that i can pickup rotation off of the main-shaft by the collett.
--pete
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Many Thanks for sharing
Franco
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thinking about adding some blue LED's inside just for fun
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Hoho, that's the ticket right there!
That would light up the letters on the face plate if it wasn't painted on the back?
Brad :icon_biggrin:
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I think the Blue looks pretty cool
That would light up the letters on the face plate if it wasn't painted on the back?
I guess you mean edge lighting the plastic?
If you did that, then you would not be able to see the words in regular day light
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I meant back lit.
Brad :dontknow:
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You mean like cut all the metal away until there is nothing holding the front panel on the amp :icon_biggrin:
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Dho! That's right the chassis.
Brad :laugh:
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I guess it could be done
Not sure how you would remove all that metal?
Then you would have to figure out a way to evenly light every bit of text plus all 11 pot detents
Plus, picture what is right behind all of those cutouts
Pots, wires, etc
It would look like this I guess
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To have light on labels
why don't to add a plastic faceplate with labels engraved on the back side as HotBluePlates has done on his Standel ?
(http://el34world.com/Forum/index.php?action=dlattach;topic=14263.0;attach=34448;image)
K
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There ya go Brad
I like the black on white faceplates personally
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You mean like cut all the metal away until there is nothing holding the front panel on the amp :icon_biggrin:
This would be a great application of those EL panels I was showing you. Engrave the black faceplate as normal, cut an EL panel to fit the faceplate and affix it to the back of the faceplate or just sandwich the panel in between the faceplate and chassis front.
Hmm... I know you can cut these down to whatever size you want, but I don't know about holes for the pots and switches... Let me research that. If you can cut them to size, I'd think holes would be OK.
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They would have to be about zero thickness
The face plates are .0625 inches thick (1/16") and there are really no much more threads left on the pots when combined with the .09 inch thick aluminum chassis
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That could be a problem... they are about 0.5mm thick.
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I have had that problem with my aluminum chassis' and face plates too.
I found that the Mojo brand pots have a little bit longer threaded bushing that works. Problem is they only stock so many values. So far they have been most of what of I needed but I have had to use a few PEC military pots which cost a lot more.
OTOH, with a steel chassis, because their thinner, there might be enough room?
Brad :think1:
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That could be a problem... they are about 0.5mm thick.
.5mm is pretty thin
That may work
Check them out and let me know what you come up with
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I found that the Mojo brand pots have a little bit longer threaded bushing that works. Problem is they only stock so many values.
I thought about stocking those pots, but like you said, the values are limited
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Maybe next time you talk with you could bring up the bushing length for more values of pots for guys building with aluminum chassis and thicker face plates?
Brad :dontknow:
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I could mention it and see
Don't hold your breath :)
I didn't really have any problems with the Alpha pots I stock
A .09 inch chassis and a .0625 inch faceplate works out just right
The Stout Chassis + Alpha pots is a good combo
Years ago, my Hoffman chassis were .125 inch thick aluminum with the same faceplate material
That was right on the edge of being too thick
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I found that the Mojo brand pots have a little bit longer threaded bushing that works.
yes, they are .4" long - specifically for vintage fender amps. 16ga (.058") chassis + faceplate + brass backing plate + internal tooth washer necessitates that: the values mojo stocks are used in the most common vintage fender amps.
--pete