Hammond L100 AO-43 amp project help?

For those building and repairing amps on their own. Learna and share ideas.

Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Thu Feb 26, 2015 1:41 am

Unit_1 wrote:Can't wait to see the cab!

Are you going to make a matching guitar to go with it? Maybe with a magic eye?
:thumbsup:

LOL. A Magic Eye in the guitar would be cool but might be kind of tough not to mention dangerous. B+ voltage and possible liquor might spell disaster :Zap:

However in beginning to lay out the cab, it seemed like no matter what I tried it was going to look awkward in creating a window for the ME tube so it seems the right solution to allow for some symmetry in the cabinet design is to add a second tube. So I've decided upon that as the solution and not wanting two of the same I will be putting an EM83 in the chassis as well.

The EM83 has a right and left side that can be fed independently so I've added high-pass and low-pass filters which I hope will do the job and allow 1/2 of the tube to display the bass and the other 1/2 to display the treble. I've situated the EM83 and EM87 tubes on opposite ends of the chassis so once in the cabinet, they will be symmetrically located on the upper front face visible through windows sized appropriately to the tubes.

I realize this is just eye candy (dumb sh*t by any other name) but this whole build has been an experiment from the beginning and really an exercise for me personally. With all the great help I've received it is now sounding quite nice using most all of the original circuitry so a little eye candy on a personal practice amp doesn't seem too far out of whack. I play like crap nowadays so at least I can enjoy mindlessly watching the tubes.
:excited:

Arthritis sucks :fingersx:

Here's the updated schematic with the EM83 and low and high filters added and also now properly representing the input jack wiring as recently offered by Statele52 for the Heathkit TA-16] thread. Thanks for that too as it made yet another improvement in the sound on this one-off.

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:cheers:
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Re: Hammond L100 AO-43 amp project help?

Postby PeterS on Thu Feb 26, 2015 5:44 am

Awesome...

Your hi pass filter isn't...
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Thu Feb 26, 2015 5:59 am

Oh crap, I see I didn't draw what I wired. I've updated the schematic to reflect what I actually implemented. I haven't yet any means of testing it though as the EM83 is still in transit. Volt meter readings have me a little concerned though as the readings from the bass side seem low (1.5-2.5 volts) and the readings from the treble side seem higher (7.5-20+). Given the EM83 appears to max at roughly 10v I'm not anticipating being done with these filter circuits yet.

Please don't stop my education. I am more than interested in knowing suggested values if those I've used seem inappropriate!! No feelings here to be bruised I assure you ;-)

Thanks for making me check my work :-)
Last edited by housekustoms on Sat Feb 28, 2015 11:56 pm, edited 1 time in total.
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Sat Feb 28, 2015 9:34 pm

Plugged the new Magic Eye tube in and fired it up. One half worked and the other didn't seem to respond. It took me a day and a half but I found two things. I had a wiring error in implementing the low and high pass filters the consequence being I had very little signal going to pin 2 of the EM83 tube (the side I'm using for treble). Once fixed the level between the bass signal presented to pin1 and treble signal presented to pin 2 was not balanced so the treble display was still very weak unless I turned the volume and gain up to max and had the gain boost on as well.

I removed the cap and resistor between pin 2 (signal) & 3 (ground) of the EM83 to free up more signal to the side I'm using for treble and that made the difference.

Both Magic Eye tubes work great now!
Last edited by housekustoms on Mon Mar 02, 2015 1:33 am, edited 1 time in total.
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Re: Hammond L100 AO-43 amp project help?

Postby PeterS on Sun Mar 01, 2015 1:38 am

a matching guitar to go with it? Maybe with a magic eye?


Careful what you suggest, I'm beginning to think he's crazy enough to do it ! :cheers:
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Re: Hammond L100 AO-43 amp project help?

Postby PeterS on Sun Mar 01, 2015 1:38 am

a matching guitar to go with it? Maybe with a magic eye?


Careful what you suggest, I'm beginning to think he's crazy enough to do it ! :cheers:
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Sun Mar 01, 2015 2:11 am

Haha indeed! LOL

I have two Firebolt guitars in the house made from Canarywood! I love Canarywood. One was my prototype when I developed the Firebolt design along with the help of 2 notable friends, A.J. Yenser and Arnold Enriquez both of whom contributed significantly to the design. Thanks!!

The other is one I made lefty for my youngest son.

Canarywood has beautiful grain and color and is easy to work with. Remodeled a bathroom here at home in it too. Got me lots of points with Mrs. Housekustoms.

Right-handed prototype
Image Click for full size image

Left-handed version for my son (Bill Lawrence pups)
Image Click for full size image
Image Click for full size image

Canarywood Firebolt prototype build photos:
http://www.housekustoms.com/SH1003FB/build/index.html

Now if I could just figure a safe way to get B+ up into the guitar!!!

:Zap: :Zap:
Last edited by housekustoms on Tue Dec 15, 2015 11:58 pm, edited 2 times in total.
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Mon Mar 02, 2015 1:33 am

I added a few more controls to the Overdrive circuit today and they give more flexibility to the available tones when the overdrive is engaged.

1. Added an on/off spst toggle switch to the overdrive circuit in general.
2. Added a .1uF cap in parallel with the zener diodes and an associated spst miniature slide switch to add a treble cut ability. It reduces the treble response of the overdrive making a somewhat sweet and dark sound. It can be disconnected by the switch.
3. Added a .1uF cap in series with the whole circuit and associated spst miniature slide switch to add a bass cut ability. It reduces the distortion in the low frequencies and can be bypassed by the switch.
4. Changed the overdrive control pot from an A50K to a B25K for smoother control of the overdrive level.

These changes allow more range of the overdrive tone and the frequencies affected when it is engaged.

I think I am done messing with the circuitry now. It has quite a range of available tones without the use of pedals and pretty neat eye candy provided by the 2 different magic eye tubes.

Thanks to all who contributed!

Next up is to make a faceplate for the controls and then commit it all to a cabinet!

:highfive:

Original and Updated Schematics
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Last edited by housekustoms on Tue Dec 15, 2015 11:56 pm, edited 2 times in total.
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Re: Hammond L100 AO-43 amp project help?

Postby PeterS on Mon Mar 02, 2015 3:55 pm

That canarywood looks great. How hard/soft is it?

Now if I could just figure a safe way to get B+ up into the guitar!!!


The safe way to do that is to limit the current - you put the plate resistor in the amp, so the high voltage to the guitar has its current limited by say a 500k
resistor. 500 volts into 500k is 1mA which is only enough to cause you to fall down and hit your head on something, not enough to make your heart stop.
So it's only a little bit potentially fatal. Whether this is okay depends on your attitude towards the sweet release of death.
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Mon Mar 02, 2015 9:49 pm

Thanks...I think...:-)

Peter, do you also throw fuel on the fire? HAHA!!

I think I will probably pass on trying although it does sound doable now. The B+ to the tubes is only 250V so maybe even more manageable :-)

:dumass: :dumass:

I think I'll go with this for a face plate.

First attempt at Faceplates
Image Click for full size image

:cheers:
Last edited by housekustoms on Tue Dec 15, 2015 11:55 pm, edited 1 time in total.
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Re: Hammond L100 AO-43 amp project help?

Postby Unit_1 on Mon Mar 02, 2015 10:52 pm

that looks great steve

hey you could always go the way of a ladder divider and UV leds, since it's a semi hollowbody you could mount it where it doesn't show and still see the glowing effect, put a door in the back for a 9v batter and it's done!!!
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Wed Mar 04, 2015 1:55 am

In thinking about using this amp more, I think because it is a personal (practice) amp I want the faceplate lettering readable from the front rather than being oriented to be readable from the back as if it were a small stage amp that you would be standing behind. So with that in mind while I was adding the numbering I forgot for the control pots on the faceplate I went ahead and reversed the lettering orientation too. Also simplified the reverb area and changed the font to anything other than the generic Times font I initially used and then added colors to the faceplate that will coordinate better with the tones of the Canarywood that will be used for the 2x12 combo cabinet. I found I could have my local UPS store print my press quality PDF output file generated from my Visio source file at 1200 dpi on 80lb card stock and laminate them for $4.25 per 11x17 sheet. I varied the colors a bit on each of the four faceplates I could fit on a single 11x17 sheet and that way I will pick the one that matches the actual wood I end up using once I build the cabinet.

First attempt at Faceplates
Image Click for full size image
Last edited by housekustoms on Tue Dec 15, 2015 11:54 pm, edited 1 time in total.
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Fri Mar 06, 2015 5:13 am

Sorry for responding to my own post...had the crud for a while and have been hit and miss on getting much done.

PeterS wrote:That Canarywood looks great. How hard/soft is it


Canarywood is a pleasure to work with Peter. It is akin to walnut in that it is medium density and hasn't any tendency to chip or split. It is dimensionally stable, has no built up internal stress so doesn't warp or twist when cut. It cuts and routs clean as a whistle. If something turns out poorly...it is my fault not something I can blame on the qualities of the wood. I will warn you it has bright orange saw dust and is a bit on the annoying side as far as my allergies go. I need to wear a respiratory when working it...others may not. All in all I always enjoy working with Canarywood.

Unit_1 wrote:hey you could always go the way of a ladder divider and UV leds, since it's a semi hollowbody you could mount it where it doesn't show and still see the glowing effect, put a door in the back for a 9v batter and it's done!!!


I like the idea Al but feel I would be copying another good friend of mine who did some really neat things with LED lighting in some of his Telecasters a couple of years ago. He used a plexi front on one and it was a light show when it was played. Although I like the idea in general and as a challenge to accomplish it, I will probably pass as the few guitars I build are showpieces with exotic woods and inlaid with fine shell or stone and I wouldn't want to take away from that. I also worry with the magic eye about legal liability due to the voltages; even reduced in current flow as Peter pointed out.

Now as far as for myself, if I ever have enough downtime to cater to me personally...I am likely to try one or the other!! I do have two 5A Ziricote book-matched front and back sets I resawed and a Ziricote neck for my personal use that will become a Telecaster. Maybe I'll chamber it and add some flash!!

Ziricote book-matched guitar top
Image Click for full size image

Thanks again for any input, suggestions or criticisms as they all make for a better end result.

:cheers:
Last edited by housekustoms on Tue Dec 15, 2015 11:53 pm, edited 3 times in total.
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Re: Hammond L100 AO-43 amp project help?

Postby Unit_1 on Fri Mar 06, 2015 7:00 pm

Faceplates look great!

I'll have to do something similar when I get the hammond converted to a lightning, but I'm gonna leave some room for my logo!!!!

I haven't started on it yet 'cus I didn't want to test the capacitors until I got rid of that nasty cold (400 volts and all that, you know? :Zap: ). Since that's happened now, I think I'll get right on that.

Most of the cats got the cold too. Pretty miserable around here with all the cats sneezing and sniffling and me and ms. unit as well.

Man I'm glad that's over.....
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Re: Hammond L100 AO-43 amp project help?

Postby housekustoms on Fri Mar 06, 2015 7:17 pm

Unit_1 wrote:Faceplates look great!

I'll have to do something similar when I get the hammond converted to a lightning, but I'm gonna leave some room for my logo!!!!


Yeah it's not an omission though for me. I'll be inlaying my logo into the cab in Mother of Pearl.

:cheers:
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