vox ac-10 build in a ac-30 chassis, set up to be able to do 15 watts...21st Century Voxy

Discussion in 'Shock Brother's DIY Amps' started by Dennis Perusse, Apr 1, 2020.

  1. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Hello,


    Welcome to my Frankenstein project. I chose to build a Vox AC-10 in a semi period way as I have a love of the Beatles music and want to learn the guitar at some time. For those who have seen some of my previous builds with my Kalamazoo Model 2 or my champ amp some will remember that I said that one day do what I then called a 20th Century Voxy but haven't had the time. Well the time is now with the Beer Bug 19 going around so I figured that I would post these pics finally and do a little show and tell along the way.

    I do also want to give special thanks to a few people, some on this list and some in other places. On the Tdpri forums here I wish to thank Andyfromdenver as he was kinda the catalyst for this build as I chose to build the Kalamazoo Model 2 instead of a Vox AC-4 which he was doing at the time. Lotsa similarities between these two amps in some respects but different in others, but I wanted to tip my hat to him and let him know that I did manage to get around to it. Also Steve Grosvenor who wrote the book "A Service Engineer's Guide to the Vox AC-30 Valve Amp". It was his book that made it possible to translate from schematic to tag board layout as I wanted to do this in a semi-period way. SteveWalsh730 on Youtube for his demos of all things Vox and for answering my questions that I had. Believe me I had a lot of them which did make me rethink a few things in this project. Lastly Rsmrecording who I was fortunate enough to meet in person who sold me the chassis. If you ever tried to build on of these things you know that trying to get dimensions on any of these chassis is hit or miss as you can't just purchase them anywhere from the electronics stores that sell chassis's and things. I was fortunate even though it made this project larger in size than I originally wanted it but I like it now, it has kinda grown on me. :)

    So it all starts with a chassis pic I guess. IMG_0629.JPG
     
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  2. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Continuing on with this thread as you can see the chassis is of two materials, Aluminum and Steele. It also has a few mistakes in it as well so I just worked around it as I realized that it will make it unique to me and anyone of my friends whom I know will want to borrow it. So it begins with Schematics and here are two of them, one being the actual AC-10 Schematic and an AC-15 Schematic. If you look at them both you can see that they are essentially the same in some spots. In fact to make the amp to go from 10 watts of a rating to 15 watts you ac10_2.jpg voxac15.jpg only need to do a few changes to the circuit.
     
  3. Dennis Perusse

    Dennis Perusse Tele-Meister

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    As mentioned I wanted to do this in a semi-period manner, which means that I had to use tag board to do the circuit. Plus I also had to to a top plate onto the top as I needed to hide some holes as well as make it so that it would look a little bit better. I also had a few parts in my parts stash which cut my cost down quite a bit as I had the tag boards saved plus an output transformer (classictone #40-18090) which is a 5E3 Output Transformer but it has the spec rating that I wanted (20 watts) and is multi-tapped. Regardless if I were to have stayed with a 10 watt version of this amp or even 15 which is how I have it set for I still have more than what I need electrically.
    IMG_0675.JPG IMG_0676.JPG IMG_0677.JPG
     
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  4. Dennis Perusse

    Dennis Perusse Tele-Meister

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    As my next pics show once you start getting under full steam with these things sometimes enthusiasm takes over. Each night I started wiring more and doing more things in the garage. Where I didn't have many tools some of this stuff is going to look crude but my view is that it reflects me perfectly, considering that I just want to do one more amp left after this and then take a look break from it so that I can enjoy what I've built. My hope that this stuff is an inspiration to those who want to do this and not have to suffer buying something that they know they might not like. It is a balancing act in some ways, spend the dough and get something custom or buy what's off the rack. I'm just fussy at times of the things I want I guess. :) Either way more pics for you to gaze at.
    cleaned up bottom plate.jpg.JPG cleaned up panel.jpg.JPG drilling the top plate.jpg.JPG stickered.jpg.JPG top plate conected.jpg.JPG
     
  5. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Trucking right along in these post as I am trying to do the whole thread in one go so no one has to wait here. Here are a the pics of the wiring process. Some will ask if I can show the wiring layout diagram but I can't. I got that from Steve Grosvenor's book and I'm don't have his permission to do so. But if you like what you see here by all means please buy his book. I can't plug this book enough for how detailed his book is on how the original ones were made. He has a web site do if you wish to peruse it when you get a moment. Here is his site (http://www.thevoxac30guide.com/ ) for those who want to go there.

    Anyway here are more pics of the progress of this. They might not be in proper order as I have this semi haphazardly ordered but you'll get the gist when I did stuff just by the things done. I also don't want to show any of the major changes that I did as I want to keep any confusion down to a minimum. I did have a major change in some aspects of this build on the bottom of the chassis as I originally tried to do it via tag strip which proved problematic to say the least. Here is the top end of the chassis build.

    sockets added.jpg.JPG sockets and tag strip.jpg.JPG initial stages.jpg.JPG
     
  6. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Now we're starting to get to the meat in this sandwich. :) Here are some pics of the tag board put in on the top panel and some of the bottom chassis being put on and wired. Now you'd think that this would have been much easier where there is some much space than the smaller chassis in the AC-10. Sometime the old saying, "more can sometimes lead to more problems" seems to be in place in this build.

    top wiring shot1.jpg.JPG top wiring shot2.jpg.JPG wiring for the input section.jpg.JPG
     
  7. Fretting out

    Fretting out Friend of Leo's

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    I think you’ve won! For the most disturbing avatar

    As far as the amp I’ll give it a look when the nightmares subside
     
  8. Dennis Perusse

    Dennis Perusse Tele-Meister

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    And now some pics about the bottom chassis.

    beginnings of the bottom chassis.jpg.JPG bottom shot1.jpg.JPG dual wiring shot with earlier wiring on top.jpg.JPG dual wiring shot1.jpg.JPG
     
  9. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Okay, so as not to bore people to death with endless pics of wiring and all of that I will show a few more as you can see this has trucked along quite nicely. So, a few beauty shots are in order then onto the cabinet. I did purchase most of the parts from Tubedepot, in case anyone is wondering where some of this stuff came from, most of the others came from an electronics store in my neck of the woods that closed down recently. as you can see I did change around the orientation of both the Power and the Output transformers but I don't think that that will cause any problems along with the way. I will have to double check my handy work to make sure that I don't have any issues with the wiring but I'll do that later before I power this beast up. This concludes the chassis side of things, next stop the ugly cabinet. :)


    glamour shot1.jpg.JPG glamour shot2.jpg.JPG transformers in initial situ.jpg.JPG
     
  10. Dennis Perusse

    Dennis Perusse Tele-Meister

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    It's funny. I work in a woodshop but doing boxes has to be the hardest thing for me. In either event I present, for good or for bad, my cabinet pics. All of the wood was purchased at Home Depot and is 3/4 inch thick so it is sturdy to say the least. I'm not going to cover it since I don't even play the guitar yet so I don't feel that I need to make it as bullet proof since it's only going to be in either my house or at a friends house or studio/basement. Enjoy the horror that is my woodworking skill when it comes to boxes. This is salvo one in these pics. ;-)


    021.JPG 023.JPG IMG_0761.JPG IMG_0829.JPG IMG_0832.JPG IMG_0833.JPG
     
  11. David Barnett

    David Barnett Doctor of Teleocity

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    Nifty!

    I'm glad to see you provided the Thomas Organ schematics for the AC-10 and AC-15, the ones originally provided by JMI seem designed to obscure rather than enlighten.

    Someday I need to start on my AC-10 project, I've got a nice replica chassis and faceplate.
     
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  12. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Salvo number 2 of the cab build. Sorry for the delay as my router booted me off of the net. Just rebooted it and here are some more pics. IMG_0834.JPG IMG_0836.JPG IMG_0852.JPG initial side shot1.jpg.JPG test assemble.jpg.JPG
     
  13. David Barnett

    David Barnett Doctor of Teleocity

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    I always wondered if they deliberately hobbled the output of the AC10 to punish people who wouldn't pony up for the considerably more expensive AC15?

    Moving the screen grid resistors to the plates seems like an odd move.
     
  14. danlad

    danlad Tele-Meister

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    Never noticed before but it really is the only difference in the output stage. Going to patent miswiring the screen resistors as a power reduction method...
     
  15. danlad

    danlad Tele-Meister

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    Looks great. How are you finding populating the tag board? I have a few that have been lying around for years but I always worried it would be very cramped to get the components in
     
  16. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Okay, final pics for everyone here. I did have to change out how I did the drawer slide. Originally I had it as a platform and that didn't work as I had did my numbers wrong. I eventually recalculated it and decided to change the setup to just four pieces of wood at a certain height and that fixed it. I'm quite happy with that in some ways as I didn't think that it would have worked well but it does.
    Now I won't do a demo of it as my six string needs to be fixed and I also want to take the time to make sure that my wiring is correct. I've had some help from Mr. Grosvenor so I'm confident that I could just power it up but prudence dictates that I should check it first non powered and then if satisfactory then do it. If and when I do complete a demo of it I'll have friends of mine play it as their playing is far better than mine.

    I hope everyone enjoyed this build. Any questions are welcome as well as comments. I hope that I can answer them as best that I can. My last amp that I want to do next is another Vox amp called the UL715 which is the 15 watt version of the amp that was used on the Beatles albums Rubber Soul, Revolver, and SGT Pepper as well as Yellow Submarine on some songs. It is a hybrid solid state/tube amp and I can't wait to attempt that one. In short enjoy the pics.

    IMG_0842.JPG IMG_0845.JPG IMG_0846.JPG IMG_0849.JPG IMG_0850.JPG IMG_0851.JPG IMG_0852.JPG IMG_0853.JPG IMG_0854.JPG reworked slide.jpg.JPG
     
  17. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Tag board was okay. I would have preferred to do it via garolite board in my own configuration but space was limited so some creativity was necessary.
     
  18. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Lol, yeah the image comes from British the series Dr Who. It is from a story called the 10 planet.
     
  19. Dennis Perusse

    Dennis Perusse Tele-Meister

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    Don't forget the input resistors also. They hobbled them too. I can see why they did it though. They probably thought that by using the same essential design of the circuit yet using the same components you get more product with only a variation of parts. I'm seriously amazed that no tech ever looked at the difference between the circuits and did the mods to make it louder.
     
  20. scottser

    scottser Friend of Leo's

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    Good job dude. How does it sound?
     
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