18 whatt - “paint by numbers”

Discussion in 'Shock Brother's DIY Amps' started by RollingBender, Feb 5, 2019.

  1. RollingBender

    RollingBender Tele-Holic Vendor Member

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    2 years ago, I bought a bunch of parts from ubuyguitars.com. Included in my haul was basically all the parts to a VHT Standard 18. Total cash outlay for the collection of parts, including shipping... about a hundred bucks. Finally getting around to assembling the amp.

    First step is chassis conversion. The chassis is actually for their 36 watt combo, but I am going with an 18 watt head so I will need to make a bunch of new holes in the top for tubes and move the circuit board a little bit. The faceplate is fine as-is. The power and standby switches will be upside down but that’s OK.

    I don’t have a Greenlee hole punch so I made due with the tools available.
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    Last edited: Feb 5, 2019
  2. RollingBender

    RollingBender Tele-Holic Vendor Member

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    The grade aluminum used in amp chassis is wonderful for bending, forming, punching and welding but is awful for machining. It doesn’t really cut, it just sort of smears but with some chamfering after the fact, it comes out OK. At least all the holes are exactly where I wanted them to be.
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    Last edited: Feb 5, 2019
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  3. RollingBender

    RollingBender Tele-Holic Vendor Member

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    The new hole for the rectifier socket wanted to be a little offset from where an existing hole was. This is where my “ hole punch” really shines.
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  4. RollingBender

    RollingBender Tele-Holic Vendor Member

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    As long as I had it in the machine, I thought I may as well put on a personal touch. It didn’t turn out very good because the metal is not perfectly flat. The lettering was dialed in to be cut 0.005” deep (a standard sheet of paper is 0.003” thick). It’s really deep in one spot and quite shallow in another. I spent some time “truing” the surface with a straight edge and a dead blow hammer but this was as good as I could get it.
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  5. RollingBender

    RollingBender Tele-Holic Vendor Member

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    One of the components I bought was a “partially loaded chassis”. It looked like it had been used as a test bed for components and then run over by a truck. It contained all the pots, jacks and switches on the front panel as well as the OT. I was able to move all the front panel stuff to the new chassis pre-wired!

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  6. RollingBender

    RollingBender Tele-Holic Vendor Member

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    I will be making a cover plate for the back to hide all those holes. It will have the speaker jack, fuse and IEC power plug.

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  7. jtcnj

    jtcnj Tele-Holic

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    Nice work, awesome tools you have there!!

    Since my 6G2 chassis was on the bench, I have been playing my VHT 18 build the last several days!
     
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  8. RollingBender

    RollingBender Tele-Holic Vendor Member

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    Here’s why I’m calling this “paint by numbers”... most of the work is done. This is the “18watt handwired el84 circuit board loaded” from ubuyguitars.com. With the faceplate components prewired and the board with all the leads attached, all I have to do is wire them together according to the color coded layout included with the circuit board.
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    Last edited: Feb 5, 2019
  9. danlad

    danlad Tele-Meister

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    I hate you. I did mine with a knackered, inherited file of some kind I don't even know the proper name for. There are probably still bits of aluminium in my thumb.

    Whatever that is, I want one.
     
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  10. jtcnj

    jtcnj Tele-Holic

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    Yep I got that board, PT and chassis from him, along with some sockets, cheap tubes, pots, etc.
    AND 2 LP type guitar husks that turned out to be nice builds.
    Routes and hole done, fret slots cut but they are my first 2 fret installs.
    Tedious but a great learning experience.
     
  11. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    I managed to get an 18W, (combo style), and a 36W (head)chassis, and a couple of 18W PT's from them. Just didn't know soon enough!
    Sorry you're stuck without a Greenlee punch, and have to improvise!
     
  12. KPAE

    KPAE TDPRI Member

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    Great job on the build, looking forward to further posts!

    I had good luck with one of the UBuy 18 watt closeouts. My only major complaint is the "Cliff-style" jacks on the pre-assembled chassis promptly started to fall off! Eventually I wound up replacing a whole bunch of stuff anyway, but it was a really cheap way to get an idea of what 18 watts sound like!

    Sacdave built a real beauty with similar parts, his is a real work of art!
     
  13. old wrench

    old wrench Tele-Holic

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    I did the same thing with some the old VHT buyout parts. I bought some of the 5E3 based stuff and modified it a bit using some of the info and tips I picked up here and on Rob's site. It turned out great!

    When I finished that 5E3 build and played through it for awhile, I regretted not buying the stuff for an 18 watt. Good deals like that are rare as hen's teeth ;).

    Good to see you putting them together!




    Best Regards,
    Geo.
     
  14. SacDAve

    SacDAve Poster Extraordinaire

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    Bought 3 18W chassis, 2 18W PT',1 Celestion G12 30W speaker (should have bought them all) and 7 5E3 chassis yeah they take a lilies modifying. I did build an 18W It's really turned into one of my favorite Amps. Plan on building another my wife has to buy about 4 more pairs of shoes before I can start :p
    http://www.tdpri.com/threads/18-watt-underway.796718/
     
  15. RollingBender

    RollingBender Tele-Holic Vendor Member

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    Thanks, SacDAve, Just went back and re-read your build post...I’m sure I will be visiting it again as my work continues.

    Thought I had the necessary wires for the heaters but turns out my stash was heavier gauge than I thought. I think I have another stash that I pulled from an organ donor that I can check in the morning. Also, going through the layout and schematic, I discovered that I’m missing 3 resistors. I have a buddy in town who builds amps...I’ll have to go rummage through his parts bin.
     
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  16. RollingBender

    RollingBender Tele-Holic Vendor Member

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    What does everyone think about this crazy idea...??? Rather than daisy chained heater wires, run individual twisted pairs to each tube and gang them together with the PT on a tag strip? It's a bit tight in the chassis with this layout and it would make it less of a micro wrestling match to wire the heaters and still keep things neat and tidy inside.
     
  17. SacDAve

    SacDAve Poster Extraordinaire

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    Did you see haw I did the heater wires in my 18W? The amp is dead quiet. Not something I came up with I copied it from my Fargen custom amp.
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  18. gusfinley

    gusfinley Tele-Holic

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    There was a discussion about heater wiring a while back, where I joked about wiring them like a 4x12 cabinet in serial/parallel.....

    ... a recommendation was made that certain heaters could actually be wired in series or parallel depending on how the tubes were used in order to minimalize noise.

    The biggest difference I have seen in noise reduction is by using an artificial center tap with 1% 100 ohm or so resistors.
     
  19. RollingBender

    RollingBender Tele-Holic Vendor Member

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    Well, this thing kicked my backside all day but I finally prevailed!

    I found some suitable heater wire and ended up doing it the twisted wire, daisy chain way. Then I spent the last two evenings “painting by numbers” hooking the board up to the pots, jacks and tube sockets and connecting the transformers. Then I hooked it up to the light bulb limiter and could not get the damn light to go dim after installing the pre-amp tubes. After 5 hours I discovered a heater wire creeping against pin #3 on V4...fixed that and all is well.

    Still need to make the rear plate and after playing it for an hour or so tonight, I can say that all the pots and jacks need to be upgraded.

    It sounds pretty cool though. I was running it through my unfinished 5e3 as a speaker cabinet loaded with a vintage organ speaker (a 12” Rola from 1951!) and it gets pretty flabby when you hit it with much gain but clean it sounds very nice. The tone controls are not very drastic throughout their range, I wonder if new pots would help that also. I wish the high/low input channel was not affected by the master volume... for me, that would make it more versitile.
     
    Last edited: Feb 10, 2019
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  20. kleydejong

    kleydejong Tele-Holic

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    I just saw Blueglow build a single ended KT88 amp with this kind of method. The amp came out very quiet. I personally find it appealing just because I kind of hate micromanaging the heater wires on the tube sockets when you have to put them in series. The amp turned out very quiet. Very detailed video here:

     
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