NAD! ...well, sort of...

Sovereign_13

Member
Messages
188
...some assembly (okay, all of the assembly) required.

I'm building a Hiwatt! A DR103 clone, to be precise, with the linked-input configuration. Do I need 100W? Nope, but I don't want to get done with a DR504 and wonder "I wonder if...". So, short answer is "yes, I need 100W".

The first box of parts arrived this past Tuesday from Mouser. I haven't had a chance to start on it yet, but there will be pictures when I do (probably tonight).

A few details for the interested:
I'm using predominantly Xicon 1/2W resistors and Cornell-Dublier capacitors. Electrolytics are mostly Nichicon, but some of the big can caps are coming from Mojotone (which will be the next order, probably at the end of the month). I'm also using 1k 5W screen resistors (also Xicon - the big white box ones).

I'm using turret-board construction (yes, you can still find turret boards - Mouser sells them) so that I can use the same layout found in the Hylight-era Hiwatts.

Transformers will be the Heyboer units carried by Mojotone and used by the extremely knowledgeable and helpful Mr. Mark Huss in his own Hiwatt build. I've scoured his website on Hiwatts and exchanged a few emails with the man himself. Many thanks to him for all his information.

I haven't bought a chassis yet, so suggestions there are welcome. Currently my front runner is a Protocase 19"x9"x2.75" 16ga cold-rolled steel 5-sided enclosure. With all the holes done, the chassis painted, and the front digitally printed, it runs about $350. I'm also considering the same enclosure, but 302 stainless and with black letters on a bare front, which would run about $300. And I'll have a pretty unique-looking "Silverface Hiwatt". Off the shelf chassis probably won't work for me (my hole layout differs a little from the usual DR103). Given the weight of the transformers, aluminum is probably not the best choice, which also rules out me being able to drill the holes myself (and I don't really have the time).

I've already made up my mind on this, so please don't just come here saying "oh you should just buy X instead".

This is probably going to be a long(ish) build, mostly because I'm pressed for spare time. Hopefully not more than a few months of building and testing.

Whew! Long post. Sorry about that. Stay tuned for updates!
 

Sovereign_13

Member
Messages
188
Got to work on the turret boards for a bit last night. I had almost finished the preamp boards when I realized that I was one 2.2k resistor and one 47nF capacitor short! :facepalm:bkw No worries there, as I can tack them onto my Mojotone order, but still! Now I'm paranoid, and will probably end up doing a full dry layout just to make sure I didn't do the same thing elsewhere.

Pics as promised:
Work space
First board dry fit
Two parts short!
 
Last edited:

Sovereign_13

Member
Messages
188
Update #2:
Had to postpone my build efforts for a few weeks, as it's been very crazy (seems like everyone my fiancee knows is getting married or having children). Anyway, this weekend I finally found some free time to finish up the boards as much as possible without being mounted. I ended up going with Antique Electronics Supply as a supplier for most of the stuff like tube sockets, knobs and the pilot lamp - they had better prices. I will be going back to Mojotone for the transformers, since they are the retailer listed on Heyboer's website.

I also got a new desk/work surface (that now has drawers to store things when I'm not using them), but the surface is an ebony color. So for now I'm taking pictures using white printer paper as a background.

Pictures will follow once I have better ones - my desk lamp cast some deep shadows on the ones I took this weekend. Next steps will be to order the transformers and, once I have accurate measurements on the mounting hole positions, the chassis. Then comes assembly, wiring, and testing. I'm hoping to order transformers at the end of this month, and the chassis shortly after (those will be the largest investments to date - components and hardware are pretty cheap).
 

broken_sound

Silver Supporting Member
Messages
3,289
Looking forward to watching this build. I built my DR504 kit back in 2008 and it's been my #1 since. Smart move on the Heyboer's.
 

Sovereign_13

Member
Messages
188
Looking forward to watching this build. I built my DR504 kit back in 2008 and it's been my #1 since. Smart move on the Heyboer's.
Somebody else cares! :eek::eek:

None of the other transformers I looked at were really even close to the same spec, and I didn't want to try and make an out-of-spec transformer work with an otherwise-unaltered circuit. And when I found out Heyboer was making them as a non-custom item, I couldn't justify not getting the modern "real deal", so to speak.
 

ROKY

Member
Messages
7,217
I haven't bought a chassis yet, so suggestions there are welcome.

Currently my front runner is a Protocase 19"x9"x2.75" 16ga cold-rolled steel 5-sided enclosure. With all the holes done, the chassis painted, and the front digitally printed, it runs about $350. I'm also considering the same enclosure, but 302 stainless and with black letters on a bare front, which would run about $300. And I'll have a pretty unique-looking "Silverface Hiwatt". Off the shelf chassis probably won't work for me (my hole layout differs a little from the usual DR103). Given the weight of the transformers, aluminum is probably not the best choice, which also rules out me being able to drill the holes myself (and I don't really have the time).
http://www.tube-town.net/ttstore/Ch...::6179.html?MODsid=m934lud6n8v59phqv7l3mai1e6
 

Sovereign_13

Member
Messages
188
That's an interesting proposition, but I'm afraid I've deviated too much on some of the panel-mount parts sizes to make it work. I have, however, successfully pared down the cost of a custom, laser-cut 16ga steel chassis to just under $250 shipped. Still a bit steep, but I don't think I'm going to find much better for a custom one-off. I will, of course, consider any other suggestions people may have.
 

Sovereign_13

Member
Messages
188
Pictures as promised earlier.

Finished turret boards

Dry layout of sorts (as would be viewed looking down into the inside - top is front)

Close-up of ceramic 8-pin sockets

Close-up of ceramic 9-pin sockets (one with shield for display purposes)
 

Sovereign_13

Member
Messages
188
Update #3:

Transformers came in yesterday. They are...well, a bit heftier than I had expected (around 10lbs each). Those of you with experience dealing with heavier iron, what gauge were your chassis boxes? I'm still thinking 16ga (most likely 302-stainless), which would be just under 1/16" thick. Is that too thin?
 




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