|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
63.246.168.59
I've just discovered that my local source for chassis boxes has dried up. I can work with either steel or aluminum, but it's not worth the trouble to craft an amp with the paper-thin stuff offered by the big names. Does anyone know a U.S. company that's making these in a decent gauge (thicker than Hammond/Bud/LMB etc.) at a decent price?
Follow Ups:
boo Ivan303\
Very good. But I was referring to the organs on either side of the tounge, and a few inches higher up Steve . :-)No, not the eyes .
got pics?
aa
I agree with you about Hammond chassis. Very nearly trash. Forget about that crap.Alright. I'm gonna let you in on my little secret.
First of all, these are blank. No pre-drilled IEC (is this French for "pain in the ass?"), no banks of neat little RCA jack holes. You're gonna need some layout savvy and a step bit (Greenlee models can be had on ebay for $20-30) or a chassis punch. You don't wanna drill yer own chassis, stop reading now.
The link below takes you to a commercial aluminum cake pan. Turn it upside down and you have a blank chassis.
They're cheap, they machine easily, and their corners are 90 degrees and WELDED. They're an eighth-inch thick, strong enough that you can stand on 'me and they'll giggle. You can cut huge hole out of them to mount horizontally-oriented transformers and they don't lose their strength.
Like the Bud or Hammond stuff, give these a quick rub with emory paper, wash with dish soap, dry, and they're a breeze to paint. (after you finish drilling!)
They come in all sorts of sizes, square and rectangular, 1, 2, 3, & 4 inches deep. In other words, they come in power supply box size, stereo power amp size, preamp size, phono stage size, etc. They even make ones that are like the old-school monobloc amps; 4-6 inches wide, similar depth, and 16, 18, 20 inches long.
You can find other sources online (sorry, I forget the manufacturer). I list this one because I can just drive over, pick out the size I want, pony up my $20, take it home.
Do me a friggin favor, though, will ya? Do not contact the manufacturer and tell them that they're missing a great opportunity to shake down a bunch of geeky shut-ins with nothing better to do than butcher their generic cake pans. Price starts climbing, I'll hunt you down like a rabid dog.
; )
But seriously. They're perfect. Even got the little old-school flange around the edge. Perfect for stick on rubber feet just like an old Fisher. Or use it to attach a bottom cover. Don't like the flange, you can cut it off.
Happy soldering!
Thanks for the tip! I went to the site you suggested, then searched locally online. I found a bakery supply outlet here that sells "sheet pans" that appear similar, so I drove over for a look. They had two types; one U.S. made, the other Chinese. Both have striaght sides and welded corners.The Chinese pans, "Decorator Preferred," are available in rectangles like 9 X 13, 11 X 15, etc. I measured the metal with calipers and came up with roughly .060". The American pans, "Magic Line," are available only in even-multiple squares from 6 x 6 to (if memory serves) 16 x 16. The corner welds were cruder on the U.S. pans and would need to be ground down if one wanted to flush mount wood sides. The metal measured roughly .065"-.070", and they were physically more stout (more difficult to flex by hand) than the Chinese product.
Unfortunately, both types shared a common flaw. They all had the manufacturer's name, logo, pan size and country of origin stamped into the bottom of the piece in the center (it would be on the top if used as a chassis). That's OK for a prototype, but not for anything else. I suppose one could plan a layout so transformer cutouts remove the maker's mark, but that still means they wouldn't work for just any purpose. Every project would have to be planned around the blemish, and to be honest, that adds complication I don't want.
I suspect you're buying something else, being as you said they're 1/8" thick. Do yours have a mark like the ones I found, stamped in the center? If not, I'll order a few from the outlet in your area. Also, if you know the brand, that would be a big help. I can note it on the order, just to be sure I get the same thing.
I'll try to round up the manufacturer name for the ones I use.I, too, was concerned about that brand stamped dead center on what ends up being the top deck. I'd intended to leave the aluminum raw. Kinda like the post-war Pentagon utilitarian look, anyhow.
Again, while really strong, this stuff machines like a dream. I used a 3/8" cordless drill & step bit for all but the socket holes. For those I strapped the drill to one of those cheesy $30 "drill press" things they sell at Sears! Although I was clearly at the contraption's raggedy edge, it managed to hang in there with a few extra clamps. One of my socket holes drifted a little, but only I notice it.
I'd not used it before but Rustoleum makes a hammertone green paint that a blind butcher could manage. I think I put on three coats in an afternoon. Don't touch it for a couple days. It feels dry in a hour but it ain't cured enough. It'll grab your fingerprints, requiring another coat. I think it ended up being about three days until it was cured/dry enough to not pick up fingerprints.
I dig the Stanley/Thermos green but they had the colors familiar to anyone who's attended school in the US between WW2 and the Internet boom. Something like Marantz bronze, grey or silver, maybe even red.
Liked this hammertone paint so much that I decided to try the Krinkle stuff on one of the old chokes. Same routine. Couple coats, leave it dry a few days.
Oh! The reason I even started the paint ramble in the first place was to tell you that if you use these textured paints, the very first coat completely obliterates the brand logo. Gone. Nada. No need to try to sand it out first.
If you go to Jim Hagerman's "DIYer of the Month" page linked below, then scroll down to the January '07 pic, that's my Cornet. (sounds fantastic, by the way! Herr Hag hit the nail on the head with this elegant circuit)
Okay, so it's not the greatest photo. But you get the drift. WAY better than those flimsy Hammond things with the spot welded corners.
Like you, I'd intended to dress the edges with wood plinth. I cut and finished four chunks of lovely mahogany (sp?) for duty. I ran a curf down the backside of the pieces into which the pan's--ahem--the chassis' flange fits. Works fine but I never attached it. Still tweaking so who the heck needs it?
If you decide to go with the wood plinth/trim, I'd do it a little differently. I think I'd either buzz off that flange entirely or maybe keep an eighth to quarter of an inch. Reason is, the flange is half-inch so you need three quarter stock to bury the flange in a curf or rabbet on the back side. Horses for courses--obviously!!--but I found the 3/4" stock to be too chunky. Laugh if you must, but I thought it ruined my look.
The flange would be easy to cut. If your pan is two inches deep, just drop a 2"-thick block into the pan to serve as a plane to support the jigsaw. Couple clamps on a straight edge guide makes cutting the metal a whole lot easier, neater, too.
After drilling or cutting, two or three quick passes with a standard bastard file (rat tail for holes) knocks down the burr or sharp edge. Super easy and clean.
The brand I use is definitely 1/8" thick. I hear ya about the corner welds, too. I picked through a few to find the best ones. File quickly knocks down any slag. Have to take this into consideration when fitting any plinth material. I made it work with very little effort, though. If you know anything about trim carpentry, it'll be immediately obvious how to back-cut and/shape the miters enough to hide whatever metal you can't file.
I'd guess that even if you wanted to go with a gloss enamel or something like that (that may not do the best job of covering the etched brand label) it would be easy enough to fill. Just get a small container of Bondo or something like it, mix up a half-teaspoon, putty knife it into the crevices, and clean it up. Presto.
Heck, even if you wanted to leave the bare metal, buff, polish, or clear finish it, I think that a DIYer could manage to turn the cake pan brand into a badge of honor!
Besides, like my humble beast, any peanut gallery snickering stops the moment the needle hits the groove. You'd need serious dough to outrun a tuned-up Cornet.
First friend I had over to listen, I could practically feel him smirking behind me as I cued him up his first Lp. (ZZ Top's "La Grange" if you must know). Those rim shots started, I turned around, saw him get real serious. He sat down, opened his eyes wide, looked like the Maxell martini man for the next four minutes.
Thanks again, Mr. Hag! Octal Cornet rules!
Maybe I was too hasty regarding the brand stamp. Even before I read your post, I was thinking that painting the chassis isn't such a big deal, and that the stamping could be filled if necessary. Too bad it prevents using it in a natural aluminum finish; I like that look for some projects. Incidentally, I do most of my own cutting using hand tools. I also have limited access to a small machine shop at work, so it might be possible to use a mill to clean up the welds and cut down the flanges on these cake pan chassis.My main concern right now is whether the pans on Surfas' Web site are the same ones you're buying in the store. A thickness of .065" is great for preamps and small amplifiers, but for larger iron, .090" or more is needed. I have sent an e-mail asking them to confirm the thickness and brand of the pans, just to make sure I get the right ones.
I like your DIY'er of the month project - very inventive! Unless I missed one, Hagerman phono preamps are all 9-pin, so I assume you designed the octal version yourself. I use octals wherever possible, and particularly with octal output stages. Even where I don't use octals, I almost never mix the two types on the same chassis. Tubes like 6BQ5s generally get driven with EF86 / 12AX7 / 12AU7 / 7044 types, with 6SL7 / 6SN7 / 6BL7 octals (and 12V counterparts of the first two) reserved for use with 6V6s, EL34s, 7591s and large SETs. There are always exceptions, but this is how I generally attempt to keep a sense of order in the designs.
About the aluminum chassis, I am currently building a few guitar amplifiers. I have a fair amount of vintage hi-fi iron that's well suited to this purpose, but it's heavy. That's why I need to confirm that the chassis on Surfas' site are in fact 1/8". I have to say, I really don't understand what Hammond is thinking, making .040 and .050 chassis. Those boxes wouldn't last a week in a guitar amp. Even many of Hammond's own transformers would collapse their boxes. Could it really cost that much more to use .080"-.090" material?
Thanks for all your help and good ideas on this. If you come up with more info on the exact chassis your buying at Surfas, please let me know.
Here's another link to what I believe are the same pans.I used a 13x9x2 for the Cornet. And by the way, while I'd like to take credit for the octal version, I'm afraid I can't. Mr. H posted the schematic on the Hagerman Discussion Board. It's all his circuit. The only thing I changed was the chokes. I plan to remove the second choke, too, as it didn't drop the noise floor. I'll cover up the gaping hole with another plate--in which, I'm putting a stand-by switch.
Speaking of which. Wha'd'ya think's the best way to implement a stand-by switch? I think I'm going to put a SPST on/off toggle on the power trans' center tap. I'm terrible with the simplest electrical logic but it seems that simply lifting the ground on the HV winding will kill the supply to the tube plates. Make sense?
I understand your concern about the flimsy thing. I just measured the Cornet's flange thickness and it's 1/8". That's .125 inch and I think it's plenty stiff.
The iron on my example is an NOS Stancor, electrostatically shielded, 300/0/300 @ 120mA, 6.3 CT @ 5A, 5V @ 3A, so it's plenty heavy. Both chokes are old iron, 15 and 10 Henrys.
The power trans is horizontal orientation so it require a big, rectangular cut out for one half of the winding to drop below the chassis deck.
Altogether, a lot of aluminum cut away in a small area and it's still strong, pretty stiff. Lord knows I've plugged it in, unplugged it, carried it to-and-fro for a hundred tests and mods. Every time I lug it I feel it not flex, think of that Hammond I'm glad I sent back. (and which I'm eternally thankful that partsconnexion's vicki agreed to take back!)
My guess is that if you put a power trans and a couple OPTs on a bigger pan, it'd hold tough. If you thought it wasn't quite up to snuff for a guitar amp that'll get knocked about, you could always slap another chunk of 1/8" aluminum under the trannies. Quarter-inch of aluminum would be strong as hell and pretty light, too.
Do you know the stock number of the 9 x 13 pan you purchased at Surfas? They haven't answered my e-mail, and I'm really confused about the source of your 1/8" pans. The link in your last post goes to a page listing Magic Line pans, but I just measured those at my local supplier. They are only .065" (1/16"). Many outlets on the Web also list Magic Line with a description stating that the pans are 14 gauge (approx. .065"). What the heck are you buying?? Help!
"What the heck are you buying?"For my thickness quote, I'd measured a scrap that I thought was the cut-out from the power transformer. Just now, I dug in the scrap box and found evidence that it was possible that I'd measured the wrong scrap of aluminum.
Well, I just pulled the actual Cornet off the shelf...
Good lord, this is embarrassing. It is 1/16-inch, which is why they're telling you it's .065 inch. Man-O-man am I sorry.
Here's the good news, though. It is tough stuff and it absolutely outclasses any of the Bud or Hammond boxes that I've tried.
I see, now, how I confused myself. In order to banish even the thought of having to order something from Hammond again, I've been experimenting (duh!) with all sorts of readily available products. The chunk I measured, then swore to you was 1/8" thick, was a piece of a commerical COOKIE SHEET.
Yes, it appears that I'm a serial bakeware mutilator.
I sincerely apologize.
Here's what I think you should do, though. Indeed, Magic Line is the ticket. Go ahead and order one. I know you're a penny pincher but so am I. I can't bear to order a nice chassis for $75 and that's how I ended up with these things. I arrived at the cake pans via commercial aluminum bakeware that I'd scored in thrift stores for cheap. (same place I got my other experimental materials) These turned out to be so ideal that I went ahead and bought a new one (horrors!). See, by the time a bakery or restaurant tosses them to the thrift, they are--how shall we say?--less than presentable.
Sorry again. Although you may feel misled, I assure the mistake is insignificant. Like I posted earlier, I must have 12-15 pounds of iron on that thing, as well as four octal holes and their surrounding vent holes. Still stiff as a board. The corner welds, while not perfect, posed no problem that I couldn't easily remedy with hand tools.
I do agree about the finish, though. I'd liked to have polished the raw aluminum, sealed it with clear coat. You know what they say, though. Fast, cheap, and good; pick two.
Great
I appreciate the suggestions, but I'm looking for a substitute for the Hammond-Bud-LMB-type chassis shown in the image. I don't want a bolt-together, rack-type chassis with a .125 front panel. I need simple, folded boxes with the corners spot welded and metal thickness like .062-.080 aluminum or 16 gauge steel. I did find one source online (see link below), but so far, he's not answering e-mails. Anyone know of anything else available like this at similar pricing?
TKGo to his Home Page and you'll find out why
he's not taking care of "business properly".
He's got other priorities right now.
I won't say anything further.DanL
Not quite as cheap, but you get what you pay for I suppose: http://triodeelectronics.com/70chasb.html
It says "ST70 size".
What size is that ?
It is the size of a Dynaco Stereo 70, if that helps. I don't have one anymore, but I think it is something like 17x14x2 or so.
Stereo 70 is 13" x 10" x 2".Aloha,
Hey, It's been 9 years, and I had the 2" right!
Hi Chris,Did you ever see the two posts I did for your amp schematic query on the Magnequest Forum ?
http://www.iagaudio.com/index.htmhttp://www.par-metal.com/
The IAGs are pretty but care must be taken not to scratch the mirrored aluminum finish. Parmetal will do custom finishes and has several guage options.
Par-Metal is pretty nice for the money. This is one of their black anodized front panel/gold chassis models. This box, unpunched, was about $85. IIRC the box is .080" and the front panel is .125".
Check with Newark Electronics because they had a cabinet I bought for a hammarlund sp600 that was nice and I believe they have some 8 to 10 guage chasis without punched holes.
8-10 gauge? Wow, I'd have to take 'em to a CNC to have the holes cut. That's not a problem though, really. Do you remember where you saw them in the catalog? I looked for ten or fifteen minutes but didn't come up with anything. Thanks!
This post is made possible by the generous support of people like you and our sponsors: