voodoochile
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Posts posted by voodoochile
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Big planks like that would make some gorgeous furniture......
Big planks are getting so scarce now. I still cringe when I think of my grandfather taking a skilsaw to those 12'x13"x5/4" mahogany planks. *sniff*
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Nice. I agree about the 7MDH, it's massive. My whole laptop bag would fit inside it.
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I'm always available to haul away old lumber, or stashes of tubes! Say the word.
Even old quarter-sawn doug fir is stunning when well finished out. Amazing, and extremely expensive for softwood.
This stuff I have would machine really well. I wish it were 5/4 or 6/4 though.
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I know there are more than a few of you on here.
My grandfather was a woodworker by hobby, and also worked in boatyards (old lakeside marinas selling/servicing Shepherd, Chris-Craft, Century type boats) from the late 40s, though early 60s. I acquired a small stash of lumber from him in the mid 70s, consisting mostly of 5/4 rough oak and mahogany, with a few other odd bits. Sadly, he had cut several longer planks down to about 4' to fit the trunk of his car.
Some of the boards were odd material, and all were fairly dusty and dirty. Most are reasonably flat, but a few are somewhat warped, or have big knots and/or checking, so have gone largely unused this whole time. I wanted to make some sort of base for a project I've been working on, and was about to slice up some ordinary white pine, when I thought "why not try to get something useable from some of those odd boards I've been moving from here to there over so many years?"
Well, the stuff looks pretty nice under the grime. It looks much like cherry, but seems a lot harder than most cherry I've worked with. Physical properties are much closer to maple than cherry, but it looks more like cherry than anything else. ROCK hard, like working with Corian.
The grungy old planks:
[ATTACH=CONFIG]2993[/ATTACH]
This is well-lit, they look a good bit dirtier, really.
A lot cleaner inside:
[ATTACH=CONFIG]2994[/ATTACH]
Comparison with some other bits on hand:
[ATTACH=CONFIG]2995[/ATTACH]
This is with only one wipe of natural Watco:
[ATTACH=CONFIG]2996[/ATTACH]
(with a slice of unfinished for comparison)
Grain is looking pretty nice so far:
[ATTACH=CONFIG]2997[/ATTACH]
I've only sanded it with 220 grit, and only hit it once with clear Watco. I don't think I could find lumber like this at the local hardwood dealer where I normally find lumber for an amp base.
The sapwood looks for the world like maple, the darker portion when unoiled looks exacltly like cherry. It handles like rock maple, and feels significantly heavier than cherry- which I have turned and sawn on many occasions. My best guess is cherry, but it's the hardest cherry I've ever seen by a wide margin.
Anyway, thought you might like to see an old plank, sliced up and oiled. I'm pretty happy with the look so far. You never know for sure what some old wood will clean up like. Anyone else found any gems in the scrap box?
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no, that's just the bog standard 18-55 zoom. it takes pretty decent close in pics, though. most of what is in that picture, with the exception of the striped glass, is cheap as chips Ikea. it's the black and white conversion that makes it look nice.
Not that I saw the original image, but that's an outstanding B+W conversion. Looks great!
Haj- is that the 5MDH in your pic... you like?
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You know you're old when...
It's still almost half full, too. Or half gone; I'm undecided.
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After more careful measurements I found my input stage's voltage a bit high relative to the output stage, so made some adjustments there. Also had to make an adjustment to my filaments; they weren't floating high enough. It sounds good, and isn't running quite as hot, though still pretty hot. The 12B4As are at 23ma.
I want to try some tweaks with the rectifier next, then have another pair of OPTs to compare.
Another shot in the dark-
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My RCA book says 7.5A, up to 8A if the V is 5.25. Upshot is only dropping 10v I suppose.
15 amps for a full wave setup? It would make a neat nightlight, but the transformer would be quite a heater.
These things are huge... [ATTACH=CONFIG]2929[/ATTACH]
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Holy crap, Kevin! That's a huge chunk.
You could make high-end wetbar sinks on the sideline.
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Interesting sources is an understatement! Sounds good to me.
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It will be interesting once I see exactly where it's at. The tubes are capable of 5.5 watts at 550 volts. I'm not going that far, but it's running at about 50% higher voltage right now, and the bias is up there, too. I remember now why the voltage ended up higher than expected with the 80 rectifer- I had a dropper between the transformer and the 5V4-GA. I dropped the dropper when I decided to go ahead with the 80. It seems to demonstrate better transient response with either a dropper- or the higher loss of the 80. The 80 wins by virtue of having an st bottle. I have a gorgeous pair of Tung-Sol 80s, and they really arent fat enough for anything much nuttier than this little project, so I really wanted to use one here. Old school even as tubes go, but they are pretty.I do have a half dozen 872-A rectifiers, but I need a filament ransformer the size of a lawnmower to run them. Bummer.
We need to set a date for some qualified listening soon. With appropriate bebidas, of course!
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Finished wiring last night right at 11pm. No smoke came out, voltages looked good enough initially, so I hooked it up to a source, and got sound! I was surprised, since I was pretty tired. Wondering if I had swapped the filaments and B+ or something.
Darker shot with power on:
Yes, I did end up going with an old 4-pin 80 rectifier, which I originally wanted to do. I thought the voltage would be too low with it, but after making some further adjustments, I was actually running too high with the 5V4-GA. I'm going to make some careful measurements tonight or tomorrow to see how close my currents are.
I suspect that the output tubes are running a little less current since the voltage is slightly higher, but I wanted to start a bit lower and work it up, so this is okay.
One foible is that the present cathode resistors on the output are only 3W. I thought I had some 5W, and I was wrong. Those little bastards are running extremely hot. I'm going to end up changing them anyway to tweak the operating point, and will be sure to get some 5-watters in there. I only ran it about 5 minutes at a time last night, sutting it off to let it cool a bit. No discoloration though. I'll know better once I really get in there with the meters. In my present amp I have 5w resistors in this location, and they are dissipating a little more than 3w... but the voltage is a good bit higher in this amp.
Before you ask, Nate, those load resistors did not actually smoke, but you can tell the amp is on with your eyes closed by the smell of the hot paint above them!
The ground bus is like a radiator until I swap them out, you'd love it.Fired up the cowboy junkies for a bit, then some gorillaz to see how it handles heavy bass, just for fun. I was exhausted, it was late, so of course it sounded "really good to me". Some subjective impressions will follow later on, after I get the loading where I want it, along with some better pictures.
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Like my analog layout program?
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Got some work done on a (temporary) chassis, made from an old scsi optical drive housing. Painted with some bronze hammerite, which is sort of like a warm shade of very dark gray, almost black. Tube box is for color reference.
The smaller oil caps are a pretty baggy fit, but it's the closest size punch I had, and this is just for trying out some different configurations easily.
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Taig Micro Lathe II with a whole host of options and accessories.
*schwing*
Look at all the gibbs!
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do you solder standing up?
Occasionally. You can see the edge of the barstool to the right. I was using it as a temporary table near the tablesaw, which is where I was doing a bunch of layout and markup of a chassis.
I would have done this on the workbench if it wasn't so cluttered already. Or neat, if you ask Kevin.
The blue chunks of iron on the right hand end are a jointer I'm still in process of doing over. Still looking for bearings... Walker-Turner used some odd lot for that model. I do have about 5 projects going, but only three are on the bench. I should have some legitimate progress to show by the end of the weekend.
Nate: You bought a big tool?
I have a co-worker who qualifies as a big tool- I'd have paid your mileage to take him away.
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Thanks! The Delta was my grandfathers. The Sprunger on the floor I just picked up and refurbed a few months ago.
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Guilty. The cap is fastened down, and I didn't want the choke to slide into something uninsulated. OSHA loves this project so far!Is that tape wrapped around one of the capacitors?At last, I don't feel alone anymore!
I don't see the obligatory ground wire to the wood chassisI couldn't find a wood screw to fit a star washer, so I floated it.
And you desk is way to clean.A clean desk is a sign of a dirty mind.
Oh come on... Nate must have told you how bad it USED to be. Let me back up a little bit...
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Great work as usual Mark, can't wait to see the amp you've got cooked up.
Meh, it's not going to be uber-sexy or menacing, but it should sound good at least.
If the amp goes as as well as the PSU did, it ought to be pretty sweet.Economic stimulus by gear lust. It isn't bad, its...patriotic.Absolutely. Both those meters, and my 45, were made in USA.
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Lust is supposed to be bad, but I wouldn't worry about it. It probably drives the community.
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I finally stopped dicking around with psud and actually dead bugged this psu I've been mulling over. It's alive, and no parts were killed. Glad we don't have a cat anymore.
Loaded it down, and it was pretty close to what psud predicted. Not knowing what the regulation of the transformer was, I adjusted the setting in psud until it matched the output, and it scales properly. Added a small resistor up front to bring the output down a bit, and I think I'm done.
No electrolytics, with a shared C-L-C, then it splits into two channels, each having an L-C-R-C string. The output power tap is at the L-C jct, the gain stage tap is at the end. Rectifier is a 5V4GA I had on hand.
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No charger or batteries to deal with would make it so simple. You could also use a remote reader for the SD card slot or flash drive.
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That would be interesting to integrate into a car as a standalone.
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Yes. I'll be on the hunt for hidden, criminal cat pee stains.
I was afraid to ask if that was it.
~Mark, who formerly owned a cat.
It will be interesting once I see exactly where it's at. The tubes are capable of 5.5 watts at 550 volts. I'm not going that far, but it's running at about 50% higher voltage right now, and the bias is up there, too. I remember now why the voltage ended up higher than expected with the 80 rectifer- I had a dropper between the transformer and the 5V4-GA. I dropped the dropper when I decided to go ahead with the 80. It seems to demonstrate better transient response with either a dropper- or the higher loss of the 80. The 80 wins by virtue of having an st bottle. 
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