Re: [diyAudio] Newsletter Issue 1 for jsn: Amplifiers, Speakers, Tshirts and Feedback!
jsn
The loudspeaker article is nice too.
jsn
This is pretty cool. I especially like any new content from Nelson Pass. Has anyone built any of the Zen amplifiers? I am especially interested in the soon to exist power JFETs mentioned.
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23rd February 2010
Issue 1: Amplifiers, Speakers, Tshirts and Feedback!
Welcome jsn to the first issue of the diyAudio newsletter! Each month, more or less, we'll be offering a concise roundup of what's going on in the community as well as some premium articles.
To kick things off we've got the outrageously simple De-Lite amplifier from Nelson Pass that anyone can build in an hour or two, but has a few tricks up its sleeve if you want to put in a bit more effort. Also, the Arpeggio, a full-range loudspeaker design by tube guru Morgan Jones. These both can be found in the new Articles area.
Jan Didden gives us a quick tech note on Voltage Regulators courtesy of his blog on diyAudio, and this is your last chance to grab a "10 Year Burn In" tshirt or mug before they officially become collectors items!Lastly, if you'd like to give some feedback, the diyAudio Feedback Survey is the place to do it!
We've got lots planned to get more people building more great sounding gear in 2010. So dust off that soldering iron and dive into the forum. There's a thread or project for every skill level.
Mark Cronander
diyAudio Editor-In-ChiefForum Update
I started diyAudio back in 1999 as a web-based alternative to the email-based lists of the time in order to "make our fun easier to find". It's been astonishing to watch that humble DIY project grow into the premier forum for discussing DIY audio worldwide.2009 was a big year but mainly in the back room as we catered for the enormous growth we've had over the last 12 months. This included a total software upgrade, shifting to a vastly more powerful server, implementing donor benefits, articles, blogs, galleries, a ticketing helpdesk and a fundraising store (amongst other things!). This newsletter is yet another piece of the puzzle, providing an easy way for all members to stay abreast of what's cooking on the site and keep up to date with the latest DIY news.
In 2010 the focus will be on a better browsing and searching experience and an improved signal to noise ratio as we do our best to give you more of whatever you're looking for. If you have any comments, please take a moment to fill in the feedback survey.
Thanks for your support and may you complete many projects in 2010!
Jason Donald
diyAudio FounderArticle: The De-Lite Amplifier by Nelson Pass
The third annual Burning Amp Festival was held in San Francisco last October, drawing a couple hundred DIY Audio enthusiasts, many from long distances. At previous BAF gatherings I have simply brought a truckload of parts that might appeal to DIYers, but this year an announcement went out that I would have a presentation. It was news to me, but a quick talk is a lot less effort than hauling a ton (literally) of parts, so I decided to pretend it was my idea.
Procrastination being as much a part of my life as anyone else's, I found myself two days before the event having nothing prepared. What better opportunity to throw together something totally easy for beginners...
Many of you have never built an amplifier, and this article is intended to get you to do it. One of the biggest problems helping people to take the leap into building their own electronics is offering something really easy but satisfying – a simple but exotic project with low barriers and cheap satisfaction.
This power amplifier is just such a piece of low hanging fruit. Read the rest of the article »Article: The Arpeggio Loudspeaker by Morgan Jones
This article follows the design process from theory to measurement of a loudspeaker engineered to be driven by a low powered single-ended triode amplifier.
The author has a broadcast background, so accuracy was a key requirement. This is not a loudspeaker designed to sound “nice”, it is a loudspeaker engineered to sound “right”.Some Loudspeaker History
In the early 70s, a landmark series of JAES papers written by A N Thiele and R H Small blew away decades of empiricism and put the relationship between a loudspeaker and its enclosure on a firm engineering footing. At the same time, the cheaper and lighter transistor had usurped the valve, and transistor power amplifiers quickly settled down to variations of the H C Lin circuit. Between them, these two events defined an unspoken assumption that has underpinned loudspeaker design for the last forty years.
The Thiele and Small papers showed that a loudspeaker in an enclosure was analogous to an electrical high pass filter and could therefore use electrical techniques to model bass response. Crucially, it was shown that the Q of the bass high-pass filter was determined primarily by the flux density in the gap and the sum of voice coil resistance and amplifier source resistance.
The vast majority of transistor audio power amplifiers use sufficient voltage negative feedback to ensure that their output resistance is essentially zero, and since most amplifiers are transistor, loudspeaker designers since the 70s have assumed that their designs will be driven from zero source impedance. Read the rest of the article »
Best of the blogs
Did you ever wish for a way to document the progression of your project or post a series of interesting discussions without having your posts drowned out by replies? The diyAudio blogs might be your answer - it's a space for you to post where you stay in charge!
Every issue we'll pick a highlight from the blogs to showcase in this section. This month Jan Didden brings us a great tech note about voltage regulators...Jan Didden on Voltage Regulators
There are lots of types of voltage regulators, but in this installment I’ll talk about series regulators.
What’s a regulator? It’s all in the name: it REGULATES the voltage to the circuit to be powered to keep it constant and as free of noise and ripple as practical. The ‘regulation’ means that there is some circuitry that compares a reference voltage, like from a zener diode, to the regulated output voltage, and then uses the difference between the two to adjust another element to null that difference. The ‘compare-and-correct’ is crucial for a regulator, and is done by negative feedback. Read More »
Quick! Last chance to get the "10 Year Burn In" Tshirt (or mug)!
About the only thing hotter than a burning amplifier is (this girl wearing) the limited edition diyAudio "10 Year Burn In" tshirt that celebrates the flame fest that was the first 10 years of diyAudio. We're doing one last print run for the benefit of those older members for whom this newsletter might be the only notice they get and then that's it.
All tshirts come with free shipping worldwide. Sales stop forever on February the 28th before becoming a cherished possession of those who were truly fanatical about diyAudio. Last chance! Grab one at the diyAudio store before February the 28th »
diyAudio Feedback Survey
Would you like to help shape the future direction of diyAudio? It just takes a minute to fill in the (anonymous) diyAudio feedback survey and let us know how we're doing and where you think we should be going!
This is a great opportunity to be heard and offer constructive criticism that will help shape the year ahead. What's working, what's not, what do you want to see more of and what do you want to see less of? Let us know by filling in the quick, anonymous survey!
Upcoming Audio Events
The diyAudio event calender lists the worldwide "DIY audio" related events that are coming up. If you know of one that might be of interest add it into the diyAudio calendar!
6th March, 2010 - Houston TX Audio Get Together (Houston, Texas, USA)
10th April 2010 - Atlanta DIY at Earth Shaking Music (Atlanta, Georgia, USA)14th May 2010 - Lone Star Audio Fest 2010 (Dallas, Texas, USA)
20th August 2010 to 22nd August 2010 - 7th Annual Vancouver Island diyFEST 2010 (Victoria, BC, Canada)October 30, 2010 - Burning Amp Festival (San Francisco, California, USA)
In this issue
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jsn
robert taylor
Haven't built any Pass amps.
Have heard a few, and A/B a couple w/ good tube amps.
Rather, uh, underwhelming i thought...
Kinda like Lynn Olsen, writes well, (convincingly), but when listened to, compared to other good amps, well...
Made me re-think things...
Date: Tue, 23 Feb 2010 09:44:14 -0700
Subject: Fwd: [diyAudio] Newsletter Issue 1 for jsn: Amplifiers, Speakers, Tshirts and Feedback!
From: j...@boozhoundlabs.com
To: audio...@googlegroups.com; soundb...@googlegroups.com
This is pretty cool. I especially like any new content from Nelson Pass. Has anyone built any of the Zen amplifiers? I am especially interested in the soon to exist power JFETs mentioned.
jsn
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jsn
lack of following for his stuff. I am really interested in
transistors lately though. Probably won't last though :)
jsn
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Matt Wiebe
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jsn
And most importantly - when are we having the next listen-fest? I
would love to hear that thing.
Is "Festerex" a typo? What does that mean?
jsn
Matt Wiebe
I don't follow Pass' DIY stuff at all, you will have to google it to
see if kits are available. The J2 uses a new electric car controller
from SemiSouth, 1700V SiC JFET SJEP170R550. The J2 unit Phil has was
assembled. Sorry it was a typo, the speakers were Feastrex.
A listen session would be nice, but I cannot host too small a house.
Matt
robert taylor
a 75TL & something else, don't remember what.
much nicer, clearer, not just more emotional, and got rid of the roughness in the high end, which i don't think phil hears in his either, (so if ya don't hear it, it doesn't matter :) )
i did, it really bothered me.
better imaging w/ the tube amps as well.
also heard A/B with earlier pass amp (F4? F5) w/ lowther open baffle, was REALLY trying to like it (ask my wife, kept going back...). gave me a bad headache the highs were so bad.
heard the same w/ a 304TL amp and it was much better.
still open baffle sounding, but much better-- smoother, nice lows & mids, and now decent highs w/o the harshness.
but hearing is "in the ear of the beholder?"
phil likes it, so cool, that's what counts!
From: mwi...@unm.edu
To: audio...@googlegroups.com
Subject: Re: [diyAudio] Newsletter Issue 1 for jsn: Amplifiers, Speakers, Tshirts and Feedback!
Date: Tue, 23 Feb 2010 12:48:32 -0700
That's interesting. Phil has the new Firstwatt J2 from Pass on his Festerex back horns. J2 sounds great, nothing wrong with it. Then we subbed in a 300b amp with the cheap James outputs (JS-6112HS) and while the change wasn't more "accurate", we could both hear plenty of things the J2 did better, the emotional content of the music with the 300b amp was better.
Built a Decware Zen amp.
Haven't built any Pass amps.
Have heard a few, and A/B a couple w/ good tube amps.
Rather, uh, underwhelming i thought...
Kinda like Lynn Olsen, writes well, (convincingly), but when listened to, compared to other good amps, well...
Made me re-think things...
Date: Tue, 23 Feb 2010 09:44:14 -0700
Subject: Fwd: iyAudio] Newsletter Issue 1 for jsn: Amplifiers, Speakers, Tshirts and Feedback!
From: j...@boozhoundlabs.com
To: audio...@googlegroups.com; soundb...@googlegroups.com
This is pretty cool. I especially like any new content from Nelson Pass. Has anyone built any of the Zen amplifiers? I am especially interested in the soon to exist power JFETs mentioned.
jsn
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Matt Wiebe
jsn
Matt - that is awesome that those transistors were designed for
electric vehicles. I love it when new technology has "fringe
benefits" for little niches like ours.
jsn
John Galbraith
> > And most importantly - when are we having the next listen-fest? I
> > would love to hear that thing.
It's easy for me to host! If folks are willing to move their stuff here and
back.
John
robert taylor
No, I don't think the BVRs or OBs image that well.
Tried both, & don't like either of them.
I had heard Phils Feastrex BVRs before, w/ his 45 amp.
I have a pair of FE138 BVRs; have the same "family sound," of muffled midrange, was otherwise ok. Phil said the J2 made his BVRs sound a lot better, come listen.
I brought mine to see how much the amp changed my speakers (box/vs/driver) also.
The amp change did help the mids in both BVRs a lot.
Bass was weak before on Phils, now more balanced.
Bass was more balanced on mine, now overblown.
Deb & I both thought the highs were rough, harsh sounding with the J2 with any combination (compared to 45, EL84 SET, EL84PP).
Feastrex, FE138, (with or without low pass filter, good components), with or without LCY ribbon tweeter.
Played one of Phils PM6s in a 140Hz LeCleach front loaded horn there also.
Noticable rougher highs than I've heard before...
--"before" was:--
RMAF couple years ago, Jons OB Lowthers, Nelson's Amps.
Really, really wanted to love it; I mean this was the combination I wanted to love at the show. Kept dragging Deb back in the room, half a dozen times; couldn't stay in for an entire song, the highs were so bad-- really hurt my ears, gave me headaches (I'm sensitive to highs). Deb (my wife) finally ask why i keep going back...
Right across the hall, same front end, w/ Lynn Olsen amp & front loaded horns.
sounded pretty good, narrow sweet spot, but best imaging I'd ever heard.
Next day, changed out amps for Dennis Frakers 2A3 SET-- sounded great...
Listened to entire albums, no headaches, nice highs...
Went to VSAC. Johns OB Lowthers playing w. Jeffrey Jacksons 304TL amp.
whole different sound, much better than the same set-up sounded @ RMAF...
but down the hall, Jeffrey was playing his five way horns, w/ 75TL amp--order of magnitude better.
enough I don't feel like messing with cone drivers anymore.
I'm sure you'll hear those Lowther field-coils, the blued pair is Phils.
I first heard them in Jons OBs w/ J2 amps @ RMAF last year (had just finished some of the pieces). Noticable smoother than regular Lowthers, in highs, and especially in top end. Got a lot of comments about that "they don't sound like Lowthers" from people used to "Lowther shout."
You can dial in qts with magnet strength/field coil voltage.
Then spent a couple days w/ Jeffrey, Dave, Frank... swapping out components and comparing @ John P's house, regular Lowther & field coil Lowthers in 140Hz LeCleach Azurahorns on Klipschorns, Jeffrey J amp, Dave Slagle pre/phono, cart,
Frank S setting up his tonearms etc... went through a lot of stuff in a quick couple days, but have to say the tube amps & horns were way, way better than the J2 & OBs.
No comparison...
Feastrex--
uh, I don't really, honestly know.
Never messed w/ them that much.
Unfortunatly I haven't been that impressed w/ Phils yet--
I really do like the tone in the mids, but feel it's missing out high and low,
and needs a lot of power to make it usable even as a midrange.
I liked the Nessies a couple years ago, when kept within their limits
(not too complex of material, and limited dynamic range). Beautiful.
I thought the Granada's were a big step down-- lost the magic of the Nessie,
and all they gained was the ability to play loud, like something from best buy...
I didn't go to CES, but heard from a couple sources that they were even worse there; so digitally processed that you couldn't tell vinyl from cds.
I like compression drivers. Field coil compression drivers.
That's the current project.
The 650Hz one on the myemia table @ RMAF, & I've just draw up the 140Hz one.
Much more sensitive, don't need crazy power to drive.
--and a field coil cartridge...
you guys know about jeffrey & dave's blog?
http://hifiheroin.blogspot.com/
Matt Wiebe
robert taylor
Yeah, was a really great time.
I like Phil's 9-inch Feastrex / Tone Tubby better than a regular Lowther.
Would have to hear it in same room/system to comment on how it would compare to field coil, but as you mention, that would be system dependent, AND at that point, probably even more so, "horses for courses," getting pretty subjective, personal preference.
I just don't like OBs; not just the comb filtering, but the delayed signal bouncing around off the back & side walls blurs the sound too much, details run together, especially "big" things.
I didn't realize DACs could sound that different until Phil sent me down that rabbit hole... I like NOS too.
Jeffrey told me Lynn has actually never built anything, doesn't even solder, he just writes... I believe Gary Pimm & Josh built the amp Lynn talks about...
Yes, mostly analog @ Johns & Steve Kaufmanns too.
Speaker / Amp synergy... That's a big one... I'm working on getting a handle on it... Trying to learn from Jeffrey & Dave. That's one of the reason's I really respect those guys, they have that down a lot better than most, can "voice" things really well, quickly, predictably, and consistently. They both told me part of it is never building the same thing twice, "custom building" every amp, every opt, etc, a few times each until it sims right, and sounds right...
140hz LeCleach-- I have one fiberglass Azurahorn that I got from Steve K, was going to use it to make a mold to make carbon fiber horns. Try to get less "ring"/vibration than the fiberglass. It is the early Azura, the first few were 140, then Martin went to 160. (This is w/ Martin's blessing, he said it was costing too much to ship to US). I was gonna build a pair for Steve, Deb & I, see if Phil wanted a pair for his field coil lowthers. make them so I could cut the throats back to 2", 5" or 8". Turns out to be a pretty expensive project... Then Jeffrey got together w/ Victor Sierria in the Philippines, who can turn them out of mahogany for less $... see http://www.elevenhorns.com/ so I just built a lathe big enough to turn a 65Hz mid bass horn to match, and ordered a pair of 140Hz & 650Hz horns from above. Already have a pair of tapped horns for subs from 20 to mate w/ the mid bass horns, & a pair of 2405 JBLs to use from 10kHz up until the plasma tweeters get built. That's the five-way project I'm in the middle of.
Yes, based around some of the myemia drivers. http://www.myemia.com/horn.html has some photos of the 650Hz driver. Jeffrey has the only ones now, still finalizing some details on the diaphragms & surround materials & configurations. I made some teflon dies to put rolls in the mylar surrounds to make them more compliant. That build a few, compare, listen, swap out...
I just finished the rough draft of the 140Hz driver last week. Dave's doing the FEM sims, then re-draw, build protos...
Then want to build big field coil compression drivers, to replace the 15" drivers in the mid-bass horns. (and keep everything @ ~109dB sensitivity).
The Lowther was an experiment, a "learning exercise." Dave wanted a lowther, is keeping one (Phil gets the other one), neither Jeffrey nor I even want one. I kept trying to think of what I could do with one, but anything I could come up with, I truly believe a compression driver does much better. Lowthers just make it easy. The basket, cone, voice coil is already there, of decent quality, and the magnet just bolts on. So just build a better magnet, and play w/ the flux in the gap, and what it does. To build a better cone driver, well, yes, I'd throw every part of the Lowther away... and they have some pretty serious pc issues...
Cogents drivers were based on RCA 1428.
myemias are all new designs.
e.g. the first six inches of the horns expansion (the most critical part) is part of the driver, and cnc'd steel, so very accurate.Date: Tue, 23 Feb 2010 19:53:58 -0700
Matt Wiebe
Robert,
What a speaker project. I’m surprised given your ability to turn a 65hz horn you don’t also turn the 140 and 650. Those horns from Sierra don’t look inexpensive to me, and shipping has got to be fairly hefty. I’m going to be curious at your crossover and how you keep the efficiency up through four crossovers. I guess you have to go with an active crossover, though Dave probably has outputs that roll off in a crossoverly fashion. Are you blogging your progress anywhere? Or will Dave and Jeffery be posting progress on their blog? I would love to see the speakers come together.
I think part of my preference for OB is I listen in a small room close to the speakers. In the room I listen in the reflected sound is much less with OB than infinite-baffle speakers. But I do miss good bass, so I’m thinking about adding a woofer at some point.
I can see the steel horn on the myemia compression horn, but not enough details on the driver itself. What’s the design goal for the frequency range of that driver?
This got my attention, “Then want to build big field coil compression drivers, to replace the 15" drivers in the mid-bass horns.” Are you knocking the big GoTo drivers off or do you have another thing going? I’ve seen guys take the ubiquitous Jensen 12-inch fieldcoil, cut the cone way down and horn load it for a bass compression driver, but it sounds like you are doing a bigger version of treble driver like the Ale/GoTo. What a cool project. If you CNC-lathe the horn start, why not keep the horn all metal? Or CNC pedals which are welded up into the horn? Anyway I look forward to hearing your progress reports.
Matt
robert taylor
crossover-- points mentioned are rough, what Jeffrey uses now in existing five-way, same freq horns, is starting point, will start w/ passive, the old box of oil caps & chokes, & have a slick dave box w/ autoformers that's x/over/attenuator, to find actual desired freq.
then, yeah, the real work, seperate amps for each driver, that roll on/off in right range. Kinda like Romy, crossover wise, but pretty different amps. Merc vapor, choke input; Aa, transformer coupled to 4-65 & such. Breadboard & more experiments... Time...
The 650Hz myemia compression driver has a 650Hz LeCleach flare.
The steel part is the first part of the flare, a wood (walnut in the pict) piece completes the horn, and the LeCleach "roll-back," a matching wood piece is the back cover of the horn. Using it from "~1k - 10kHz," actually roll it in ~1k (a cap for now, dedicated amp later) & let it roll off where ever it rolls off, then cross a super tweeter in where it sounds right, which is ~10k. (five-ways w/ 6dB crossovers have very big overlaps.) only other thing inside is a couple hundred bucks worth of copper wire, voicecoil/diaphragm/surround & phase plug.
There's a pict on the blog "night and day," w/ that driver on one side & Jeffrey's goto on the other side, doing a comparison, the one w/ breadboard amps on the floor, and five-way gotos they're replacing in the other pict.
No knock-offs of anything. The big Ales & Gotos are pretty small dia, have time alignment issues, (especially in bass, but this is for mid-bass).
Something closer the Shearer horn of 1933 if I have to point to something that was already done, but no, just starting w/ a clean sheet of paper (on solidworks), and drawing a 65Hz Tractrix compression driver, whatever seems will work best...
I don't have a CNC, run them all day @ work, but have to pay someone else to build toys... something that large would get expensive.
And wood damps vibrations better, I believe would sound better than metal, carbon fiber, fiberglass. Josh does the cnc plasma cut & weld petals--so much quicker. and in two layers, and fill between w/ damping material, then paint. pretty blingy looking for me, but sell like crazy...
Ok, I like the way wood looks. So does the wife...
Nice old classic look.
For now though, (& for a while) we'll be listening to a single driver set-up, good old Nagoka Swans & little EL84 SET.
"Thinking of adding a woofer"
an OB woofer? a dipole? Frank had an OB set-up @ RMAF that I thought integrated pretty well, couldn't hear where it crossed over @ all (I usually can, that bothered me on Phil's large Feastrex, etc). It used a dipole woofer, kinda like the Linkwitz W sub thing.
Matt Wiebe
Robert,
I see the timesavings of buying for sure, and given the nature and complication of the project, time is going to be important.
So than your plasma tweeter will roll in at 10K for the top?
Sorry about implying knock-offs, I just know there are a variety of ways of doing compression drivers, and I was just curious about the designs. I’ll noodle around on that blog to see what I can find. I know Emilar did some large opening drivers and another company that escapes me. One of these days I’ll read up on the math behind the compression in compression driver because that has always interested me. I’ve always wondered why large opening compression drivers have never caught on in the market, I guess it could be a fashion thing, a large woofer is easier and is used by more people. Since a few companies have developments of the big RCA style fashion may be changing.
Going from swans and EL84 to a five-way horn with five DHT SET amps is a lifestyle and complication shift of a few orders of magnitude.
I don’t follow your comment about smaller drivers having more time alignment issues.
Do you work much with the Brush Wellman beryllium/aluminum alloys? Some of those alloys ring less then wood. But I concede your point on looks, wood’s better looking than metal or plastic horns.
On OB woofers, the W- and H-boxes look interesting but it’s a build and play issue. I did experiment with a small Fostex FF85K on top a JBL LE8Ts that was really nice and may play around developing that. I just don’t have the space to do too much speaker experimentation in my house.
Matt
robert taylor
-If- they can sound seamless... Really like Acapellas, really don't like some others I've heard.
No prob. on the knock-off thing, just trying to say they're not clones; for the time spent it would have been easier to have just bought any other driver, or just made a goto, ale, WE, RCA, whatever :)
Yes, Jeffrey met w/ Brush @ CES, i'm finishing up some more adaptors to mount several different existing drivers on the same horn for comparisons w/ different diaphrams, will then get protos to do A/B test w/ alum, ti, be... will try to use existing size dome, may have to custom make die for larger ones (obviously will have to for mid-bass, Brush said he could go that large, but might not be needed/wanted for that freq).
time alignment issues-- having trouble communicating in this format...
right, no inheret time alignment issues w/ large or small throat, but small throat dictates longer horn. w/ bass horn, means very long horn. means very large offset for everything else to time align, or digitaly delay, or ignore. that's what i meant by "issues."
yes, order of magnitude more complex than single driver/amp...
is it worth it...
i sure do question it sometimes...
am i just doing it because "doing it" is fun?
maybe...
jsn
Jorgenson by any chance?) a little MAX NC 10 desktop mill to play with
and it is up and running. Too small for most of this stuff, but it
could probably do whatever small bits you might need.
jsn
Matt Wiebe
Robert,
Okay, I understand the longer horn for the smaller throat. It’s those phase shift issues that seem so hard to deal with to me.
So how big is your planed mid-bass driver? How big can you go and still qualify as a compression driver? Are you looking at something in the 4 to 6-inch range?
I know there is some interesting metal foil with consolidated ceramic stiffener materials out there. The ones I know best are ti foil with internal boron strands. Of course they could not be stamped into shape because of the ceramic, but they are wicked stiff and light. I’ve always thought they would be good speaker diaphragm materials. Too bad there is not a desktop sinter machine allowing you to easily crank out parts tweaking alloy mixtures.
I’m with you on the fun more than the arrival at Nirvana.
Matt
robert taylor
The mid-bass horn i'm building has a 7.5" throat, so something around that size, maybe 8".
Metal foil w/ ceramic stiffners?
Sounds interesting...
robert taylor
does it actually hold 0.00025"?
that would be cool!!
how do you program it?
g code?
or does it have it's own program?
might be really good for some cartridge/tonearms stuff i want to build.
want a tonearm?
> Date: Wed, 24 Feb 2010 08:39:35 -0700
> Subject: Re: too long answer to Matt
jsn
Justin is writing g code for it directly, but I can't help but think
there is an easier way. We did buy the software that would have come
with it. It seems like there should be a way to go from a drawing to
g code relatively easily, but we haven't done that yet.
As for 0.00025", I have no idea.
And of course I want a tonearm - especially a cheap DIY one :)
Here are some pics:
http://picasaweb.google.com/boozhoundlabs/CNCMachine#5191088650331584962
jsn
Matt Wiebe
Matt Wiebe
robert taylor
so i can draw picts, as solid models in 3d, but can't convert directly into tool paths, g code :(
some machines come with a "conversational" program, that lets you draw, or just ask what you want to do, and you tell it.
the hurcos & mazaks are like that, pretty easy.
g & m takes (quite) a while longer, especially if you don't do it a lot...
> Date: Wed, 24 Feb 2010 12:47:46 -0700
robert taylor
cool.
will be a little while, a few weeks anyway;
and this won't be a totally low-buck project.
i was thinking along the linear tracker @ first, (and had considered the magnetic bearing idea, also for platter suspension), may build one later to compare, but to make a long story short, i believe a better pivot design can be built...
there are a couple ways to build 'em w/ zero tracking error...
dave has one, frank has one...
frank (schroder) is the expert i'll be leaning on here.
he has some ideas (like implementing the zero tracking error thing) that he wants to "give" the diy world, is many months behind building the tonearms he sells now (for upwards of $7-10k)...
anyway, plan a, step one-- quick, cheap, simple (yes) is to basically "clone" the arm dave has now (RS labs A1), which is a really basic, simple, crude looking, unipiviot, with a pivoting headshell, (which gets around the tracking error problem). the base just sets on the plinth, easy to change out. and--you can build multiple top sections (wands) with different carts to quickly compare carts. just play one, pick it up, and set the other one on (after weight, VTF, azimuth, etc have been set).
these now sell for like $1500, and when set-up right, i was told came close to the sound quality of franks arms (which sound at least as good as anything i've ever heard, at any price).
so; step one, measure, draw out daves arm,
make at least one just like it.
listen to both to make sure it sounds at least as good.
then work on improving it.
(there's already a pretty good list worked up, more will probably be added, but want to always change one thing at a time to be able to evaluate...)
then sell enough to at least cover materials, maybe a little time.
i have a small & medium mill & lathe, but a nc machine would save more time, could bring price down for everyone. :)
Date: Wed, 24 Feb 2010 13:08:00 -0700
robert taylor
Yes, it was used in a folded horn.
Some more links if you're interested:
http://community.klipsch.com/forums/storage/4/1224245/1933%20Phila%20Speaker.pdf
http://www.aes.org/aeshc/docs/bell.labs/auditoryperspective.pdf
I just want to make a driver maybe half that size for a mid-bass horn.
Technology has moved on for lower freqs--
Already have a pair of tapped horns built.
Don't need to be anywhere near that large.
Flat freq response (+/- <1dB) from like 27 to 90 Hz, 6-10 lower than that in-room, corner loaded.
Ask Phil, he heard them.
Subs you can drive w/ a couple watts.
want to build an OTL for them though, get rid of transformer problems @ low freqs,
& have low pass & high pass filters built in the amp.
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