Good advices for a newbie (threading tools lathe)

[PJs]

Been a bit anxious to know how you've been doing with this great project. Excellent news and progress Stefano! The Plasma Flame looks perfect and if it's quiet and tubes running as indicated, that is wonderful. Was that flame at 1KHz? Your makeshift cage also seems to be pretty effective. Are you still planning on running it horizontally into your horn? How are the ozone levels with this plasma size?

Small advice about raising the input voltage to max data sheet. Typically you would want to run it at about 80-90% to stay out of distortion range and not generating too many harmonics. A test at max is fine but running should be below.

- try higher mhz working frequency, different coils and cap (flame is fully silent)

A little confused by this...is the flame not completely silent now? What frequency are you running at now? Not sure a few MHz will make that much difference for all that work.

Very happy for you and the progress you've made...a long way over a 18 pages and a years work!!

Till The next installment, ~PJ

[rendoman]

Hi PJs!
Thanks! Yes both the pictures of flames are close to 1khz, I've seen that with full flame there is some more fuel to low frequency and a bit more volume (but not so much). Makeshift cage is made from 0,8mm steel, a scrap folded with no glory , but really effective looking the neon result, I'm impressed!
Imho ozone now is not so much, even at high flame, you can only smell a little with nose over flame, in normal room I don't think it is a problem.
I want to make quartz chamber as the initial idea, coupled with a 900-1000hz cutoff horn, that means +14-15db of spl, plus the full degradation of ozone.

Max g2 imput of oscillator is 250v, now I'm running at 160v, near 65% , I'm not so sure about giving more volt, can be useful as study, but not for sound maybem you're right about distortion

Flame is completely silent and with a good shape,now freq is 12mhz, I want to try 25\30mhz, flame for sure will be shorter. I want to make this experiment to see what will happen to sound, honestly I think the actual frequency is good enough.
I'm thinking about position of flame, orizontal horn for sure, with vertical coil and a sort of ceramic connector for tungesten - copper wire, I have to found some good old isolator and Mount it over a teflon round bar.

I'm thinking for other options

[rendoman]

Hi!
Something interesting today!
No tech or dissertations, only video and some feelings about plasma.

How does it sound? Sound is amazing! (not because I built it )
Circuit is running as fullrange, with no input filter, not the best condition for music, but very good for test.

There is some clipping at full volume probably due to presence of bass, overdriving the el34 amp.
Highs and mids are something different from normal diaphragm speaker. Sound pressure is high, with a good aluminum horn and a very good coupling I bet this circuit can face my sensitive fullrange system.

I'm at the beginning, circuit is running in safe mode, I have many things to try and to adjust.
I did a fast measurement with Rew in the room, just to know more or less how this thing works. I see a very good response from 4k up to 20k (sorry but I have poor microphone, it reaches only 20k) I hope with some ideas I have to gain 2k range. It's still impressive how much sound can produce at 1khz, considering size flame and driving.

The funny thing is that it took me so long to make running the circuit hot (do you remember red cherry plates?) , consuming lot of current, and now I got the same flame size with half clean current!

I post 3 videos, recorded with camera, not best quality but better than nothing

https://www.facebook.com/stefano.ran...1212254124884/

https://www.facebook.com/stefano.ran...1212406048682/

https://www.facebook.com/stefano.ran...1212316966455/

Ps: flame in orizontal is perfectly straight

[PJs]

Actually quite remarkable considering the simple protocols for these tests and you were streaming audio from a video probably in MP4 format. It doesn't surprise me the DB levels that you achieved, with good clean interfaces between stages at proper power levels. However I noticed these were run without running the Calibrations on your sound card, and ECM8000 mic they are likely skewed a bit. For me the Ears have it in the long run as to the f response once you take a look at some detail in the RTA.

I can't remember if your frequency generator has a sweep function but that would be where I would be heading once I calibrated the sound card and mic. If it doesn't it might be available in your REW software and I would also run a 24 octave RTA test with the mic at 1 meter. Once you take it through those places I would probably use some solo classical piano to get a feel for what it can do in real life. The celtic was great to hear but violin strings have some interesting harmonics for this level of testing, imho.

Personally when I test speakers for my ears and a room I use a vinyl of

not only because it is beautiful (imho) but the pacing and individuality of the notes on her Steinway give you a clear indication of what the speaker/system can reproduce particularly the last bar or so.

If I may pontificate a bit more : Consider that you have built a wonderful analog tube amp with tenacity and verve that feeds an incredible plasma speaker you designed and Built! But when you feed it with an mp3 or 4, these are nothing more than an "Interpolated" version of an "AC" audio signal (an algorithm to simulate the sine wave). For MP3's anything above 192K begins to add artifacts and at 320k about 1/3 of the signal is artificial. I was shocked a few years ago when I developed a circuit that would decode a 19.2Khz (narrow BW ~±.2Khz) signal from an audio MP3, that I had to build a 4 stage modified Butterworth filter just to get it out of the "Interpolation". Beyond 192K sample it started to fail because of the artifacts introduced. Even adding stages didn't really help. The Scope doesn't lie and 24 octave RTA shows it on a grand scale. None of this changes the fact that it is a Digital age anymore but even AAC Lossless has some, and imho Wav/AIFF is the better way if possible if that is all you have to drive it musically...keeping in mind any conversions are just interpolations! Best of all, I recently heard that England is experiencing a rush back to vinyl (Yeah)! If you could drive this from a turntable I bet you would be surprised by what you hear!! Nuff Spew.

Terrific Job Stefano, my hat is off to you....Congratulations Sir. On the downhill side now!

Thanks for sharing. ~PJ

[tonyfoale]

As a newbie with just a few posts under my belt I was directed to this thread as an example of how things can take off on here. I read the first page and saw that there were 18 more so I skipped to the last one to see how things were going. I'll try and catch up with the rest later, but it is just to easy to spend too much time on the net reading interesting stuff, I like to make interesting stuff and finding time for both is always difficult. I work slower now than I did 55 years ago.
I notice that I have several things in common with some of the people here.

Stefano, I share your enthusiasm for motorcycles (you may find my web site and Facebook of interest). I live in Spain and suffer the same problems as you when it comes to buying what are regarded as industrial tools. The shops here don't sell to private people. Fortunately, I make 5 or 6 trips each year to the US, mostly to race but sometimes for work. When a trip is coming up I scour eBay and have stuff sent to a friend there. I have enough air miles to be allowed 2 free checked cases of 23kg each. If the trip is for a job then I fly business class and get a luggage allowance of 3 bags of 32kg each. So I usually come back loaded with hard to buy stuff here.

C-Bag (you must have a real name?), A mandolin player I see. that reminds me when I was between 8 and 11 ( I know that from where we lived at the time) my mother decided that there should be another musician in the family, she played the piano. My elder brother worked away from home and nobody ever expected much from my younger brother so I was nominated. The mandolin was chosen as my weapon. We lived in a country area of Australia then with no music teachers within a large distance so I was enrolled in correspondence lessons. The lack of a real teacher and my total lack of any musical talent eventually shone through and I was allowed off the hook.

PJs, I'm with you on the use of HSS tools for threading in non-hard materials. You can get a very keen edge which is difficult with inserts. I know that many people shy away as much as possible from screw cutting but really there is no need for fear. I am completely self taught as regards machining, in fact anything requiring manual skill, my education was theoretical, but being too ignorant to know that it was difficult I never had any trouble doing it.

Although I got interested in electronics at 8 years old when first introduced to a crystal set, and later became a ham operator, I never did develop any interest in hi-fi and fancy speakers so I don't expect to be able to contribute much to this interesting thread.

[C-Bag]

Ok, now I'm officially intimidated For the record my name is Tony too and when I went to register my usual net name was taken so I used a good pickin' buddy's call sign as it wasn't taken.

I'm not sure folks who play classical, which was probably what your mother was wishing you'd play, would call what I play mandolin. I play mostly bluegrass and in bluegrass the violin is called a fiddle. Unfortunately they still call a mandolin a mandolin in classical and bluegrass. But like the difference between fiddle and violin, the approach is 180deg different. The joke is "How do you stop a bluegrass musician from playing?" .......put musical notation in front of him. When people ask what Bluegrass is a banjo picker said " 3 chords, a cloud of dust with sad stories sang through the nose in a upbeat way!" Nuf said.

[PJs]

Hi "Tony" Foale,
Just for the record I'm a novice to machining and mostly self taught, although I've been around shops all my life and careers. Thanks to HMT's and the great people here and Projects, I may be approaching the amateur level now.

I got into electronics about 7-8 grade also. Galina radio to my first hand build O'scope in early teens, but had converted TV's to O'scopes earlier and worked summers for the local repair shop too, then to EE college...but never really used it as they were laying off EE PhD's when I got out. I was a tweener of tubes to transistor gen and started my education with the Radio Amateurs Handbook but never could pass the blinking key test for a first class license yet aced the rest of it. Stefano's Cone project peaked my interest and morphed through 19 pages now to this very difficult project of a plasma speaker which has always interested me all the way back to the 70's. Even though I haven't done tube stuff for at least 3 decades it's been great fun...And he has pulled it off other than some dial in, polish and pomp. Tenacity and verve is something I admire greatly!

I really enjoyed the article in the paper. Interesting it brought my trip in 01' to mind. I took a month long trip to Australia after an intense 3 year project and rode a RS1100 from Sydney to Melbourne down the coast. Just after leaving Sydney it started raining and by the time I got to Narooma I was a giant (6'6") drowned rat and stayed the night at a great pub. I thought about keeping the bike to finish my trip to Adelaide, then Coober Pedy...but did the train and bus instead, then 2 weeks in the outback camping and off to Cairns for some diving and sadly back to Sydney and one last Oysters on the Rocks with a pint and a fine cigar. Definitely a bucket list trip meeting great people and some golden adventures. I've ridden for 40+ years until an accident in 05' on my Sprint 1050ST. Been a family thing since childhood and dirt bikes. My Bro still rides HD's now. Always too big to race but ground 3 side cases off my 73' Z1 as a wanna be and got Gary Nixon and a few others to sign my Bell Hat. Also built a custom/blueprinted 68,69,70 Bonney with a trick Tiger Head from a pile of stuff I got from flat track racer I knew, way back when.

BTW, don't let C-Bag fool you, I know for a fact he has audio chops well beyond mine on top of his musical talents and mad shop prowess.

Based on seeing your DP sensors, flow bench and other projects, my hit is you can add to any conversations going on here. It's about sharing our ideas, thoughts, builds & Stuff with our peers and young guns freely here at HMT's IMHO. Jump in the water is great.

~PJ

[Frank S]

I've been lurking in this thread for months now. and like so many other threads it has morphed completely into something about as far from the original subject matter as possible which I have to say is probably why I visit it every time a new post has been made.
About as close as I can relate to any of the most recent postings in this thread would be C-bag's description of bluegrass.
I am one of those rare persons on this planet who just about never listens to any kind of music at least not for more than a few minutes at a time. to my ears it doesn't matter the type be it classical rock metal acid disco rap country, bluegrass or whatever by the time it reaches my ears it sounds like the screeching of fingernails on a chalkboard, but then again so does the voices of most groups of people I encounter unless I am looking directly at any single person.
However this wasn't always the case as a young Teenager I used to look forward to the few random times when the famed Mr Earnest Tubb would come to our farm for a little pickin with my dad they having gone to school together as kids. I once met Him again at a USO show long after I had gone into the Army when he saw me sitting near the front row he stopped right in the middle of his song and singled me out.
Hey frank does your dad still make the best Hooch in Texas? When I told him that he had passed away. MR Tubb had me come up to the stage and do a duet with him as a tribute to my dad You have never heard a worst adlibed version of Waltz across Texas in your life but you should have seen the faces of 200 GI's when he calld me up

[C-Bag]

Good one Frank.

Ive been auditory all my life and music has always been a big part of it even though no immediate family played. Not until I took up guitar did my Okie G-pa and my Portuguese G-ma say they had both played mandolin when young. My great G-pa's it turned out were both musicians. But my parents on both sides only played the radio I didn't start playing until I left home because everybody was such a critic. I'd been playing mandolin for a couple of years and we would always go out to breakfast with everybody on Saturdays and on the way home I'd always listen to friends who were dj's on KUOP the University of Stockton radio station. They would play all the many flavors of acoustic music all day long on Saturdays. As luck would have it, they played Rose and the Maddox Bro's big hit "Philidelphia Lawyer". After it got done I said to my then spouse " how did Rose ever get so famous with a voice like that!". I all but got hit, my X saying don't you dare talk about Rose Maddox that way! She was my grandparents favorite singer! You'd be lucky to play with somebody so famous!

I said yeah right.....and as we pulled in to the car port I could hear the phone ringing. I ran in and it was our fiddle player and he was all excited because, yeah, you guessed it, Rose Maddox was playing the big concert on 4th July in the park and we were picked to back her up. Since her bro's died she would just have some local bluegrass band back her up. We never did get a chance to practice with her and our band would open and then back her up. We met her right before we were to open backstage. We had just gotten her best of albums and went over her songs. Since we had our instruments the guitar player said to Rose how about we do a song? She called something and we knew it. The guitar player who was classically trained started to play it in the key on the album and Rose said"hold on there son! I've been singin' in Reno for 3wks and we're going to have to drop er down a coupla frets!" So she would hum in Tony's ear(I was in a couple of bands where there was two of us Tony's) and he'd call the key, and she would have to do a vocal kick because she couldn't come in from a instrumental kick off. We did part of that song and I thought uh oh. Rose also felt no mercy for musicians who couldn't keep up and had fried the backup band the month before on the big stage at the big Grass Valley bluegrass festival in front 1,000's of fans. I tried not to think about it and the fiddler said to me as we went to do our set " what have I gotten us into.."

Our set went good and Rose came on to thundering applause. She right away stepped in front of our female bass player and once again hummed in Tony's ear, he called the key and she started singing and we came in. This went on for a couple of songs and Rose turned to me and said "what do you call your band?" I said we are Flatland String Band. She said, " a string band?" I said yes. Rose said " oh, you don't blow it, you pluck it".....the crowd roared and my face was so red I glowed. We went on like that with Rose strategically stepping in front of our pretty bass player every time she move out from behind her like she has eyes in the back of her head. Here Rose had been helped around and onto the stage by her niece, but after that first song the crowd just propelled her along and she was moving around like a kid. About a hour non stop in she called a song and it was a friend ours who was sitting in on banjo's favorite song(because of the banjo kick off on the album). He started in and Rose off mic said "hold on son" but Randy was in hog heaven and goin' for it. She tried again, hold on son and when she saw he wasn't hearing her got on the mic and screamed "STOP!" I swear the whole town of Modesto stopped and the first ten rows of seats had to pick themselves up off the row behind them! Poor Randy looked like he'd been shot. Rose just said, lady's first! And we went back at it. We did 90min and Rose said her thank you's and "for my last number I'd like to do a song in the key of love". We all just stood there while she grinned ear to ear...."the key of F!" And the crowd roared. I got to see first hand how a pro feeds off a crowd.

Unfortunately a few days after we heard she'd had a heart attack and thought we'd go down in infamy as the last band she played with. She came back from it and sang for several years after. I've been blessed since to meet some of my biggest hero's who would probably be unknown to most, but some of the best mandolin players in the world and the nicest folks.

[Frank S]

So would I be correct in assuming that you are a 2 finger guy most bluegrass guys I've known played more 2 finger cords than anything else