Sundries 23 January 2022

 

Call me Artie

 

‘main power amps’

 

‘vinyl turntable’

 

‘speaker system’

 

Boomengineering

 

‘Homemade hang glider made in the late 1970s’

 

LeMon3

 

 

 

‘First up a couple for Boom. – Mill & MillWiring show the mill I picked up last year. 1980 build, 110hrs on the clock – it’s like brand new.
Everything works except the relay that holds the feed motor on. The wiring diagram is in Polish and one of those horrible ones where the
thing is broken up into a whole lot of drawings where there’s no real indication of where they connect together. Then to top it all of they
wired it all up with identical green wires. The relay in question is one of the two circled in red and in my copious free time (between 3 & 4 am) I should get it sorted eventually…’

 

 

‘The other two are for Artie. SoundCabinet shows the homemade surround sound system I put together a few years ago. SideSpeakers shows the side/rear speakers. It’s all ugly as sin but works surprisingly well. The drivers in the front left/right are by ScanSpeak out of Denmark in a cabinet that are driven by the preamp (just under the turntable) and a 100W power amp (second from the bottom). The design is a mod of one I found on the internet. The sub is a 15″ driver in a -6dB enclosure (my own design) driven by the 350W mono amp just above the 100W jobbie (repurposed NAD enclosure).  The vent in the cabinet is of the labyrinth type and is over a metre long (kinda hard to fit in the space but we got there) and gets a decent response down to 24Hz. The centre and rear/side speakers use a 4″ full range driver (made from banana of all things!!!) – own design agan and are driven by the bottom amp in the stack. I’ve built the thing in stages over the last 35 years or so. As I said, it’s all as ugly as, but the sound is pretty special. It’ll be even better if I ever get around to replacing the capacitors in the power amp (they’re 35 years old now…)’

‘One for the gardeners, this morning’s plum harvest – one tree on dwarf rootstock. Next stop, plum jam, chilli plum sauce and bottled plums. This farming lark is the hardest work I’ve ever had to do.’

 

desmodromic

‘On Friday went for a 70 km cross-country jaunt from Adelaide Hills to Goolwa Beach for a swim and a catch-up with friends. Stopped at the garage in Macclesfield for coffee.’

 

 

 

 

Ermington Plumbing

This 1966 plaque is located on and commemorates the first inland and second settlement in Australia.

Behind those trees are Meriton apartments.’

 

‘Nearby is the memorial to the war that kept South African Diamonds and Gold British.’

‘Just up from old government house. Not a bad place to visit.’

 

 

‘Amazing they’ve managed to keep the developers out Parra park’

 

 

 

 

Anyone looking to post recipes, poster shots, flora, fauna, automotive projects, gardens, 8 Irons out of the bunker etc

[email protected]

will get you there in time

 

 

Comments

  1. Geeze Artie, you trying to make me feel inadequate or what?
    The angled wings on your presumably electrostatic speakers are to improve the off axis performance, yes? I had a mate in Qld that was building his own electrostatics and off axis was driving him nuts (this was 20 years ago, lost touch with him, so I don’t know how he resolved it – he was talking about building them in three separate panels at the time).
    How much heat do those amps produce?
    I am definitely more than a little envious, congrats.

    • boomengineeringMEMBER

      The components to the right of your red box mark are 1 contactor and connected below it a thermal overload. Check the continuity of the contactor solenoid ( the blue wire underneath ) as they are the usual culprits. Your red Mark is obscuring where the other wire to the solenoid may be ( between the contactor and the overload).
      A quick way to see if the rest of the feed system is OK is to push the button in the middle of the contactor with a non conductive rod with all power on but be careful not to touch any of the li e wires or Terminals.
      Looks like an excellent buy.
      Doing this from my phone while she’s driving is hard so when I get home will be able to see it better and see if the voltage to the said solenoid is 24, 120v or otherwise.

      • boomengineeringMEMBER

        Thanks Merkwürdigliebe.
        LeMon3,
        Be careful of the LIVE wires. The door may have a cutout switch on it so to get power to do the test you may have to depress it with a clamp or such.
        If the feed powers up when you push the contactor central button then it is definitely the contactor solenoid fault. This can be be replaced but most are different so mostly the only option is to buy a complete contactor for about $100 or less.
        Still couldn’t see the two transformers outputs ( at hm atm).
        brw sometimes the solenoid wires are on the same side but still below the 440v power terminals. It looks like they may be on opposite sides and diagonally opposed.

        • boomengineeringMEMBER

          Diametrically opposed.
          Did the expensive vice and rosemill come with the mill sale?

        • Hi Boom, yeah the feed works fine if I press the “inch” button on the controller or push the button in the middle of the solenoid. All that’s going wrong is I’m going nuts trying to read the soviet era wiring diagrams and relating them to the nuts monochrome physical wiring scheme. All the wires are numbered, but there’s no rhyme nor reason that I can see.
          And yes, the vice and tooling came with it – it has quite a bit for the vertical and horizontal modes of operation…

          • boomengineeringMEMBER

            The inch button bypasses the latching of the ( usually 4th terminal on top) which holds power to the solenoid to keep it running rather than always inching. When the contactor is energized via the solenoid the 4th or sometimes 5th top terminal is used as a loop to return the low voltage power back to the solenoid to keep it on. A wire to a NC switch (off) on your control panel from the loop (in series) will break the circuit when depressed releasing the holding pattern ( turning it off) permanently until the on button is pressed.
            The fact that the contactor works when the inch button is depressed and it starts without staying on means it is OK and the off button is OK and not open circuit. It is the latching system at fault. This is not always achieved via the designated contactor and can be activated remotely via another contactor or relay. Without seeing it in person you could be right in suspecting one of the relays in your red mark. You can test these by continuity test or by running wires from the same voltage transformer BUT make sure you have the correct transformer and voltage as you have two which means their outputs are different. You can buy a replacement relay cheaply and it doesn’t have to be very similar as long it has NC or NO or both amount on terminals. It can also be different amps but not less. The input for the relay solenoid input must be the same voltage though.
            Basically you can replace it with any part as long as the above is adhered to.

          • boomengineeringMEMBER

            If testing the relay with the low voltage power make sure it is its solenoid terminals not the power terminals that you touch the wires to.

        • Hi Boom, I didn’t really post in order to get a free consultation – I was just showing off the weird soviet era wiring. Thank you for trying to help.
          If you really want to see if you can see what’s what, then the photo of the wiring without my defacing can be seen here:
          http://theedibleforest.com.au/mill/
          cheers,

          • boomengineeringMEMBER

            Some machinery have that loop going in series through multiple checkpoints stopping feed when a spindle is not in operation thereby saving tooling from being broken etc.
            If it isn’t going by the time I’m up the way next it will cost you an orange drink to fix.

          • boomengineeringMEMBER

            Oh, another way the flow could be interrupted would be if the latching contact on top ( of contactor) is burnt out but is not common in low voltage transfers as in this case. To test this, test the unpowered terminals on both sides for continuity whilst depressing the middle button.

          • Description of Polish wiring reminds me of “This Old Tony” on YouTube and his exploits with the MAHO.

            I’m hoping to get my hands on a Colchester Bantam lathe. The fella that owns it is terminal so it’s a matter of time. Ex TAFE machine and it’s spotless.

        • Geeze, I hope you’re not coming up this way for a long time. I won’t have oranges until at least July and they’ll be as sour as all get out until August…
          But seriously, thanks for the tips, I’ll see what I can see in the next week or two.

          • boomengineeringMEMBER

            Btw, when I referred to the 4th or 5th I was referring to auxiliary contact poles which are marked as 13 and 14 for the 4th pole.
            A1 and A2 are the solenoid coil terminals.
            Hope this helps.

          • boomengineeringMEMBER

            Maybe nothing wrong with the machine. It could be that it has traveled too far on X,Y or Z and tripped one of the cutout switches. Usually too low on the vertical down.

        • Hey Boom, cutout switches are of the momentary contact variety and the feed stops if I operate them manually, so I don’t think they’re the problem.

          • boomengineeringMEMBER

            OK,
            My home mill has 4 cutout cams on each axis. If it trips one on one direction it can reverse but if it trips the second it has to be wound by hand to pass the second to allow it to reverse

            All the cutout wires function to create an open circuit directed to the components above to save the leadsrew and leadscrew nuts.

          • boomengineeringMEMBER

            Disclaimer.
            All the advise above is exclusively for LeMon3 and no other person should follow or is permitted to adhere to any of my comments .

    • call me ArtieMEMBER

      Hi LeMon. I have made many systems over the years. This is just the latest (and biggest) one. It’s pretty impractical because I have to dedicate and entire large room for it. I like the look of your speakers. Those are the SEAS magnesium drivers? They are excellent, but a little tricky to work with regarding crossovers due to their HF resonant peak. Is it a SEAS tweeter, too?
      Have you tried near-field listening with them. If I ever change my system again, which is a definite possibility given what I said about the big speakers being impractical, I would go back to small monitors listened to near-field (i.e. less than 1.2 M). It’s a great way to listen as it almost eliminates room effects. I can’t recognise the power amp and turntable from the photos. Locally distributed?

    • call me ArtieMEMBER

      Hi again LeMon. Sorry I didn’t read your notes carefully enough. You’ve already answered my questions above. Happy to talk more audio anytime. Where are you? Artie

      • I live in a place you’ve never heard of called Wherrol Flat on the NSW mid-north coast.
        Yes the drivers as SEAS magnesium, tweeters also by SEAS. The xover was definitely a bit fiddly, as was the porting.
        I use an active xover in the amp to break out the sub signal, as that is the weakest part of the system. The sub has a resonance spike at 16Hz, which was evident at the design stage, but I designed a passive filter to get rid of it – in my usual half-arsed way, didn’t actually consider the construction aspects of the filter until after I’d finished the cabinet build and then realised the filter was going to need a coil with nearly 10kg of copper that would take up nearly 1/3 of the volume of the cabinet. So I just put up with the spike. I only have two albums with any signal down there – I’ve learned not to play them too loud.
        The turntable is a mid-fi Harman/Kardon from the 80’s – the T65C. I had my sights set on a Garrot brothers upgrade, but they closed their business and topped themselves before I got there. 🙁 So I went with an Ortofon MM cartridge which is still going strong.
        And yes, I listen near field whenever I want to sit and have a proper listen. If I put on something like Patrica Barber’s “Fortnight in France” I can close my eyes and “see” exactly where each performer is on the stage and pick out exactly what they’re doing – I love it.

        • call me ArtieMEMBER

          Hi again. This is a bit late. Maybe you won’t see it. Anyway, regarding that low frequency peak at 16 hz in your subbies.
          As you are already using an active crossover, you can probably build in an RC-based notch filter to deal with that peak at the line-level, rather than trying to do it at the speaker-level using an LC notch.
          Only thing is, the filter design can get a bit complex if you need high-Q filtration. If it’s not critical then it’s quite a simple thing to do.
          If you get this, I can help you with resources how to approach this. Artie

      • No worries Artie, they fixed the delayed email notifications, so I saw your note.
        Thanks for the offer, but as I said, there’s only a couple of albums that trigger the problem and the missus hates both of them, so if I play them it’s quietly after she’s gone to bed.
        So, I probably won’t try and fix the problem as my electronics concentration is currently focused on fixing some issues with my off-grid system and that’s likely to take up my free time (3am-4am) for the foreseeable future…
        Thanks again for the offer
        Cheers,
        Les

  2. boomengineeringMEMBER

    Desmodromic.
    That’s some serious riding you’re doing. Nice gravel bike. Has it got 28″ wheels?.

    • desmodromicMEMBER

      Yes, boom. I run 700c wheels with a 40mm tyre. The frame is a titanium Curve GRX out of Curve Cycling in Melbourne. It’s my all-time, go anywhere, forever bicycle. The gravel bike gives me access to much more terrain and keeps me away from the hazards of mixing with the traffic,

      • Know IdeaMEMBER

        Nice work.

        As it turns out, I am currently researching gravel bikes (I live in the Snowy Mountains) to open up a more options for rides. I will have a look at Curve to see what they have on offer. I tend toward metal frames over carbon (cue: vitriol and abuse from the carbon fanatics) although whether I would stretch the budget to titanium is another question.

        • desmodromicMEMBER

          KI, Curve webpage is here https://www.curvecycling.com.au/pages/bike-overview

          Curve are known for Ti bike frames and quality carbon wheels. The build quality is excellent and I expect mine to be the last bike I buy. They do make a steel version of the GRX that isn’t shown, it is much cheaper, and needs to be ordered well ahead as most shipments are sold before they are landed. Gravel bike options are expanding all the time, so good luck with your search.

      • Hey desmo, how does the Ti frame handle? I have a vague recollection that Norton or BSA tried a Ti frame for the Manx TT way back when and found it too flexible. Or does a bit of flex help a gravel bike along?

        • desmodromicMEMBER

          LM3, it handles just fine and is a much nicer ride than the carbon framed Giant road bike I rode prior. Being a gravel bike the rear stays are a little longer, the bottom bracket a little lower and the steering stem a little less steep. It all makes for more control on a loose surface or descending an unpaved hill. All frames flex and flex is good in the right places such as the rear stays. Flex is bad around the bottom bracket. The tubing is ‘double-butted’ in that the wall thickness varies along its length, usually thinner in the middle, to get the balance between flex and rigidity. Look here https://roadbikeaction.com/ask-rc-butted-titanium-tubes-and-their-effect-on-frame-stiffness/ and here https://www.baumcycles.com/about/

          • Still running the LeMans 3.5, though not very often any more. My arse really can’t cope with more than a few hours in that saddle any more. Historic rego helps – 60 bucks pa instead of 600 makes it easy to keep on the road.

      • Good work on the CX/Gravel. Makes me wish I was over there for the TDU/not TDU. Maybe next year prop up at Willunga for bikes beach and wine!

        I have new bike day on Sunday. 2nd hand SL4 SWorks Roubaix (coz I still insist on mechanical rim brakes!) which suits the roads in the Northern Rivers (which look like the Luftwaffe have just conducted a carpet bombing of, at least compared to the country roads in Vic).

        • desmodromicMEMBER

          Lots of good riding options over here Swampy. I’ve not engaged with the Corona restricted substitute TDU but am hoping for a return to normal next year.

  3. call me ArtieMEMBER

    Thanks LeMon and Mr Beach. Details:
    Yes, electrostatic speakers (with servo subs). Built by myself from panels supplied by E.R, Audio in WA (great guy there, Rob). The wings are actually to extend low-frequency response. Electrostats are dipole radiators, hence you start to get cancellation from front and rear outputs combining as frequencies go lower. The wings make the cancellation path longer, hence lowering the effective response.
    The amps produce a fair bit of heat. They aren’t so good on very hot summer days but are great in cold weather! They were built by me from a kit supplied by Transcendent Sound in the USA. However, I have modified them a bit. The system uses an active crossover and three sets of monobloc power amps. The OTL tube amps pictured run the upper frequencies in the electrostatics. There are solid state amps running the electrostatic bass panels and of course the servo sub-woofers have their own dedicated power amps (800 W/Ch).
    The turntable was designed by myself using some commercially available parts and a lot of my own parts. I had the components made by various machine shops and instrument-makers around Melbourne and assembled it myself. The drive is by Teres Audio in the USA. The tone-arm is an air-bearing linear tracking unit from Great Britian, however the guy who built it has retired now. The turntable uses magnetic-repulsion in the main bearing to float the heavy platter just lightly in contact with the inverted point-contact tungsten bearing

    • MerkwürdigliebeMEMBER

      Artie, I read through a spiel like that and the only thing that occurs in my mind is

      ‘This guy is a speakers/sound nut’

      I am hoping the Neil Diamond or the Toccata and Fugue in D Minor comes through on that superbly!

      • Absolute BeachMEMBER

        After repeated listening to Crunchy Granola Suite (Live at the Greek from Hot August Night), I have formed the opinion that it is not about muesli.

        • MerkwürdigliebeMEMBER

          I reckon I listened to that Album (Hot August Night) virtually every weekend of my childhood. I havent listened for a few years but just the mention of Crunchy Granola Suite and instantly I know every riff and bar and it is running away through my mind.

          • Absolute BeachMEMBER

            I listened to IT this arvo whilst punching the bag. Great to get motivated. But I have been puzzled about the words. It seems unusual to have a homage to muesli. Not that muesli isn’t an ok food. It just seems strange. If it was a homage to Mango Weis Bars, now that is worth a song. So a while back I looked up the ”meaning of Crunchy Granola Suite” and Mr. Google said it was indeed about muesli. Now, I think Mr. Google is smarter than me, but I actually think Mr. Diamond is singing an ode to something else. What could it possibly be? I throw that to the wise audience…..have a listen.

    • Absolute BeachMEMBER

      Well Mr. Artie, that is beyond the horizon of audiophile. Full analog alone is pretty cool but you give it all possible thought. From the cross section, if that platter is solid metal, it alone would weigh more than my stereo. I guess it would minimise wow and flutter when it creates it’s own gravity!
      So I’m intrigued about electrostatics. My brother has a pair of cream B & W dm70’s that he reckons sound good, but I think they sound pox (could be poorly driven). But I did hear some amazing massive electrostatics at a show in Melbourne back in the 1980’s- maybe Sting or something. They seem so sensible (to make) compared to frail cones. Do they cost more or are they hard to drive?

  4. Arti, I’m guessing you live alone, there’s no way that my wife would accept me decorating the living room with speakers and audio gear.
    Just out of interest have you ever measured the wow/flutter for the turntable?
    Many years ago I had a friend with a similar setup and he was all smiles until we actually measured the turntable speed using an optical sensor system, that’s when we discovered that what he loved about the sound of the Turntable was actually an artifact of motor speed control hunting. There was a huge change in the sound when we stabilized the motor driver system. The new system measured great but sounded terrible, a real quandary for anyone in the tech industry.
    Audio Signal thickening due to Intermodulation distortion from the motor speed hunting turns out to be a pleasant artifact …who would have thought it.

    • call me ArtieMEMBER

      Hi dodgy.
      Yep. It measures well. However, I don’t have a copy of the results. I should have saved the file but it was an audio-buddy who came around with his gear and did the measurements and I was just pleased that he approved. Should have asked for a copy. D’oh!
      EDIT: The Teres Audio rim drive system I used actually allows for adjustment of how tightly the feedback system controls the platter speed. It’s down to the owner what degree of stiffness sounds best in the control circuit. I ended up biased a little towards tighter control, but not all the way

      • Interestingly Electrostatic speakers themselves have a distinctive sound that results from the 2nd order non-linearity caused by the effective plate-to-plate distance changing with driver displacement. this also results in voice signal broadening (intermodulation with other low frequency (woofer) signals), it’s a characteristic which many people seem to value and when you try to correct for this “distortion” they complain that you’ve ruined the speaker “ambience”.
        Ah memories from a past life

        • call me ArtieMEMBER

          Ye…es. But honestly, electrostatic speakers all sound different from each other. I believe thee are more significant sound factors in play than this one. Frequency response anomalies are by far more significant in determining a speaker’s subjectve sound quality than anything else. At least, for me.

      • Re turntable: I wouldn’t have thought it possible to do a Rim drive for a magnetic/needle main bearing, does it have an idler somewhere to balance the force? or how does it get around the problem of the rim drive adding a lateral force vector to the needle bearing? just curious..

        • call me ArtieMEMBER

          Well, it’s no worse and probably better than a belt-drive in that respect. It’s just a matter of design. The inverted point bearing rides fairly lightly in a small locating conical depression (which contains lubricant). There is enough vertical force on the point to easily maintain centricity of the dynamic system

          • I wasn’t having a shot at the design just curious
            At one time long ago I designed a speed control system for a gas Centrifuge which also used magnetic levitation bearings. The electric motor stator was effectively integrated into the base platter of course it had to spin just a little faster than 33rpm.
            Fun project especially designing the control to get it quickly through resonances where it would otherwise tear itself apart in just a few seconds.

        • call me ArtieMEMBER

          Should have added…
          The rim-drive contact is exactly aligned vertically with the point of contact of the vertical bearing. Hence there is no tilting moment

    • Absolute BeachMEMBER

      Wow Mr. Dodgy. I’m genuinely impressed. You have cut way deep into the factors that go towards what actually sounds good to the flawed human ear. Not what is technically optimal. I am contemplating doing a AV product for the mainstream market. What is your area of expertise?

      • Lets just say I’m very experienced in Audio component design and leave it at that.
        That said, what interests me these days is more the Psychoacoustics than just the Acoustics or electronic / physical driver distortion minimization, I got over being technically right. a long long time ago.
        The sole purpose of a good Audio setuo is enjoyment …sometimes it’s actually the music that Audiophiles enjoy.

    • NoodlesRomanovMEMBER

      I’ll help bring the level down to softer core. I’m just back from a 4hr ride with the wife and kids. Fitbit says the only time I was in a fat burn zone was when I was pushing 2 bikes at a time up a particularly steep hill. About to crack a tinny and have a swim and try and ignore the pool deck frame that needs a final coat of paint.

        • NoodlesRomanovMEMBER

          Bah! It was an attempt at humorous comparison. That is my interests and experiences this weekend are banal and pedestrian in comparison to cycling the backroads of SA or a room dedicated to my home brewed op amp.

  5. All the Audio gear reminds me of the 32 speakers in my 67 Kombi, 6 piezo tweeters in the roof liner lol.

      • Mid 80s TTP while I was working at Clarion, custom install guy for the CES show offerings was a mate named Frenchy and we sorted it at his place. Not a thumper but clean sound front to back, 4x4s under the dash, two way 6″ in doors, honeycomb mid woofers on back of front seats, big 4x4s on pedestals on engine cover, 12″ sub under back seat with 3 amps, additional HD battery with upgraded alternator, etc. Great for going down to Baja Calif on Surfaris and open it up to crank the tunes while surfing and at night around the campfire.

  6. The Travelling PhantomMEMBER

    Great work Ermo, are you now the government house official plumber? Lots of properties to look after!
    Premier Plumber, it has a ring to it! PP!

      • The Travelling PhantomMEMBER

        Same here ! i always wonder why i get the far away jobs! I bet the technicians who live far away service my shire and adjoining ones and I go to their suburbs ! just if we can streamline all these jobs to localise the effort.
        I bet harry can do an app like ubereats

  7. boomengineeringMEMBER

    BTW Story too long to tell, but broke my arm in the terrible hang glider upside down crash..

      • boomengineeringMEMBER

        Other one. About forty years ago The 2nd hospital didn’t believe it was broken as no pain until they saw the 1st hospitals x rays. Then they tried to push pain drugs onto me.If it ain’t hurting don’t push them.

  8. Hats off all round – some stunning photos and very interesting past times. Thanks for sharing.
    If the world goes to custard the MB bunker would thrive for generations.

        • The Traveling Wilbur 🙉🙈🙊

          Pardon? (heh)

          As a result of the collection of amps and speakers bunker denizens would haul in with them.

      • Waddaya talkin about? I’m already hearing impaired. And seeing impaired (never buy a cheap welding helmet). And typing impaired (never ride a mountain bike). And feeling impaired (you right mate? No, I’m married). I could go on…

  9. reusachtigeMEMBER

    Is it ok if I post photos of the relations parties but with black squares over the interesecting bits, or maybe Japanese p0rn style out of focus on those good bits?? And does poop need to be blurred?