I thought your place looked familiar...
.Concrete Paving Slabs are a cheap high mass solution.
Two slabs separated by a layer of neoprene or the like would make it totally dead and get the mass up for tuning Fs.
Have fun with it !.
Dan.
Yes, this is what I used - heavy enough to do you major damage if you don't concentrate while moving the stuff,
...The baffle speakers are 80% wonderful and 20 % very awful. The weird bit is they now need a tweeter. The Dynaco A25's shows me that should be easy. I will not attempt to get a 99 dB /watt tweeter. 92 dB active should do it. The crossover a simple 2u2, or 4u7. It can be DC coupled except I doubt the resonace needs controling at 6 to 8 kHz.TDA2050 would be OK. The 20% awful is a typical sound that baffle owners seem not to notice. The Vitavox being worse to my ears. Fostex also. I hate it when critical judgement goes out the window and religion of hi fi takes over. The elcheapo 4700 uF seems OK. It might get a 100 uF and 2.2 uF high grade in paralell. Before anyone says it the loss above 10 kHz is not this. They are 4700uF 100 V 5 amp. The Quad clone PSU will get 8 of them. That's 37,600 uF or would be 75,200 uF if a +/- PSU. They were bought for a rediculous £2 a piece in a Rapid electronics flog off. Worth 5 times more. I have one in my Armstrong 625 PSU. It is a nice upgrade.
I will do something good. Theoretical speaker design says crossover > 7 kHz as ideal. The 12 Lta has beautiful self damping so needs no treble cut.
One thing that has come along is the plywood+ MDF is throwing energy back into the tweeter. I have 3 balls of toilet paper to damp the tweeter to main cone. This works very well. What it kills is the ability to rise above 10 kHz. The stiff roll suround causes this energy transfer. It also makes the almost impossible control of an undamped unit to work fine. No matter how loud it says no problem and no bottoming.
These OB show source differences although with no negative results. The LP12 is clearly what they need. FM also over DAB, that was a big shock. I am rather happy with my LP12 + Quad 33 upgrades now. I don't hold the LP12 in high regard. This is changing my mind a bit. The DL110 if using a correct gain pre amp is great, it sounds like it could cost £1000+. The Quad still almost hiss free at full volume. Not bad when 2 transistor is all it has and 99 dB/watt. The LP12 + Ekos+ DL110 sounds very neutral which is a bonus. The DL110 no doubt. There is a bit of the LP12 bloom. As the speakers have none that is welcolm. I am convinced most people have no idea how good DL110 is. Never in a high grade arm and never with the correct gain. I am buying a Jelco for my 401. I doubt it is good enough. I would be happy to be wrong. RB300 also. The Hadcock might be OK. It should beat the Ekos on micro detail. SME 5 is not my cup of tea. Idealy Origin Live conquerer which is too many pennies. I own a Naim Aro. It seems to perfer to live in Koln Germany these days. That also would be ideal.
Unlike any speaker I know of these improve with distance. That is in another room they sound more real. I think that simply is they drive the house better than the BC1's or Dynaco's. The wood has reduced micro detail. I am sad about that. It is what I hear with all conventional speakers also. I now know it is not just the drive unit. This tells me a box is good in one special way. The box allows a very floppy roll suround to be used. If so IB must be best and that Theile and Small stuff needs to be junked. The soft surround will stop reflected energy better. All you fools who could not equal AR you are now defrocked with you bogus ported speakers. The Dynaco is not if asking. It has Q adjustment. We tuned a pair recently where my friends brother knowing more than Mr Hafler took the resistance out. It has taken months to get it right. They now sing and some. You almost loose the box. This is in a glass conservatory. Absolutely no problem!!! Harbeth £1500 mini monitors didn't.
The OB's have one nice quality . They are super joyful. They distort at very high volume which is no bad thing. It is not awful and is then not hi fi. The SMGa do not distort and are mildly dangerous. SMGa are also joyful. BC1 less joyful , Dynaco more so but less hi fi. OB going so loud ( Montego Bay and T Rex ) when washing up the amp didn't get warm, the neighbours must have heard it. With SMGa it runs at about 50 C. The OB's are charming. In the loft I have a very high grade Sony tuner. It even has ultra high grade shortwave. Music on shortwave is not unusual. I think the people who broadcast want to educate the listener in the pre 1950's way. The Sony has often surpriseed me. Time to give it a try.
The shed must be warm now. Off to do some work now.
I will do something good. Theoretical speaker design says crossover > 7 kHz as ideal. The 12 Lta has beautiful self damping so needs no treble cut.
One thing that has come along is the plywood+ MDF is throwing energy back into the tweeter. I have 3 balls of toilet paper to damp the tweeter to main cone. This works very well. What it kills is the ability to rise above 10 kHz. The stiff roll suround causes this energy transfer. It also makes the almost impossible control of an undamped unit to work fine. No matter how loud it says no problem and no bottoming.
These OB show source differences although with no negative results. The LP12 is clearly what they need. FM also over DAB, that was a big shock. I am rather happy with my LP12 + Quad 33 upgrades now. I don't hold the LP12 in high regard. This is changing my mind a bit. The DL110 if using a correct gain pre amp is great, it sounds like it could cost £1000+. The Quad still almost hiss free at full volume. Not bad when 2 transistor is all it has and 99 dB/watt. The LP12 + Ekos+ DL110 sounds very neutral which is a bonus. The DL110 no doubt. There is a bit of the LP12 bloom. As the speakers have none that is welcolm. I am convinced most people have no idea how good DL110 is. Never in a high grade arm and never with the correct gain. I am buying a Jelco for my 401. I doubt it is good enough. I would be happy to be wrong. RB300 also. The Hadcock might be OK. It should beat the Ekos on micro detail. SME 5 is not my cup of tea. Idealy Origin Live conquerer which is too many pennies. I own a Naim Aro. It seems to perfer to live in Koln Germany these days. That also would be ideal.
Unlike any speaker I know of these improve with distance. That is in another room they sound more real. I think that simply is they drive the house better than the BC1's or Dynaco's. The wood has reduced micro detail. I am sad about that. It is what I hear with all conventional speakers also. I now know it is not just the drive unit. This tells me a box is good in one special way. The box allows a very floppy roll suround to be used. If so IB must be best and that Theile and Small stuff needs to be junked. The soft surround will stop reflected energy better. All you fools who could not equal AR you are now defrocked with you bogus ported speakers. The Dynaco is not if asking. It has Q adjustment. We tuned a pair recently where my friends brother knowing more than Mr Hafler took the resistance out. It has taken months to get it right. They now sing and some. You almost loose the box. This is in a glass conservatory. Absolutely no problem!!! Harbeth £1500 mini monitors didn't.
The OB's have one nice quality . They are super joyful. They distort at very high volume which is no bad thing. It is not awful and is then not hi fi. The SMGa do not distort and are mildly dangerous. SMGa are also joyful. BC1 less joyful , Dynaco more so but less hi fi. OB going so loud ( Montego Bay and T Rex ) when washing up the amp didn't get warm, the neighbours must have heard it. With SMGa it runs at about 50 C. The OB's are charming. In the loft I have a very high grade Sony tuner. It even has ultra high grade shortwave. Music on shortwave is not unusual. I think the people who broadcast want to educate the listener in the pre 1950's way. The Sony has often surpriseed me. Time to give it a try.
The shed must be warm now. Off to do some work now.
If you look at my circuits I gave they have a hint of that. Instead of just two pole compenstaion I also let whatever is nasty from the output re-enter there. I only have tried this very carefully and have to say it is marginal on most amps. Douglas Self shows this looks nasty on analysis. As long as it doesn't compromise stability it seems worth having. One amp I built seemed betterwith it. If it worked exactly as I hoped I can not be sure. It seems a mighty free lunch if it did. The idea is any low impedance point is Ok so why not have some local feedback/ As MOSFET's do produce high up nasties why not get rid of them? The two pole comp might have a nasty high Q blip. This seems not to be a problem.
For isolation from structure-born vibration, my brother had good results with his turntable placed on a simple platform hanging from the ceiling with long lengths of surgical rubber tubing at each corner.
There is an article in Silicon Chip magazine issue of July 2011 entitled "Getting to grips with Amplifier Stability and Compensation" it is to explain the method used in their "Ultra LD Mk3. Audio Power Amplifier which is available in kit form from Altronics in Australia. At the end of this the author Nicholas Vinen indicated that models of the circuit in SPICE were being made available at their website (SPICE_Amplifier_Stability.zip)
Q is a symbol that is used to designate transistors and resonances in other fields that I have not seen in reference to Bode plots. The penny dropped when I read Nigel's reply to your post and his mention of two pole compensation.
I have the series of Silicon Chip magazine issues for this project.
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17326. Just a doodle so will almost certainly have things upside down etc. The FET is the device this idea suits best. When I tried this it was single VAS. The VAS balancing is by test results and not the values stated. It should be somewhere near if two devices.
I was speculating MPSA 42 might exceed it's book Ft if driven common base as diagram. Don't look at the biasing . It is just to say something must be done. Douglas Self has it CCS driven to the MPSA42 bases. He doesn't seem to use the idea which surprises me as it looks the very best choice. Two ordinary devices out perform nearly anything. Here is a question. Hitachi and all like low Cob devices. These nearly always need swamping with the Cdom. I see the point that C internal is of a lower grade. What I don't see is how an amplifier is aided by this device being low Cob ? Even in my example > 22 pF is sensible. Looking at my favourite devices BD139 they are moderate Cob ( 6 pf if Philips ). MPSA 42 4 pF. The Hitachi prefered device 2SD756 1.6 pF.
BTW. Multiple MPSA 42 and 92 can be used. The VAS current mirror can help. You can used 1N4007 as the mirror diode. it is good enough for 2% overall balance ( LTP 1 & 2 ) For example the emitter resistor sets the current. No harm having many. The Cascode lower half will be happy to drive many devices as it will not see 6 V. If a BC547C will might have a current gain of > 500. The FET needs about 3 mA max even to drive an unrealistic 25 kHz full power. I am told the Cgs of the FET is bootstrapped the the speaker load. Thus the awful > 1000 pF of the two devices is not seen by the VAS. This has to be true as the Hitachi graphs for twin devices and 7 mA VAS go to 30 kHz full power and are not far down at 50 kHz. If anything Cgd is the problem as this is effectively to a ground impedance through the PSU. The British Bumble Bee can not fly also. It would have to be three times more efficient than is possible. Guess what.....
Do not beleive all that is said. I will quote Mr Self back at himself. If wrong it will show in measurements. Guess what, it measures rather well. The idea the twin VAS can not be accurately predicted is not helpful. I would say two legs always better than one. The HF balance will need adjusting ( 12K 6n8 typical when +/- 52V Hitachi on VAS leg 1 )
Mjona. I am building a Quad clone. 303, 0h I wish I hadn't started as it is not a simple amp. Doubtless I will get it to work. Problem is will I ever understand why and how? It is another Bumble Bee. So far I have run in the output cap. These are rather wonderful considering they nearly cost zero pounds. I thought they would be. Running from a real Quad 303. I have a tweeter feed at 33.5 V which is usually connected to 10 uF polyester or whatever the speaker needs. I simple put the 4700 uF there.
Do not beleive all that is said. I will quote Mr Self back at himself. If wrong it will show in measurements. Guess what, it measures rather well. The idea the twin VAS can not be accurately predicted is not helpful. I would say two legs always better than one. The HF balance will need adjusting ( 12K 6n8 typical when +/- 52V Hitachi on VAS leg 1 )
Mjona. I am building a Quad clone. 303, 0h I wish I hadn't started as it is not a simple amp. Doubtless I will get it to work. Problem is will I ever understand why and how? It is another Bumble Bee. So far I have run in the output cap. These are rather wonderful considering they nearly cost zero pounds. I thought they would be. Running from a real Quad 303. I have a tweeter feed at 33.5 V which is usually connected to 10 uF polyester or whatever the speaker needs. I simple put the 4700 uF there.
Like most OB speaker users I am now addicted. Kora music from Africa and Paris Texas were the telling things and Salsa via the same man, Chan Chan . The 20 % very awful might be the recordings? Caruso is not awful. I do not understand the dynamic range of those 1904 recordings. Bumble bees get everywhere. I had them living in the house and told everyone not to touch them as it was their house also ( 1600's construction ). No one was ever stung and the bees somehow knew it was OK. They came in the room and always left quickly ( my music choices ? ) . They are now endangered due to parasites etcetera. Spiders are protectd in my house, don't like them much. Only kill wasps if you want trouble. I do kill bacteria. Above that I think about it. This is nothing to do with liking them much or disliking them. More about live and let live. I draw the line at Cockroaches. Even so they perform a wonderful service in the jungle. Is it their fault they don't understand where the jungle ends? I suppose that is the telling remark. Not sure I do either?
https://www.youtube.com/watch?v=oToZfPGMMBY
https://www.youtube.com/watch?v=LVUlzNXxljg
https://www.youtube.com/watch?v=oToZfPGMMBY
https://www.youtube.com/watch?v=LVUlzNXxljg
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Sounds vaguely familiar, Nige. My next door neighbor who moved in some years ago turned out to be a girl colleague from student days way back in the early 70ies. Soon she acquired a little dog called Milo. He and I struck it off as son as we saw each other (happens to me a lot). So these days he strolls into my apartment all perky and important as if he liberated Belgrade from the nazis single handed, behaving as if he owns my apartment with wife and me thrown in. Until I accidentally stepped on his paw, he may as well have been mute, never barks yet always captures the full attention of everyone present. He has a special routine with me, sits next to me, turns on his back, paws in the air and that means "Gon on, tickle my tummy".
Love that dog, just like you and your bumble bees. Once one understands that animals are not toys, but actual peronalities, all is well in the world, you will get along together just fine with a little give and take. Not too different from people, with one exception in the animals' favor - they do not lie.
Love that dog, just like you and your bumble bees. Once one understands that animals are not toys, but actual peronalities, all is well in the world, you will get along together just fine with a little give and take. Not too different from people, with one exception in the animals' favor - they do not lie.
Actually, with some VAS topologies using two rather than one transistor will do wonders for your open loop bandwidth and will significantly reduce distortion.
In the early 90ies, Nelson Pass used doubled cascode stages, with twin pass and twin cascode transistors.
Marantz used a twin parallel transistor VAS in several of their upper market models with some success.
At present I am indisposed in that regard. I will follow this up when I return from a short holiday.
I took the same stance with wasps.I forced everyone to leave them alone. And guess what. Never had a problem with them. We have wasp nests or three in the loft and they buzz arounds me when up there. The builders lost their cool when doing work when the wasps turned up. They insisted I got a professional in to clear the wasps out. Relunctantly I showed them how to do it. I just took small parts of the nest away and placed it on the ground for them to relocate. It was like I was superman. Wasp came before bees in evolution and seem related to ants. Flowers were late on the planet. If you kill a wasp by crushing it they can smell it. You will be in great trouble and not just for that day. See two wasps carry the dead friend away. That proves how much they care. When they eat fruit they get drunk. Then all bets are off. The next part is true. When I sit in the garden they come to rest on me. I can stroke them and weird bit is they seem not to care. They do not fly away nor give any indictation it happened except to lower their wings and abdomen. Perhaps they think it is rain ? I am very gentle when I do it as mostly it is a dare and I know one false move and we both get hurt. If you think about it the sting is in the wrong direction to get hurt. It is just very weird they do nothing. My Grandfather had birds settle on him. Maybe wild life knows we will not harm them? I took my friends dog to get to know the cows. Collleen had a fit. I would not walk with the cows with Colleen as she gives out fear. The dog and the cows are fine. Not when Colleen walks the dog. Then I fear for us all.
Whilst this is not hi fi I feel being in tune is a hi fi quality. My son had never seen a snake in his life aged 4 nor had we talked about them. He nearly jumped out of his skin when he saw one. I thought to myself it is inbuilt to react this way. I must say they are not my cup ot tea.
Whilst this is not hi fi I feel being in tune is a hi fi quality. My son had never seen a snake in his life aged 4 nor had we talked about them. He nearly jumped out of his skin when he saw one. I thought to myself it is inbuilt to react this way. I must say they are not my cup ot tea.
Not entirely true - Deception_in_animals
Never-trust-monkey-Researchers-reveal-lying-evolved-animals.html
Dan.
When I lived in an apartment there was a large Huntsman spider that lived outside on the verandah.
At night this spider would come inside and explore the lounge room, climbing the walls and walking upside down across the ceiling.
Whilst I was sitting watching tv this fellow would sometimes walk across my feet....startling the first time but thereafter I had no problem with this occurring.
It seemed that the spider somehow knew that I was not out to harm him and had free reign.
Once in the downstairs garage I moved a box revealing a huntsman with a large cockroach in it's pincers.
I vowed to never harm them after that.
Dan.
There are limits ... they decide that crevices in car doors are a good place to hang out, and go for an explore, unbeknowst to you, when you climb in. So, when your wife's driving, and they decide to wander across the windscreen, on the inside, or they drop off from the visor into the driver's lap - this may not have the best outcome ...
Nige, wildlife usually has a fraction of s second to decide whether you are a threat or not. They are allowed only one istake if wrong. Nobody really knows how they do it, but they do do it. How does a dog I have never seen and which has never seen me KNOW 6 feet away, before it can smell me over, that I am a friend and easily sort of glide over, tail working hard?
But they definitely feel it, somehow, and they are NEVER wrong, never saw a dog make a mistake. Even cats do that, although I am not particlilarly fond of cats, even if my wife and son had one at our home for 17 years. My wife says he had a glassy junkie look when I cuddled him, he really let himself go 100%.
I have never tried making friend with a dolphin, while believing I could. That's a sort of a life wish. Too bad I don't live in Oz, there's a place by the sea where dolphns come once a year and swim right up to the shore and sociaize with the locals and many visitors. Saw that on Animal Planet channel. Incredible! One year, a badly hurt dolphin was in the group, a shark bit off a good part of its back, so the local transported him on a stretcher to the nearest animal hospital and they did what they could. The dolphin lived. He was fed and nurtured and nursed by almost the entire town for a year, until the nex coming of the dolphins, when he was reinserted into the group, which fortunately accepted him as one of their own. Kudos to those people, my hat off to them in deep respect.
Do you know that dolphis use twice their brain capacity we humens do? And that little hump obn their forehead is ther sonar, which is still better than anything man has ever built? WE use around 10% of our brain capacity, they use around 20%.
My "theory" is that anything that moves of its own accord just wants to be loved. Respect the animal, give it your love, and you'll have friend. Rest assured Nige, your wasps have identified you and think of you as a friend, hence their free behavior with you. How, nobogy knows, and ultimately, who cares? But they do differentiate you from everybody else.
Animals are just as much of a miracle man is. Life is eternal.
But they definitely feel it, somehow, and they are NEVER wrong, never saw a dog make a mistake. Even cats do that, although I am not particlilarly fond of cats, even if my wife and son had one at our home for 17 years. My wife says he had a glassy junkie look when I cuddled him, he really let himself go 100%.
I have never tried making friend with a dolphin, while believing I could. That's a sort of a life wish. Too bad I don't live in Oz, there's a place by the sea where dolphns come once a year and swim right up to the shore and sociaize with the locals and many visitors. Saw that on Animal Planet channel. Incredible! One year, a badly hurt dolphin was in the group, a shark bit off a good part of its back, so the local transported him on a stretcher to the nearest animal hospital and they did what they could. The dolphin lived. He was fed and nurtured and nursed by almost the entire town for a year, until the nex coming of the dolphins, when he was reinserted into the group, which fortunately accepted him as one of their own. Kudos to those people, my hat off to them in deep respect.
Do you know that dolphis use twice their brain capacity we humens do? And that little hump obn their forehead is ther sonar, which is still better than anything man has ever built? WE use around 10% of our brain capacity, they use around 20%.
My "theory" is that anything that moves of its own accord just wants to be loved. Respect the animal, give it your love, and you'll have friend. Rest assured Nige, your wasps have identified you and think of you as a friend, hence their free behavior with you. How, nobogy knows, and ultimately, who cares? But they do differentiate you from everybody else.
Animals are just as much of a miracle man is. Life is eternal.
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On another topic, I would like to reccomend to you gentlemen to see the movie "Lucy". It's the Graet Frenchman Luc Besson's latest work, with Scarlet Johansen and Morgan Freeman. In my view, the man is a genius, and he always bases his movies on strong storylines, so the excellent effects are not the point, but serve to underline the point. Exceptionally well spent 2 hours. Broadly, it would I suppose be classified as science fiction, minus the monsters jumping out of your stomach etc., but with lots of brainwork in it. Do yourself a favor.
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