Why Not Part Deux

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I'm sur y'all remember when I got edumacated thar my invention had been inventd before and is known as a Dickson pump charge. Thos who were in that will remember it is a single ended voltage doubler which can be stacked on top of its input to make a voltage tripler.

People admonished me that capacitively coupled voltage multipliers are not very good with current, but I beg to differ. And to also should get an ideawhat kind of capacitors I am talking here. In its current build it has on the top 8,200 uF, the bottoms are 10,000 I think. I decided to have the topones be lower just for those awkwark power up moments. Justin Case, y'know? Doesn't matter, at 6 Khz they could be 470s if they could handle the current. The Xc means noting here.

those huge capacitors are put into power supplies that use oscillarors or just raw transformers off the wall. In either case, every ampere that goes through the circuit is stored and discharged by the capacitors. The olnly diffeence here is that the capacitor is floating. Itis a similar concept to acoupling capacitor. It can do it. I don't kno23 if I'll get the current out of it I want in its preent build, but the most that cna happen is the smoke comes out. I'll do it outside.

So much for that. Let's jusr assume I have the capacity to get triple voltage. That is 36 volts.

The original amps that ran off of 12 volts were patterned off of the old Mindblowerr car speakers. I'll not go into all the details of those at the moments but here is the basic circuit :

https://dl.dropboxusercontent.com/u/29948706/mb01.jpg

In a way it's like a tube amp, but you're driving the secondary directly. you can actually call the output stage DC coupled. That DC coupling is not all it's cracked up to be. Yes there is no better way to get good bass and maintain the dampering factor, but some people think DC coupling means all the way from the source. Never did.

Anyway, since I feel not like building a suitable car amp to feed the few (two actually) input transformers I have, I am going to have to do some designing. Not much, but no more transformers. If I can't do this, well, **** me.

So I come up with this :

https://dl.dropboxusercontent.com/u/29948706/mb02.jpg

Understand something here, because the drive has to go negative without a negative source, what do you do ? In the first one the transformer resolves all those issues, but we do not want the transformer.

To DC couple it would require a negativ source, and before you go into thatonchip magic using only a 0.1 uF on the outside, remember this is audio, hopefully esoteric, high end audio.

The MOSFETs shown, well you know how they go, the sources go to the junctions of R10, 11 and 13, 12. Those give it voltage gain. The depletion moe FETat the input there splits the phase for it, and after the capacitive coupling, bias is dealt with without interference from the DC components produced by non-linearities in the output devices/drivers.

In such a circuit, there is no room for an enitter resistor. the voltage drop is quadruple3d so it is extremely inefficient for the design's intent, so there are none. The only good thing here is that for common mode DC, the choke's windings themselves will provide some degenration of the DC withoutgreatly affecting the signal.

That FET at the beginning of it, it doesn't have to come so fast. Once the phase splitter is there, I will have to combine any feedback. It might be easier as well as better to keep the two feedback paths separate farther back in the chain. I don't like dealing with the thermal stability of something DC cpoupled that far back, but you know, if it gets the audiohead goldenears award I get to sell them for a shitload of money.

Think of these audiophiles out there who buy my amps. Dem niggas pulls up with "BOOM mufufa BOOM mufaka BOOM mufoika" and Whitey is up there smailing,right biotch ! = fucking Beetoven ten times louder. All the kids in the neighborhood gain ½ an IQ point and everybody happy.

Sometbing like that.

Thank you for your time, we have downloiaded all your bank money.

Also, if anyone has any more sonically pure ideas on how to drive this output choke type circuit, please do.

 

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A bit of refinement is upon us. One of the major problems with this is driving it without the transformer. I have solved that in an audioally (SP) acceptable way as per :

https://dl.dropboxusercontent.com/u/29948706/scem10.jpg


you know it is a bitch to try to make this thing all dC coupled, and DC coupled amps do not mean that anyway. It only means the ack of an output capacitor. Is the choke shunting it considered something that disqualifies it from being caled DC coupled ? Maybe not. Perhaps it cannot be called "DC transparent", but it cerainly is DC coupled as evidenced by the lack of output caps.

The image there is a good configuration, though it does not deal with bias.The quasidarlington congiguration means full stauration, to the point where the current must be limited for the sake of audiophilia. Can't throw too many carriers in there because it take slonger to recover. Recovery is the reason this thing is not alot simpler actually. If not for the rectification effect of driving bip[olars through caps in this fashion in an AB amp, wewouldn't have all these problems.

The action of Q6 and 7, with their collectorss tied directly to ground willassure full conduction inn the outputs. At the same time, having a relatively stable bias point will assure they will not be fighting the output nor developing negtive bias like the grid of a tube. Know what I mean ? I am not getting into content based bias regulation. Shoot me if I show any signs of doing so.

You see the circuit, it is good and it will work with almost any resistor values. Obviously R18 has to feed Q8 enough, and R6 has to feed Q6 enough through Q3. Not that complicated really.

Then we get to Q1. I suppose I could somehow bridge the thing and make tha phase splitter unnecessary but I think the phase splitter is a good thing. You almost can't get distortion out of them if you try, and they are as stable as the......ummm, let me think abou that.

The only real problem comes at power up. Q1 could have been fed by the mainVcc coming in, but any positive excursions would result in transient current spikes in both outputs of the channel, and in common mode they would be prett much transparent to the listener. It would just be a source of inefficiency and though it would not saturate the choke core, it would certainly heat it and we do not want that.

W ealso do not want our audio outputs acting as shunt regulators, that would be worse than stupid, though I think I saw some designs that.......

Needless to say, I am not going to design something like that..

Now the transistor, cap, diodes etc. whatever marked with the X are common mode current suppressor(s). you see when the power is applied the action ofthe bias to R2 will cause unnecessary vonduction in both outputs.

If you look where the base is capacitively tied to the Vcc, you see that itmutes all drive whenever the Vcc is going positive. I erred I believe in that this cap should be tied to the source created by the zener diod off of R1, feeding R2 and thus Q1. There should still be some holdon (rather than holdoff on a scope, this is the opposite), keep it going for a few more milliseconds.

the resat of this is a piece of cake, I can pick resistor values out of my head for this almost. Really. All we need now is a bias source. Simple two resistors to the gates of Q2 and 4. Determine tht voltage and that is that,have it drop with heat from the heatsink. It doesn't get much simpler thanthat really. Technically it might be a bit more critical because ideally you have no emitter resistors, but you do in the windings of the output choke. I'll have to break out the Fluke and see just what that resistance is.......

The real problem is there can be no current limiting. Well maybe but it would have to be calibrated for each unit's different output choke. I don't even know if I can get any mor eoutput chokes, especially bad to the bone enough to handle this.

Understand here, I might be getting these output transformers form 50 or 70watt amps and I am pushing them alot harder. I think the secondaries (which I use) can take it, but I don't know if the primaries can (which I do notuse). I am really thinking of taking them apart and trying to insulate thewires inside for the primary because I am going to probably induce a thousand volts or more into it.

Anyway, look it over. Tell me I am full of shit and it will never fucking work because that will impel me to build it. And tell me how I might do thisin Spice. I started to try, but I culd not find the center tapped coil needed for the output choke. It seems it is totally ignorant of their existence. I'm sure ther eis a way to put in a custom pmponent, but I just don't know how yet. I started to get drawing and it seemed the damn thing won't work.

Anyway, this is not the saviour of the worlkd or anything, ust throw me your isdeas when you run out of weed or get tired of internet porn or your olady or something. I got my DC convertor as shown in a previous thread. If this babyy chokes it then it does.

Just bear in mind that every capacitor used as a filter does exactly the same thing every day that I am asking mine to do. It's just that one side of mine is not grounded.

More later.