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Discussion Starter #241
Well wired the transformer wrong on the first side of the board and let the magic smoke out. Lol

Got it right on the other side though.

Tested with 2 12 volt headlights in series for a 3.4 amp draw. After 1 hour of on time..... The magic number is 4 deg Celsius temp rise on the mosfets and that's with them standing!
 

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Pretty good!

4 degrees in an open environment.

So in an enclosure you will roughly be double, unless it is a large enclosure.

But a really nice safety margin.

Do you have a multimeter that can measure Ac and DC simultaneously, or just measure the Ac on the rectified output?

A scope is good to but not really necessary.

I'm interested in the switching noise off of the mosfets. You effectively have a switching power supply working as an active synchronous rectifier.

I have read the application note on it, and am now interested in how it really behaves!


P.S.

All electronics run on smoke.

When you let the smoke out they stop running!
 

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Faster faster you slave you slave.

Quoting the great Ben Stein on Saturday night live
 

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Discussion Starter #245
Sorry for the lack of updates, been busy building.... Spent 2 days machining and milling the heatsinks to match my design, just about done and got 1 assembled.

Also got most of the power supply boards soldered, as well as the NX-amplifier. I am waiting on my transistors for the pass amps, hopefully will arrive this week.

Also got some new/old measurement equipment. :T

I also finalized the design of the DSP and Transformer Enclosure.
 

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Nice toys in the last pic.

I have a similar scope ( Tektroniks ) And the same family of Volt meter.

Good stuff.

I learned how to do speaker testing with a resister, function generator and a scope. If you wanted a frequency response you need a pen plotter, which I borrowed.

Now I can do it all with a little box and a laptop.

My distortion analyser is also same said little box.

Like what you are doing.

Here's a teaser:
20140422_160540 (Custom).jpg

20140422_172846 (Custom).jpg
 

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I have to say this thread has been one amazing read! I find this thread from my thread on AVS asking for advice on a no holds barred horn subwoofer system (because everyone is willing to fold up 8 monster sized horns right ?) and this thread has been awesome to read!

I just wanted to say thanks to everyone who have contributed to make it so great ! Well done!
 

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I have to say this thread has been one amazing read! I find this thread from my thread on AVS asking for advice on a no holds barred horn subwoofer system (because everyone is willing to fold up 8 monster sized horns right ?) and this thread has been awesome to read!

I just wanted to say thanks to everyone who have contributed to make it so great ! Well done!
My thoughts exactly. A real treat. Thanks. :T
 

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Discussion Starter #249
Well it seems that it has been far too long since I've update you all on what's happening. Don't worry still making progress towards completion at some point this year.

I have reworked the electronics and DSP's. You can see by the attached block diagram of the signal flow, but what I have changed is;

Added more miniSharcs to allow me more processing power and FIR taps per driver, the input now goes into a nanoDigi which allows me to split the SPDIF signals to the multiple miniSharcs.

With the miniSharcs I am able to invert the signal 180 degrees, so each driver will be fed from two DAC channels in a balanced configuration, which also when I tested lowered the THD+N and noise floor by at least 3db over going single ended.

It will then be fed into a custom Balanced to single ended converter I designed, before being fed to the amplifiers, which also has adjustable gain to allow me to match and balance the systems, so I don't have to do it digitally and throw away bits. It uses two opamps, an AD8597 and a LT1028.

At this point the DAC measures around .002% THD+N and the converter measures and the lowest level of my test equipment so <.001%. The noise floor of the DAC is around -106 db and the converter is also at the level of my test equipment so <-108 db.


Also you can see the attached picture of my final rectifier bridge with RC snubbers, that will be used for all the power supplies.

I have completed and biased 1 amp and power supply so far, no smoke and biased perfect with around +-.1mv DC offset after warmed up. I biased a little hotter then designed, 1.5 amps instead of 1.3 amps, and with the active cooling works well.

I also changed the power supply and added another 3mh inductor, so now its a CLCLCLC supply, and under load I measured 0.15 mV RMS ripple

And finally my new to me, and amazing scope HP 54542C, lot better then my old 2 channel 60 mhz.....And best part it has a color screen!
 

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Discussion Starter #250
So 1 speaker channel complete, biased very nice and with the active heatsink stays very cool and stable. I also completed 6 balanced input boards, for the left and right channel amps. The amps also measure very well, with a little tweaking of the P3 pot, I was able to get .002% into 1 watt @ 8 ohms, and noise floor less than -105 db, this was all outside of the case, so should do better once isolated for stray EMI.

Since I am installing all transformers into 1 enclosure separate from all my amps, I needed a soft start solution to fire up all the transformers, and amps. So I designed and built a delayed soft start board using 555 timers, with a 1 sec delay for each one, allowing me to fire up everything and not melt the house wiring...LOL. Only problem was I read the datasheet for the relays wrong and had to install them on the bottom of the PCB......and rework a couple resistor values to due power dissipation issues with the original values. But works perfect now. Testing with my fused 3 amp variac at full power, I was able to fire up 3 amps, 150,000uf of capacitors, transformer and all, and never blew the fuse.

So still making progress, all primary testing is complete so now its on to final assembly of the rest of the amps, and stuffing it all in some cases.

Also changed my mind on the Ovation NX amp for the subs, going to use that for the surround speakers instead, and building a F5 Super Turbo Amp for the Subs, looking at 425 watts class A into 8 ohms, and a hell of a lot of heat dissipation! It will use parallel input Jfets x4 and x8 Mosfets per Side biased at .65 amps each. Big Fan and Big Heatsink for that!
 

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So the 555 is used as a timer, I see the resister capacitor sections to set the time delay.

The resisters are the delay part. Are the caps and diodes and a snubber?

So your souped up F5 is 450w/channel? Nice. A link to that would be appreciated.

I'm sitting on a boat load of heatsinks.
 

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Funny I was looking at that F5T also and figured I would just have to wait for now. I didnt have the room for a pair of 6RU enclosures. Any idea what look you will be going for when you build yours yet?
 

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Discussion Starter #253
So the 555 is used as a timer, I see the resister capacitor sections to set the time delay.

The resisters are the delay part. Are the caps and diodes and a snubber?

So your souped up F5 is 450w/channel? Nice. A link to that would be appreciated.

I'm sitting on a boat load of heatsinks.
Yes there are 4 555 timers, each one controls its own softstart circuit for each transformer, so as power is applied, the first 555 closes the relay engaging the softstart, which bleeds some power for about .5 secs then that relay will close bypassing the power resistors. About a sec after that the next 555 starts it's cycle, etc. So it takes around 5-6 secs to gradually engage each one, saves a brown out lol.

Most of the capacitors and diodes are the power supply's for each circuit, as it is transformer less, the reactance of each capacitor sets the current for each. There is also a Neutral protection circuit in the top left corner, that will shut down the whole board if the hot and neutral wires have been crossed at some point.

Funny I was looking at that F5T also and figured I would just have to wait for now. I didnt have the room for a pair of 6RU enclosures. Any idea what look you will be going for when you build yours yet?
At this point it is still in the design phase, just finished up the schematics, and component values, I haven't even laid out the PCB yet. The final design/enclosure will be the same as my other F5's with different heatsinks, as all of my equipment is in another room, I can get away with active cooling to keep it under control. If you are running efficient speakers, you should really try the regular F5 to start, you would be impressed at the dynamics and sound of that little amp, it is really impressive for 25 watts.

This will be a scaled up version of the F5 Turbo, using 8 output devices instead of 4 per side, as well as parallel input Jfets, and 90 volt rails. This will power my 6 ULF horn subs that are built into the front stage and rear seating risers, which will give around 120 db output at 18hz at my seat :whistling:
 

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I was wondering where the relays were?

Thought you might be a right sneeky guy and be using mosfets as solidstate relays.

And nice touch protecting the neutral. Although on a dead short I'm pretty sure those diodes will let the smoke out. Come to think about it that is what they are supposed to do!
 

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Discussion Starter #255
I was wondering where the relays were?

Thought you might be a right sneeky guy and be using mosfets as solidstate relays.

And nice touch protecting the neutral. Although on a dead short I'm pretty sure those diodes will let the smoke out. Come to think about it that is what they are supposed to do!
Could of, Should Of, Would Of......But I wanted to here the clicking :D
 

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Reminds me of one of my favorite Widor symphony number 5 recordings. I think many people have heard it at weddings and such. The finale has a crashing chord at the end, full bore all the stops pulled out. But first there is a little silence, a click and Kaboom! TUned jack hammers.
 

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So a little bit of progress on the animals front channels. I keep chanting animal, animal haaahhhggghhg.


If only I could work that fast in real life!

Here is the basic idea:

LeCleach Midbass Horn.png

Here are the parts:

Horn profiles laminated smaller.jpg

I'll keep you guys posted. These are going to be just a bit of fun to listen to.
 

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Any updates fellas?
 

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Unfortunately I am holding up the progress on my end.

Catching up on a surprise wedding and the associated work around on my end.

I also have a tweeter groupbuy that is getting attended to. To many irons in the fire to begin with!

Little brother decided to get married a little faster than we knew! (Not a shotgun wedding!) Just the timing and availability windows worked out a little faster than we expected.

But in the next few weeks there shall be some progress made towards getting these parts turned into functioning horns.

Andy will get the info and up to him to post.
 

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Cool!
 
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