pyrohaz

Hi, thank you for the reply hero :) I am fine with a simple push pull amplifier, even to slightly more complex stages, e.g. replacing the resistors with current sources etc. I was merely practising the concept of a transformer coupled amplifier. I just wanted to know what flaws my circuit had! Thank you for the help anyway! :)

Also, what do think about the zeus amp then? http://www.susan-parker.co.uk/zeus.htm That is a transformer coupled mosfet amp with some quite impressive specification!

I wasnt born! (I'm 17 years old!) I was mainly going on concept for this design. Would NFB really add a significant change in sound quality? I'm using a transformer for the phase splitter now, if I drove that by a transistor, could I add NFB? Cheers :)

Hey guys, long time since i've last been here! I've recently designed myself a low wattage transformer coupled transistor amplifier out of parts i've got. I've built it on a breadboard using literally just parts that I could find and at low voltage levels, its quite pleasing to my ear! has a quite sweet sound. I'm using Acoustic Solution Instate 90 MK 2 speakers (Picked em up from a carboot sale,

Hey guys, Im currently researching into depletion mosfets I was wondering if anyone can tell me where I can get some high(er) power mosfets from, im currently using DN2540's I got off ebay. I have spice'd an amplifier (about 9w), it is only a simple one with no NFB and runs off 60v. I will include a screen shot of it. It only has about 360mA on each of the mosfets and a bias voltage of ~1.4v (Cathode voltage). For the phase splitter, I used a simple 2N7000 Cathodyne (Sourceodyne in this case? :P) Tips and help please :) cheers!

Thats good thinking, a chip amp could make this project much easier, lots of little cheapo unbranded guitar amps use chip amps, my marshall 30w bass combo has a TDA2030 chip amp. Audio, wouldn't it be easier for him to understand a simple opamp preamp? I mean a simple TL071 inverting amplifier isn't too hard to understand? The jfet amp is quite nice, jfet distortion does have quite a nice sound :) Obviously not if its pushed to power supply clipping.

The 74C14 is the same as the 40106 isn't it? I'm happy with the voltage it is at (the capacitors I have are only rated to 63v, hence why I only used the 4 stages). Would adding another stage not decrease the current I could supply? I was thinking of using one of these switched capacitor boosters in a guitar pedal. For a schottky diode, would the BAT46 be suitable? Afaik, they're rated up to 100v aren't they? Any other tips you can give me? Cheers

Hey guys, i've recently designed myself a simple switched capacitor voltage booster, just using the simple 4069 inverter chip. I was wondering though, can you give me any simple information on increasing the efficiency of my switched capacitor booster? I will include a schematic of what mine looks like :) The reason is, im only using a 4 stage booster (2 of the inverters for an oscillator, the rest for voltage boosting.) And im using it to drive my tube preamp :) After I tested it, I got an output of 58v (68k load) and a frequency of 42khz. Now obviously, the calculated voltage should be 60v but im sure the combined voltage drop of 4 diodes is about 2 v (0.6*4=2.4 so actually, a little less) Are there any tips you can give me to improve this circuit? After having a quick look with my multimeter, it said it was only consuming about 7.4mA which actually seems a tad low for a voltage booster IMO. I calculated the efficiency of the current circuit at a mere 55%! Im using 63v Axial 1uF capacitors, they have a blue plastic coating on the outside if that helps :) 1N4148 diodes and a PI filter on the output may be a bit of an overkill but its feeding the preamp audio stage so I want as little noise as possible.

I do know about the power output being about 10x less with the TA2024 than the TDA8920 lol otherwise, I think I would've made a pretty large mistake! I do know that Tripath went bankrupt but I really don

Just to answer incase anybody is looking for the future :) I used two 4.7uF 63v capacitors on each of the positive terminals of the power supply and connected them to the earth terminal on the power supply. The electric shocks have now gone and the noise has been reduced too! Thank you hero :)

Hi, i was so happy with my Class D amplifier (tda8920) that I thought I would try class D of another brand, so I went ahead and bought a TA2024, Only

Hey guys, I have recently realised... Since the power supply for my bass amplifier is essentially just a single 48v power supply, I seem to get electric shocks when I touch the rear of my amplifier! (The case is "grounded" and metal). So what I was wondering, can I connect the metal case to earth to stop the shocks? Because since I am using two switching power supplies in this fashion, my bass is at 24v potential to earth since it is also grounded which may cause a few problems! The power supplies are wired up in Series to create a 48v power supply. Essentially, its just - +- + 0 24 48 Can I earth the supply at the 24v point? Thanks, Haz

Hi, good luck with getting the transformer working, unfortunately if the outputs are sorted, it might be unfixable :/. If the transformer in itself is quite large, I can imagine the secondary coil is that large for the current capability of the transformer. Hopefully the 'Guy in the shop' will be able to give you a hand with your rectifier though it should just be a silicon rectifier with enough current capability :) here is an example of one: http://www.rapidonline.com/Electronic-Components/Discrete-Semiconductors/Bridge-Rectifier-Diodes/6A-Bridge-rectifiers/29672 The brand or anything shouldnt matter too much aslong as it rectifies. For your idea with the bulbs, running them on 12v AC would be fine but for the fans, yes you will need DC. If you don't run your bulbs off the same DC supply, your filter capacitors will not need to be as large. :) The 7812 will only be able to provice 1A current if heatsinked. If you require more, you might want to look towards a switching regulator to save efficiency and reduce heat :).

Have you tested resistance on the coils? Just to ensure that theyre not shorting or anything? If that all checks out, try replacing the rectifier unless the rectifier and transformer is as one package then that may be a small problem. With your other transformer, try reading each winding to get which one is the secondary and primary by using the resistance option. The primary coil with be the one with the most resistance. Bridge rectifiers really aren't majorly expensive and all you need is a correctly rated one (Peak of 12v = 12 x 1.414 = 16.9v but bridge rectifiers are normally quite high voltage components for voltage spikes etc. Aslong as the voltage is within the range, you would really just need to see if the current rating is suitable. a 6A 200v bridge rectifier off Rapid would cost: ~

I think the output voltage will be dependant on the load. I can imagine the 220k resistor is there for safety reasons. When the night light is unplugged, the resistor will ensure that the 560nF capacitor is safely discharged. I couldn't find anything from a quick search on google but I can imagine adding parts together that this would be called a Series Capacitor Regulator? I'm quite sure that this will drop the load through acting like an AC potential divider. It seems as if it would be equivelant to a High pass filter. Example: If the capacitor has a reactance of 5.6kOhm (at 50Hz), and its driving a 100R load, due to this being the same as a potential divider I suspect the voltage across the load would be 5.95v Peak. (Vin*R2)/(R1+R2) Since the capacitors reactance would be R1, that value would be 5.6k. R2 would be the load so in this example, that would be 100. The voltage in would be the peak voltage of 240v afaik, (240v*1.414 = 339.36v) As you can imagine, as the resistance of the load varies, the output voltage will also vary. I made a visual represenation of this circuit on the free applet: http://www.falstad.com/circuit/ Just click on File>Import Then copy in the code below and click import :) $ 1 5.0E-6 6.450009306485578 50 5.0 50 c 208 144 368 144 0 5.6E-7 -62.32904764451111 r 368 144 368 272 0 100.0 O 368 144 480 144 0 g 368 272 368 304 0 R 208 144 160 144 0 1 50.0 339.39 0.0 0.0 0.5 x 400 218 453 224 0 24 Load x 136 97 218 103 0 24 240vAC x 214 185 355 191 0 24 PP Capacitor o 2 16 0 34 9.353610478917778 9.765625E-55 0 -1 out h 3 1 0 As you can see in the waveform, the voltage across the load is 5.97v, close to what I had calculated! Also, in your schematic the 100R resistor will just be to limit the current probably as a safety feature to keep the capacitor safe. After having a quick search of your chip, it turns out the thing I thought was a photodiode, it actually is PIR sensor, usually used within a motion sensor. I found out that the chip operates at 5v meaning you would need to use a regulator for whatever voltage you are using for this project. In your pictures you have shown me, I can see two Zener diodes (Possibly) so it must be an regulated supply for the chip. I have attached a PDF file of your chip. Unfortunately its in chinese but I hope its helpful! hs0001.pdf