Seems to me one might want to measure the BW of a three term voltage regulator. Most gear uses them for regulation.
The Xfmr, rect and filter cap used in a PA also. The Z of the filter cap isnt low for ever. Large Ls inside. Hmmmm could a 0.1mfd bypass help reduce HF/RFI let-thru??
I wonder what you will find
THx-RNMarsh
The Xfmr, rect and filter cap used in a PA also. The Z of the filter cap isnt low for ever. Large Ls inside. Hmmmm could a 0.1mfd bypass help reduce HF/RFI let-thru??
I wonder what you will find
THx-RNMarsh
JN,
I have done magnetics. The key word on generator design was the word practical. The design goal is typically .5% distortion and make winding easy. (High school summer job.)
Waly,
Great! Now try a differential probe between the amplifier and a music source. Disconnect the interconnects and just measure between RCA outer shell contacts.
BTY better if you can post images.
As to the other suggestion, just use a pile of bank notes much more fun.
I have done magnetics. The key word on generator design was the word practical. The design goal is typically .5% distortion and make winding easy. (High school summer job.)
Waly,
Great! Now try a differential probe between the amplifier and a music source. Disconnect the interconnects and just measure between RCA outer shell contacts.
BTY better if you can post images.
As to the other suggestion, just use a pile of bank notes much more fun.
The low EMI location should be easy to find in my sleepy village. (It was sleepier 100 years ago Our Village by Mary Russell Mitford - Free Ebook but still quite sleepy).
My worries were about 100kHz-10MHz as this is out of the realm of the average hobbyist unless I have missed something wonderful that has come out leveraging some of the superfast ADCs out there. But if we ignore then and stick to the bottom 80kHz of mains grot then we can probably work something out.
Now are we supposed to be looking at Voltage waveforms, current waveforms, both, or doesn't matter? Reason I ask is that inductive clamps are a pain, so a sense resistor setup has some charm.
The idea here is to try and come up with something that those who can't afford the good stuff can build to get an idea of what's going on and if it actually matters.
Where's the data? Didn't get done if there's no data...
jn
I have lot's of data. No I am not going to draw the -7000 schematic for you all. You can buy one and reverse engineer it, if you like. No, I am not going to tell what the material composition of the cores are, either.
Just build what you know or idea shown here and LISTEN. Put it on your CD and one on the DAC.
Got to git. Git out of Dodge City before sun-down. .
THx-RNMarsh
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Scott look at post 5274. It shows what Richard has posted for the $20 device.
Problem with that is that the output 'neutral' is no longer a neutral. You have single phase 120, or 2-phase 60v, with a delta wired neutral, which is where the center tap tied to ground.
Not sure about the legal liability created if the output is wired to standard wall socket (Type B, here: IEC - World Plugs ) which would imply the neutral is tied to ground somewhere upstream and remains close to ground voltage aside from a possibly small neutral voltage due to IR drop. That what is meant by the socket having one of the slots longer than the other, the long slot is neutral and the shorter slot is hot. Only the hot needs to be switched and fused in end-use equipment.
Seems to me one might want to measure the BW of a three term voltage regulator. Most gear uses them for regulation.
The Xfmr, rect and filter cap used in a PA also. The Z of the filter cap isnt low for ever. Large Ls inside. Hmmmm could a 0.1mfd bypass help reduce HF/RFI let-thru??
I wonder what you will find
THx-RNMarsh
I like to install a RC before the reg to roll off the HF content. Some times two for a 12db filter. I have heard no loss of dynamics with this.
Richard you are spot on with the 150 ohm power line Z. I have see this figure elsewhere. Thanks for all your input to this forum.
One of the nice things about the older TEK scopes are the wide array of tests which can be done with just a Plug-in change. I use the TEK 7905 scope with 7A13 (Differential Comparitor) and TEK plug in 7A22 (Diff Amplifier).
It never hurts (much) to invest in test equipment.
THx-RNMarsh
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That's not a schematic, no source or spec for the transformers, and he also later said:
So, pretty useless info in terms of being able to reproduce his results.
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If you have 39.37 inches, you don't have to worry?
But if you want to measure at the limits of perception the minimum would be a good quality sound card and a battery powered computicater thingy. Then all you have to find a nice low emi location.
Does an Audio Precision need to be battery powered?
All you have to do is lift your finger and push down on mouse button to blow up the picture and you can read all the transformer info on it. I bought them on eBay... cheap. Then a pp cap is between them... you can read that values also.
That is good enough to find out via listening if it makes any difference. You dont have to have 100+ DB rejection over MHz BW. I'm not doing a DIY construction project on a forum here. You have to read, look and listen. The rest, you are on your own.
I expect a lot of creativity and T&M and Listening from you guys. Not just copy cat what I did or can do with a room full of test equipment. I can learn from your efforts also.
This is what it means IMO to create Uber Hi-End equipment. Leave no rock unturned. Unless you live under one.
THx-RNMarsh
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Thanks that's funny, this afternoon I was going to ask if 4 -12.6V filament transformers would work but thought I was on the wrong track.
16 - T105's would give +-48V and lots in between @220 AH. You could charge them with solar panels.
That's not so important as long they can deliver enough power to feed the load. On the picture, it is:
Primary COM/120/308/240
Secondary: 24VAC 75VA.
Note they are mounted with a 90° angle to minimize magnetic coupling between them.
Perish the thought. A DIY project on DIYaudio! That would be dreadful
BTW did you recognise Othneil as one of your ancestors?
For those interested in switchers for line level stuff Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects - Pro Audio Design Forum Wayne has done some measurements showing how a bad switcher can have a measurable effect on the noise floor of a circuit. I remain unconvinced that -130dB at 25kHz would cause any issues, but shows an output rather than an input. Not too shabby at all on that measurement. Would be interesting to see how that unit does under Howie's torture tests...
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