john curl said:
Now, you're talking! I've wanted to do that for years. Amps above a few watts would be so expensive as to be impractical, but preamps and other low level components sound like a cool idea. The problem is that I'd have to use batteries to get by at night or on cloudy days, and I've never been that enthusiastic about batteries. An enormous cap bank might do the trick, but that's going to get expensive, too.
john curl said:
I'm still trying to build solid state that equals what I did with tubes. I'll worry about Conrad Johnson, Audio Research, et. al. some other day. I keep getting closer and closer, but I fear the curve is asymptotic and I'll never get there.
At least I no longer have to buy new tube sets every year or two.
Grey
Ok, let's try this again with a different approach and see if perhaps it can provide some illumination.
From the top.
Unfortunately, many here think only of the forward filtering and not so much about the return path back to the power line.
Two simple questions to which I hope I can get two simple, straightforward answers:
First, John, exactly what filtering are you referring to when you say "forward filtering"?
Second, in order to filter the amplifier's "return back back to the power line," where exactly would such filtering be applied?
se
From the top.
Unfortunately, many here think only of the forward filtering and not so much about the return path back to the power line.
Two simple questions to which I hope I can get two simple, straightforward answers:
First, John, exactly what filtering are you referring to when you say "forward filtering"?
Second, in order to filter the amplifier's "return back back to the power line," where exactly would such filtering be applied?
se
--I interpret John's 'forward filtering' to mean removal of ripple and power line hash. The problem with thinking solely in these terms is that you're neglecting the effect the circuit has on the power supply (and by extension, the AC line beyond it).
--A 'forward' filter has to be on the secondary side, after the rectifier. The interesting thing about a 'reverse' filter (my spur of the moment term) is that it can be on either side of the transformer. If you've got a small value cap on the secondary side of the transformer to absorb spikes coming in, it will also tend to trap digital trash (for example) that your circuit might be generating...but so will a cap on the primary side.
Grey
--A 'forward' filter has to be on the secondary side, after the rectifier. The interesting thing about a 'reverse' filter (my spur of the moment term) is that it can be on either side of the transformer. If you've got a small value cap on the secondary side of the transformer to absorb spikes coming in, it will also tend to trap digital trash (for example) that your circuit might be generating...but so will a cap on the primary side.
Grey
GRollins said:
I don't want other people's interpretations of what they think John said. That's what got things flying off in other directions already.
C'mon. John's a grown man with a professional career spanning several decades. He's written AES papers and other articles. Does he really need others to speak for him?
se
I think that you fellow engineers got it right. Forward is obvious. The usual way you consider when making a power supply do what it has to do. Reverse is less obvious, but still important, and it is the 'ground' return, or where the loudspeaker current goes after it goes through the loudspeaker.
john curl said:
Ok.
Now, just to be perfectly clear, when you say "current" here, are you referring to actual electron current that's flowing through an actual conductive path? As in the Wikipedia definition which is "Electric current is the flow (movement) of electric charge"?
Is this what you're saying?
se
Jeez...if we've got to have a semantics argument, can't we just argue about what constitutes feedback? That one's like an old, soft shoe. Everybody knows their lines and we can all do it in our sleep. Okay, so the shoe stinks and it's threadbare from being chewed by the family dog, but still...
Grey
Grey
I would like to talk about a few other 'features' that a power supply can have. One is full wave bridge rectifier wired into the 3rd (ground) wire in such a way as to open it unless more than 1.2V is attempting to drop across it. I will leave the details for your discovery. I designed this into the JC-80 preamp.
Another addition might be a common mode choke. These are readily available through Digikey and other sources. They can help to limit any RFI input that might get past the transformer.
A third addition is putting Bybee filters in series with the hot and neutral line respectively. I do this in my preamp outlets, and have even put them inside the final CTC Blowtorch, as they appear to work best closest to the action. Yes, Bybee filters are real, and real listeners can hear them. I personally know Jack Bybee, and have used his devices for more than 12 years. However, if they are put into the audio circuit path directly, I have sometimes found a slight reduction in detail, (that might have been artificial in the first place) and I tend to avoid them in series with the audio line, except for loudspeakers and for lower quality sources, such as TV or DVD.
Another addition might be a common mode choke. These are readily available through Digikey and other sources. They can help to limit any RFI input that might get past the transformer.
A third addition is putting Bybee filters in series with the hot and neutral line respectively. I do this in my preamp outlets, and have even put them inside the final CTC Blowtorch, as they appear to work best closest to the action. Yes, Bybee filters are real, and real listeners can hear them. I personally know Jack Bybee, and have used his devices for more than 12 years. However, if they are put into the audio circuit path directly, I have sometimes found a slight reduction in detail, (that might have been artificial in the first place) and I tend to avoid them in series with the audio line, except for loudspeakers and for lower quality sources, such as TV or DVD.
- Status
- Not open for further replies.