Uh, we're trained engineers and you are obviously not. I am very objective and get a chuckle out of "audiophiles" that talk out their hindquarters.
I don't know what you're trying to accomplish by swinging your dick around here, but it's not going to work. This isn't twitter and don't you forget that.
Keep it civil or mutes will be issued.
Unfortunately I can not download your Preamplifiers.
But can you attach some file here in forum?
And is it alright if I post some simple preamplifier here?
I have a few.
In terms of safety, I am concerned with the safety of the circuit, yes. I should not cut safety for performance, but, I do. The most important point is to ensure the JFET, front amplifiers. I do not want to put diodes, because of non linearity and leakage. I prefer a large value resistors in series to the inputs. I think, 10K will be OK. 10K is, also, not as large as to introduce noise. In case the guitar can output a maximum of 3V, when the device is powered off, the maximum current which can get through is 3V / 10K = 300uA. This current may not damage the JFET inputs.
In regards to some amplifiers, such as Texas Instruments audio amplifiers, with built in diodes in the input, I would use a 3.3K in series to each input of the amplifier. Even in case all 30V go to an input, the maximum current would be 30V / 3.3K < 10mA. The built in diodes can take 10mA. This is shown in the ADOD.doc document, which, is JUST AN IDEA. Just a BLOCK DIAGRAM. I will make some evolution and variation of this, but, probably, in remote future.
In regards to protection of other equipment, I think, all equipment must be able to take + - 15V. Of course, the output can be limited or +- 5V power supply can be used. Most amplifiers would work at + - 5V, but, their parameters deteriorate.
The simplest output protection would be a resistor and Zeners before a buffer. True, Zeners are noisy, but, they may not be as noisy when they are off and they must be off to avoid distortion, unless, they are, also, used for overdrive, when, the noise is not as important. The noise can be eliminated or reduced by heavy filters after the Zeners and before the buffer.
Another protection I do not like, but, may need to use is a capacitor in series to the output to stop DC. I rely on the output buffer, which, must not have more than a few mV DC, even, uV in some cases. I do not know, I have not decided yet.
I have never had problems with Tantalums, even, in industrial equipment. Only with a batch of Chinese, 25V, 10uF. The same value, 35V and 16V are OK.
When you click the link, you will be brought to a Google Drive folder. In this folder there are two documents. One of them, called " A Couple of Simple Preamplifiers.doc " is for preamplifiers, made in practice. They are simple, only 4 amplifiers in each as far as I remember. The other file, " ADOD.doc "has not been made in practice and has not been completed. Just a block diagram. I will make something alike. This will contain 10 to 20 and more amplifiers.
Obviously, the other way around. I do not think you know what you talk of. Neither do they.
You can post whatever you like. Whatever you post, I will not change the design, based on what you post, so, I do not care. Post them all.
Thank you but just one additional information. Your tone control in first schematics is not a real tone control, it's a filter tuning. That's interesting but it tunes only frequencies not gain. Please find a very simple but very efficient tone control for guitar preamp.
Attachments
You think you know more than trained engineers? Dr. Dunning would like to talk to you.
I tried to help yopu and you just went into ahole mode. Again this is not twitter and there are guidelines here.
I'm out.
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