Also, assuming such advice is good, perhaps someone should contact Martin Koch and tell him what he got wrong in his book.
Martin Koch, Hartbergerstrasse 22, A-2800 Gleisdorf, Austria
martin.koch@buildyourguitar.com
www.BuildYourGuitar.com
As a matter of fact, I think I will do so, and ask him about it.
Martin Koch, Hartbergerstrasse 22, A-2800 Gleisdorf, Austria
martin.koch@buildyourguitar.com
www.BuildYourGuitar.com
As a matter of fact, I think I will do so, and ask him about it.
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What options did you feel were changed? As mentioned, it is 30mins for anyone, except the first post in a thread, that can be edited by the thread starter anytime. Also, you cannot quote the last post in a thread, as that would effectively duplicate that post. See the forum rules and setttings.
Jan
As a user of his book, you might want to shoot him a mail.
Edit: you may first want to ask him why he did it the way he did. There may be some valid reason we don't know, especially not having seen the circuit and description. He may have been designing-in a noise generator, for all we know!
Jan
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OK. I will do just that. And I guess I was mistaken about seeming changes to my posting options. Thanks.
^ This!
You may want to read some textbooks first, Sir ;-)
Please see my correction in post #15. The mistake in post #14 was a typo. I actually meant to say directly proportional, and don't know why I wrote the opposite. But the site would not let me later edit the post, so I had to post a retraction. Even so, there's no need to be insulting. I made a mistake. Sue me.
But please be patient. I realize now that all of you guys are perfect people who never make mistakes.
But please be patient. I realize now that all of you guys are perfect people who never make mistakes.
I have just replaced all of the diagrams in post #1 with updated versions, corrected according to the advice I have been getting here. So, now the replies based on the originally-posted diagrams, admittedly containing mistakes, have been rendered moot. However, if flaws are noticed in the updated versions, or other recommendations might be made, I will take them seriously and update whichever diagrams need it, as additional issues come to light.
Oh, and maybe I'll read a textbook or manual (in addition to the dozens I have been studying since becoming a certified Radio & TV Repairman in 1980).
And by the way, I concede that I was also mistaken about my editing options. That was my conspiracy-nut mind poking through. My apologies.
Oh, and maybe I'll read a textbook or manual (in addition to the dozens I have been studying since becoming a certified Radio & TV Repairman in 1980).
And by the way, I concede that I was also mistaken about my editing options. That was my conspiracy-nut mind poking through. My apologies.
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Not an accusation, a factual observation from many posts and reactions.
As I said, many of us have been there or are still there. Education permanente.
Jan
jan.didden,
Sorry, but I still take offense. Making mistakes is only human, and does not necessarily mean one has a lack of understanding.
But since you insist on claiming that a "limited understanding" on my part is a "factual observation", then I must conclude, as a factual observation, that you are a rather inconsiderate person who lacks empathy. Oh, but I forgot. You guys don't make mistakes.
Sorry, but I still take offense. Making mistakes is only human, and does not necessarily mean one has a lack of understanding.
But since you insist on claiming that a "limited understanding" on my part is a "factual observation", then I must conclude, as a factual observation, that you are a rather inconsiderate person who lacks empathy. Oh, but I forgot. You guys don't make mistakes.
But yet another mistake I made was to misinterpret one of Koch's circuits, which is how the main error in my diagrams entered the picture. I in fact sent an email to Koch but then had to send another asking him to forget the first one, after I finally noticed what I had done wrong. [Human failing, not lack of understanding.] I have since corrected the mistakes in my diagrams and replaced the originally-posted diagrams (in post #1) with updated versions.
There are a plethory of stompbox schematics available for free on the internet.
Many of them being poor designs imho but will do as starting point for own exploration.
At the end it depends on your preferences and the context of usage.
For battery driven amplification supply voltage range and power consumption are paramant properties.
Have a look into commercial pre-amps found in active acoustic guitar electronics.
What do you find in 99%?
Good old TL062 and TL064 - draws about 200uA per channel at an unbeatable price.
With a whopping noise voltage level of 30nV/sqrt(Hz) looks extremely noisy.
But considering hi-Z output of guitar pickups this is peanuts in reality.
In other words - you gain little by using op-amps with lower voltage noise.
On the other hand the JFET input stage of TL062 offers very low current noise compared to BJT inputs like NE5532,
which is much more important in this application. So audible noise of NE5532 will be much higher than TL062.
Certainly this is exclusively applicable to hi-Z input guitar pre-amps and may not be mistaken as a general rule.
As a general rule I would say that generally general rules do not fit everywhere and often are misleading in another context.
From this point of view I would not apply OPA2156 here:
-Bandwidth and noise voltage far exceed requirements
-with 4mA current draw per channel they are battery suckers
-too expensive
My current favourites are OPA2196 and OPA2197
just my 2c
Many of them being poor designs imho but will do as starting point for own exploration.
At the end it depends on your preferences and the context of usage.
For battery driven amplification supply voltage range and power consumption are paramant properties.
Have a look into commercial pre-amps found in active acoustic guitar electronics.
What do you find in 99%?
Good old TL062 and TL064 - draws about 200uA per channel at an unbeatable price.
With a whopping noise voltage level of 30nV/sqrt(Hz) looks extremely noisy.
But considering hi-Z output of guitar pickups this is peanuts in reality.
In other words - you gain little by using op-amps with lower voltage noise.
On the other hand the JFET input stage of TL062 offers very low current noise compared to BJT inputs like NE5532,
which is much more important in this application. So audible noise of NE5532 will be much higher than TL062.
Certainly this is exclusively applicable to hi-Z input guitar pre-amps and may not be mistaken as a general rule.
As a general rule I would say that generally general rules do not fit everywhere and often are misleading in another context.
From this point of view I would not apply OPA2156 here:
-Bandwidth and noise voltage far exceed requirements
-with 4mA current draw per channel they are battery suckers
-too expensive
My current favourites are OPA2196 and OPA2197
just my 2c
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Another comment I was not allowed to edit. I came back later and said the tone-control could go on the feedback loop, which I can prove is viable, but was booted off the site (I guess I was taking too long) and when I came back my edit had not been saved, and the site would not let me back in to edit the post again. However, in my updated diagrams I have elected to put that control at the output Volume control. And it does not need a fixed resistor in series with the pot and cap unless you want to limit the range of frequencies the pot adjusts for. I do not want to do that. And yes, while such a control is redundant on diagrams with other tone-controls, I decided to keep it as a way to include an extra adjustment for the high-end.
How can you say that to a guy who is actually trying to help you?
From what I have seen and read, I could make an electronics knowledge ranking:
1. Jan Didden
2. Me myself and I
3. Kurtus Richter
4. my mother in law
and I don't see why that would be insulting to anyone.
@KURT Richter:
In the revised schematics in your post #1 I do not see any changes when it comes to what rayma put forward in his post #13, and what prompted Marcel to put forward his post #17.
Could you please elaborate on this?
I see it in the pictures embedded in post #1, but not in some attachments. There should be a capacitor in series with the resistors to ground, though, because of the single supply.
Robert H. Gribnau,
Sorry, but you are mistaken. The resistors to ground from the inverting inputs ensure that the adjustable feedback loops work as intended. They were not there before, so I agree that the circuits without them were in error (the feedback control would not work well). But their inclusion solves that problem. Check the design equations for op-amps. Gain equals output voltage Vo over input voltage Vi, which ratio also equals the ratio of the sum of the resistances in the feedback loop plus said resistor to ground, over the value of that same resistor. Thus, the Gain controls are now valid. There are only two diagrams that use a different gain control topology, but those are not of my invention. To find fault with either of them is to call into question the validity of proven long-standing designs. I may have tweaked them according to my purpose, but the topology and many part-values are the same. These are; (1) the first stage in the second preamp, based on a design by Craig Anderton, and (2) the first stage in the sixth preamp, based on the Gretsch Controfuzz stomp-box circuit. If those circuits do not work properly, then I don't know what to tell you.
Sorry, but you are mistaken. The resistors to ground from the inverting inputs ensure that the adjustable feedback loops work as intended. They were not there before, so I agree that the circuits without them were in error (the feedback control would not work well). But their inclusion solves that problem. Check the design equations for op-amps. Gain equals output voltage Vo over input voltage Vi, which ratio also equals the ratio of the sum of the resistances in the feedback loop plus said resistor to ground, over the value of that same resistor. Thus, the Gain controls are now valid. There are only two diagrams that use a different gain control topology, but those are not of my invention. To find fault with either of them is to call into question the validity of proven long-standing designs. I may have tweaked them according to my purpose, but the topology and many part-values are the same. These are; (1) the first stage in the second preamp, based on a design by Craig Anderton, and (2) the first stage in the sixth preamp, based on the Gretsch Controfuzz stomp-box circuit. If those circuits do not work properly, then I don't know what to tell you.
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MarcelvdG,
The attachments include the old incorrect diagrams along with the new updated ones. Please ignore the attachments and consider the diagrams now showing in post #1, which are the newly updated diagrams. However, if you see issues with any of those, please feel free to mention them. My goal is to arrive at viable diagrams and greatly appreciate the help I am getting here (even from those being derogatory). Thanks.
The attachments include the old incorrect diagrams along with the new updated ones. Please ignore the attachments and consider the diagrams now showing in post #1, which are the newly updated diagrams. However, if you see issues with any of those, please feel free to mention them. My goal is to arrive at viable diagrams and greatly appreciate the help I am getting here (even from those being derogatory). Thanks.
Without studiying your revised schematics in your post #1 yet again, two strong appeals to you:
1) Please make sure that the schematics you post are viable in the first place. Noting that they are "experimental" for me is "too easy". You could at least run them through available software before posting them.
2) When changing something in your first post in one of your threads, please make perfectly clear in your first post what you did change, in which schematic, and the reason for that/those change(s).
1) Please make sure that the schematics you post are viable in the first place. Noting that they are "experimental" for me is "too easy". You could at least run them through available software before posting them.
2) When changing something in your first post in one of your threads, please make perfectly clear in your first post what you did change, in which schematic, and the reason for that/those change(s).
FYI
I became a certified Radio & TV repairman in 1980. That's 44 years ago. I had to know all kinds of electronics, solid-state and tube-type, to obtain that certification, and have been using my knowledge of electronics on the job ever since, plus studying audio electronics as a past-time the whole while. My understanding of electronics served me well on the job, helping me work in many fields, including holding electrical / electronics oriented positions, mostly as a repairman, but also including work in industrial automation (robotics), industrial engineering, and standby generator servicing and installation; all of which involved more electronics knowledge than most people can even imagine. What is more, I have an Elite certification in backup generators from Generac Corporation and a State certification in Refrigeration. I also have a 3-year AS degree with a dual major in Math and Computers, which included a course in computer design (not computer-aided design, but actual computer design) at UNC Asheville. Further, I spent 2 1/2 years in the Physics program at UNCA, though I was unable to stay long enough to get the degree in Physics due to running out of funds, forcing me to re-enter the workforce. But the point to saying all of this is that I have probably forgotten more electronics than anyone here knows, so when I make a mistake, it's a mistake, not a reflection on my understanding of electronics. Consequently, maybe now you can all see why I might get so offended when my knowledge or understanding are belittled.
Got it?
I became a certified Radio & TV repairman in 1980. That's 44 years ago. I had to know all kinds of electronics, solid-state and tube-type, to obtain that certification, and have been using my knowledge of electronics on the job ever since, plus studying audio electronics as a past-time the whole while. My understanding of electronics served me well on the job, helping me work in many fields, including holding electrical / electronics oriented positions, mostly as a repairman, but also including work in industrial automation (robotics), industrial engineering, and standby generator servicing and installation; all of which involved more electronics knowledge than most people can even imagine. What is more, I have an Elite certification in backup generators from Generac Corporation and a State certification in Refrigeration. I also have a 3-year AS degree with a dual major in Math and Computers, which included a course in computer design (not computer-aided design, but actual computer design) at UNC Asheville. Further, I spent 2 1/2 years in the Physics program at UNCA, though I was unable to stay long enough to get the degree in Physics due to running out of funds, forcing me to re-enter the workforce. But the point to saying all of this is that I have probably forgotten more electronics than anyone here knows, so when I make a mistake, it's a mistake, not a reflection on my understanding of electronics. Consequently, maybe now you can all see why I might get so offended when my knowledge or understanding are belittled.
Got it?