now, SIT pcb - change R11 to 2K7 or 3K3, re-adjust P2 to get output node voltage equal to other amps; leave R10 out/not populated
do not touch trimpot on MOS pcb
do not touch trimpot on MOS pcb
we care and you are going to check it
but - no need to alter anything with trimpot at MOS pcb, because - again - you already set Iq and have output node few volts lower than needed
now, altering output node voltage slightly would not alter Iq
anyway, as I said - do not try to fix/set/whatever and , in same time, understand how circuit works
you had time for understanding and you didn't use that time - first while reading and re-reading relevant threads ( all info really being there), and then while assembling pcbs and doing all mechanical work
I'm not blaming you for not understanding, we all are having different specializations in life, and nobody can't blame Greedy Boy for making an amp in Lego fashion; Buddha knows that I'm not an Expert in food preparation, but even I'm from time to time making BBq........ go figure
but, as I said, work with me while I'm helping you to make it OK, think later ....... while I'm thinking about other things
but - no need to alter anything with trimpot at MOS pcb, because - again - you already set Iq and have output node few volts lower than needed
now, altering output node voltage slightly would not alter Iq
anyway, as I said - do not try to fix/set/whatever and , in same time, understand how circuit works
you had time for understanding and you didn't use that time - first while reading and re-reading relevant threads ( all info really being there), and then while assembling pcbs and doing all mechanical work
I'm not blaming you for not understanding, we all are having different specializations in life, and nobody can't blame Greedy Boy for making an amp in Lego fashion; Buddha knows that I'm not an Expert in food preparation, but even I'm from time to time making BBq........ go figure
but, as I said, work with me while I'm helping you to make it OK, think later ....... while I'm thinking about other things
OK - latest results:
with 3K01 - about 34.5 volts while Iq stays in the 455 mV range - did not measure Vgs
Went to 3.3K - 45.5 volts while Iq stays in the same range - Vgs 3.73
As an aside the mosfet trimpot is turned all of the way up (clockwise) as it has been for all of the measurements reported since fixing my mistake.
I do not have exact resistors so I used a 3K01 in series with 300R.
My guess is another 100 Ohms but I will wait for your direction and do what you recommend tomorrow/
Now to go listen.
Have all day to play with this stuff tomorrow and the next four days for that matter.
Sorry I have made you mad.
with 3K01 - about 34.5 volts while Iq stays in the 455 mV range - did not measure Vgs
Went to 3.3K - 45.5 volts while Iq stays in the same range - Vgs 3.73
As an aside the mosfet trimpot is turned all of the way up (clockwise) as it has been for all of the measurements reported since fixing my mistake.
I do not have exact resistors so I used a 3K01 in series with 300R.
My guess is another 100 Ohms but I will wait for your direction and do what you recommend tomorrow/
Now to go listen.
Have all day to play with this stuff tomorrow and the next four days for that matter.
Sorry I have made you mad.
you didn't made me mad, quite contrary
it's just so hard to keeping you restrained, to read and follow instructions, while being focused enough to not make a mess even more
so, increase it few hundred ohms more, until you get output node voltage spot on
do not work more on beautification ...... gray smoke is near
it's just so hard to keeping you restrained, to read and follow instructions, while being focused enough to not make a mess even more
so, increase it few hundred ohms more, until you get output node voltage spot on
do not work more on beautification ...... gray smoke is near
I do not think I am near grey smoke. Seems to me I would have already experienced that.
I built the amplifiers for listening to music - not for some science fair project. They are situated in my system and I would like to use them and not continually fiddle with them. It is not as if you live next door so it makes sense to me to extrapolate what you are saying and see what happens in the interim between asking a question and getting an answer. What I consider a learning process.
On one hand you seem like you want to build understanding of amplifiers in general but then this quickly segues into do not think for yourself. I cannot keep up.
I am sorry I made such a foolish mistake and wasted so much of both of our time.
No fancy construction will ever follow.
I guess I am on my own. With a post so cryptic I have no idea whether to pay any attention to it.
I built the amplifiers for listening to music - not for some science fair project. They are situated in my system and I would like to use them and not continually fiddle with them. It is not as if you live next door so it makes sense to me to extrapolate what you are saying and see what happens in the interim between asking a question and getting an answer. What I consider a learning process.
On one hand you seem like you want to build understanding of amplifiers in general but then this quickly segues into do not think for yourself. I cannot keep up.
I am sorry I made such a foolish mistake and wasted so much of both of our time.
No fancy construction will ever follow.
I guess I am on my own. With a post so cryptic I have no idea whether to pay any attention to it.
Rick, point was, and is, that - in this moment you have just one step to get it done
you changed R11 to 3K3 and now you're nearly spot on with output node voltage
what I'm saying is - "add few hundred ohms to that" - meaning - change it to 3K9 or 4K3 or 4K7, and you'll be able to set output node voltage exactly spot on
regarding understanding of circuit - my intention was - let's focus on getting it done, without sidetracking (you must agree that we had enough sidetracking; let's look at this way - I am easily confused ( age, multitasking, whatever) and I can't keep with too much lineups in solving one problem)
so when done, we can chat how is that and what is that, while you're having wide Green listening, and I'm in no obligation to have too much mental concentration - being able to reply whenever I feel to, not rushing to reply before you do something else
I had no intention to harm your feelings, and I believe that I did show exactly opposite behavior more than once
If your feelings are still harmed, well ..... my conscience is clear and problem is not mine
you changed R11 to 3K3 and now you're nearly spot on with output node voltage
what I'm saying is - "add few hundred ohms to that" - meaning - change it to 3K9 or 4K3 or 4K7, and you'll be able to set output node voltage exactly spot on
regarding understanding of circuit - my intention was - let's focus on getting it done, without sidetracking (you must agree that we had enough sidetracking; let's look at this way - I am easily confused ( age, multitasking, whatever) and I can't keep with too much lineups in solving one problem)
so when done, we can chat how is that and what is that, while you're having wide Green listening, and I'm in no obligation to have too much mental concentration - being able to reply whenever I feel to, not rushing to reply before you do something else
I had no intention to harm your feelings, and I believe that I did show exactly opposite behavior more than once
If your feelings are still harmed, well ..... my conscience is clear and problem is not mine
Rick, we’re all with you. Chasing down that last little tweak can be a huge frustration, so keep posting questions. And when it comes to ZMengrish, I always imagine it’s coming from a kind, jokster uncle. Helps me decide what’s serious, and what’s not. 🙂
yes, ZM is combination of speed-chess player and blind-chess player [blindfolded that is]. Awesome! 😎
All that was needed was a YES.
It is amusing that one who is so busy could find plenty of time for a snarky note of a length unusual for the sole(sic) of brevity.
To go from telling one to keep them informed to being offended by being needed. Oh, well. No one ever said life on earth was going to be predictable.
No guessing allowed here. The impugned question was whether to raise the value of R11 or lower the value of R12. I will find this out for myself. Been involved in getting a xilica Solara installed - skipping the DAC and going from the MUTEC straight into the DSP along with being able to put the PEQs exactly where you want (applying to speaker as a whole or individual drivers). So I have not done anything yet but getting the desired value will not be difficult.
I figure this will be one of the last posts on this subject since ZM is somewhat like a more realized John Broskie - all of these designs proposed but none of them are ever developed beyond what is first published before something else is being promoted. The SINGING BUSH is a great amplifier and I am very grateful to have them. One would think this a project worth continuing its development/evolution - but this is it - so I guess the thread is basically dead. Not many of the devices left anyway.
No gray smoke yet and I have never said my construction methods were accomplished and beautiful. If only I could have found an old cassette player box to stuff this amplifier into then I could be among the mighty.
Oh, well, I know my place.
It is amusing that one who is so busy could find plenty of time for a snarky note of a length unusual for the sole(sic) of brevity.
To go from telling one to keep them informed to being offended by being needed. Oh, well. No one ever said life on earth was going to be predictable.
No guessing allowed here. The impugned question was whether to raise the value of R11 or lower the value of R12. I will find this out for myself. Been involved in getting a xilica Solara installed - skipping the DAC and going from the MUTEC straight into the DSP along with being able to put the PEQs exactly where you want (applying to speaker as a whole or individual drivers). So I have not done anything yet but getting the desired value will not be difficult.
I figure this will be one of the last posts on this subject since ZM is somewhat like a more realized John Broskie - all of these designs proposed but none of them are ever developed beyond what is first published before something else is being promoted. The SINGING BUSH is a great amplifier and I am very grateful to have them. One would think this a project worth continuing its development/evolution - but this is it - so I guess the thread is basically dead. Not many of the devices left anyway.
No gray smoke yet and I have never said my construction methods were accomplished and beautiful. If only I could have found an old cassette player box to stuff this amplifier into then I could be among the mighty.
Oh, well, I know my place.
What a violent reaction @rickmcinnis. You have been spoon-fed from
the start on this matter....and now - when everyone has lost patience with
your inability to follow ZM's extremely lucid help - you throw your toys out of the
pram...shame on you.
the start on this matter....and now - when everyone has lost patience with
your inability to follow ZM's extremely lucid help - you throw your toys out of the
pram...shame on you.
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I consider the singing bush an evolved version of NP’s 2016 BAF 50W amp. And I could be wrong, but there are rumblings of a ‘Lazy’ Singing Bush coming in the future (follower). I’m excited for that one! Point being that these are all evolutions of a core set of ‘building blocks’ and have plenty of overlap. And based on the sound of Singing Bush, I expect builders to continue tackling it for a long time to come 🙂
I do not think anyone has been more grateful to ZM than I. And I remain grateful
Bricasti, maybe you do not realize that I built four of these things which are working just fine. Even the one that will not get within the prescribed window.
The one that has created this furor contains an SIT not behaving as expected by ZM's circuit. I had kept a post from the original thread that said one resistor change would be all that is needed to accommodate that. The resistor was not identified in the post. Then I was told to change two resistors (Rs 11 & 12) and made the foolish mistake of not looking at the pcb closely and tried to make it easy to adjust the two resistors and instead made a mess. Luckily no harm done to the amplifier just useless results and annoying posts.
Many of my posts contained admissions of my mistakes in hope that others who might build this amplifier, which as far as I can tell, you are not one of them, might find my experience useful.
I was hoping ZM would give me guidelines to pursue the correct values for resistors 11 and 12 for this amplifier which will not get to 35 volts Vds with the recommended Iq. (33.9 volts with R11 at 4K) I had and have no desire to keep asking questions if I can find the answer myself. I was hoping it would get to the approx. 36.5 volts of the other three and ZM thought this was what should be done. I was told that R11 would need to be raised and R12 would need to be lowered. Whether there was a ratio between these values remains a mystery.
Hardly wanting to be spoonfed I was hoping for some guidelines to try various values to find the good result. I had no desire to be spoonfed and I know ZM was trying to be nice in a way I do not quite understand. When one has three amplifiers that are within the recommended range I was taken aback to be asked if I knew how to adjust the amplifiers.
I did read over the many posts on both threads before starting work on the amplifiers. Of course, reading about something and then actually building it are very different things.
As far as i can tell there is never a mention as to what the Vgs should range in a finished amplifier. I copied all of the posts I thought were relevant to building the amplifier and do not see Vgs anywhere except in reference to the test values.
These are the first amplifiers I have built from parts. I have played around with other amplifiers but never have done anything like this. I told ZM when I ordered the parts that I would likely be needy.
When I was told to keep him informed I thought he meant it.
I had never made any claims for the beauty of my amplifiers, if anything, I thought I made it clear I KNOW my methods are for ease of assembly and disassembly. I have no metal working skills whatsoever. Now I see my hesitance to post pictures was justified. I think what got me the most was the comment about not putting the things in a box since they were going to blow up. So far nothing has blown up and I would be very surprised if that happens.
My desire was to minimize the questions and simply get the amp working at its best. Obviously I failed at that.
Raising R11 is not getting much of anywhere. Even with the value at 4K I get 33.9 Vds - 3.64 Vgs at 460 mV Iq. This has not changed much at all from 1K6 so it seems this is not the problem to my sense of logic that has only the barest of electrical theory to guide it. I continue to think that, based upon what I have experienced, that R1 on the mosfet board needs to be raised, based on nothing more than observation, since the pot is at full resistance and to get the prescribed Iq of 460 mV always requires adjusting the Vds down.
So that is what I will try next.
Happy New Year.
Bricasti, maybe you do not realize that I built four of these things which are working just fine. Even the one that will not get within the prescribed window.
The one that has created this furor contains an SIT not behaving as expected by ZM's circuit. I had kept a post from the original thread that said one resistor change would be all that is needed to accommodate that. The resistor was not identified in the post. Then I was told to change two resistors (Rs 11 & 12) and made the foolish mistake of not looking at the pcb closely and tried to make it easy to adjust the two resistors and instead made a mess. Luckily no harm done to the amplifier just useless results and annoying posts.
Many of my posts contained admissions of my mistakes in hope that others who might build this amplifier, which as far as I can tell, you are not one of them, might find my experience useful.
I was hoping ZM would give me guidelines to pursue the correct values for resistors 11 and 12 for this amplifier which will not get to 35 volts Vds with the recommended Iq. (33.9 volts with R11 at 4K) I had and have no desire to keep asking questions if I can find the answer myself. I was hoping it would get to the approx. 36.5 volts of the other three and ZM thought this was what should be done. I was told that R11 would need to be raised and R12 would need to be lowered. Whether there was a ratio between these values remains a mystery.
Hardly wanting to be spoonfed I was hoping for some guidelines to try various values to find the good result. I had no desire to be spoonfed and I know ZM was trying to be nice in a way I do not quite understand. When one has three amplifiers that are within the recommended range I was taken aback to be asked if I knew how to adjust the amplifiers.
I did read over the many posts on both threads before starting work on the amplifiers. Of course, reading about something and then actually building it are very different things.
As far as i can tell there is never a mention as to what the Vgs should range in a finished amplifier. I copied all of the posts I thought were relevant to building the amplifier and do not see Vgs anywhere except in reference to the test values.
These are the first amplifiers I have built from parts. I have played around with other amplifiers but never have done anything like this. I told ZM when I ordered the parts that I would likely be needy.
When I was told to keep him informed I thought he meant it.
I had never made any claims for the beauty of my amplifiers, if anything, I thought I made it clear I KNOW my methods are for ease of assembly and disassembly. I have no metal working skills whatsoever. Now I see my hesitance to post pictures was justified. I think what got me the most was the comment about not putting the things in a box since they were going to blow up. So far nothing has blown up and I would be very surprised if that happens.
My desire was to minimize the questions and simply get the amp working at its best. Obviously I failed at that.
Raising R11 is not getting much of anywhere. Even with the value at 4K I get 33.9 Vds - 3.64 Vgs at 460 mV Iq. This has not changed much at all from 1K6 so it seems this is not the problem to my sense of logic that has only the barest of electrical theory to guide it. I continue to think that, based upon what I have experienced, that R1 on the mosfet board needs to be raised, based on nothing more than observation, since the pot is at full resistance and to get the prescribed Iq of 460 mV always requires adjusting the Vds down.
So that is what I will try next.
Happy New Year.
if you desire slightly increase of Iq, two ways of do it - slightly increase value of R3 or slightly decrease value of R1, both at Mos/Mu pcb
say R3 to 150-220R
say R1 to 3K9 to 5K1
better fiddle with R1; R3 is trickier to get right
in both cases go back with P1 at Mos/Mu pcb (to have increased starting sum resistance of R1+P1) prior to powering up
say R3 to 150-220R
say R1 to 3K9 to 5K1
better fiddle with R1; R3 is trickier to get right
in both cases go back with P1 at Mos/Mu pcb (to have increased starting sum resistance of R1+P1) prior to powering up
Well, now I know increasing R1 on mosfet board did nothing useful.
My mother was from Missouri so it is in my blood. I have to see it for myself.
I am using 3k for R11 and have tried various smaller values for R12 - it reminds me of Rod Stewart singing about combing his hair in a thousand ways and it comes out looking just the same.
R10 remains open.
As I fiddle with P2 I end up in the same place - less than 34 volts Vds and approx. 455 mV for Iq.
I am thinking I need to get a slightly higher voltage power transformer. ANTEK has a 54 volts. I know with the SIT 1s B+ made a big difference in getting the recommended voltages, As stated before this was an SIT 1 with a choke input power supply.
BUT without hesitation I will try smaller values in R1. Certainly much easier to get to! To reassure I always dial back mosfet P1 before turning on.
With gratitude to the diplomatic asphalt for his wisdom.
And as always deeply felt gratitude for ZM and his patience.
My mother was from Missouri so it is in my blood. I have to see it for myself.
I am using 3k for R11 and have tried various smaller values for R12 - it reminds me of Rod Stewart singing about combing his hair in a thousand ways and it comes out looking just the same.
R10 remains open.
As I fiddle with P2 I end up in the same place - less than 34 volts Vds and approx. 455 mV for Iq.
I am thinking I need to get a slightly higher voltage power transformer. ANTEK has a 54 volts. I know with the SIT 1s B+ made a big difference in getting the recommended voltages, As stated before this was an SIT 1 with a choke input power supply.
BUT without hesitation I will try smaller values in R1. Certainly much easier to get to! To reassure I always dial back mosfet P1 before turning on.
With gratitude to the diplomatic asphalt for his wisdom.
And as always deeply felt gratitude for ZM and his patience.