Posting here since it is a weekend.
Number three is absolutely silent - 2 out of three!
I had a thought on the buzzer - as you know I sliced off the areaa behind the output cap - is there a possibility that with this board I have created a small short?
I noticed yesterday that when setting up this amplifier - after turning it off to connect the "purple" wire that it took a good long time for the voltage to return to zero - which is how i had remembered it with the second amplifier.
When I exchanged the SIT board on the buzzer and went through the setup process I noticed the voltage went down much more quickly - not like it would had the purple wire was connected but this must give come clues to the problem. It was less than a minute to drain where the other two took closer to ten minutes if not longer.
I am going to exchange the MOSFET board this afternoon but first I will look at that cut edge and see if there is anything unusual.
Number three is absolutely silent - 2 out of three!
I had a thought on the buzzer - as you know I sliced off the areaa behind the output cap - is there a possibility that with this board I have created a small short?
I noticed yesterday that when setting up this amplifier - after turning it off to connect the "purple" wire that it took a good long time for the voltage to return to zero - which is how i had remembered it with the second amplifier.
When I exchanged the SIT board on the buzzer and went through the setup process I noticed the voltage went down much more quickly - not like it would had the purple wire was connected but this must give come clues to the problem. It was less than a minute to drain where the other two took closer to ten minutes if not longer.
I am going to exchange the MOSFET board this afternoon but first I will look at that cut edge and see if there is anything unusual.
BUT you said to be creative!
And I took you at your word.
Well, it isn't the cut that is the problem.
I still do not know what the problem is.
Replaced MOSFET and the board and the buzz is still there.
The transformer makes noise as it did before unlike any of the other transformers.
I did use the other configuration of my favorite rectifiers - when I changed them out..
I never had transformer buzz with any of the iterations from swapping out parts until I installed the different transformer.
Any possibility it is the SIT? At this point that is the only thing I have not swapped.
Do you think this noise is from the transformer and the initial problem has been fixed?
Not going to do it today but I guess it has to be done.
The sound and the level of the buzz has not changed with any of the substitutions.
It still sounds fantastic but it is a challenge to find out what it is.
Yes, the latest amplifier makes music when asked and is silent when it should be.
And I took you at your word.
Well, it isn't the cut that is the problem.
I still do not know what the problem is.
Replaced MOSFET and the board and the buzz is still there.
The transformer makes noise as it did before unlike any of the other transformers.
I did use the other configuration of my favorite rectifiers - when I changed them out..
I never had transformer buzz with any of the iterations from swapping out parts until I installed the different transformer.
Any possibility it is the SIT? At this point that is the only thing I have not swapped.
Do you think this noise is from the transformer and the initial problem has been fixed?
Not going to do it today but I guess it has to be done.
The sound and the level of the buzz has not changed with any of the substitutions.
It still sounds fantastic but it is a challenge to find out what it is.
Yes, the latest amplifier makes music when asked and is silent when it should be.
buzz is there with grounded input?
I mean, logical thing is to test amplifier alone/isolated from everything else ...... but I must ask
I wrote before - xformer buzz can transpose to speaker only in case when xformer is so catastrophically bad that you'll sniff problem before you hear it
so, lets judge only at speaker side - if all measurements are ok, slight xformer buzz is irrelevant
well, yeah, replace SIT and observe for buzz
I mean, logical thing is to test amplifier alone/isolated from everything else ...... but I must ask
I wrote before - xformer buzz can transpose to speaker only in case when xformer is so catastrophically bad that you'll sniff problem before you hear it
so, lets judge only at speaker side - if all measurements are ok, slight xformer buzz is irrelevant
well, yeah, replace SIT and observe for buzz
Vds - 36.15 volts - 460 mV across the resistors - I could have got it to 36 and 460 if I kept twiddling. I did keep fiddling with the other one to get 36 & 460.
No question the amplifier sounds very fine. I cannot imagine anything being much better with horn loaded loudspeakers and even to approach one would have to spend thousands of dollars.
The transformer noise is completely inaudible unless you are standing over the amplifier.
Very faint. I only brought it up in hopes it was an indicator.
I am still going to install another set of rectifiers just to be sure.
I am confident number four will be quiet.
I have decided my amplifiers will be called PLONKERS in honor of poor old earnest Rodney.
No question the amplifier sounds very fine. I cannot imagine anything being much better with horn loaded loudspeakers and even to approach one would have to spend thousands of dollars.
The transformer noise is completely inaudible unless you are standing over the amplifier.
Very faint. I only brought it up in hopes it was an indicator.
I am still going to install another set of rectifiers just to be sure.
I am confident number four will be quiet.
I have decided my amplifiers will be called PLONKERS in honor of poor old earnest Rodney.
well, he's Rick
I tried logical approach, it works just up to the point
I tried scientific approach, it works just up to the point
I tried crystal ball approach, it works just up to the point
his aspiration for greatest possible fun is .......... approach above all others
(just means that I'm lost in our correspondence
)
I tried logical approach, it works just up to the point
I tried scientific approach, it works just up to the point
I tried crystal ball approach, it works just up to the point
his aspiration for greatest possible fun is .......... approach above all others
(just means that I'm lost in our correspondence
)Four days long weekend here. Time to finish amplifier number four and another long look at buzzy number one.
I would think the chances are slim, too. Just cannot imagine what I am missing. As soon as my imagination is not required and the problem is identified you will be the second to know.
I have no idea what you don't know! Highly unlikely I would know what you do not know.
Thanks and take care,
I would think the chances are slim, too. Just cannot imagine what I am missing. As soon as my imagination is not required and the problem is identified you will be the second to know.
I have no idea what you don't know! Highly unlikely I would know what you do not know.
Thanks and take care,
I will use all of the "discarded" parts on this amplifier number four. If it works without noise it would seem the process of elimination would lead to the SIT.
I do not know how much more logical one can get!
I have not tried shorting the input since the buzzy amp lies below amp #2 and it is not easy to get to the input. I will try it this weekend when I have more time to disassemble.
I do not know how much more logical one can get!
I have not tried shorting the input since the buzzy amp lies below amp #2 and it is not easy to get to the input. I will try it this weekend when I have more time to disassemble.
well, one of things to be sure that amp is in malfunction is to exclude everything surrounding it - meaning - shorted inputs ......... if buzz is still there, problem is in amp, not in preamp/whatever or damaged inteconnect
I mean - that goes even without saying
at least to ones having hands in electronics every day ....... but those ones (Moi included) are sometimes forgetting that other people are less experienced
same as I'm experienced in Cooking ..... when Boss sez - take care of that Meat ( on Stove) I'm in state of mild hysteria - what to look?
I mean - that's not BBQ, I'm savvy with that .......
I mean - that goes even without saying
at least to ones having hands in electronics every day ....... but those ones (Moi included) are sometimes forgetting that other people are less experienced
same as I'm experienced in Cooking ..... when Boss sez - take care of that Meat ( on Stove) I'm in state of mild hysteria - what to look?
I mean - that's not BBQ, I'm savvy with that .......
I can scramble eggs.
Preamp is xilica DSP box feeding two other amplifiers and there is no buzz with those amplifiers or the speakers they are connected to so the preceding components were cleared of wrongdoing early on in the investigative process.
Since then I have inserted in this order:
first set of ZM CAP BANKS
SIT board
second set of ZM CAP BANKS with the KEMET caps AND the power transformer
MOSFET board and MOSFET
No change in the buzz while still maintaining extraordinary musical sound with great depth and tonality and everything else one could ask from an amp other than perfect silence.
There is only one thing that has not been exchanged. Well, two things - I have not changed out the heat sink and have no intention of doing that.
My "logic" is if amplifier number four makes no noises, which I feel sure will be the case, I have an unusual SIT.
When I had it apart to install the Mosfet and board I checked the isolation of the SIT and it measured infinite on both a ZM approved little red meter and my better than average FLUKE.
I have asked pras for another SIT - I heard from her once but not in a substantive way - one in which a money request has been sent. I wrote to her again this morning.
If it is not the SIT then this is a mystery beyond logic, science or even cooking! Only Dal-boy would have the insight to understand what is going on with the amplifier and this is a skill only acquired by those who can drive three wheeled Reliants without tipping them over. (Reliant made a four wheeler called the SCIMITAR which was not half bad looking and when they made a estate like thing with it it was very nice looking from the side. They never quite figured out what to do with the front of it, sadly.)
Preamp is xilica DSP box feeding two other amplifiers and there is no buzz with those amplifiers or the speakers they are connected to so the preceding components were cleared of wrongdoing early on in the investigative process.
Since then I have inserted in this order:
first set of ZM CAP BANKS
SIT board
second set of ZM CAP BANKS with the KEMET caps AND the power transformer
MOSFET board and MOSFET
No change in the buzz while still maintaining extraordinary musical sound with great depth and tonality and everything else one could ask from an amp other than perfect silence.
There is only one thing that has not been exchanged. Well, two things - I have not changed out the heat sink and have no intention of doing that.
My "logic" is if amplifier number four makes no noises, which I feel sure will be the case, I have an unusual SIT.
When I had it apart to install the Mosfet and board I checked the isolation of the SIT and it measured infinite on both a ZM approved little red meter and my better than average FLUKE.
I have asked pras for another SIT - I heard from her once but not in a substantive way - one in which a money request has been sent. I wrote to her again this morning.
If it is not the SIT then this is a mystery beyond logic, science or even cooking! Only Dal-boy would have the insight to understand what is going on with the amplifier and this is a skill only acquired by those who can drive three wheeled Reliants without tipping them over. (Reliant made a four wheeler called the SCIMITAR which was not half bad looking and when they made a estate like thing with it it was very nice looking from the side. They never quite figured out what to do with the front of it, sadly.)
It is already!
It is the challenge of finding out what the noise is.
There is no challenge to the enjoyment I am receiving from them.
Should have number four in place tomorrow evening and listening forward to yet another step forward in blissful audio entertainment.
My sincere thanks to ZM and to the great instigator of home musical entertainment and a veritable Trevi Fountain of amplifier innovation, the Colin Chapman of amplifier design, ZM's Pa.
Both Mr. Chapman and ZM's Pa have a sincere love of simplicity. The simple things ARE always complicated but they are better. (with thanks to Mr. Townshend)
It is the challenge of finding out what the noise is.
There is no challenge to the enjoyment I am receiving from them.
Should have number four in place tomorrow evening and listening forward to yet another step forward in blissful audio entertainment.
My sincere thanks to ZM and to the great instigator of home musical entertainment and a veritable Trevi Fountain of amplifier innovation, the Colin Chapman of amplifier design, ZM's Pa.
Both Mr. Chapman and ZM's Pa have a sincere love of simplicity. The simple things ARE always complicated but they are better. (with thanks to Mr. Townshend)
so, suspicion moved upstream
feed it with same freq. range but other channel
with some swapping, you'll deduce is it interconnect or DSP output
you said - when you did move it from bass to mid , buzz stopped
in short - declare that DSP channel (I believe bass freq. say R channel) suspicious; put some other amp there - if it buzz - then DSP is in case - electronic itself, or interconnect ( I hope)
keep us informed