I think you will be happy with it just as it will be. Be sure the centre voltage is correct. That is between the large transistors going out the the speaker capacitors. In theory you should do other adjustments. I suspect they can be kept as the original circuit. The thing to remember is virtually no one can say if 8 watts is more than 5 watts. It has to be 100 watts to be certain. That usually is more about wave shape than how loud.
I just read a convoluted text of a friends friend who tries to say religion and amplifier design are related. It was a complicated way of saying designing things is a bit of a gift. When dancing there is no dispute some can and I can't. The book is very confussed and sets about saying how we might go on this road. I don't think it's correct to say this. JLH was on the road and the road I suspect found him? I say this as he always was prepared to say sound quality verses measurements. One amplifier could be made to measure better whilst to him sound worse. That's the real deal. In his mind he could see where the problem might be. My friend Spencer Hughes said approximately . " My speakers are said to be and easy load, they are not. Imagine you are an amplifer looking down some speaker cables. Do you seee a drive unit? No, you see capaitors and chokes. You might say, I'm going home. The better amplifier says , I know there is a drive unit there." To me that's genius. He looked a simple man and spoke in a modest way. By saying this he balanced off all of his technical knowledge by realising something could sound bad despite it passing all the usual tests.
That book came up with one interesting statement. Schade of RCA recomended capacitor fed rectifiers. Our author becomes mysterious and says it is a very different outcome from the usual and not hard to do. This if true could work with JLH. My instict is the inductance of the transformer is of more importance. All the same it has the feeling of something interesting.
The Road Not Taken ( Robert Frost 1916 ).
Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;
Then took the other, as just as fair,
And having perhaps the better claim,
Because it was grassy and wanted wear;
Though as for that the passing there
Had worn them really about the same,
And both that morning equally lay
In leaves no step had trodden black.
Oh, I kept the first for another day!
Yet knowing how way leads on to way,
I doubted if I should ever come back.
I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I—
I took the one less traveled by,
And that has made all the difference.
That book came up with one interesting statement. Schade of RCA recomended capacitor fed rectifiers. Our author becomes mysterious and says it is a very different outcome from the usual and not hard to do. This if true could work with JLH. My instict is the inductance of the transformer is of more importance. All the same it has the feeling of something interesting.
The Road Not Taken ( Robert Frost 1916 ).
Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;
Then took the other, as just as fair,
And having perhaps the better claim,
Because it was grassy and wanted wear;
Though as for that the passing there
Had worn them really about the same,
And both that morning equally lay
In leaves no step had trodden black.
Oh, I kept the first for another day!
Yet knowing how way leads on to way,
I doubted if I should ever come back.
I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I—
I took the one less traveled by,
And that has made all the difference.
So we speak for a higher voltage as for all my test a p.s +/-18 used.
JLH PARTS
I have abandoned my JLH builds and many useful parts for any of the JLH amps are on ebay, such as various heatsinks, power transistors - MJ802g & MJ15003g, LM338K 5amp TO3 regulators, 18v AC transformers and the high power (ESL) pcbs.
JLH CLASS A HIGH POWER (ESL) BARE PCB | eBay
click on other items to view the rest.
I have abandoned my JLH builds and many useful parts for any of the JLH amps are on ebay, such as various heatsinks, power transistors - MJ802g & MJ15003g, LM338K 5amp TO3 regulators, 18v AC transformers and the high power (ESL) pcbs.
JLH CLASS A HIGH POWER (ESL) BARE PCB | eBay
click on other items to view the rest.
So we speak for a higher voltage as for all my test a p.s +/-18 used.
I Think 24 V overall was meant. That would be +/- 12 for you. Thank you for your good work. Thorsten
So we speak for a higher voltage as for all my test a p.s +/-18 used.
+/-12V. Probably too low to test.
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+-12V ( or 0 24 V ) 2 amp looks good.
If you liked the other poem Adlestrop by Edward Thomas it is linked to the other one of Robert Frost. I live close by so more so to me.
Edward Thomas – Adlestrop | Genius
If you liked the other poem Adlestrop by Edward Thomas it is linked to the other one of Robert Frost. I live close by so more so to me.
Edward Thomas – Adlestrop | Genius
Very good. 10 kHz needs circa 190 kHz bandwidth. Looking at this one it's slightly less. The slight overshoot looks OK,
Hi thimios
Your results are good for a 2N3055H. In a simulation of the JLH with original (RCA hometaxial) devices and an epi-base device, I get much worse performance with the RCA than with an epibase, which also shows your slight overshoot.
I suspect that although your transistors might be labelled 2N3055H they are actually an epibase type from a process that gives a good second breakdown performance. I am sure ON Semiconductor have several choices of lines (MJ15003, MJ15015 etc) that they could use to provide an "H" -like second breakdown device.
I have also had to generate a model for the RCA device as most models available use a tf parameter that is more like the epibase. But it is a moot point as the RCA original is no more.
Your results are good for a 2N3055H. In a simulation of the JLH with original (RCA hometaxial) devices and an epi-base device, I get much worse performance with the RCA than with an epibase, which also shows your slight overshoot.
I suspect that although your transistors might be labelled 2N3055H they are actually an epibase type from a process that gives a good second breakdown performance. I am sure ON Semiconductor have several choices of lines (MJ15003, MJ15015 etc) that they could use to provide an "H" -like second breakdown device.
I have also had to generate a model for the RCA device as most models available use a tf parameter that is more like the epibase. But it is a moot point as the RCA original is no more.
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