Hi juma,
You should listen to jackinnj. He is correct.
You can't design a winner unless you pay attention to both your ears and what your instruments are telling you. Not unless you have so much experience with doing this that you already know what works and what doesn't. Then you will check the numbers just to confirm performance.
When various measured numbers and your perception of what you are hearing diverge, the design will not be nearly as good as one where the sound quality and numbers are both improving. You should never judge your own work, let perfect strangers do that for you if you want honesty.
You should listen to jackinnj. He is correct.
I'm one of those funny people who do the same thing. Except, I find that when the numbers are improving along with the sound quality, you are on the right track. Measurements and listening tests support each other. From long experience servicing audio equipment, mostly higher end ones, this is universally true.
You can't design a winner unless you pay attention to both your ears and what your instruments are telling you. Not unless you have so much experience with doing this that you already know what works and what doesn't. Then you will check the numbers just to confirm performance.
When various measured numbers and your perception of what you are hearing diverge, the design will not be nearly as good as one where the sound quality and numbers are both improving. You should never judge your own work, let perfect strangers do that for you if you want honesty.
I put one together -- by tweaking the supplies V+ to 22.6 and V- to 6.2, was able to get the THD% down to 0.005% very good indeed!
YMMV -- with the original values the result (2%) was worse than the sim (0.2%). Depending on the gm and Idss of the JFETs other voltages may be optimal.
YMMV -- with the original values the result (2%) was worse than the sim (0.2%). Depending on the gm and Idss of the JFETs other voltages may be optimal.
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I find fundamentally rude and ethically disqualifying when someone gives himself God's prerogatives by telling unknown people what to do and gives unwanted advice.
You tell me that your servicing experience qualifies you and I tell you that I've transcended that kind of knowledge and experience long ago.
Decades ago, as a young engineer, I used to search patterns in measurement numbers and perceived sensations, so what happened was inevitable 'cause you cant code love. I have too much serious work in other areas of my life so audio had to stay love and hobby - that's the only way it makes sense to me.
You can go about it any way you want and I won't tell you it's wrong - it's your way to do it and I'll do it my way. Allow for possibility that your/his/her way of doing things is not the only one that's unerring. Pursuit of happiness should be basic and personal right...
So please, don't give me lectures, advice or tell me what to do, I know why and what I do. I don't need to design a "winner" or to please anyone else. By chance probably, it happens that some of the things I make for me tend to please other people too. That's great and I'm happy about it too but that's not my goal - making this stuff is just what I love to do, exactly the way I do it. Everybody else are free to do it their own way...
Giasou Niko !
I'll be living and working here for next 3-4 years, the same way I was in the Athens. Those were nice days, had really good times in Greece, hope I come again as soon as work and other obligations permit. I know, things are bit tough there right now, but I'm sure it will work out all right in the end. We never had it easy, did we...
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Yes, those small Epos speakers that I got from you still follow me
Not only that they are still fun, they tie me sentimentally, too.
Na'sai kala !
I'll be living and working here for next 3-4 years, the same way I was in the Athens. Those were nice days, had really good times in Greece, hope I come again as soon as work and other obligations permit. I know, things are bit tough there right now, but I'm sure it will work out all right in the end. We never had it easy, did we...
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Yes, those small Epos speakers that I got from you still follow me
Not only that they are still fun, they tie me sentimentally, too. Na'sai kala !
Hvala!A friend here has put together Cubie and Cubie2 by the way and he told me over the phone that Cubie2 sans output stage feedback is his favorite little simple amp ever. He had done a dozen of alike circuits. I hope I will meet him in September and listen to your amp. Keep up the hobby, and best of luck.
"Scientists" talk sweet spot cancellation in an already robust concept. This pre is like the classic cascade two triode gain and follower. Used to good effect for ages by tube heads. Since they got the time and the test gear give their suggestions an ear IMHO. And let your taste say if their tweak should stay. Maybe a comparably less THD than originally but detuned cancellation result with bit more 2nd in the end. Unless you have done this already back when first developing the pre.
Put the bias adjust potentiometers on the front panel! Let people adjust them by ear. Maybe you'll discover that the scatterplot of preferences, is not centered on (+22.6v , -6.2v). And that would be interesting!
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Sure thing. I've been suggesting that through all my threads/projects: try, experiment, find for yourself what you like the most. If someone is lazy, afraid or simply likes result with the values I gave, that's all OK too.
As already said, texts about load line optimization are long known and plentiful. It's all public domain and everybody is free to make his own choices...
Last time i did a listening test at my house, the New Jersey Audio Society splinter group drank 3 bottles of cab, 2 bottles of chardonnay and ate an entire lasagna.
