I stated clearly in post #7 that I was not expecting any change in sound. But two people elsewhere...guys who I know to be more knowledgeable than you...have indicated that this cap could potentially have an effect on high frequencies.
Someone in this very thread indicated the same thing. Why are you not calling that poster out?
Tell me this Mr Fahey... how is my merely asking whether this cap could affect high frequencies going to convince "some poor soul who reads this thread in the future" that is is indeed a fact?
I am only asking a logical question, especially so in light of the fact that three people have indicated that it is or could possibly be the case.
No, I don't think that you are here to save some poor soul from picking up some (possibly) incorrect information. I think that you are just being rude. The tone of both of your posts in this thread is unwarranted.
I come here maybe 3 or 4 times a year and ask a question. The vast majority of DIYaudio members are helpful, respectful, civilized, and easy to get along with. Yet even though I visit rarely...I remember your name because I have seem multiple threads where you are rude and condescending to "some poor soul".
I think the Admin and Mod team here should consider how many people you may be driving away from the site. Good, gentle people who leave rather than enduring your meanness. I wonder how many?
Hi I think JMFahey is a knowledgable man but he might not be the most of easy going towards the often OCD like audiophile reasoning indeed. This does not take away his vast amount of knowledge in the Pro audio field. It may not be clear but he designs and manufactures PE equipment and does know what he is talking about for sure.
So I suggest we keep on moving without paying too much attention to courtesy, manners, strong opinions etc as most just come here to get answers from exactly people like JMFahey.
You could read post from the audiophile crowd where the most minuscule details make a day and night difference and also read posts of pro people and make a choice.
So I suggest we keep on moving without paying too much attention to courtesy, manners, strong opinions etc as most just come here to get answers from exactly people like JMFahey.
You could read post from the audiophile crowd where the most minuscule details make a day and night difference and also read posts of pro people and make a choice.
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Thanks to abraxalito, Markw4, wg_ski, rayma, jean-paul, 2 picoDumbs 
Just trying to get this little amp refurbished and not screw anything up. And jean-paul...all electrolytic caps are, or will be, refreshed. Lots of 4.7uF Wimas went in...you didn't see the tone amp board...there were four caps (per channel) in the signal path small enough to fit film (3 Wimas and a Panasonic ECQ-V).
Key resistors are upgraded to .1%, 15ppm metal film, new trimmers, actives in the regulator, etc. I do methodical, cautious rebuilds. I am careful about every part that goes in. That is why I am so picky about questions about parts where I do not fully understand the circuits.
I appreciate everyone's input....
Just trying to get this little amp refurbished and not screw anything up. And jean-paul...all electrolytic caps are, or will be, refreshed. Lots of 4.7uF Wimas went in...you didn't see the tone amp board...there were four caps (per channel) in the signal path small enough to fit film (3 Wimas and a Panasonic ECQ-V).
Key resistors are upgraded to .1%, 15ppm metal film, new trimmers, actives in the regulator, etc. I do methodical, cautious rebuilds. I am careful about every part that goes in. That is why I am so picky about questions about parts where I do not fully understand the circuits.
I appreciate everyone's input....
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As someone who went the same route long ago I now can understand the view of pro people a bit better
The master recordings went through a lot of cheap opamps and did not meet 0.1% 15 ppm resistors on their way.
It is just not a sum of parts but also of topology and how things are designed and constructed. When things are not 100% understood many focus on very tiny details as a result of insecurity. That is normal but it may cause strong reactions of people that do audio for a living.
The master recordings went through a lot of cheap opamps and did not meet 0.1% 15 ppm resistors on their way.
It is just not a sum of parts but also of topology and how things are designed and constructed. When things are not 100% understood many focus on very tiny details as a result of insecurity. That is normal but it may cause strong reactions of people that do audio for a living.
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I would focus your attention on poor quality connections. Anything that could have oxides on the mating surfaces, or is not tight.
Check all ground connections.
If you see any evidence of oxides on the copper wiring replace them, I prefer tin plated copper (or silver plated copper), mostly because it sucks rewiring an amp, tin plated or silver plated will basically never need to be replaced once it is done.
Regarding components, focus your attention on components that sit outside of a feedback loop.
Then after that, components that make up the feedback loop.
Good old CMF55 or RN55 vishay dales are usually more than adequate.
Spending more is fine provided the amp is actually worth investing in.
Check all ground connections.
If you see any evidence of oxides on the copper wiring replace them, I prefer tin plated copper (or silver plated copper), mostly because it sucks rewiring an amp, tin plated or silver plated will basically never need to be replaced once it is done.
Regarding components, focus your attention on components that sit outside of a feedback loop.
Then after that, components that make up the feedback loop.
Good old CMF55 or RN55 vishay dales are usually more than adequate.
Spending more is fine provided the amp is actually worth investing in.
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@jean-paul NFB resistors is what I am referring to. Even Bob Cordell's book mentions those specifically. And jean-paul...you made a reference to "the resistors" yourself.
I understand that topology trumps components. But I am not a designer or builder. I am a restorer. I love the older amps. And when an amp is on my bench and opened up for a few weeks...It makes sense to do the best I can, within reason, for that limited time. Once I am done with that amp it will likely never see any attention again.
If I am too picky or if my approach irritates someone, then they don't have to post. I did make a conscious effort to keep my questions simple and to provide all information relevant to anyone who might be willing to answer those questions. But...things get messy sometimes. That's life.
IMO it does not matter how much knowledge a person might have...in any particular field. Other people have may vast knowledge in thousands other areas than electronics and/or audio. And some people may not have the ability to learn as easily as others. All people are equal and should be treated with respect.
I understand that topology trumps components. But I am not a designer or builder. I am a restorer. I love the older amps. And when an amp is on my bench and opened up for a few weeks...It makes sense to do the best I can, within reason, for that limited time. Once I am done with that amp it will likely never see any attention again.
If I am too picky or if my approach irritates someone, then they don't have to post. I did make a conscious effort to keep my questions simple and to provide all information relevant to anyone who might be willing to answer those questions. But...things get messy sometimes. That's life.
IMO it does not matter how much knowledge a person might have...in any particular field. Other people have may vast knowledge in thousands other areas than electronics and/or audio. And some people may not have the ability to learn as easily as others. All people are equal and should be treated with respect.
It DOES matter how much knowledge one has. People are equal but that does not make much of a difference for technological matters.
The original resistors in that device are not the best to put it mildly but 0.1% 15 ppm is way overrated for instance. The device won't perform better as a result of using those. Replacing electrolytic caps used in the input circuitry and better decoupling will result in an improvement.
I think it is called "the law of diminishing returns" in your language. You are right that one better does a job good at once though. Many leave worn-out large filter caps because of cost only to receive the device back after awhile because they did break down. Replacing those nearly always results in measurable/audible improvements (when the old ones were dry).
BTW make sure you replace C403a for a bipolar one like the muses series. When that device was built bipolar caps were expensive but there is AC signal there.... Also a 100 nF film cap as bypass won't hurt.
The original resistors in that device are not the best to put it mildly but 0.1% 15 ppm is way overrated for instance. The device won't perform better as a result of using those. Replacing electrolytic caps used in the input circuitry and better decoupling will result in an improvement.
I think it is called "the law of diminishing returns" in your language. You are right that one better does a job good at once though. Many leave worn-out large filter caps because of cost only to receive the device back after awhile because they did break down. Replacing those nearly always results in measurable/audible improvements (when the old ones were dry).
BTW make sure you replace C403a for a bipolar one like the muses series. When that device was built bipolar caps were expensive but there is AC signal there.... Also a 100 nF film cap as bypass won't hurt.
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Connections between boards are all either directly soldered wires or wire-wrap pins (which I never touch).
I disagree with you about the feedback loop, I believe that components inside a feedback loop are the most important. I could site references....but this thread is getting way too long and off-topic.
I love Vishay Dale CMF resistors...non-magnetic end caps. Those are my first choice. But I couldn't find the correct values in CMF for the resistors that I replaced in this amp. I believe that the RN55's would be too large physically. In this amp I used TE HOLCO series for the first time. Very precise but the end-caps are not non-magnetic. They look nice though
Did you notice my remark on the 100 µF 25V in the feedback loop? The bipolar Nichicon muse caps have copper lead wires too
How parts look is of no importance except that they might please the eyes. Socalled boutique parts are bought for their appearance and the "for audio" text. Industrial parts often are better and might just be relabelled for audio use...
How parts look is of no importance except that they might please the eyes. Socalled boutique parts are bought for their appearance and the "for audio" text. Industrial parts often are better and might just be relabelled for audio use...
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I wasn't saying they weren't important. I was saying they are indeed bloody important.
My point is. If the input components are faulty or terrible the feedback can do nothing to correct it. It's too bloody late at that point isn't it, regardless of whether you have $50 resistors/capacitors in the feedback loop or not.
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If I am going to replace CF resistors with MF....and if I am going to search Mouser for a replacement part....and invest time in de-soldering the old and soldering in the new...why does it matter if I wish to choose the best part I can find? The search time is the same, the labor time is the same reg. Are you suggesting that I should use a .10 cent MF resistor instead of a $1 one?
LOL we can agree to disagree on that I guess
I am already planning to use Nichicon ES for C403 in the NFB
Don't have it yet, will be in the next order...
If using 1$ resistors makes you feel better then go ahead. Any tech can point out that price is not an indicator of quality. let's say you are a manufacturer of resistors. You produce 1000,000 per week. You sell to the industry. Now someone discovers a fault in the resistors which makes them fail. After this you make sure your product does not fail as recalls means the end of your business. Now a customer shows up if you can produce audiophile resistors, quantity 1000 per value. What would you do?
BTW if you give half information and already made up your mind it does not make much sense to ask.
BTW if you give half information and already made up your mind it does not make much sense to ask.
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Did you notice my remark on the 100 µF 25V in the feedback loop? The bipolar Nichicon muse caps have copper lead wires too
How parts look is of no importance except that they might please the eyes. Socalled boutique parts are bought for their appearance and the "for audio" text. Industrial parts often are better and might just be relabelled for audio use...
The NFB cap, C403, is 22uf/16v (I am going to use the largest Nichicon ES that will fit physically, 33uF/25v at 8mm diameter)
C416 is the 100uF/25v cap. Is there AC signal on C416?
I didn't think there was AC signal on C416. But it does connect to the input diff pair (through a resistor) so perhaps it does have signal present. I don't know.
I just want to be on the same page with you. We agree that the NFB electrolytic, C403, should be bipolar. But C403 is NOT the 100uf 25V cap.
Do you think that both C403 and C416, both should be bipolar?
I just want to be on the same page with you. We agree that the NFB electrolytic, C403, should be bipolar. But C403 is NOT the 100uf 25V cap.
Do you think that both C403 and C416, both should be bipolar?
OK. Got it thanks. Yes I will order that on my next Mouser. Already searched the largest that will fit is 8mm diameter. And the largest value in that physical size if 33uf 25v Nichicon ES. I really like those caps. I read the thread here (somewhere) about how well they tested...
They look good too
Now I must go to bed
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