I just finished recapping the preamplifier section of a Sansui AU 4900, I used Chinese capacitors that I bought in the local market. They have insisted that I choose Nichicon, Vima, etc. Impossible to get here, and if there were they would cost an amount of money that I personally do not justify in this amplifier. I have been roundly disqualified by the brands I chose, but a search on the web makes me think that it is not garbage, and that they will last without failure for probably another 40 years longer than the amplifier has.
I did a meticulous measurement of all the electrolytic capacitor´s , I did not find any with significant losses in capacity, only one showed that it did not retain a charge.
I did a meticulous measurement of all the electrolytic capacitor´s , I did not find any with significant losses in capacity, only one showed that it did not retain a charge.
Hi Indigent Audio,
Well, if you understand circuit design and components you'll understand that no one component in the coupling position will ever be transformational. In circuit locations where components do make a difference is it the type, not the brand that matters. Matching of some parts will also greatly improve performance and sound quality.
Unfortunately, what matters does require knowledge, skill and instrumentation in order to get the matches. It also requires time, and time is money. You can't whack through a bunch of stuff doing it right. Someone has to know what they are doing and invests the time.
Anyway, the magic part simply does not, and will not exist. Improving sound quality requires a system view and actual engineering concepts.
Well, if you understand circuit design and components you'll understand that no one component in the coupling position will ever be transformational. In circuit locations where components do make a difference is it the type, not the brand that matters. Matching of some parts will also greatly improve performance and sound quality.
Unfortunately, what matters does require knowledge, skill and instrumentation in order to get the matches. It also requires time, and time is money. You can't whack through a bunch of stuff doing it right. Someone has to know what they are doing and invests the time.
Anyway, the magic part simply does not, and will not exist. Improving sound quality requires a system view and actual engineering concepts.
Hi IWC Doppel,
I am trying to address several factors here.
Agree.
I look at the entire system, and individual components in the chain. For a CD player, the basic is the quality of the RF pattern (eye pattern). Beyond that you're into chip sets and then the quality and design of the audio stages. Lot's there. Same for streamers. Lots involved in tuners and other sources. Once you have the basic issues solved you can upgrade certain sections. However in some equipment there are circuits that kill any improvements you can possibly make. You have to identify those and either eliminate those problems, or move on to another replacement piece. Also, it doesn't make sense replacing an NE5532 buffer in a tuner with anything better. So common sense must prevail.
Listening is the final reckoning. However I have found that when it measures well (looking at the spectrum) it will sound good also. Measurements keep you on track, the final decision is how it sounds. Also, to be honest, how it looks. Appearance matters as you have to look at the thing. This may decide between a few equivalent performing pieces. Nothing I have just said conflicts with anything I have said in the past.
No one brings a suite of test equipment shopping. But, when I shop the gear comes directly to my bench to confirm and look for problems. Measurements keep us honest and on track.
Measured results often show little difference between equipment where one is considered far superior for sonics. That's assuming equivalent build quality (electronically). You can strip away all kinds of mis-information on the bench.
Proper measurements have almost never lead anyone astray. Never in my personal experience, but I'll accept a percentage may since I'm not all-knowing.
If something sounds dreadful but measured well, I guarantee the measurements were not made correctly or were incomplete. This occurred early in time before we could "see" down far enough, or knew what to look for. This situation doesn't exist today with folks who actually do know what they are doing.
I am trying to address several factors here.
Agree.
I look at the entire system, and individual components in the chain. For a CD player, the basic is the quality of the RF pattern (eye pattern). Beyond that you're into chip sets and then the quality and design of the audio stages. Lot's there. Same for streamers. Lots involved in tuners and other sources. Once you have the basic issues solved you can upgrade certain sections. However in some equipment there are circuits that kill any improvements you can possibly make. You have to identify those and either eliminate those problems, or move on to another replacement piece. Also, it doesn't make sense replacing an NE5532 buffer in a tuner with anything better. So common sense must prevail.
Listening is the final reckoning. However I have found that when it measures well (looking at the spectrum) it will sound good also. Measurements keep you on track, the final decision is how it sounds. Also, to be honest, how it looks. Appearance matters as you have to look at the thing. This may decide between a few equivalent performing pieces. Nothing I have just said conflicts with anything I have said in the past.
No one brings a suite of test equipment shopping. But, when I shop the gear comes directly to my bench to confirm and look for problems. Measurements keep us honest and on track.
Measured results often show little difference between equipment where one is considered far superior for sonics. That's assuming equivalent build quality (electronically). You can strip away all kinds of mis-information on the bench.
Proper measurements have almost never lead anyone astray. Never in my personal experience, but I'll accept a percentage may since I'm not all-knowing.
If something sounds dreadful but measured well, I guarantee the measurements were not made correctly or were incomplete. This occurred early in time before we could "see" down far enough, or knew what to look for. This situation doesn't exist today with folks who actually do know what they are doing.
Hi engin_ear,
I did warranty on those amps, so I'm very familiar with them. I still service them.
Look at the ripple on the main filter caps. If the waveform shows certain changes, or features, it is time to replace them. I will say that often those capacitors are fine and do not require replacement. They are made better, have much better seals and more electrolyte inside. Smaller capacitors in high stress areas are far more likely to fail. The other major factors are run time and ambient temperature.
Anyway, using an oscilloscope and a brain will answer your question.
I did warranty on those amps, so I'm very familiar with them. I still service them.
Look at the ripple on the main filter caps. If the waveform shows certain changes, or features, it is time to replace them. I will say that often those capacitors are fine and do not require replacement. They are made better, have much better seals and more electrolyte inside. Smaller capacitors in high stress areas are far more likely to fail. The other major factors are run time and ambient temperature.
Anyway, using an oscilloscope and a brain will answer your question.
I have two stupid questions, do tantalum caps dry and age like regular electrolytics?
If not, why aren't they used more in diy, where voltage regulators usually require a fair amount of capacitance at the output (for stability)?
I was trying to get rid of the electrolytics in some of the projects I have been working on, but the regulators seem to need 100uF to 200uF in order to have good phase margin (on the simulator).
Thanks,
Alex
If not, why aren't they used more in diy, where voltage regulators usually require a fair amount of capacitance at the output (for stability)?
I was trying to get rid of the electrolytics in some of the projects I have been working on, but the regulators seem to need 100uF to 200uF in order to have good phase margin (on the simulator).
Thanks,
Alex
Hi,
Tantalum capacitors don't dry out. They do suddenly short. I'm sure there is a wearout mechanism for them.
Why don't we use them more? They are expensive, you have to underrate their voltage rating specs - a lot! They do not handle reversed polarity at all, and spikes can sometimes kill them, over-voltage does for sure. That and they have horrible dissipation specs and terrible performance for audio. Try a Poly-Aluminum for improved HF characteristics.
Positives for tantalum caps are low leakage, stable capacitance and small size.
Tantalum capacitors don't dry out. They do suddenly short. I'm sure there is a wearout mechanism for them.
Why don't we use them more? They are expensive, you have to underrate their voltage rating specs - a lot! They do not handle reversed polarity at all, and spikes can sometimes kill them, over-voltage does for sure. That and they have horrible dissipation specs and terrible performance for audio. Try a Poly-Aluminum for improved HF characteristics.
Positives for tantalum caps are low leakage, stable capacitance and small size.
Ceramic capacitors are good if one is not using a RC filter (as in supplies for digital logic). Audio requires not injecting current into the ground plane. That necessitates a RC filter where the capacitor has low reactance from audio through RF. Tantalum is the only capacitor that can do that.
Ed
Ed
Ed,
Where do you think any type of capacitor will couple noise current to??? Capacitor type is immaterial if that capacitor is effective.
So let me tell you where. Noise current will be returned to either a "dirty ground" return, separate from the signal common, or to the other supply rail (negative for positive noise currents). Where your noise current goes to is a matter of circuit and PCB design, not capacitor type.
An R-C filter can be an effective attenuator for higher frequencies and has nothing to do with where the noise current ends up. More effective is an L-C filter and it depends on the frequencies you are trying to attenuate.
-Chris
Where do you think any type of capacitor will couple noise current to??? Capacitor type is immaterial if that capacitor is effective.
So let me tell you where. Noise current will be returned to either a "dirty ground" return, separate from the signal common, or to the other supply rail (negative for positive noise currents). Where your noise current goes to is a matter of circuit and PCB design, not capacitor type.
An R-C filter can be an effective attenuator for higher frequencies and has nothing to do with where the noise current ends up. More effective is an L-C filter and it depends on the frequencies you are trying to attenuate.
-Chris
it all depends on aplication.in neutral amp BG is no go. put them in laidback ,midrange recessed Pass labs amps and they do miracles. I have tried many caps ,but in pass labs they sound amazing complementing pass sound. unfortunatelly i remooved them form all pass labs amps I have for economical reasons. the capacitors set in amp can not cost 1000+ eur = half of amps price. they become too expensive to keep in amps. I also remooved most BG from my cd transports( where BG prices exceeded transport prices 2-6x times)
