Actually i wasn't aware that size was an issue, but i do appreciate all the help guys, thankyou!
I've done some searching and i think all the MKP is going to be way too big. The MKT is around 9mm so i guess i'm stuck with MKT : (
With film caps, lets say all MKT, is there any difference in sound between Kemet, Epcos and Vishay?
I've done some searching and i think all the MKP is going to be way too big. The MKT is around 9mm so i guess i'm stuck with MKT : (
With film caps, lets say all MKT, is there any difference in sound between Kemet, Epcos and Vishay?
If you are using the Zener as a regulator, all circuits I have seen use a parallel cap, next to the device, depending on the current requirements they are often used with a transitor in emitter follower mode to up the current. But for low current requirements they can be used on their own. They can generate some electrical noise so decoupling will help minimise any ripple on the output.
No. Two physical objects cannot occupy the same position at the same time. The cap can be close to the zener, although if it is just noise filtering you are doing then closeness is not necessary. Usually, decoupling caps are close to what they are feeding - not what they are fed from.Sonic77 said:
I suspect you might not be asking the question you think you are asking, or at least not for the reason you think. Tell us some context, then we may be able to answer more helpfully.
Capacitors do not have a sound. Capacitors in circuits may have a sound, especially if the circuit is poorly designed. There is no such thing as a 'good' cap; there are good caps for particular uses in particular circuits, the same cap used for another purpose in another circuit may be quite bad.
The power of wanting to find:
http://www.mouser.de/ProductDetail/...=sGAEpiMZZMv1cc3ydrPrF7yRxWMKYHonStDT2Ki7HX0=
http://www.mouser.de/ProductDetail/...EpiMZZMv1cc3ydrPrF%2bsu0%2bUU4qEgZe1Ftr3eLbM=
http://www.mouser.de/ProductDetail/...c3ydrPrF/UH96ueUpCvhc31vtRks6t7HEdB%2b7iSGA==
http://www.mouser.de/ProductDetail/...=sGAEpiMZZMv1cc3ydrPrF17gIuUB4mH19p7pfrfhjlQ=
http://www.mouser.de/ProductDetail/...=sGAEpiMZZMv1cc3ydrPrF7yRxWMKYHonStDT2Ki7HX0=
http://www.mouser.de/ProductDetail/...EpiMZZMv1cc3ydrPrF%2bsu0%2bUU4qEgZe1Ftr3eLbM=
http://www.mouser.de/ProductDetail/...c3ydrPrF/UH96ueUpCvhc31vtRks6t7HEdB%2b7iSGA==
http://www.mouser.de/ProductDetail/...=sGAEpiMZZMv1cc3ydrPrF17gIuUB4mH19p7pfrfhjlQ=
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There is nothing wrong with using MKT as a DC blocking and AC coupling capacitor.
Provided you do not use it to filter some of the wanted signal.
Move the filter to at least one decade lower than the lowest signal you want to pass.
eg.
for an Rin = 100kohms and wanting 20Hz to pass, the filtering effect should be set to <=2Hz
F-3dB = 1 / {2 Pi R C},
therefore C >= 1 / {2 Pi R F} >= 0.796uF, use 1uF, or 1u5F, or 2u2F, or etc.
Which ever size you adopt, the amplifier must be designed to handle all the signal that passes the input filters. You as the "modifier" must be able to check that your modification does not create an arrangement that destroys the performance.
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As I said previously it is standard practice to decouple a zenor used as a voltage reference or a small voltage regulator with a small value local decoupling cap, this on literally hundreds of designs over many years. It is therefore good practice to do this on such a circuit, once the design is laid out as a PCB you can determine whether the cap is required by measurements. Quite often you may not need it, but if it is there it can suppress the noise at source. this is just part of the many good practices you can follow when designing a power delivery system.
You do decouple other devices supplies locally, preferably with local caps. next to the pins and larger reservoir caps. spread out on the board and near areas of high current density, but the power sources themselves will have local capacitive decoupling.
You do decouple other devices supplies locally, preferably with local caps. next to the pins and larger reservoir caps. spread out on the board and near areas of high current density, but the power sources themselves will have local capacitive decoupling.
Ha ha, let's do as much blah blah as possible house of parliament style 
It would be wise to check the schematic of Quad 909 for real values. Of course I already did the math as indicated some posts earlier. Quad uses 330 nF with 62 kOhm. I would not go higher than 470 nF. There is a DC servo in this amplifier.
Tea anyone ?
It would be wise to check the schematic of Quad 909 for real values. Of course I already did the math as indicated some posts earlier. Quad uses 330 nF with 62 kOhm. I would not go higher than 470 nF. There is a DC servo in this amplifier.
Tea anyone ?
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Thankyou jean-paul, much appreciated!
I never thought to try the euro sites.
If i use 470nF 450V Polypropylene will this change any of the natural settings in the amp? I don't want to change the gain or change the natural settings ect, just want to use the best quality parts.
Also is Polyphenylene Sulfide the same as Polypropylene?
I never thought to try the euro sites.
If i use 470nF 450V Polypropylene will this change any of the natural settings in the amp? I don't want to change the gain or change the natural settings ect, just want to use the best quality parts.
Also is Polyphenylene Sulfide the same as Polypropylene?
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I wish to de-couple Zener diodes D1, D2, D12 for a Quad 909 using 100nF MKT.
Many people have highly recommended this mod but i am not sure how the de-couple caps are supposed to be applied here because frankly, i have no idea lol.
Dada electronics recommends using them in parallel to the Zener diodes on the opposite side on the PCB, but i wasn't sure, what do the pins on the MKT need to make contact with? Or if they need to go through the same hole ect?
What exactly do the pins of the MKT need to make contact with?
Many people have highly recommended this mod but i am not sure how the de-couple caps are supposed to be applied here because frankly, i have no idea lol.
Dada electronics recommends using them in parallel to the Zener diodes on the opposite side on the PCB, but i wasn't sure, what do the pins on the MKT need to make contact with? Or if they need to go through the same hole ect?
What exactly do the pins of the MKT need to make contact with?
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Think global, act local
I think 470 nF 450V MKP will be way larger than the original ones. It is simple. Choose a physical comparable cap with a "better" dielectric with 100V or higher rating. I pointed to 4 possible caps that fit. Check those all by comparing physical size and parameters. Make a choice and order 2 of the type you want to try. You need just 2, desolder the old ones and solder in the new ones with a "light" way of soldering to prevent solder pads to peel off. Make sure to solder in the new caps the same way in both channels as the outer foil has some shielding properties. Then switch the amplifier on and make some coffee. Start listening after 15 minutes. Listen for some time, repeat after some hours and leave the amp on all the time. You like it ? Then solder definitive. You don't like it ? Then solder the old ones back in. Gain and natural settings (whatever that may be) won't change. I never experienced rightly chosen "better" coupling caps making amplifiers perform worse. As said, I did experience owners that complained amplifiers sounding different when I replaced bulging defective electrolytic filter caps for new ones. Apparently one gets used to a slowly worsening sound character. I also experienced DIYers using D cell like caps with melt glue contraptions that picked up hum and RF and such.
* Polyphenylene Sulfide (PPS) is not the same as polypropylene (MKP).
OK how many more words can be spent on 2 caps ?
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100nF is a small value and thus only for high frequency duty. Therefore it must go as close as possible to minimize stray inductance between cap and device being decoupled.
The cap can either be soldered piggy-back on the zener diode's leads, or on to the solder pads on the other side of the circuit board.
The cap can either be soldered piggy-back on the zener diode's leads, or on to the solder pads on the other side of the circuit board.
A 0.1uF cap will only reduce RF noise from a zener. It is far too small to deal with audio noise. I suspect that the people suggesting this mod have no idea.
Adding extra components on the track side of a PCB is a standard means of patching up a design. The component leads simply solder to the relevant pads; they usually don't go through any holes.
Adding extra components on the track side of a PCB is a standard means of patching up a design. The component leads simply solder to the relevant pads; they usually don't go through any holes.
compare the pin pitch/spacing of the new capacitor to the pin pitch of the installed Zener.
You are likely to find that the Zener is either 0.4", or 0.5" pin pitch.
If you are lucky it may be 0.35", or even 0.3"
You are best to use a capacitor that gets pretty close to the zener pad spacing.
It is best if you don't need to bend the cap pins to fit the PCB pads.
But you will almost certainly need to bend the pins a little bit to get the pins to touch the PCB pads. Don't crack the insulation where the pins enter their package. This insulation is usually quite brittle.
If the cap needs to lie flat against the PCB so that the PCB still fits inside it's enclosure, then insert a layer of sticky tape between the cap and it's pins and the PCB, just to help avoid shorting. A double sided sticky tape could hold the cap in position till you make the first solder connection.
This "flat" installation will require the pins to be bent slightly towards the PCB so that the pins just touch the pads next to the existing cut off pins of the Zener.
You are likely to find that the Zener is either 0.4", or 0.5" pin pitch.
If you are lucky it may be 0.35", or even 0.3"
You are best to use a capacitor that gets pretty close to the zener pad spacing.
It is best if you don't need to bend the cap pins to fit the PCB pads.
But you will almost certainly need to bend the pins a little bit to get the pins to touch the PCB pads. Don't crack the insulation where the pins enter their package. This insulation is usually quite brittle.
If the cap needs to lie flat against the PCB so that the PCB still fits inside it's enclosure, then insert a layer of sticky tape between the cap and it's pins and the PCB, just to help avoid shorting. A double sided sticky tape could hold the cap in position till you make the first solder connection.
This "flat" installation will require the pins to be bent slightly towards the PCB so that the pins just touch the pads next to the existing cut off pins of the Zener.
