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Old 4th September 2012, 10:58 PM   #1
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Default Where do you start? PS, Op Amps, Capacitors etc

I'm going to start two mod projects soon. A Musical Fidelity VPS II and a Schiit BiForest. I looking over other peoples mods and it left me wondering... what do you change first where do you usually get the most bang for the buck with upgraded parts. Do you change the power supply first or the Power regulators with a super regulator, op amps 2nd, caps, etc. ? What do people recommend?

Where do start?
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Old 4th September 2012, 11:39 PM   #2
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If the amp is older I would change the power supply capacitors first.
Changing the op amps should give a better frequency response but look out for oscilation with faster op amps.
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Old 4th September 2012, 11:42 PM   #3
Enzo is offline Enzo  United States
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I don't mean to sound snooty, but I start by defining my goals. And part of that is assessing the current performance. If my exsisting voltage regulators are doing a good job, then changing them goes way down my list. If I want a better noise floor, that is a fine goal, and we address that. I am in pro audio, not hifi, so I am not up on the latest op amp du jur. others can suggest types for you. But having specific goals in mind lets us plot a course to get you there.

Remember that an amp is a system, not just a collection of parts. SO incremental improvements of a number of things can result in overall changes in opertion, and sometimes one thing impacts another.
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Old 5th September 2012, 12:00 AM   #4
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My goal is to reduce the noise floor, get more inner detail without it sounding harsh. Like you said it's not just a collections of parts but a system. With that said I would say that there is up stream and down stream parts. In that case of the power supply it's the source of the river it may affect everything downstream So do you replace parts upstream to downstream or you randomly choose areas. If you change the power supply, regulator, or op amp can the final result be the same? Example does a better power supply make a cheaper op amp sound better due to quality power as a better op amp that can handle less then quality power. How how do you decide which one to change first. The cheapest part?
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Old 5th September 2012, 12:04 AM   #5
ide2003 is offline ide2003  Indonesia
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I have modded many CDP, DAC, and of course my own amp's. Like Enzo I have my own goal, that is the sound I want. When modding branded system I always look where the maker likely skimp on components, most of the time it was PSU caps, DC blocking caps, then decoupling caps. After that active parts such as opamp.

On power amp I'll look for possibility in changing the bias first, this gives imo more improvements before changing other passive parts. Over the years you'll know where to apply certain brands
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Old 5th September 2012, 12:22 PM   #6
marce is offline marce  United Kingdom
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Learn some electronics
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Old 6th September 2012, 06:20 PM   #7
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Simple answer, based on my limited experience and knowledge: improving/replacing capacitors will usually give the most obvious results. Not always improvements, but most obvious.

These electronic systems have been tuned to have a certain overall sound. As some have already stated, change a few components and you will change that overall sound. Perhaps for the better, perhaps not.

I'm not trying to discourage you. The results are usually positive, especially with caps, especially caps in the signal path, especially electrolytic caps in the signal path. Of course, ultimately, almost every component is "in the signal path", including the PS. However, I mean the caps that are directly part of the path, such as input/output coupling caps. In some equipment, these can be large values that are most economically, and detrimentally to the sound, 'lytic types. If film types are used, they may be lower quality. Start there. Do some research. Spend some money. Better quality caps cost more, although the correlation is not always direct, and after a certain point yield is no longer proportional. Only you can determine that point in your system.

Changing opamps, unless they are very old designs or very low quality, can cause as many problems as it solves, and will yield lesser results for more effort. Because of many different performance parameters, they can be a bit more exotic to the novice. Not every opamp, even though it's "better", will work well in every application. Unless they're in sockets, changing them can damage pads or other parts. If they're in sockets, merely removing the sockets and soldering directly to the PCB may yield improvements. Better bypassing may also yield improvements, but designers of better equipment already know to do that.

Power supply mods may yield improvement, but involve modest risk to you and the equipment if you don't know what you're doing.

Resistors also have a sonic signature, and improving the quality of those can change the sound, usually for the better, but in small increments.

The objective of every manufacturer is to maximize profit. This is accomplished by using the cheapest parts that will meet their design goals. Frequently, a better quality (usually, more expensive) or a newer design part will yield improved sonics, but that means nothing to the manufacturer if their objective is already achieved. Your mission is to find those places where money and effort and time will yield improvement. Caps are the biggest target.

Peace,
Tom E
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Old 6th September 2012, 06:55 PM   #8
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Depends on so many things, including your motive.

If a machine is in a fit state to use, then do so for a week or so and get to know what you like about it, and what you don't. There are several routes from this point.

One option is to find out what afficianados of your particular machines have been doing, and go with the flow. The advantages of this is that you can identify known weaknesses, and get a feel for what's possible to achieve. Some sneer at this route to enlightenment, but music's a social thing. It's perfectly legitimate to follow a crowd. You get to know the people who hear what you hear.

Another is to see if your impressions are reflected in its measured performance. Not much good if you can't measure. Get the service manual and check it's working properly, and see if you can see reasons for your impressions and measurements in the circuit design.

Whatever, bear in mind that the machine was probably designed by engineers who had reasons for doing what they did. Your reasons have to be better than theirs, from your point of view.

The machine must have at least one good thing going for it. There's no point in changing everything, obviously. Decide how the good bits are let down by bad, and start from there. No point in recapping a power supply only to decide it needs replacing.

Don't throw the baby out with the bathwater.

If you are only able to make a stab in the dark, it's often the case that new caps make a worthwhile difference. The biggest bang for your buck, if you factor in time and effort, would be to look at the caps and what they do, and swap for ones with better specs for each job. This can be cheap if you avoid speciality products, read datasheets, and buy from reliable high-turnover sources. Arguably, cap quality is one thing that has improved over the years. If electrolytics are old, and the machine is worth preserving, then replacement is worthwhile anyway.
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Old 6th September 2012, 06:58 PM   #9
ide2003 is offline ide2003  Indonesia
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Hi Steven, I have a look at your shiit pcb here at 6moons. Look like it's well made and designed, black lytics are Epcos, quite good to my experience, don't know the 2 big brown ones. Silmic II may be good here.

I will check the fuse/fuse holder, RCA's & IEC pins with magnet, if they are ferrous then copper will sound better. In all, not so easy pcb's here to work with.
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Old 6th September 2012, 07:05 PM   #10
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Depends on so many things, including your motive.

If a machine is in a fit state to use, then do so for a week or so and get to know what you like about it, and what you don't. There are several routes from this point.

One option is to find out what afficianados of your particular machines have been doing, and go with the flow. The advantages of this is that you can identify known weaknesses, and get a feel for what's possible to achieve. Some sneer at this route to enlightenment, but music's a social thing. It's perfectly legitimate to follow a crowd. You get to know the people who hear what you hear.

Another is to see if your impressions are reflected in its measured performance. Not much good if you can't measure. Get the service manual and check it's working properly, and see if you can see reasons for your impressions and measurements in the circuit design.

Whatever, bear in mind that the machine was probably designed by engineers who had reasons for doing what they did. Your reasons have to be better than theirs, from your point of view.

The machine must have at least one good thing going for it. There's no point in changing everything, obviously. Decide how the good bits are let down by bad, and start from there. No point in recapping a power supply only to decide it needs replacing.

Don't throw the baby out with the bathwater.

If you are only able to make a stab in the dark, it's often the case that new caps make a worthwhile difference. The biggest bang for your buck, if you factor in time and effort, would be to look at the caps and what they do, and swap for ones with better specs for each job. This can be cheap if you avoid speciality products, read datasheets, and buy from reliable high-turnover sources. Arguably, cap quality is one thing that has improved over the years. If electrolytics are old, and the machine is worth preserving, then replacement is worthwhile anyway.
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