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Havoc
2007-11-09, 13:43
when reading the questions they ask just means they shouldn't be allowed to touch a soldering iron?

I mean, when you read some questions about power supplies it is just clear that those askinf them don't have a clue what this is all about. It is very clear they don't understand what they are doing, have no idea about the safety issues and probably make things worse than they were. And very likely they make it unsafe.

All suitable candidates for a Darwin award.

haunyack
2007-11-09, 15:02
All suitable candidates for a Darwin award.

So, where does one start?
I'm sure Edison broke a few things along the way.

.

Havoc
2007-11-10, 05:40
You don't start with modifying circuits you don't understand but by building simple stuff and getting experience and knowledge.

zanash
2007-11-10, 06:54
your answer presupposes that the modder has some prior knowledge....

as haunyack says where do you get that knowledge or experience if you don't first ask or try ?

What may seem stupid to you ....may be perfectly sensible to others.

As to safety well you can just as easily get run over by a bus ....but any sensible response should offer advice as to the safety and safe practice of any mods. The whole of life is one long risk assessment...

Also you learn by your mistakes in general terms. As the old saying goes someone who has made no mistakes has done nothing.

iPhone
2007-11-10, 07:15
I guess I would start with What does Evolution have to do with Electronics?

Evolution implies that over time (and that is lots of time) and specific conditions a species develops skills or changes. Are people new to electronics expected to grow a soldering iron on the right hand and have solder feed out of their left hand before they are allowed to Join the modification part of our hobby?

They already have to learn a second language (the language of Electronics) and become proficient with a soldering iron. They have to start the same places we did, but they are trailing because they are new to the hobby and do not have all the years of training, hands on experience, project building, or working in the electronics industry that we do.

Isnt it good for our hobby and the future of audio modification to encourage and nurture the spark of wanting to improve on a product by finding suitable modification projects that either replace OEM parts with better parts because the manufacture was building to a price point or modify output circuits to improve the purity of the audio path?

I do agree that opening the back of the SB3 and soldering away is probably not the best place to have ones first modification lesson or experience. Building an outboard PS project is a much better place to start. The SB3 will remain intact and undamaged as long as they insure that the center pin is plus 5 VDC and the outer is ground. It is to bad that all the electronic kit companies have all but disappeared. Heath was a great place to get somebody interested in electronics that start they needed but was not already knowledgeable in the arts of flowing solder. My first projects were crystal radio sets and test equipment kits. Moving on later to build a Conrad-Johnson PV3 Pre-Amp and building tube amps.

Better yet, one of us should probably take the time to post a few simple projects to get them started. If they can handle them, then they can consider moving on to the inside of the SB3 as their skills increase. If they can not complete the projects, they should probably leave the modifications to others. Maybe start a new section in Modifications or DIY just for beginners: Hello and welcome, Modification Newbies start here!

haunyack
2007-11-10, 11:43
Hello and welcome, Modification Newbies start here!

It's been many years since I touched an Iron.
When I was 16, I had a Heathkit 2ch stereo amp kit that I built and promptly fried the power transistors.
That was my last kit.

OK...so for a beginner (as I am) what would be a good starting toolbox to have on hand for when one decides to jump in again?

.

maniac
2007-11-11, 18:26
For starters, a very useful kit to build would be a power supply kit. Since if you do experiment, you will need that from time to time to power up some part of the circuit while you measure the result.

As for useful tools to have in the toolbox.
*multi-meter
*63/37 eutectic solder, preferably with rosin that does not stink. (you can't imagine how bad some machine stink once you started modding...)
*a good soldering iron (good depend on your budget, cheap ceramic heating element soldering can be quite good for the price.)
*a soldering iron stand that have a good sponge "tray" thing, wiping your iron clean EVERYTIME you solder is one of the KEY to doing it right.
*Big Blue Solder Sucker, the one and only.

Anything else I missed?


I've just got my first SB3, and I'm now planning to mod it with big antennas... Ah, the pain of living in an apartment with very sturdy build. The solid concrete/rebar construction of the walls is just too much to have a good strong signal to my SB3.

iPhone
2007-11-11, 22:15
It's been many years since I touched an Iron.
When I was 16, I had a Heathkit 2ch stereo amp kit that I built and promptly fried the power transistors.
That was my last kit.

OK...so for a beginner (as I am) what would be a good starting toolbox to have on hand for when one decides to jump in again?

.

Hey Haunyack. Did the finals fry because you were playing it to loud or they went up in smoke when you first powered it up? Big difference between the two as one means the kit might have been misassembled or was not properly verified before applying power. The other means you did an OK job on your project and just needed to build the other kit with bigger finals!

As for toolbox, I think it is best to fill it as the need arises. Sure there are tools you will use again and again, but I would tell you this, nothing works better then having the right tool for the right job. Can tools be used for things they were not meant for and still get the job done, of course? But nothing makes a job easier then having the right tool.

Good tools to start with (off the top of my head):

A pair of precision true-flush cutters
A pair of quick cutters (dont cut Ty-wraps with your good true-flush cutter)
A pair of precision needle nose pliers with smooth jaws
A pair of precision needle nose pliers with serrated jaws
A pair of lineman pliers (for powercords and wall outlets)
A solder pullet (sucker)
Solder Wick Tape
A roll of WBT 4% Wonder Solder (use it for signal connections)
A roll of Reliacore 15 62/36/2 SN/PB/AG (use it for components)
A good soldering station (not your dads big black Weller gun!)
Weller WLC100 to start or Metcal PS-800E ($135)
Squeeze to open spring-loaded tweezers
Straight Hemostats
Curved Hemostats
Set of alignment tools (tweakers)
Precision #1 Phillips screwdriver, #2 Phillips, flattips
Static Wrist Strap with proper ground (the simple 3M grounded outlet unit works good)
Get the best DMM (Digital Multimeter) you can afford
If you really enjoy the hobby and start doing SMD or do a bunch of soldering, think about getting a Metcal Soldering Station
Always keep the soldering iron tip tinned and clean it on the wet sponge before every round of soldering. When you are finished, clean the tip, over tin the tip, then turn the station off, this will keep the tip from oxidizing and safe you money from having to buy new tips all the time.

I am absolutely sure I have forgotten some tool that somebody thinks is absolutely necessary, but I beg forgiveness in advance. In 20 years, I have collected just about every tool imaginable to work on electronics. So since it is in one of the draws of my roll-around, Im not thinking about it now (even harder to think back to when I first soldered).

tyler_durden
2007-11-11, 23:24
I'm with the OP on this one. There is some weird "mod-culture" that has developed in which people have an uncontrollable urge to modify everything, including things they know nothing about. For some inexplicable reason, they think they will improve the device by randomly swapping parts. If they had any concept of the sort of work and the underlying knowledge base that goes into designing the device in the first place they would know how futile their efforts will be.

If you want to learn about engines, do you go out and take apart your car or do you play with an old lawn mower engine?

OK, you want to learn a little about electronics. Do you think playing with a $300 piece of hardware is the place to start, or would a small construction project or two make more sense?

This is one of those things that make you go hmmmmmmm.

Regarding Thomas Edison- many people have the idea that Edison invented everything with his name on the patent. This could not be further from the truth. Once he achieved a bit of success, he hired people to do the vast majority of the lab work. I've heard claims that thousands of different materials were tried for use as filaments for light bulbs. Edison didn't sit there year after year trying different materials. He had lab rats doing that for him. When they found anything with remotely commercial potential, Edison filed a patent. No one remembers any of the lab rat's names but everyone has heard that Edison "invented" a lot of stuff and has a huge number of patents. Engineering companies do the same thing today. Engineers have to sign away rights to anything they discover/develop as a condition of employment. They get to put their names on the patent, and sometimes a small cash bonus, but the company owns all commercial rights to the invention.

TD

maniac
2007-11-12, 00:20
One of the things that Edison did was to piss off Tesla so much that he quit and started his own lab. Which we should thank both of them for this bit of interesting history, because without that, we might not have the AC power system that we have today. :)


Anyways, about modding. I've modded a fair bit of stuff, mostly for fun and my own enjoyment. One of the latest project was updating a B&K CS-117 pre amp, basically refreshed the whole thing with better parts, and in some cases, installed extra components to activate some of the optional features. (Like the XLR balanced out that my amp so badly needed) As well as a Musical Fidelity A220 that had some fairly badly dried out caps and aging pots. They all responded quite well to the refresh and upgrade. One interesting result is with A220 integrated amp.

At the time of refresh, we swear not to mod anything more than swapping OP Amps on this amp again, since it is such a pain to tear down and put back. We would have replaced the OP-Amp with national's new OP-Amp, but we don't have them on hand. So the amp was not touched, just updated caps and Alps Pot. The friend took it back and found the bass was much better controlled, and sounded much cleaner and enjoyable. A few days later, the Quad amp from NS had arrived, and he naturally was itching to try it on. As with his previous experience, he expected such high performance/resolution OP to sound harsh, bright, and scratchy even in the beginning, and slowly get better as it get burned in properly. That wasn't the case, the sound got surprisingly better without much ran in, detail/resolution, sound stage, ambiance and more.


IMHO, some modder are modding for the sake of modding, some mod so that they got colorful parts (I know a few), some mod for the gold/silver/diamond encrusted parts (I also know a few), and some mod because it actually sound better.

I personally have my friend do the listening trial for me, they have no idea how it is supposed to sound, and would not be "tainted" like the modder (myself) could be. It is quite an interesting experience to say the least, but you do need to have a "known good" reference so that they can compare it directly, rather than asking them to compare it from their memory.



IMHO, start modding on a kit bench power supply, then move on to regulators and OP-Amp circuits. It is a lot of fun, and can later be applied to SB3 if so desired. Also check out datasheets and app notes from those big semi companies, as they often bury some rather juicy tips in there. ;)

zanash
2007-11-12, 00:36
All good advice .....

I started by following a step by step modding guide that was in a uk hifi mag a few [20] years ago....it was just a case of removing the parts and fitting substitutes....from this I tried to find out why replacing one bit of wire with another effected the sound ....

You can learn a great deal just by opening kit up and looking at the parts fitted ....

As mentioned MF are notorius for fitting cheap parts particularly caps in the gear and after about 5 years these can need attention. A simple caps substitution in the MFxdacv3 can yeild huge sonic improvments for instance.

maniac
2007-11-12, 00:46
All good advice .....

I started by following a step by step modding guide that was in a uk hifi mag a few [20] years ago....it was just a case of removing the parts and fitting substitutes....from this I tried to find out why replacing one bit of wire with another effected the sound ....

You can learn a great deal just by opening kit up and looking at the parts fitted ....

As mentioned MF are notorius for fitting cheap parts particularly caps in the gear and after about 5 years these can need attention. A simple caps substitution in the MFxdacv3 can yeild huge sonic improvments for instance.

The funny part is that we didn't even knew the cap is drying out. We simply saw the cap bulge a bit, and felt that it would be in everyone's best interest to replace the cap before it blows. Alas, we later found the cap was almost completely dry and basically have no juice in there to blow. (Hummm... does that qualify as a paper/foil cap now that the electrolyte is completely dry? :P )

I requested my friend to leave me one of the dry out cap as payment of the service and parts, it is quite an entertaining piece, just shaking it and hear the sound it makes is funny enough.

Havoc
2007-11-12, 14:30
I'm surprised at the replies it looks as if I'm not the only one thinking along those lines.

Just a few more remarks:
- changing opamps: anyone ever thought that maybe that slow opamp is there for a reason? Or that that -on paper- noisy part is perhaps 10x more silent than the whole circuit? What modder has calculated the noise gain of a stage with a new component?
- caps: that a bit of internal impedance can be a very good thing to have? That larger caps sometimes are worse? That some regulators don't work with all types/values?
- has anyone modding recalculated the stability of a circuit after modding? Has anyone ever measured the phase margin of a modded power supply?
- has anyone done some objective tests, even minimal/basic ones? Like checking for power line harmonics before and after?

Like said above, most don't have any idea what is involved before a circuit sits in a box at a customer. Electronic design isn't just slapping a few components on a board and guess that it will work.

maniac
2007-11-12, 16:45
I'm surprised at the replies it looks as if I'm not the only one thinking along those lines.

Just a few more remarks:
- changing opamps: anyone ever thought that maybe that slow opamp is there for a reason? Or that that -on paper- noisy part is perhaps 10x more silent than the whole circuit? What modder has calculated the noise gain of a stage with a new component?
- caps: that a bit of internal impedance can be a very good thing to have? That larger caps sometimes are worse? That some regulators don't work with all types/values?
- has anyone modding recalculated the stability of a circuit after modding? Has anyone ever measured the phase margin of a modded power supply?
- has anyone done some objective tests, even minimal/basic ones? Like checking for power line harmonics before and after?

Like said above, most don't have any idea what is involved before a circuit sits in a box at a customer. Electronic design isn't just slapping a few components on a board and guess that it will work.

For reasons that you listed above, and more... That is why we kept the part that we remove, just in case. However, I have never found a single case (other than insufficient current) where the original JRC op AMP is better than whatever op amp that was installed in its place. Not to mention, noise isn't the only parameter when you are picking an op amp.

Let me ask you, have you ever heard of the sound that resistor can make when you drop some very high quality ones into the feedback path? (I guess I'm going places that people would think it is a total myth...)

tyler_durden
2007-11-12, 21:25
Let me ask you, have you ever heard of the sound that resistor can make when you drop some very high quality ones into the feedback path? (I guess I'm going places that people would think it is a total myth...)

The problem is defining/recognizing quality. 99.999% of modders think that a more expensive resistor is a better resistor, and the guys who sell the expensive parts to them present them as such. Will a $10 resistor be higher quality than a $0.10 resistor? It won't be if the $10 resistor is a high precision wirewound part and the $0.10 is a run of the mill 1% tolerance, 1/4 watt metal film resistor AND the application is the feedback resistor for an audio signal op-amp.

The cheapo resistor would make the circuit behave as the designer intended and the other would not. You might even be able to hear the difference, and the expensive resistor would NOT be an improvement.

TD

maniac
2007-11-13, 02:01
The problem is defining/recognizing quality. 99.999% of modders think that a more expensive resistor is a better resistor, and the guys who sell the expensive parts to them present them as such. Will a $10 resistor be higher quality than a $0.10 resistor? It won't be if the $10 resistor is a high precision wirewound part and the $0.10 is a run of the mill 1% tolerance, 1/4 watt metal film resistor AND the application is the feedback resistor for an audio signal op-amp.

The cheapo resistor would make the circuit behave as the designer intended and the other would not. You might even be able to hear the difference, and the expensive resistor would NOT be an improvement.

TD

What if the resistor for the feedback is high precision non inductive metal film (or bulk-metal as vishay likes to call it), with temp co of less than 5ppm? Or simply also a 1/4 metal film resistor that is 0.1% tolerance?

No modder with a bit of knowledge will use a huge wirewound resistor for feedback, it simply defeats the purpose of using a very high quality resistor for feedback...

Havoc
2007-11-13, 13:48
Have you calculated what change to the feedback 50ppm/C and 1% will make worst case in your living room? How many dB?

maniac
2007-11-13, 18:33
Have you calculated what change to the feedback 50ppm/C and 1% will make worst case in your living room? How many dB?

Have you actually compared the sound quality of resistor that is of the same temp co spec and tolerance? As strange as it maybe to you, they can sound quite different, even if they are all of similar rating and construction type. Of course, high spec is not always better, some ultra precision stuff can actually sound too "artificial" if used incorrectly, there's many cases of that happening. However, I'd say those people who did it and reported the result is doing everyone a service, so that people don't fall for that again. ;)

ar-t
2007-11-26, 10:39
I'm surprised at the replies it looks as if I'm not the only one thinking along those lines.

Just a few more remarks:
- changing opamps: anyone ever thought that maybe that slow opamp is there for a reason? Or that that -on paper- noisy part is perhaps 10x more silent than the whole circuit? What modder has calculated the noise gain of a stage with a new component?
- caps: that a bit of internal impedance can be a very good thing to have? That larger caps sometimes are worse? That some regulators don't work with all types/values?
- has anyone modding recalculated the stability of a circuit after modding? Has anyone ever measured the phase margin of a modded power supply?
- has anyone done some objective tests, even minimal/basic ones? Like checking for power line harmonics before and after?

Like said above, most don't have any idea what is involved before a circuit sits in a box at a customer. Electronic design isn't just slapping a few components on a board and guess that it will work.


The answer is probably none. Truth is, not all "designers" are any better. Ergo, we have a cottage industry of pseudo-designers, who pretty much slap anything onto something and claim it is an improvement. (And somehow get a lot of you guys to fork over $$$$$$ for it.)

Engineers........maybe. Up until you tell them that op-amps and resistors sound different.

Anyway, all of your points are valid. I suggest more folks here think about those concerns before they start prying parts off of some PCB.