Hello everyone. I've decided I'm going to make a gainclone. Maybe some of you can remember that starting from zero is a bit overwhelming. I've come up with a few fundamental questions but they are all over the place. Since forums are messy enough I'll keep them separate.
I'm trying to put a list of what I need together and order it all, (plus some other stuff) as I can't stand paying $15.00 on shipping every time I want to build something new.
My electronics kit is growing but incomplete for sure.
Here's my question:
Somewhere in the forums I read a reference to a specific brand regulator. I'm not trying to save $0.005, or even $10, but it might be inconvenient to try to shop for specific labels for some of this stuff.
I'm assuming that for some things (maybe over-specified resistors?) manufacturer can't matter, maybe I'm wrong.
I'm interested to know where "generic" components might be a problem.
Thanks.
I'm trying to put a list of what I need together and order it all, (plus some other stuff) as I can't stand paying $15.00 on shipping every time I want to build something new.
My electronics kit is growing but incomplete for sure.
Here's my question:
Somewhere in the forums I read a reference to a specific brand regulator. I'm not trying to save $0.005, or even $10, but it might be inconvenient to try to shop for specific labels for some of this stuff.
I'm assuming that for some things (maybe over-specified resistors?) manufacturer can't matter, maybe I'm wrong.
I'm interested to know where "generic" components might be a problem.
Thanks.
In my oppinion (and it is only an oppinion) the capacitors are the area you are best not to go too generic on (especially the electrolytics).
Buying a good brand such as panasonic (fc or fm series) or perhaps nichicon audio range will be worth spending a bit more (and it won't be that much) over generic brand caps.
Film caps try and go for polypropylene if you can (size could be a problem). I actually used polyester caps in my gainclone for the bypass caps as polypropylene would have been too big.
Any quality metal film resistors should be fine (though I personally do tend to obsess over all components
).
Also buy the chips themselves off a reputable supplier, as there are fakes out there.
Tony.
Buying a good brand such as panasonic (fc or fm series) or perhaps nichicon audio range will be worth spending a bit more (and it won't be that much) over generic brand caps.
Film caps try and go for polypropylene if you can (size could be a problem). I actually used polyester caps in my gainclone for the bypass caps as polypropylene would have been too big.
Any quality metal film resistors should be fine (though I personally do tend to obsess over all components
). Also buy the chips themselves off a reputable supplier, as there are fakes out there.
Tony.
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What say you on transformers? Seems threads point to Plintron for high end and Avel for lower cost alternative.
I realize that you get what you pay for, but I guess I'm not exactly sure what it is that I'm paying for yet.
I also have a suspicious that neither are going to 'wear out.' Maybe this is misguided, but I have a feeling that either brand of wrapped wire will outlast my own mortal coil. Maybe I'm wrong about that, but I'm leaning toward a Plintron because I (perhaps wrongly) assume that it will outlast the chip (and every replacement that would follow) and will not depreciate.
Since I'm just jumping in, I don't know how deep or how cold the water is---In fact, I'm not even sure there is water down there!
I realize that you get what you pay for, but I guess I'm not exactly sure what it is that I'm paying for yet.
I also have a suspicious that neither are going to 'wear out.' Maybe this is misguided, but I have a feeling that either brand of wrapped wire will outlast my own mortal coil. Maybe I'm wrong about that, but I'm leaning toward a Plintron because I (perhaps wrongly) assume that it will outlast the chip (and every replacement that would follow) and will not depreciate.
Since I'm just jumping in, I don't know how deep or how cold the water is---In fact, I'm not even sure there is water down there!
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Wintermute gave good advice. Over the past several years, I've played with lots of different components in the MyRef chip amps. What I have found is that electrolytic caps do make a difference in quality of sound. You don't need Mundorf's, but you should buy caps that are rated at 110 degrees with a long life. Caps do wear out, even if it is a long time.
The quality of your transformer will not matter much. I've never heard of one wearing out or deteriorating. The size (capacity) of the transformer is more important to sonics. You can buy more transformer of a cheaper brand, but I wouldn't get the cheapest junk. Antek seems decent quality and good value.
In descending order of importance, this is what I've heard make a difference, but it a lot depends on where these parts are in the circuit:
Make sure the chips you use are legit.
Electrolytic caps: Elna, Panny, Nichicon are good, basic brands, but others have their favorites. Do not skimp on these. Pay attention to service temp and service life. There are some other technical specs that aren't too important at first. You can use a higher voltage cap than specified, but you should not use a lower voltage. You can use larger value (more uF) cap in some places in the circuit, but it doesn't necessarily mean it will sound better.
Film caps: polypropylene is good enough, teflon the best, polyester okay. Wima is pretty much the standard for a good reason. Avoid the cheapest brands. Film and foil are better than metalized film if they fit. Long leads can be bad, so don't buy a huge cap and have it inches away from where it connects to the circuit.
Quality of ceramic caps for bypassing chip power supplies are not too important. Some report better results with silver mica or polypropylene, yet others say lossy ceramic caps are better. The important thing is close proximity to the chip.
Binding posts and RCA jacks: copper content is important, but you don't need to go nuts to get good quality. Avoid plastic and nickel. Vampire and Furutech are excellent quality.
Resistors don't contribute much unless they're bad. Some resistors do sound a little smoother (carbon film), some a little brighter (metal film), some a bit more open or accurate (bulk metal foil). In critical parts of the signal path, you might want to spend a few more cents or even a few dollars to get something special, depending on the resolution of your system and hearing. I would avoid the very cheapest brands, as they're made to pretty low standards. Vishay/Dale, KOA Speer, and PRP are reliable at a few cents each. Exotics such as tantalum, Vishay bulk foil, Amtrans, Caddock will set you back a few bucks each. Avoid carbon comp, as they can be unstable and noisy. Avoid wirewound, as thick film is generally better for sonics.
Power supply components such as diodes and rectifiers contribute to the sound in subtle ways. Buy brand name parts.
Controversial, as it makes a substantial difference with some amps and listeners but very little or none with other amps and listeners, is the power cord. Beware costly commercial offerings. You can make the best cord yourself quite easily and safely for not much money. Connectors and geometry are more important than the wire itself. Even the power inlet on the amp can contribute. Again, no need to go overboard, but avoid the cheapest junk.
Intimate heatsink connection is critical to dissipate the heat. Spend some time getting it right. Vibration control is important, but basic measures will be adequate. If the chassis you mount your amps on is thin gauge metal, add some damping material around the places where the PCB's are bolted down. It doesn't need to be fancy. Large, non-magnetic washers, pieces of wood, some commercial elastomeric products can be effective in reducing vibration. Avoid silicone products.
These are all refinements, and my opinions only. I'm no expert. Do some research, but you need to jump in and get building. You can always swap parts and tweak things once you have a frame of reference. Don't be afraid to not get it perfect on your first shot. Few of us do.
Be careful with AC mains power. Be safe and go slowly. Check everything twice, then use a bulb tester at first power up. With just a little care, it'll sound great.
Peace,
Tom E
The quality of your transformer will not matter much. I've never heard of one wearing out or deteriorating. The size (capacity) of the transformer is more important to sonics. You can buy more transformer of a cheaper brand, but I wouldn't get the cheapest junk. Antek seems decent quality and good value.
In descending order of importance, this is what I've heard make a difference, but it a lot depends on where these parts are in the circuit:
Make sure the chips you use are legit.
Electrolytic caps: Elna, Panny, Nichicon are good, basic brands, but others have their favorites. Do not skimp on these. Pay attention to service temp and service life. There are some other technical specs that aren't too important at first. You can use a higher voltage cap than specified, but you should not use a lower voltage. You can use larger value (more uF) cap in some places in the circuit, but it doesn't necessarily mean it will sound better.
Film caps: polypropylene is good enough, teflon the best, polyester okay. Wima is pretty much the standard for a good reason. Avoid the cheapest brands. Film and foil are better than metalized film if they fit. Long leads can be bad, so don't buy a huge cap and have it inches away from where it connects to the circuit.
Quality of ceramic caps for bypassing chip power supplies are not too important. Some report better results with silver mica or polypropylene, yet others say lossy ceramic caps are better. The important thing is close proximity to the chip.
Binding posts and RCA jacks: copper content is important, but you don't need to go nuts to get good quality. Avoid plastic and nickel. Vampire and Furutech are excellent quality.
Resistors don't contribute much unless they're bad. Some resistors do sound a little smoother (carbon film), some a little brighter (metal film), some a bit more open or accurate (bulk metal foil). In critical parts of the signal path, you might want to spend a few more cents or even a few dollars to get something special, depending on the resolution of your system and hearing. I would avoid the very cheapest brands, as they're made to pretty low standards. Vishay/Dale, KOA Speer, and PRP are reliable at a few cents each. Exotics such as tantalum, Vishay bulk foil, Amtrans, Caddock will set you back a few bucks each. Avoid carbon comp, as they can be unstable and noisy. Avoid wirewound, as thick film is generally better for sonics.
Power supply components such as diodes and rectifiers contribute to the sound in subtle ways. Buy brand name parts.
Controversial, as it makes a substantial difference with some amps and listeners but very little or none with other amps and listeners, is the power cord. Beware costly commercial offerings. You can make the best cord yourself quite easily and safely for not much money. Connectors and geometry are more important than the wire itself. Even the power inlet on the amp can contribute. Again, no need to go overboard, but avoid the cheapest junk.
Intimate heatsink connection is critical to dissipate the heat. Spend some time getting it right. Vibration control is important, but basic measures will be adequate. If the chassis you mount your amps on is thin gauge metal, add some damping material around the places where the PCB's are bolted down. It doesn't need to be fancy. Large, non-magnetic washers, pieces of wood, some commercial elastomeric products can be effective in reducing vibration. Avoid silicone products.
These are all refinements, and my opinions only. I'm no expert. Do some research, but you need to jump in and get building. You can always swap parts and tweak things once you have a frame of reference. Don't be afraid to not get it perfect on your first shot. Few of us do.
Be careful with AC mains power. Be safe and go slowly. Check everything twice, then use a bulb tester at first power up. With just a little care, it'll sound great.
Peace,
Tom E
Thanks again to both of you for taking the time to answer. I'll be sure to read your these carefully as I'm still wading through the shopping list and making notes on what fits where.
I have one specific follow up. I think I understand the broad strokes on a power supply, and right now I have a 330VA 2x25 Avel in my cart at Amazon. I think I've deciphered from the TB of data on this forum that this will do just fine.
Am I missing something obvious?
[I plan on just buying two transformers and build two totally separate dual mono channel 3875s. One from the audiosector kit and another sourced from the wild WWW. ]
I have one specific follow up. I think I understand the broad strokes on a power supply, and right now I have a 330VA 2x25 Avel in my cart at Amazon. I think I've deciphered from the TB of data on this forum that this will do just fine.
Am I missing something obvious?
[I plan on just buying two transformers and build two totally separate dual mono channel 3875s. One from the audiosector kit and another sourced from the wild WWW. ]
Which chip are you planning on using? if LM3886 or LM4870 (and probably others) you need to take into consideration the impedance of your speakers!! 25-0-25 should be ok with 8 ohm speakers but you will not be able to drive 4 ohm loads with that high a voltage.
I went with 20-0-20 which is pretty close to the max you can get away with with four ohm speakers. I think a lot of people go with 18-0-18 for 4 ohm loads.
Definitely read the data sheet (probably a few times) for the chip that you are planning to use, it has a wealth of information. I'd have done some things differently with my build knowing what I know now. Unfortunately it was a very compact p2p build which makes changing things pretty near impossible. The main thing I would change now is the gain, I would have made it lower. (I think that the Brian GT schematic I used had 30X gain, I'd probably go with 20X if I were to do it again..... This article --> http://www.diyaudio.com/forums/diyaudio-com-articles/186018-what-gain-structure.html is well worth a read)
Tony.
I went with 20-0-20 which is pretty close to the max you can get away with with four ohm speakers. I think a lot of people go with 18-0-18 for 4 ohm loads.
Definitely read the data sheet (probably a few times) for the chip that you are planning to use, it has a wealth of information. I'd have done some things differently with my build knowing what I know now. Unfortunately it was a very compact p2p build which makes changing things pretty near impossible. The main thing I would change now is the gain, I would have made it lower. (I think that the Brian GT schematic I used had 30X gain, I'd probably go with 20X if I were to do it again..... This article --> http://www.diyaudio.com/forums/diyaudio-com-articles/186018-what-gain-structure.html is well worth a read)
Tony.
Yeah, that's what I'm coming to understand. I'm leaning toward the 3875, and making two go-s at them. One by a kit and another version that is a little more...freestyle?.
I want to buy 2 transformers that are as universal as possible, as I might want to try something else some time.
Taking a look at the link now...
I want to buy 2 transformers that are as universal as possible, as I might want to try something else some time.
Taking a look at the link now...
It looks like the LM3875 has the same limitations as the LM3886 with respect to low impedance loads. See attached graph from the datasheet which is available here --> http://www.ti.com/lit/ds/symlink/lm3875.pdf
18-0-18 would be fine for 4 ohm loads.
25-0-25 would be fine for 8 ohm loads, and probably ok for 6 ohm loads as well.
If you know the impedance of the speakers you are likely to be using is 6 ohms or higher then I think that the 25-0-25 should be fine.
Tony.
18-0-18 would be fine for 4 ohm loads.
25-0-25 would be fine for 8 ohm loads, and probably ok for 6 ohm loads as well.
If you know the impedance of the speakers you are likely to be using is 6 ohms or higher then I think that the 25-0-25 should be fine.
Tony.
Attachments
Frank,
Thanks for the compliment.
I wrote that these are my opinions, based on my experience.
Please don't wreck this thread by starting that silly argument. If you disagree, say so. Otherwise, please drop it.
In other words, I do not have any evidence, if by that you mean purely objective testing or measurements. Let the builder experiment and decide for himself.
To the original poster: my amps use the 3886 chip. My speakers dip to 2.5 ohms at 5k, otherwise pretty close to 4 ohms. My transformers are 21v. I have never engaged chip protection and the chips get barely warm at decent volume.
You can always change transformers later, if necessary. I would suggest you buy and build everything in identical pairs if you want monoblocks. Two amps with different power supplies and/or different layouts probably will not produce a good stereo image. You're leaning toward failure before you even start.
Peace,
Tom E
Thanks for the compliment.
I wrote that these are my opinions, based on my experience.
Please don't wreck this thread by starting that silly argument. If you disagree, say so. Otherwise, please drop it.
In other words, I do not have any evidence, if by that you mean purely objective testing or measurements. Let the builder experiment and decide for himself.
To the original poster: my amps use the 3886 chip. My speakers dip to 2.5 ohms at 5k, otherwise pretty close to 4 ohms. My transformers are 21v. I have never engaged chip protection and the chips get barely warm at decent volume.
You can always change transformers later, if necessary. I would suggest you buy and build everything in identical pairs if you want monoblocks. Two amps with different power supplies and/or different layouts probably will not produce a good stereo image. You're leaning toward failure before you even start.
Peace,
Tom E
Good quality is all you need, avoid the really cheap no-name surplus stuff. There is no need at all for the "exotic" $10 passive parts that are filled with genuine snake oil. If you buy from Mouser, digikey and the like and stay away from eBay you will be fine. The US based distributers will have manufactures' data sheets linked from the product listing. Read those and you will not be surprised with what you get.
Electrolytic caps do vary. They are not all alike and you can see this in the data sheets with specs like the number of hours of life, allowed ripple current and so on. Film type coupling caps are all very close as are resisters.
Some people claim to be able to hear the difference between exotic $50 caps and generic poly film caps but I've never seen this confirmed in a blind test. So don't over spend, unless your goal is bragging rights to the most expensive chip amp.
You are right about shipping costs. It is cost effective to buy parts for the next four or five projects all at once. But it is also expensive to buy parts you will never use.
Yes. I've looked for blind test to back this up and don't see any. By "blind" I mean a person who can tell you what kind of resister is inside the amp just by listening without having to open up the amp and look. If you can't know, except by looking inside I say it hardly matters.
That said there is good reason to suspect resisters are different and they have measurable differences too. Carbon resisters change their resistance based on the voltage across them. In other words they do NOT follow ohm's law. This happens at the "couple percent" level and is subtle but a real. The effect on the sound is "compression" or reduction in dynamic range. Some call this "smoother" sound. Carbon resisters also have high "noise" (sounds like hiss) and this noise gets higher with higher resistance values. The compression effect is very tiny if there is not much voltage across the resister so this matters mostly in tube amps that use power supply rails well over 200 volts. There is zero difference if you are using a 9V battery or a even 24V rail. but if you have a 100V peak to peak audio signal inside you preamp (as some tube amps do) to effect is really there.
Many guitar amp builders will use Carbon resisters in certain places, like for plate load resisters and it does slightly matter but adds "hiss" so they will use metal resistrs in other places.
The metal resisters do have the lowest noise.
One other this is the size. You can use a 1/4W or a 1W. the larger 1W resister will be more quiet as it runs at a lower temperature. If a resister is burning up much power, buy one 4X over size so it runs cool. Heat actually creates noise.
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Thanks again guys.
This most recent point on resistors seems to be an unambiguous claim that over-rated resistors are dominate other alternatives. Other than trying to make the smallest chipamp ever, I'm not sure I see the downsize of overrated resistors, taking make quality as equal of course. This seems like a pretty big deal and well argued.
I don't have the prerequisites to make the most expensive chipamp ever. I'm going to tune up my soldering for a little while and then start by building the audiosector kit with 25V. I'm going to do it by the book and see how it goes.
I think it is usually best to try to cook the recipe first.
Simultaneously, I'm sourcing supplies for another.
I really don't like the idea of having to piece my orders together from a bunch of places.
Mouser's shipping over $100.00 is pretty reasonable, but if you want to spend less than a c-note it is quite unreasonable. We all know it is easy to get to $100.00, so that's not really too bad.
I'd love to be able to buy everything in one place. Where do you guys get rca and speaker connections and what about the wire from the connections to the chip? That beautiful hardware from cardas is nice and all, but the website isn't even clear on how to buy it, much less how much it costs.
Seems to me it is important to identify which links are the ones where the "only as strong as weakest" proverb is binding. That's sort of what this thread is all about. Where is it crucial to spend the money and where is it useful to spend the time and energy to do it very right. That point about the power cord above is well taken. It doesn't cost a fortune to use something other than the ubiquitous 3 prong cord. I probably have 10 generic plugs from foxconn in the basement. It may not be a game changer, but it is easy and kind of inexpensive to attend to a detail like that which did not seem obvious to me until I read it.
In that giant audiosector thread PD mentions something about gold plated copper wires running from the rca connectors. That's no doubt bad ***, and it isn't like I'd rather rip open a phone wire, but is there a happy (upper) medium before having a custom alloy smelted?
This most recent point on resistors seems to be an unambiguous claim that over-rated resistors are dominate other alternatives. Other than trying to make the smallest chipamp ever, I'm not sure I see the downsize of overrated resistors, taking make quality as equal of course. This seems like a pretty big deal and well argued.
I don't have the prerequisites to make the most expensive chipamp ever. I'm going to tune up my soldering for a little while and then start by building the audiosector kit with 25V. I'm going to do it by the book and see how it goes.
I think it is usually best to try to cook the recipe first.
Simultaneously, I'm sourcing supplies for another.
I really don't like the idea of having to piece my orders together from a bunch of places.
Mouser's shipping over $100.00 is pretty reasonable, but if you want to spend less than a c-note it is quite unreasonable. We all know it is easy to get to $100.00, so that's not really too bad.
I'd love to be able to buy everything in one place. Where do you guys get rca and speaker connections and what about the wire from the connections to the chip? That beautiful hardware from cardas is nice and all, but the website isn't even clear on how to buy it, much less how much it costs.
Seems to me it is important to identify which links are the ones where the "only as strong as weakest" proverb is binding. That's sort of what this thread is all about. Where is it crucial to spend the money and where is it useful to spend the time and energy to do it very right. That point about the power cord above is well taken. It doesn't cost a fortune to use something other than the ubiquitous 3 prong cord. I probably have 10 generic plugs from foxconn in the basement. It may not be a game changer, but it is easy and kind of inexpensive to attend to a detail like that which did not seem obvious to me until I read it.
In that giant audiosector thread PD mentions something about gold plated copper wires running from the rca connectors. That's no doubt bad ***, and it isn't like I'd rather rip open a phone wire, but is there a happy (upper) medium before having a custom alloy smelted?
One topic at a time:
1) I think Digikey can ship small orders cheap. They can use first class mail for some items.
2) I buy many parts from Futurlec. They are an Australian company that ships from Asia. They sell quite a bit of what you need
3) What is the "weak link". My opinion it is the power supply. You need a good transformer, hopefuly 4X over sized and some decent filter caps and (importance) a good physical design that extends all the way to the power/ground pins on the chip. This is not Rocket Science. BTW "Antek" makes good toroid transformers and will ship as many as will fit in a Flat Rate box for the price of the box. They have good detailed specs with test results of each transformer on their web site.
4) Don't even think of using some special power cord. It will only make you look gullible. Ok if you do want a fancy cord, you may as well replace the wire in the house and on the utility poles too. Seriously, the power suly takes care of all this.
One thing you CAN do is replace the IEC connector with an "inlet filter" these things really do work and they are cheap and keep RF out.
Welcome to Delta Electronics, Inc. - Components
5) Why even use RCA connectors? What are you going to plug into the amp? Is it RCA? If you do use RCA, just have a good reason. There are other connectors. What to use depends on the source.
Wire from the input jack does matter. The best is shielded. I use RG-174 (googol wil find it for you) but any shielded coax cable is good. Yo can cut up some old RCA cables and use that, any junk RCA audio cable is good. The matal inside does not matter but the shield does. It keep noise out.
I like "speakon" speaker connectors. They outperform just abot every other type and don't cost much. And they look really cool.
I was planning on Avel. (one 250 the other 300 for separate builds.) Are Antek brand really much better for chipamps?
On power cords, I agree that spending extra money on a plug is nothing anyone would want to mention in polite company. I was thinking the idea was to buy decent and appropriate 3-wire cord and just screw on connections and not talk about it. Better than plastic crap from foxconn. Kind of like H. Lectors '...with your good bag and your cheap shoes...' argument.
RCA or whatever, I agree that the tool is the job. My question was trying to get at the connectors and I don't know all the proper names of stuff. Your suggestion is just what I need, scale and the name and terminology so I know what to read about.
On power cords, I agree that spending extra money on a plug is nothing anyone would want to mention in polite company. I was thinking the idea was to buy decent and appropriate 3-wire cord and just screw on connections and not talk about it. Better than plastic crap from foxconn. Kind of like H. Lectors '...with your good bag and your cheap shoes...' argument.
RCA or whatever, I agree that the tool is the job. My question was trying to get at the connectors and I don't know all the proper names of stuff. Your suggestion is just what I need, scale and the name and terminology so I know what to read about.
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