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Post by PinkFloyd on Feb 12, 2010 22:06:23 GMT
My personal design brief is this: Fully built amp with onboard PSU board (jumperable for 115V / 230V): £250 Kit of parts: £175 PCB: £50 Putting this into practice will be HARD as this will be a UK based project (and we all know the cost of parts in the UK!).... there won't be much profit for those involved in the design / build unless we can sell large quantities (possible). Again, this comes down to the design, it has to be better than all the rest or it's not worth doing. Maybe I'm derailing this thread which was "portable amp" probably with the intention of selling PCB's at "parts cost" I dunno but I would like to introduce a no nonsense "top quality" amp into the market that is designed by all the expertise we have on the forum..... It's unfair to class it as a "UK" designed amp, as the majority of the combined design team will be global, I've got a few plans I've had kicking about for a few years and will share them IF I think this can be a "goer" (and I do)...... As much as I love the idea of "parts cost" portable PCB's you can buy them on ebay, ten a penny..... I'd much rather spend my time here with you guys designing a world beating "desktop / semi portable" amp that combines all our knowledge into one collaborative whole and the resultant amp being the envy of the world. 1969 saw the launch of Concorde, decimalisation, man on the moon etc..... great days! Let's make 2010 the year the "ROCK" is launched Mike.
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Post by Deleted on Feb 12, 2010 22:40:56 GMT
Why not use the lid/cork as volumecontrol, that would be cool.. Claus Sorry to burst your bubble, and that of many other members, BUT there is no way that a portable amplifier of the type you describe is going to come even close to Mike's stipulation of leading the pack in SQ. Mike has also apparently realised that in later posts, where he is stipulating a switchable PSU for different parts of the world. A very high quality amplifier is as much about the quality of it's power supply, perhaps even more so than the basic amplifier topology. Sorry, but rechargeable 9V batteries do not even come close ! A couple of 12V SLA batteries in combination with other circuit refinements could result in some very good sound, but it is then far from portable isn't it ? Bear in mind also, Mike's remark about eBay offerings. The whole portable area is saturated already.Occasionally, they may even sound very good with specific headphones, but not everybody owns the same type of easier to drive than average, headphones. Alex
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Post by gomez on Feb 12, 2010 22:44:43 GMT
My personal design brief is this: Fully built amp with onboard PSU board (jumperable for 115V / 230V): £250 Kit of parts: £175 PCB: £50 Putting this into practice will be HARD as this will be a UK based project (and we all know the cost of parts in the UK!).... there won't be much profit for those involved in the design / build unless we can sell large quantities (possible). Again, this comes down to the design, it has to be better than all the rest or it's not worth doing. Maybe I'm derailing this thread which was "portable amp" probably with the intention of selling PCB's at "parts cost" I dunno but I would like to introduce a no nonsense "top quality" amp into the market that is designed by all the expertise we have on the forum..... It's unfair to class it as a "UK" designed amp, as the majority of the combined design team will be global, I've got a few plans I've had kicking about for a few years and will share them IF I think this can be a "goer" (and I do)...... As much as I love the idea of "parts cost" portable PCB's you can buy them on ebay, ten a penny..... I'd much rather spend my time here with you guys designing a world beating "desktop / semi portable" amp that combines all our knowledge into one collaborative whole and the resultant amp being the envy of the world. 1969 saw the launch of Concorde, decimalisation, man on the moon etc..... great days! Let's make 2010 the year the "ROCK" is launched Mike. +1 I agree no point in going over old ground there's no shortage of cheap nice little amps & you'll never get anywhere near the Chinese at knocking them out at the right money. But a proper serious quality Amp with sound quality 1st without the need for a mortgage now your talking Unfortunately I am only just starting on My diy audio journey so apart from being a Guinea pig I don't know what I can bring to the party "Yet" But if there is anything let me know & I'll give it a go
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Post by freddypipsqueek on Feb 12, 2010 22:50:45 GMT
For what its worth I would be really interested in amp designed on this forum. I have little electronics knowledge and I read the posts here in envy.
If I could buy a kit with all the support it would be breath of fresh air; I look at expensive kit and never really know what I'm getting for my money. Its not that I'm looking for a 'cheap' amp - just that when I spend money what it will do to improve the sound and where I'm going with it.
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Post by Deleted on Feb 12, 2010 22:56:42 GMT
If members REALLY want a portable amplifier of better than average performance, then perhaps the way to go could be 3 separate parts. A basic CMoy or similar, (with or without a buffer stage) , using 2 rechargeable 9V batteries. A commercial Battery charger as sold in Supermarkets etc. that is capable of recharging 9V NiMH batteries, and a pair of modified headphones with filters from Frans. This would guarantee better than average results. However, do not expect the people involved, (assuming they are willing) to supply these areas without reasonable recompense for their time and effort. Alex
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Post by gomez on Feb 12, 2010 23:12:03 GMT
If members REALLY want a portable amplifier of better than average performance, then perhaps the way to go could be 3 separate parts. A basic CMoy or similar, (with or without a buffer stage) , using 2 rechargeable 9V batteries. A commercial Battery charger as sold in Supermarkets etc. that is capable of recharging 9V NiMH batteries, and a pair of modified headphones with filters from Frans. This would guarantee better than average results. However, do not expect the people involved, (assuming they are willing) to supply these areas without reasonable recompense for their time and effort. Alex That sounds exactly like I've just built here rockgrotto.proboards.com/index.cgi?board=m&action=display&thread=5043 £12 kit on the Bay. I must admit I for one was hoping for something a lot better, or why bother. Don't get me wrong if that's what everyone wants who am I to say different. But with all the talent on these forums something truly special could evolve.
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Post by PinkFloyd on Feb 12, 2010 23:18:33 GMT
Why not use the lid/cork as volumecontrol, that would be cool.. Claus Sorry to burst your bubble, and that of many other members, BUT there is no way that a portable amplifier of the type you describe is going to come even close to Mike's stipulation of leading the pack in SQ. Mike has also apparently realised that in later posts, where he is stipulating a switchable PSU for different parts of the world. A very high quality amplifier is as much about the quality of it's power supply, perhaps even more so than the basic amplifier topology. Sorry, but rechargeable 9V batteries do not even come close ! A couple of 12V SLA batteries in combination with other circuit refinements could result in some very good sound, but it is then far from portable isn't it ? Bear in mind also, Mike's remark about eBay offerings. The whole portable area is saturated already.Occasionally, they may even sound very good with specific headphones, but not everybody owns the same type of easier to drive than average, headphones. Alex Alex, I am NOT suggesting the amp uses a crappy SMPS..... I was saying the design would be "jumperable" so the primaries could be either 115V or 230V..... No way would I even consider a SMPS, they're dire. Mike.
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Post by PinkFloyd on Feb 12, 2010 23:20:25 GMT
Onboard linear / regulated PSU section with a transformer you can configure for 115V / 230V duty ;D
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Post by PinkFloyd on Feb 12, 2010 23:26:06 GMT
That sounds exactly like I've just built here rockgrotto.proboards.com/index.cgi?board=m&action=display&thread=5043 £12 kit on the Bay. I must admit I for one was hoping for something a lot better, or why bother. Don't get me wrong if that's what everyone wants who am I to say different. But with all the talent on these forums something truly special could evolve. Exactly..... if we're going to do it let's show the world WHAT we CAN do. It will take a lot of effort, time and many arguments but I know it can be done.... we've got the "presence" so let's make the "amp" guys. Mike.
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Post by Deleted on Feb 12, 2010 23:32:22 GMT
If members REALLY want a portable amplifier of better than average performance, then perhaps the way to go could be 3 separate parts. A basic CMoy or similar, (with or without a buffer stage) , using 2 rechargeable 9V batteries. A commercial Battery charger as sold in Supermarkets etc. that is capable of recharging 9V NiMH batteries, and a pair of modified headphones with filters from Frans. This would guarantee better than average results. However, do not expect the people involved, (assuming they are willing) to supply these areas without reasonable recompense for their time and effort. Alex That sounds exactly like I've just built here rockgrotto.proboards.com/index.cgi?board=m&action=display&thread=5043 £12 kit on the Bay. I must admit I for one was hoping for something a lot better, or why bother. Don't get me wrong if that's what everyone wants who am I to say different. But with all the talent on these forums something truly special could evolve. Gomez Have you got your CMoy working to it's true potential ? Don't forget that simple circuits like this only sound good with specific designs of headphones. They don't adds lots of extra circuit complexity in more expensive designs just for the fun of it. As already explained elsewhere, if you want to succesfully drive other types of headphones as well, then you need a buffer stage. Buffer stages cause more current to be drawn from the power supply. This means you then have to beef up power supply capabilities.As a battery's capacity is reduced the internal resistance of the batteries increases. Just shoving an electrolytic capacitor across each battery is not the answer. Electrolytic capacitors also have a small amount of leakage current, so you then also need them isolated from the battery by a switch. A simple FET opamp design,with no input or output capacitors,and isolated from the buffer stage by 47 to 100 ohms resistors, in combination with better PSU design could be part of the answer. Alex
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Post by Deleted on Feb 12, 2010 23:41:14 GMT
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Post by PinkFloyd on Feb 12, 2010 23:48:00 GMT
Sooooo... any of you mouthpieces want to do this with me or shall I do it alone?
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Post by Deleted on Feb 12, 2010 23:53:20 GMT
It seems like it's time to decide what type of amp is wanted by the majority of interested parties. If not true portable (I admit I have little use for one) then what will be the max. size of it? My SCHA is a reasonably small desktop affair and is damn good. There is also the Aclass that Alex and others say is better than that. Soooo, 1)portable? 2)semi portable ?(poss. two power options, battery on the move and serious PSU at home?) 3)or fully fledged take-on-anything. IMHO, if 1 then go for something that is just about portable, size wise, so some decent design can be shoe horned in. if 2 then we have a niche product, covering 2 uses. if 3, as I said above, there are already 2 stonking designs on the forum, how far do we go with SQ (price?) and features.
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leo
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Post by leo on Feb 13, 2010 0:00:09 GMT
Yes, you need an idea what type of amp you want , op-amp, op-amp and discrete, just discrete,just valve or hybrid , balanced, unbalanced both etc
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Post by PinkFloyd on Feb 13, 2010 0:06:44 GMT
Yes, you need an idea what type of amp you want , op-amp, op-amp and discrete, just discrete,just valve or hybrid , balanced, unbalanced both etc Discrete. A no questions asked, kick "ass" design....
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Post by clausdk on Feb 13, 2010 1:12:29 GMT
I think that a semiportable one would be the best..
A portable one is just not enough, meaning who has the urge to really listen when on the go ?? I (almost) do not use my portable amps anymore, the enviroment makes them a bit unwanted and the sound from my Meizu is "good enough" for me on the go..
Just building a basic Cmoy, seems a bit too easy, I made a chiara last year and it was not that difficult, it is just to make a couple of solderjoints extra. no big deal.
If we go for the slightly bigger amp. I will offer to make the casings in oak or mahogoni, they will be apr. 15 £+shipping, probally cheaper..And I promise they will not disapeer up anybodys arse or break for that matter. We can make it with some shielding mesh if wanted, a bit more complicated but I am ready for the challenge.. And if other members here (heliharris) could make some "bling" for it, it would look stunning and special..(maybe we will finally be able to pick up girls with our gear. . . .)
I should be able to use the Hdam modules from GD, if I had anything to say..
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Post by andy on Feb 13, 2010 9:05:03 GMT
Well it looks as thoug hportable has gone out the window so how about we make the best that we can? Seperate PSU, helps to remove unwanted noise from the amp, or run on a kick ass battery pack (two car batteries is 24v), a nice clean power source. Being able to alter the output to suit different types of phone room for an inbuilt DAC, for those who like that sort of thing it would also be nice to be able to set the amp at differnt price points, ie. have a basic spec of more standard components but have a laid out upgrade plan using more exotic parts? This may help those of us with a more limited income. again just ideas! I would deffinately be happy to help in any way i can, though there are others hear who are much better at the electronics side of it (though i can solder very nicely!), and again others much more suited to fabrication of cases (though i dont live far from Mick, so if he needed a hand....) Andy
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Post by Deleted on Feb 13, 2010 9:45:37 GMT
andy The Class A HA in the DIY area has a separate simple PSU (18-0-18VAC), and it is readily altered to suit different types of headphones,( just by swapping 2 output resistors on PCB pins.) INCLUDING the type that Nigel and Miguel own, that normally require the use of a power amplifier. It would be relatively easy to make changes even simpler if needed. Very few available DACs that would normally be built into HAs are likely to be good enough for highest quality performance, so I would recommend a good external DAC for use with this Class A HA. A kick ass battery pack is extremely unlikely to further improve performance due to the use of a JLH PSU add on. The Class A HA clearly outperforms the Jaycar HA with JLH. Alex
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Will
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Post by Will on Feb 13, 2010 9:51:32 GMT
I've changed the name of the thread, and now removed portable from it, as it does seem that we are now in a different area. The original idea of doing a little portable came from here rockgrotto.proboards.com/index.cgi?action=display&board=review&thread=3644&page=4#62515. A small portable will have massive constraints on it. And that was the basis for my ideas. You would be constrained by batteries, and also the size of the pcb. You would never get world shattering sound out of it, as it would be a cmoy variant, which has been done many times before. But as long as it was recognised as such, then no one should have a problem. For me, it was more the idea that we would have a simple 'beginners' project (a precursor to the SCHA, perhaps) made with ideas thrown around between us, that would also be cheap to make. But, as is the way, this idea is evolving. So, if we are going to make a small, mains powered amp, that really does open up the flood gates, and is a whole different ball game. For the PSU, side, we have the JLH to provide an extremely clean, low impedance supply, we can use this as a basis. I'd prefer a discrete design as well, in fact we have one here rockgrotto.proboards.com/index.cgi?board=m&action=display&thread=3977&page=1, which meets the costs that Mike mentioned earlier. If we can design something better than that, well, put me down for two A down side to discrete is that you remove the joys of opamp rolling, and the tailoring of sound they provide to the guy who is listening to it. Everyone here likes different ways of having the sound presented, and the Class A linked to above won't suit everyone. Chris's post earlier, sums it all up nicely I think, with the three options. Jon's J310 suggestion earlier is an interesting one, and released from batteries, with a JLH or shunt supply, it would be quite interesting, but now that size is less of an issue, lets have more ideas on how we get this thing going
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Post by toad on Feb 13, 2010 10:14:41 GMT
I use my CMoy a lot and when it's in semi portable mode i.e set up at work where I only listen at my desk I use an 8 cell maplin battery holder loaded up with rechargables connected to the 9v connector on the CMoy. I just open the battery cover on the back of the CMoy and connect the lead to the battery holder. Maybe we could use one of these in the RG portable. They go up to 10 cells if needed. www.maplin.co.uk/Module.aspx?ModuleNo=31427&C=Froogle&U=31427&T=ModuleThe battery pack adds a good bit of weight to the sound as there's a hell of a lot more current available than with a little 9v battery. For mobile use the 9v is perfectly adequate but for critical listening the battery pack ... er ... packs that extra punch ;D and lasts for absolutely ages. Ian
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Post by Deleted on Feb 13, 2010 10:36:30 GMT
Ian The problem here is that the majority of members will not be using such easy to drive headphones. Some headphones also need to be driven from a 120 ohm source for best results. In that case, a simple 9V supply will not give sufficient voltage swing without excessive distortion. Alex
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Post by mrarroyo on Feb 13, 2010 15:02:00 GMT
I have read with interest the posts here as well as many other forums. Invariably they indicate that a 9 volt battery or less will not be able to power the larger higher impedance cans. I disagree and I disagree after having used my Xin Reference portable amp which uses four 1.5 volt AAA batteries as its power supply. This portable amp which fits in a Hammond case ans sports both a 1/4" and a 1/8" can drive cans like the K701, K501, and HD580 with authority and to very loud levels. Since I listen at low volumes I have loaned the amp to others who listen at much higher levels than I and they agreed the amp was able to drive their cans to way beyond any levels they wanted. Of course others here will disagree as they have in the other forums, funnily the people who disagree have never used the amp I am talking about. BTW I found the Voyager to have plenty of power to drive full size cans, as well as other amps like The Hornet or the P51 by Ray Samuel. Cheers.
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Post by clausdk on Feb 13, 2010 19:08:25 GMT
We could use batteries for motorcycles, they can deliver 10 amps without breaking a sweat..
It would also make it a good travel mate..
Big stationary amps or tiny small amps, is what the market consist of today (mostly) and something in the playfield between those would be nice.. That would also be new instead of just boiling soup an old bones..
Also it could be good to toss ideas in here and disscus the problems elsewere ?? Otherwise our beloved experts will at some point ram their heads toogether and make all us morons loose the overwiev (and interest ?), because it will get very tecnical and hard to understand, for us who paint by numbers and that was what all this was about from the beginning, getting the morons to solder something goooood..
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Post by Deleted on Feb 13, 2010 21:36:57 GMT
Claus If we did that we would keep getting requests for superb sounding results using whatever headphones were available, using low voltage supplies, where it just isn't possible. The requests would gain momentum, but there would then be no likelihood of anything special ever getting constructed. I haven't had a chance to lookthrough all recent posts, as I haven't even had breakfast yet, but has there been ANY interest shown by the 2 EEs here that know much more than I do? ( at least technically) Or are they steering well clear ? Alex
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Post by Deleted on Feb 13, 2010 21:51:26 GMT
Miguel We need to come up with designs that suit almost all headphones, and many of them are around 32 -40 ohms, which certainly isn't high impedance .Bear in mind too, that Mike wants the highest possible SQ from this project,not just the ability to drive headphones to full power, otherwise it will be just another one of the hundreds floating around the net, and available at ridiculously low prices from FleaBay already. Added to that, many people seem to have different requirements. For something basic and simple,look at the attached link. You will not be able to swap opamps, but you can replace the trimpot with a dual potentiometer. www.jaycar.com.au/productView.asp?ID=KC5152Alex P.S. In the absence of worthwhile input from some of the higher qualified members of this forum, I will refrain from any further participation.
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