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Post by PinkFloyd on Dec 15, 2010 21:59:08 GMT
The capacitors he is using are Samwha VA series, they are temperature rated at 135C..... These are what I use in my V-CAN upgrade, nice caps.... originally designed for use in hot areas such as car engines (EMU systems etc.) but very good in audio too. They have had some bad press on "badcaps.net" www.badcaps.net/forum/showthread.php?t=8072 but I can say that I have only experienced "one" failure out of quite a "lot" of them and that "one" blew it's top 20 minutes after fire up.... IMO, they are very reliable in service. The red thingies look like WIMA MKS4 metallised polyester film caps.... nice and reliable but you either love them or loathe them (SQ wise).... I, personally, like them (when used in moderation) too many of them and the "Wima" house sound comes through (thick, porridgy and foggy)...... OPA134 are ok (the dual version being the OPA2134) but they have the chocolaty Burr Brown house signature.... I think that the OPA134 combined with the Wima will be a shmaltzy, warm, gooey type listen. There's not much to the amp and it's these type of amps where the components REALLY are critical when it comes to SQ.... it's basically a dual CMOY so there's not much to play with.... it's a case of selecting your opamp and tuning "by ear" with the surrounding few components. Is it worth the money? Well.... "yes" if you don't know one end of a soldering iron from the other..... if you do know one end from the other then you could probably knock something like this up on vero board for a lot less, it is not "unique".... it is a well tried and tested design. My personal choice of opamp would be something more like the OPA627 (Burr Brown) or the AD-843 (Analogue devices).... the OPA134 is "nice" sounding but it is TOO polite (to my ears).... similarly, the AD8610 is more "organic" sounding but NOT organic enough.... You need to find something BANG in the middle of the BB "syrup" and the AD "realism"..... that chip, to my ears, would be the AD-843. Nicely built amp but (Like Frans) I can tell exactly how it will sound..... it will sound pretty much the same as the last NECO amp (it's the same thing) but this time it's in "dual mono"..... I doubt, very much if "dual mono" will sound any different to stereo
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Post by Deleted on Dec 15, 2010 22:21:19 GMT
Nicely built amp but (Like Frans) I can tell exactly how it will sound..... it will sound pretty much the same as the last NECO amp (it's the same thing) but this time it's in "dual mono"..... I doubt, very much if "dual mono" will sound any different to stereo ;D I agree, the graphs just told me the same thing. Could use a higher voltage and output power like that of the Panda... 50mW@55 Ohm and 95mW@330 Ohm is a bit meager compared to mister Panda and SC AHA
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Post by PinkFloyd on Dec 15, 2010 22:53:27 GMT
Nicely built amp but (Like Frans) I can tell exactly how it will sound..... it will sound pretty much the same as the last NECO amp (it's the same thing) but this time it's in "dual mono"..... I doubt, very much if "dual mono" will sound any different to stereo ;D I agree, the graphs just told me the same thing. Could use a higher voltage and output power like that of the Panda... 50mW@55 Ohm and 95mW@330 Ohm is a bit meager compared to mister Panda and SC AHA It is a "portable" after all...... though, you may be correct! It is a "dual mono" portable so will need dual batteries to power it! A stereo amp only requires one battery. Dual mono is special, yup? it's all to do with the database (database of fekkin' gullable people "yup?") Dual "MONO".... it's got to be better than stereo right?
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Post by JohnnyBlue on Dec 19, 2010 9:37:02 GMT
I wonder how this new Neco compares to the Larks? The great thing in this new one's favour (compared to the Larks) is that it is portable, which, all other things being equal, is more useful to me in my situation. (I've been very close to getting the Larks, I've been holding back because of the time of year and concomitant money issues!)
However, I'm wary of a slow, stodgy sound: I'm very much into PRaT and I prefer Sennheiser headphones (HD600s, HD565s), so the new Neco might not be an ideal amp...
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Post by Deleted on Dec 19, 2010 10:01:01 GMT
The old Neco is fine for Senns with the op amp upgraded. I prefer the Larks to be honest but yes, you need a plug.
Actually, the Banzai Morph with the op amp changed is also very good. I have the same op amp in that as the Neco and it's slightly more weighty which is rather good with the K701 would you believe? It actually works with it.
I treat the Larks as a 'hotel' amp. Superb for that and the Neco or Morph for moving around the house type thing!! In the end, I kept the Morph because the op amp change did improve it for me.
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elysion
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Post by elysion on Dec 19, 2010 15:04:00 GMT
With upgraded opamps (AD8160), my Neco's are a very good match for both the Senn's (HD650 and HD580 in my case) and the AKG's (K702, K501).
I have a Neco Portable V2 with gain 3.5 and linear pot, and two Neco Mosfet V2's (one with log pot and gain 5, the other with linear pot and gain 3). The AD8160 opamps are IMO very for the HD650's. They don't sound as laid back as they are usually. I like the HD650's also with other amps, but the Neco's with AD8160 opamps are probably the best thing I have in my amp armory for use with the HD650's.
I find the Mosfet V2 slightly superior to the Portable V2, but it's not a really big difference.
Maybe other opamps can give further improvement (OPA627, AD843).
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Post by JohnnyBlue on Dec 19, 2010 19:30:04 GMT
I should have added that I have a V.1 Neco portable, with the original single stereo opamp (AD8260?), which is great for portable use (in my case this means round the house, rather than beyond it). I'm guessing the new, bigger Neco will outperform my original V.1, but I'll live with the Larks' AC requirement if it gives better performance (and for less money, about half the price of the new Neco).
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Post by Deleted on Dec 19, 2010 20:28:45 GMT
Comparing the Neco with the Larks shows them both to be very good. They're just different.
I find the Neco just a tad 'harder' sounding than the Larks which is a sweet sounding amp. It's also a class A amp so delivers a fast, clean attack.
Both are built like tanks.
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elysion
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Post by elysion on Jan 9, 2011 6:17:44 GMT
Perhaps a stupid question, but I'm really not sure:
The PSU that Neco has delivered with my Portable V2 has the following specs:
MODEL: (MINWA) MC120D050 (=> I couldn't find any information about it on the MINWA homepage) PRI: 230VAC 50Hz 12W SEC: 12VDC 0.5A 6VA
My multimeter reads (without load) values between 15.88 and 15.94 VDC on the output of the PSU. The voltage is not really stable and I guess it's an unregulated PSU since the voltage is significantly higher without load than it should be according to the specs.
The rechargeable battery in the amp is 9VDC. AFAIK there's no voltage conversion inside the Portable V2 amp. Doesn't it run with 9VDC then? Draws the Portable V2 as much power from the unregulated PSU so that the PSU has a effective voltage that is within the range that the Portable V2 needs?
If someone would use a better regulated PSU with this amp, what voltage would be ideal? 12VDC or 9VDC?
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Post by Deleted on Jan 9, 2011 9:17:47 GMT
the PSU is unregulated but becomes regulated in the amp because of the 9V battery, which is in effect the regulator.
Yes the Neco runs on (regulated) 9V internally and for this reason is a low output voltage type of amp with a low output resistance.
It will NOT get better with a regulated supply. In fact the design of the chargingcircuit for this amp is BASED on the usage of these unregulated PS.
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Post by JohnnyBlue on Feb 12, 2011 21:40:04 GMT
Managed to prise open my Neco Portable Mk.1 version, and am posting a couple of snaps, so you can compare them with those of Mike's V.2 posted on page 1 of this thread. My Mk.1 has the upgraded op-amp, but there's only the one (AD8620), the V.2 has dual mono (AD8610) op-amps:
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Post by PinkFloyd on Feb 13, 2011 2:37:03 GMT
Looks good Johnny If you decide you like the opamp that is in it then I would lose that second dip8 socket and just solder the one with the opamp on it direct onto the board. How is it for juice? last quite a long time between charges?
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Post by PinkFloyd on Feb 13, 2011 2:59:46 GMT
By the way guys, I have some rechargeable Lithium Metal Hydride batteries on their way from China, they are 9V / 500mAh and usually retail for about £15 each.... I will have three spare and will let them go for £10 each.
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Post by JohnnyBlue on Feb 13, 2011 8:32:18 GMT
Looks good Johnny If you decide you like the opamp that is in it then I would lose that second dip8 socket and just solder the one with the opamp on it direct onto the board. How is it for juice? last quite a long time between charges? Ah, thanks for explaining that arrangement: I wasn't clear what that was all about with the two DIP8 sockets. My guess is that Neco built them that way so he could easily upgrade the op-amp if such an order came in. What it does mean, though, is that I can now start delving into the murky world of op-amp rollng! Any suggestions as to what could be an improvement that would work without my having to alter any of the other components? It's difficult for me to estimate battery longevity, because it's one of a number of portable HPAs I use, so I lose track of how many hours any particular one goes before needing a re-charge (or, more usually, inserting freshly re-charged batteries). If you twisted my arm, I'd guesstimate between 10 - 20 hours.
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Post by Deleted on Feb 13, 2011 9:33:00 GMT
Can two of the metal bodied LME49720HA be used as a direct replacements for the AD8610`s in this Amp.!!
Mick.
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Post by PinkFloyd on Feb 13, 2011 11:52:50 GMT
Can two of the metal bodied LME49720HA be used as a direct replacements for the AD8610`s in this Amp.!! Mick. Yes!
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Post by PinkFloyd on Feb 13, 2011 11:55:50 GMT
Looks good Johnny If you decide you like the opamp that is in it then I would lose that second dip8 socket and just solder the one with the opamp on it direct onto the board. How is it for juice? last quite a long time between charges? Ah, thanks for explaining that arrangement: I wasn't clear what that was all about with the two DIP8 sockets. My guess is that Neco built them that way so he could easily upgrade the op-amp if such an order came in. What it does mean, though, is that I can now start delving into the murky world of op-amp rollng! Any suggestions as to what could be an improvement that would work without my having to alter any of the other components? It's difficult for me to estimate battery longevity, because it's one of a number of portable HPAs I use, so I lose track of how many hours any particular one goes before needing a re-charge (or, more usually, inserting freshly re-charged batteries). If you twisted my arm, I'd guesstimate between 10 - 20 hours. OPA2227 will give you a warmer "tubey" type tone.... all depends what you find lacking with the AD8620? do you want more warmth, more neutrality, a sparklier sound, less bass, more bass, better detail? If you are happy with the SQ as it is then just enjoy it
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Post by Deleted on Feb 13, 2011 12:10:18 GMT
Can two of the metal bodied LME49720HA be used as a direct replacements for the AD8610`s in this Amp.!! Mick. Yes! Thanks Mike.
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Post by PinkFloyd on Feb 22, 2011 21:47:13 GMT
I have just taken delivery of four 500mA Li-Ion batteries.... they cost me £30 for the four. I want to keep one of them for my Neco portable so there are 3 going spare (UK only) £7 each inc. shipping.
First come first served.
Mike.
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Post by Deleted on Feb 22, 2011 22:11:11 GMT
Mike,
I presume the charge time must virtually double for the 500ma? On the Neco, there's no protection against overcharging so it's kind of a guessing game.
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Post by PinkFloyd on Feb 22, 2011 22:35:27 GMT
Mike, I presume the charge time must virtually double for the 500ma? On the Neco, there's no protection against overcharging so it's kind of a guessing game. Good question! I will ask the battery manufacturer what the ideal charge time is for this particular battery. I get them from "Great Power" who are leading edge battery experts in China. www.greatpower.net/en/index.asp
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Post by Deleted on Feb 22, 2011 22:39:03 GMT
With one of those strapped on, you could be away for six months and still going!!!
The one that I have now in the Neco just doesn't seem to die!!! A 500 could be positively annoying and end up with us all checking to see if it's connected to the mains!!
Nicely spotted Mike!!
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Post by PinkFloyd on Feb 22, 2011 23:19:05 GMT
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Post by PinkFloyd on Feb 22, 2011 23:24:29 GMT
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Post by dicky on Feb 23, 2011 7:15:04 GMT
Hi Mike, you have PM.
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