jtfoo

Good job, solder looks good.. You now the in-house solder guy.

no no! I need to NOT smoke! smoke too much my hands would be shaking At least drink red bull before you begin to keep your eyes wide open

Wah... 3rd already!! Can't the tip of your old soldering iron be changed?

No problem. Meta42 can drive alot of head phone with ease.

Even the seasoned solder guys in our lab do it under a 20X microscope, if they need to swapped IC. So good luck to those trying without a microscope. It can be done, but difficult. Also remember to check for any solder bridging across the legs before you power up, since distance between the legs is narrower than the width of the solder tip.

The ones my friend and I using are completely sealed, i.e. no spillage and outgassing. Downside as menitoned earlier is it doesn't last as long as the opened type. If you're worried, then get branded one like Yuasa. http://www.thebatterybarn.com/Batteries/Yu...uasa/Yuasa.html

Misconception. Seal Lead Acid are sealed and air tight. There's no outgassing. It's a variation from the car battery which is opened and dangerous. Sealed Acid battery are practically maintenance free. But the number of cycles seal lead acid battery can be charged is lesser than the car battery becoz it cannot be top up. But 6 months of usage times a hundred recharged,I'm sure that works out to be many years.

Yes, you can do that way, where you leave the charger on perpetually. But you have to make sure that the charger has trickle mode, so it won't overcharged the battery. But I would suggest to charge once and remove the charger from the battery, coz you won't be needing it for at least 6 month later, it really last that long. Seal Lead Acid Charger & battery can be bought at SLT basement. PM me if you need help.

How much are you willing to spend on a regulated supply? Regulated supplies can varies in quality. You want cheap one and does the job, then can diy one for less $50... Expensive one can shoot all the way more than $200, with toroid trannies, ultra fast hexfet diodes, exp caps, dual mono config..etc.. But still no matter how much you spend on a good power supply, the regulation won't be as low and linear as flat as a battery supply.

have you compared the burning from the yamaha drive to normal ones? I burnt several albums using EAC cue feature. i.e all it extrack track by track, instead of copying the image of the whole CD which most commercial CD burning software. I used mainly the OEM Yamaha brand CDR. It as good as original. But some claim they can get better than original copies with this feature, but I can't. With my previous panny writer, I notice something lacking though I can't pin-point what is it.

http://tangentsoft.net/audio/opamp-ps.html Try not to use switching power supply for reasons explained at Tanget's site... Go for linear regulated supply. As for wallwart, I don't know how many percent regulation they have? Got to measured them.

I'm also using EAC for ripping and creating cue files for my Nero burn. The reason why I used Nero to burn as it's the only software to support my Yamaha's Audio Master Quality burn features.

When I swapped opamp within my head amps, the sound also changes. This says that not all headamps sound the same, like wise even the headphone output of the cdplayer(Likely opamp base coz cheap and easy to implement) will sound different from each other. So can't say they all sound the same. BTW, I don't have golden hears and I can't hear the difference in alot of tweaks.

Mat's Meta42 must be a maxed out version I guess.. I just realised after looking at the PPA's site that it requires 12 buffers. Additional 4 buffers for gnd channel. Wonder how does the additonal gnd channel improves overall?

One buffer per channel is more than enough to drive low impedance headphone. The PPA's design is taking it to the extreme by having 4 buffers per channel, making a total of 8 buffers for a stereo.

senohpdaehGS

There're some slight technical stuff that might be helpful to know is future, like why a cmoy can't drive low impedance headphone properly. Low impedance headphone draws more current and single opamp like the common OPA2132 or 2134 could not make it. That's why in our correspondance I don't recommned a cmoy for your headphone. A A47 would be better with it's current boost. And why I suggest you should audition Jason's PPA first is because the PPA's design is better than the A47. The PPA design has 4 buffers in parallel per channel so it can drive many headphones easily. If you're buying diy amps, sometime a little technical knowledge is helpful or else you might have a mismatch between the amp and headphone.

I curious as to why the heat problem and voltage fluctuation. The PPA shouldn't draw too much current, maybe I'm wrong. A few of questions, What is heating up? The transformer or the Voltage regulator? What's the secondary voltage of your transformer?

www.diyaudio.com - For diyers. Lots of guru and Nelson Pass can be found there too.

The Korean guy's opamp is basically a meta42, but instead of the IC buffer, it's using discrete buffer. Can be better or worst than IC buffer, depending on the skill and layout of the builder. THere's also a need to match those transistors and LEDs. But this Sijosea is a master of miniature design. Simply awesome.

I was thinking whether to plonk my $50 voucher on the Marantz CD7300. Nice Pic on the internal. Some caps looks good. Mind the space in between, very mod friendly.

It always good to have reserve current capability.. but having high current capability is only one factor the wallwart has. I assume most wallwart would have poor regulation and filtering. from 18V, put on a load it can dropped to 12V type of poor regulation.

My headphone setup, Source: Rotel RCD1070 Rega Planar 3 Amplifier: Aleph ONO phonostage (DIY) Meta42 HeadAmp PPA HeadAmp Mini Zen headamp Headphone: Beyerdynamic DT-880 Grado SR125 Sony D66SL EGGO

As a matter of fact, the seal lead acid (SLA) can be recharge. The number of cycle it can recharge is more than those NiMH 9V battery. It also capable for higher current output(not that you need all of them), which is good for speed and dynamics and those deep bass. Only downside is the initial cost. One 12V 4AH SLA would cost about $30, maybe less. You need 2 for 24V. And the charger would cost another like $50. And some cost to diy a cable with spade receptables at one end and a mini DC-in at the other end.

I'm using 2X 12v seal lead acid batteries for my Meta42. They last almost forever and they're cleaner than any AC->DC regulators. All you need is a simple diy on the power cable to attach the DC-in to the batteries