Thank you guys, kerelybonto, Tim D and others, especially for your time. I had my posts deleted before and no any problem then. It is just this time, I saw so heavy criticisms in a thread and that thread was started about the locking of my thread, I had no idea what I did so wrong and to believe...

I just want to clarify the imprtant misunderstanding on my respect to moderators, if any. I said I won't post again, that still holds, forever. As soon as I don't see any more misunderstanding, I won't post again. I never, by any means, intended to show non-respect to all the moderators...

LTUCCI, This is my last post to this forum and I hope I can explain well about power rating and gain of an amp. The amps have gain of 5, which is very popular for most phones and sources. To drive Sennhiser and other hi-impetance phones, this gain may be not enough if your source's output...

LTUCCI, The magic is the op amps and the best use of them. The first op amp (AD823) is a FET type, so the sound is tube alike. The second one (LMH6643) is a hi-current (110mA!), rail-to-rail type (both input and output), which can use supplied voltage most efficiently. For example, 4V can drive...

Quote: what ive not been able to establish is how they really sound.. where are they in turn of sound quality compared with the Porta Corda/Total Airheard and Sudgen Headmaster/Headroom MAX/Corda HP-1. The reason I guess is that most Meta42 buyers could not afford those gears and...

As a scientist, a research engineer and an audio hobbyist, I'm very happy to see my amps get more and more appreciated. All the credits go to Walt Jung, the most outstanding op-amp audio researcher. Both meta42 and my amps are based on his op-amp audio theory. Even myself cannot believe how...

Jude, if you now define that post as an Ad, then no problem. But, it was not an ad at the time I posted it, right? Otherwise, why you guys have let it went for more than a month? The day I posted the pics here, my website already had " Add to Cart" for the amps. You mentioned your PM to me. But...

As the poster of the thread in concern, I respect the rules (as long as they are clear) and any decision made by head-fi staff and modulators. I posted the pictures because I had seen similar posts, and I could not help myself of sharing the new amps I developed and love to see what people...

Quote: I tried it with my Beyer 770 and there is just not enough gain to drive them to really loud levels. The amps now all have the most popular gain of 5. I don't have Beyer 770, so I can not test it. There is a 40.2 ohm resistor in the output of these amps, which makes...

For not true line-out, the difference between headphone out and the line out is not significant. This does not mean an external amp does not make a significant difference. Even from a headphone jack, a good external amp can still make a huge difference. Note: when an audiophile say "huge", it...

Quote: that has a true line-out Many line-out are not true but splitted from headphone jack and cannot do any better. The followings is a list from the best to the worst. 1) True line out - wired out before the headphone amp and no electrolytic caps. Hi-end home CD players belong...

I made the cord short because I thought a long cord would look stupid for such a tiny amp and be a hassle for ultra portable uses. In my mind, the amp's best use is to be attached to a portable CD, MD, MP3 or FM with velcro as mentioned by grinch. I've made the newer cords a little longer -...

Yeh, while the Radio Shack AAA case used for the super mini looks marble, the AA case used for mini is just so so. My building quality cannot be better than the case already is

I too found recently this fact especially with my super mini meta amp. Just like a gitar, it becomes more musical with time. I think the caps are the main cause, but the op-amps might need time to show up too.

For the burn-in, mostly because the caps need charge-disacharge cycles to reach maximun performance. The op-amp ICs may need burn-in too. Yeh, hard to explain but true.

I think it is a good idea. The output resistor of META42 can be 50-100, so a 73 (I use 80.6) shuold be no problem to other phones. Just make sure the resistor is out of the feedback loop. Putting the resistor to the headphone jack side is indeed better than putting it to the headphone side. So...

Quote: I want to give the SuperMini more time to burn in I found these amps do need sometime to burn-in, especially the Supermin. After couple days of listening, its sound becomes more defined. The sound stage becomes more distanced. Right after I built my Supermini, I got a headache...

Purk, super mini: global feedback; .12uF panasonic E-series metallized polyester film caps; 220uF Panasonic KS-series caps. mini: multi-loop feedback; .1uF panasonic P-series polypropylene film caps; 470uF panasonic FC-series caps. Refer to Tangent's website for details and I cannot give you...

The LMH6643 used in these amps cannot take more than 12.8V, so never use higher than 9V to be safe. If you use a un-regulated ac adapter such as those from Radio Shack, a 9V one can actually output as high as 20V and will mostly kill the LMH6643! The power caps in the super mini are 4V+4V, so...

N@Z, I cannot comment on the name issue - my post will be deleted anything commercial related. I can only talk on technical stuff which actually I enjoy the most. I remember someone in Korea already made some very tiny amps. I love uinque but simple things. CMoy's amp is a very good example. I...

Note that there are two amps in the pictures at the beginning of this thread: super mini and mini. The mini is only slightly larger than the super min, but can use either 9V or 3 AA. The two pictures at the bottom have been updated. Now there is no more that button connector and 9V batt can be...

I don't use any optional caps. The film inputs are Panasonic P-series polypropylene and the power filters are Panasonic FS series electrolytic 470uF. The resistors are set for a gain of 11, that's good for all headphones from lo-impedance Grado 60 to hi-impedance Sennheiser HD580/600.

Grinch, exactly. I use them with my sharp MT877. Before you attach the amp to a MD, you may want to cut shorter the power switch button.

Andrew: They have the key features of META: FET input, buffered output and multiple feedback loops. The spiders are LMH6643 used as the buffer (unit gain). This chip works officially at 3V, so the amp can use either 4.5V or 9V batteries. The caps are Panasonic P-series polypropylene. The cases...

Here is the value for my recently finished mini META: POT: 10K C1: 0.1uF R1: 0 R2: 100K R3: 249 R4: 2.49K R5: 1K R6: 100K R7: 49.9 R8: 49.9 R9: 0 Gain of 11 and sounds great!