Quote: Originally Posted by MASantos AFAIK no member here as ever tried to build a4 channel amp such as the super macro. It would be very costly to develop an amp from scratch with all the prototyping costs included. Why don't you just get a super macro? i did. the cost of...

i'm not sure if you could it Dr Xin 'technology'. maybe once i get my PhD, i could copy the PPA and then call it the 6 channel 'technology'.

Quote: Originally Posted by MisterX let me see if I got this right. The whole 4 channel thing is nothing but a op-amp used as a rail splitter then you use a separate op-amp to drive the out ground? Pft... if that is the case the Portaphile has been a 4 channel amp since it's...

Quote: Originally Posted by NeilR Hi Doc, I hope no one took my comments as argumentative, and surely not to diss your very very cool amp. Anyone that can fit all that, including a Tread, into a mint tin gets my respect. I only meant to point out that a 4 channel design is not...

Quote: Originally Posted by Eric1285 I'd like to see someone design a really awesome desktop setup...Built in STEPS would be amazing. Something that'd blow the PPA and M3 out of the water, since those are probably going to be my next projects, and well...if you can make something better...

Quote: Originally Posted by NeilR I saw that thread. It's an opamp replacing a TLE, which can be a good trade or a bad trade depending the opamps and what yout consider the greater of the various portable evils. Since most opamps sink about the same 20-40ma as a TLE, I don't understand...

Quote: Originally Posted by ozshadow Just how tiny do you think we could make that layout of yours doctor on a professional PCB using smd ? i have no idea. using only normal through hole components on a donutboard, it could be cramped into a 5cm X 3cm dimension. can't say that...

Quote: Originally Posted by Andrea I'd prefer a 2 channel amp with a serious discrete output stage (and a serious power supply stage) to any amp with 4, 8, or infinite channels employing integrated buffers i've built several designs of the Sijosae Class AB (a 2 channel amp with...

Quote: Originally Posted by MASantos the obejctive of the thread is DrXin's 4 channel circuitry, not members preferences about amp design.... Back on topic: From what I understand, Dr Xin says that one channel drives input ground and another drives output ground and the other two the...

Quote: Originally Posted by decayed.cell Noob question here, but how come you were able to remove the CE14 cap? Is it because you boostrapped the 3.3V regulator to the 5V regulator? Also, should I use tantalums or metallised propylene caps to solder in parallel with the electrolytics...

Quote: Originally Posted by Eokboy I see. Alrite hueg thanks What sort of improvement can I expect from this mod? i have no idea. i did all of the mods in one go before doing any critical listening test. but i tend to like the sound my PPAv2 routed to the Chaintech more than...

Quote: Originally Posted by Eokboy Okay, what I'm seeing: CE11 is a Pana FC, and you paralleled the tant on CE15 with the stock electrolytic at the back? How come CE13 is still stock? looks the same, but they're not. think i have a Nichicon YXA in there. i used surplus parts that...

Quote: Originally Posted by decayed.cell Great thanks - should I be going after certain brand or will anything just do as long as its the same rating and type? A couple more questions: What is the difference between normal caps and Low ESR caps? Tantalum vs Greencap vs Metallised...

Quote: Originally Posted by MASantos So it's just a matter of getting many pots and finding one that has no mismatch? good luck in finding one that has a perfect match. 1% is good enough and i'll call 0.1% as near perfect. i've never bothered to match my pots, and never heard any...

the caps marked in green are output caps (something in 47uF/16V should be more than enough). the caps marked in yellow are DAC power caps (10uF-47uF/16V should be fine, 100uF if you have the space). the caps marked in cyan are input caps to the voltage regulators (47uF-100uF should suit just...

Quote: Originally Posted by slwiser I the thread for "looking inside you amp" at the link below so far there are only two amps with r-cores. One is my AT-HA5000 and the other is a mystery at this time with a question for us to come up with which amp that is. This mystery picture was...

there's a few other caps that you could upgrade as well other than the decoupling caps from the DAC. i'll take a picture of my modded card once i got back my digicam. but for now, these are the two signal decoupling capacitors that sits on the output of the DAC.

Quote: Originally Posted by cetoole Mainly because that would make it a different opamp from L/R. Not a big deal, I know, but neither is using the TLE2426 really. or dual channel Opamp for the ground section if you're really desperate in separating the L/R channels? TLE2426 is...

Quote: Originally Posted by cetoole No, its a resistor providing the split as a reference for the ground channel opamp, similar to how the pint does it, and how the TLE2426 works as well I believe, though there is no isolated ground channel, for several reasons. I cant use the opamp...

Quote: Originally Posted by Pars I would disagree in my experience. I built up 3 sets of Mono's modified Sijosae buffers (BUF634 replacements) for a Pimeta. One set I built with generic 2N2907/2N (most common generic NPN, escapes me right now, and that is bad <g>). Next set I built with...

or, you could mod the unit by using 2 tubes (one triode for each channel), 4 buffers, 4 CCS for each anode, bigger heatsink for the heater supply, 4 gang potentiometers and use no less than 15VA transformer.

Quote: Originally Posted by Eokboy A schematic woot! I'll try drawing this back in TinyCAD. So this thing would work well with alkalines/rechargeables? I've been using BC327/BC337, no -25/-40 at the back. it'll work fine. tested and splits exactly till 32V without problem...

Quote: Originally Posted by goldenslug I found that I had this problem a couple of times before and at times it would go away. something sounds loose. try resolder all the joints.

Quote: Originally Posted by FallenAngel Thanks, but now that makes me wander. I simply put a resistor and an LED between V+ and V- which kinda closed the loop and got a completly stable (and very accurate) ground split when I was making the rail splitter. I'll check if that changed since...

Quote: Originally Posted by FallenAngel Just wanted to ask, how important is it to match the BC337/BC327 transistors? I don't exactly know how this is done so I just took the first pair of each and installed them. if the pair is working in an open loop (hope i got that right) like...