[xmokshax]

i'm still an audio DIY newbie - i've only built a couple of CMoys and a Mini^3, with an Alien DAC in process. i'm now looking for my next project, which i'd like to be an exclusively wall-powered amp for home use. i've listed a few of the obvious possibilities in the title of this thread, but i'm open to suggestions... i'm mostly trying to figure out which of these tried-and-true DIY amps, for which PCBs are readily available, might offer the best combination of sound quality and RELATIVE ease of construction - i feel pretty comfortable with the process of assembling a DIY amp at this point, but i don't know if any of the above-listed amps have any "curveballs" in construction that i'm not expecting.

in addition to just recommendations as to which amp might be a good choice, here are a couple of related questions:

- solid-state or tube/hybrid? does either type hold a distinct advantage in certain areas?

- specifically w.r.t. the MAX, is there a consensus as to which output stage (BJT or MOSFET buffers) is superior? what's the difference between the two? (forgive my ignorance)

thanks!

 

[MASantos]

Well, this is a rough question without you hearing all the amps and choosingtheone you like the best. The SoHA and Millett will give you a more colored sound, tubes give some warmth to the sound and you may like that. The pimeta can use many different opamps and thisway change the sound to your liking. The Ck2III has a very specific parts list . You can choose different cpas and resistors but that will give very little changes in sound.

HOpe this helps.

I would personally go with something like PIMETA with a tread( which will give you important knowledge about power supplies) or a CK2III( which has a built in power supply easing the built.

Manuel

 

[tomb]

I agree with Manuel in general, but I'm jaded toward the MAX, of course.

IMHO, build the other three first - you will be disappointed in them if you build the MAX first. According to many builders, the MAX is competitive with the M3 and the PPA, a cut above the other amps you list. If you study the design of the output stages, this makes sense: with the heat sinked output stage, the MAX is capable of Class A bias as deep as the M3. It's BJT version can be biased into Class A much deeper than the PPA.

As for tubes versus a solid state gain stage, only your own ears can tell you which you prefer. The noise floor of an M3, PPA, or even a PIMETA will be superior to the MAX. Whether you can actually hear that difference is a different matter. You can gain differences in sound characteristics by rolling opamps in the previously mentioned solid state amps, but it still will not equal the warmth and musicality of a tube. There is also nothing slow about tubes and they can be very detailed - it often depends on whether the output stage can keep up. That said, tubes are like organic creatures - they can be tempermental, require quite a warmup period, break-in, and sometimes need constant fiddling.

About the differences in the MOSFET output stage vs. BJT output stage on the MAX - my suspicion is that the better Toshiba BJTs are probably superior in detail. No one has made a direct comparison as far as I know, although there are many comments that a MOSFET MAX =~ an M3. The comparison between a PPA versus an M3 is probably a good indicator, vis-a-vis a MOSFET MAX vs. a BJT MAX.

All that said, you might try a PIMETA first. It's easy, goes together fast, and may still offer better sound than the Mini3 - as good as that is.

IMHO and YMMV x10.

 

[bhjazz]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif All that said, you might try a PIMETA first. It's easy, goes together fast, and may still offer better sound than the Mini3 - as good as that is.

Tomb is a guru. Trust him! I would add another vote for a Pimeta. Parts and boards quite available, as are support and info here at Head Fi.

Don't be afraid of tubes, either. Depending on your headphones and/or setup and preferences, tubes can be magic.

In regards to assembly, with higher end amps that is only part of the process. Once the more complicated amps are done, there is still some setup involved, and that can definitely challenge your skills and knowledge. As an example, setting up the Cavalli-Kan Kumisa III (or CK2III) would involve adjusting the output transistors for the right amount of voltage across a resistor. That might seem trivial at first, but the output transistors will change with heat, and the measurements will change, too. I believe setting up the Max has some challenging "curveballs" as well. I'm not trying to discourage you, just giving the facts. Working your way up through the basic configurations are great teaching tools, and can give you excellent knowlege to move towards the tougher builds.

Finally, use this forum heavily. I can't state that enough. So many questions are already answered, and this has become an amazing collage of excellent technical information.

 

[ruZZ.il]

PIMETA kept my hands busy for a little while

I added a charging circuit and I'm doing some bass boost soon. It's tweakable, easy enough, and you'll learn a lot too. It's well documented as well. x2 on the PIMETA.
But the MAX just sounds mmm so good

And talking about mmm, the M³ shouldn't be overlooked at this stage either.

 

[nysulli]

given that their power supplies are built into the board, which could make troubleshooting a bit tougher, i say go for either the PIMETA, or an M^3 if your feeling ambitious. either could be build to run with a wall wart, and both would benefit (the M^3 more so i would guess) from a seperate powersupply which you could make at a later date, allowing you to troubleshoot both portions independently

but you should definitly give tubes a shot at some point

and if you wanted to try a more basic millet, i think i still have an older style board sitting around, along with a diamond buffer board, which would be a really simple millet build, that again, you could expand upon with the DB and a STEP's later on down the road

 

[Peoples]

I am wondering just about the same thing. I have build CMOY and PIMETA, and I was wondering is there any significantly better choice out there for PIMETA? Currently I am using Sennheiser HD595, but maybe sometime this year I am buying Beyerdynamic DT880 / Sennheiser HD650/600 - or those I have thought of so far. All recommendations are welcome.

I think my PIMETA is pretty good, buffers, good opamps and decent capacitators with ALPS bluevelvet. I guess I am better off with new headphones rather than amp?

What I am looking for, a little bit more richer sound overall. HD595 are great too, but there is always room for improvement.

 

[fortney]

As I often say, look also at Szekeres (Headwize library) and Sijosae's Poorman's Zen (check search engine of your choice). These use "toobey" MOSFETS and are Class A and adjusting their current consumption is not complicated. As presented they do not amplify voltage, only current.

Neither is difficult to build especially if you use an aluminum case to heatsink the MOSFETs.

Cfcubed has a little add on circuit listed in one of these forums to protect headphones from voltage spikes when the amp is turned on/off--I just plug in or out before turning the unit on/ off, allowing about 15 seconds to pass (until I build his circuit).

Both of these have a pleasant, warm, and a bit languorous sound.

F

 

[tomb]

Quote:

Originally Posted by Peoples /img/forum/go_quote.gif I am wondering just about the same thing. I have build CMOY and PIMETA, and I was wondering is there any significantly better choice out there for PIMETA? Currently I am using Sennheiser HD595, but maybe sometime this year I am buying Beyerdynamic DT880 / Sennheiser HD650/600 - or those I have thought of so far. All recommendations are welcome. I think my PIMETA is pretty good, buffers, good opamps and decent capacitators with ALPS bluevelvet. I guess I am better off with new headphones rather than amp? What I am looking for, a little bit more richer sound overall. HD595 are great too, but there is always room for improvement.

I love the PIMETA and will continue to recommend it as a pefect 2nd build - after the CMoy (following Tangent's tutorial, of course). That said, the PIMETA is lacking in really authoritative and deep bass.

Also, after you've built some other amps for comparisons, you will notice the bad rap that BUF634's get about their contribution to the sound. There's something like a soft cushion at the top of the ceiling that give all the sounds a nice soft glow - sort of like smearing a lens with a bit of vaseline for those favorable portraits. On the other hand, a discrete output stage will show every detail, which can be a good thing or a bad thing, depending on your source.

Keep in mind that this description is within levels of comparison of widely disparate amp design, complications, and cost. The PIMETA fits a valuable niche that is not competed by any other amp. I built two of them and may never part with them. So, please accept the comments above within their proper context.

 

[xmokshax]

thanks, everyone, for all the useful advice. i think my next couple of projects might be a PIMETA (based on all the positive recommendations) and a SOHA (to get a little taste of that tube flavor). are there any "standard" upgrades that people tend to make to the standard PIMETA parts list that will make a sizable difference in sound quality?

Quote:

Originally Posted by tomb That said, the PIMETA is lacking in really authoritative and deep bass.

ahh, that's right, you're a fellow bass-head. having mostly listened to my iPod with no amplification at all until recently, i was pretty pleased with even the way a CMoy strengthens and fills out the low end compared to no amp. will the PIMETA be at least this good, or is it truly lacking on the low end?

 

[tomb]

Quote:

Originally Posted by xmokshax /img/forum/go_quote.gif <snip> Quote: Originally Posted by tomb That said, the PIMETA is lacking in really authoritative and deep bass. ahh, that's right, you're a fellow bass-head. having mostly listened to my iPod with no amplification at all until recently, i was pretty pleased with even the way a CMoy strengthens and fills out the low end compared to no amp. will the PIMETA be at least this good, or is it truly lacking on the low end?

No - of course not. Again, my comments have to be taken in context. The PIMETA's bass will blow away any CMoy and may be as good as almost any portable amp you can find. However, Peoples had mentioned the Senn HD600/650's, which can suck up as many amp $dollars as you can throw at them. It's only when the PIMETA is compared to the best of DIY desktop amps does it fall short.

 

[xmokshax]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif No - of course not. Again, my comments have to be taken in context. The PIMETA's bass will blow away any CMoy and may be as good as almost any portable amp you can find. However, Peoples had mentioned the Senn HD600/650's, which can suck up as many amp $dollars as you can throw at them. It's only when the PIMETA is compared to the best of DIY desktop amps does it fall short.

good. i assumed as much, but i wanted to make sure. PIMETA it is!

 

[Peoples]

Yeah, I agree, PIMETA which I have build from pretty good parts, is really good. I just wondered what would be the wisest move next, after PIMETA. Is there really any signifigant improvements from going even step further from PIMETA, keeping in mind that headphones might be DT880/HD600/HD650? Or would I benefit more from upping my source, which is currently EMU0404?

 

[gychang]

Quote:

Originally Posted by Peoples /img/forum/go_quote.gif Yeah, I agree, PIMETA which I have build from pretty good parts, is really good.

I have also successfully completed CMOY and looking for the 2nd project. Seems PIMETA is highly recommended.

Guess will have to check the thread for parts etc. Thanks everyone for the fascinating hobby.

gychang

 

[xmokshax]

Quote:

Originally Posted by gychang /img/forum/go_quote.gif I have also successfully completed CMOY and looking for the 2nd project. Seems PIMETA is highly recommended. Guess will have to check the thread for parts etc. Thanks everyone for the fascinating hobby. gychang

i have a BOM from the PIMETA, if you're interested. ordered the parts a couple of weeks back, but still haven't found the time to put it together. actually, tonight might be the night...

in any case, PM me if you'd like to take a peek at my BOM.

edit: maybe it's just getting late, or maybe i never did graduate from 2nd grade in spirit, but i just re-read this message and couldn't help but chuckle at the phrase, "pm me if you'd like to take a peek at my bom". that is all.