Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › New Millett Hybrid MiniMAX (what happened to this thread?)
New Posts  All Forums:Forum Nav:

New Millett Hybrid MiniMAX (what happened to this thread?) - Page 25

post #361 of 1853
11/25/08 at 4:37pm
Quote:
Originally Posted by tomb View Post
Beefy is correct; the voltage is too low in case of failure. However, you should compare ratings:

FM 1800uf 35V - 0.014ohms 3820ma ripple
FC 2200uf 25V - 0.028ohms 2400ma ripple.

Even if you go to FC's highest rated cap at 35V, -

FC 3900uf 35V - 0.014ohms 3735ma ripple,

only then is the impedance as low as the 1800uf FM, but ripple is still not as good. Of course, the FC is 18 x 40mm high at that rating, to boot. You'll find that Nichicon UPW's are very similar to Panasonic FC's. So quite simply, there is nothing as good as a Panasonic FM for the MAX in these positions and in the power supply.
Sorry, that was actually a typo, I meant 35v. There's a 2200uf 35v FC cap that's only an inch tall. But, I see your point.

Still I may try it in one of the positions, CA5 maybe since people seem to not mind or notice the worse ratings...and after checking I see the 31.5mm versions of the 2200uf, which have better ratings, will still fit in my case. I guess I'm just in a soldering mood lately
Reply
post #362 of 1853
11/29/08 at 12:12am
For anyone interested...I did just what I described above. I put the 2200uf 35v FC caps (31.5mm) in CA5.

Although the ratings of that cap are a little worse than the FMs, I notice only good changes (pretty subtle). The sound seems to have slightly more foundation, not thicker really but more solid somehow. And the bass is a tiny bit improved -- that change *could* be my imagination because it's quite subtle but I seem to notice a bit more fatness and oomph.

I wouldn't expect or encourage anyone to do this because it's a very small change, but FWIW I did it and like it.
Reply
post #363 of 1853
11/29/08 at 12:31am
Quote:
Originally Posted by slowpogo View Post
For anyone interested...I did just what I described above. I put the 2200uf 35v FC caps (31.5mm) in CA5.

Although the ratings of that cap are a little worse than the FMs, I notice only good changes (pretty subtle). The sound seems to have slightly more foundation, not thicker really but more solid somehow. And the bass is a tiny bit improved -- that change *could* be my imagination because it's quite subtle but I seem to notice a bit more fatness and oomph.

I wouldn't expect or encourage anyone to do this because it's a very small change, but FWIW I did it and like it.
Well, don't minimize your accomplishment. At the very least, you've proven that they're a complete equivalent, perhaps slightly better. So, those caps can be added to the list of possible options with known success for the MAX.
Reply
post #364 of 1853
11/29/08 at 3:01am
Almost finished my second Mini Max, and thought I'd post a photo of how I bent and heatshrinked the leads on the VitQ's......



Clearance from the heatsinks on both sides is very good, there is very little exposed metal that can make contact with stray multimeter leads, and the only bit that sticks above the height of the heatsinks is the tape around the outside of the cap.
Reply
post #365 of 1853
11/29/08 at 3:38am
Outstanding, Beefy! I hope you don't mind my using several of your pics for the MiniMAX website. I had been working hard on it before the computers in our household went haywire lately. I've got a new one almost built, though, so maybe I'll be productive soon.
Reply
post #366 of 1853
11/29/08 at 3:46am
Quote:
Originally Posted by tomb View Post
Outstanding, Beefy! I hope you don't mind my using several of your pics for the MiniMAX website. I had been working hard on it before the computers in our household went haywire lately. I've got a new one almost built, though, so maybe I'll be productive soon.
No probs at all. I've taken better construction photos of this second one as well..... with tripod, no flash. You're welcome to any of them.

Oh, and a quick question. Where would be the safest and most convenient place to measure pre-regulator DC voltage? I'm getting 27VAC loaded at the terminal block, but I don't trust my meter's AC reading. Though if the pre-reg voltage measures high as well, I might increase the regulated voltage a bit to decrease heat production on the Vreg.
Reply
post #367 of 1853
11/29/08 at 4:02am
Quote:
Originally Posted by Beefy View Post
No probs at all. I've taken better construction photos of this second one as well..... with tripod, no flash. You're welcome to any of them.
I'll take anything you can give me.
Quote:

Oh, and a quick question. Where would be the safest and most convenient place to measure pre-regulator DC voltage? I'm getting 27VAC loaded at the terminal block, but I don't trust my meter's AC reading. Though if the pre-reg voltage measures high as well, I might increase the regulated voltage a bit to decrease heat production on the Vreg.
The traces leading from the outside axial Schottkys to CR1A and CR1B are rectified postive (+). So, I would put a probe on one of the legs of those outside Schottkys - the legs closest to the PS heat sink. GND, of course, can be measured from anywhere on the board.
Reply
post #368 of 1853
11/29/08 at 5:13am
Quote:
Originally Posted by tomb View Post
The traces leading from the outside axial Schottkys to CR1A and CR1B are rectified postive (+). So, I would put a probe on one of the legs of those outside Schottkys - the legs closest to the PS heat sink. GND, of course, can be measured from anywhere on the board.
Cheers for that....... next time I wont be so lazy, and will look at the board and work it out for myself

I'm measuring 33.1VDC, so increasing the regulated voltage to 28V will still give me 5V headroom for regulation and drop heat production a tad.

When I've de-fluxed this new build, I'll take some glamour shots and send you some thumbnails. Just let me know which ones you want and at what resolution and filesize, and I'll either host or email them depending on size.
Reply
post #369 of 1853
11/29/08 at 5:36am
These BG's still need 5324566 hrs burn-in, and I'm not sure these 12FK6 tubes are fully cooked yet.... but WOW.... no concern for bass quantity or quality with BG's in CA2 and Wima's in CA9.

No concern for dynamics with 33R Kiwame in RB14 either, at least with my sacrificial KSC-75.
Reply
post #370 of 1853
11/29/08 at 7:01am
I'm doing some very similar builds and I was planning to use 10R in RB14.
Is 33R more appropriate for black gates or something?
Reply
post #371 of 1853
11/29/08 at 7:10am
Quote:
Originally Posted by rds View Post
Is 33R more appropriate for black gates or something?
I will be predominantly using my Max with Audio Technica ESW9's, which are extremely sensitive. My first Mini Max was originally jumpered and was very noisy with these phones. With 10R in my regular Max, I can hear a touch of tube noise even with music playing. Switching in 22R to my first Mini Max was a slight improvement over this; you really need very quiet bits in the music to hear it. My second Mini Max build with 33R initially seems much better, but it also has Wimas in CA9, which tomb suggested may help reduce tube noise.

[EDIT] Oh, the other thing, ridiculously low travel on the volume knob with the ESW9 when RB14 was jumpered or with 10R.

I'll do some in-depth comparisons, burn in things some more, play with different tubes, etc, and come up with some final conclusions in a few days. But if you have anything less sensitive than ESW9, 10R or jumpered should be fine. I would personally lean away from jumpering though, if only to help protect the output stage from shorts.
Reply
post #372 of 1853
11/29/08 at 12:42pm
Quote:
Originally Posted by tomb View Post
Outstanding, Beefy! I hope you don't mind my using several of your pics for the MiniMAX website. I had been working hard on it before the computers in our household went haywire lately. I've got a new one almost built, though, so maybe I'll be productive soon.
Hopefully early next week I'll have some pics of both of my Minimaxes... although you'll probably only need to use one, as they'll be identical builds.
Reply
post #373 of 1853
11/30/08 at 12:50am
*Beefy throws down the Gauntlet*

Reply
post #374 of 1853
11/30/08 at 1:01am
^^^^OK, now your being obscene LOL Two balanced thumbs UP
Reply
post #375 of 1853
11/30/08 at 1:12am
Beefy, just you wait... I'll call your two Minimaxes and raise you a BantamDAC... on monday afternoon!
Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › New Millett Hybrid MiniMAX (what happened to this thread?)