META42 v2
Jul 19, 2002 at 2:52 AM Thread Starter Post #1 of 18

tangent

Top Mall-Fi poster. The T in META42.
Formerly with Tangentsoft Parts Store
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The META42 v1.0 boards are sold out, and it's time to start talking about what v2.0 will have. Details of what I'm thinking about are in a new thread on Headwize (the soul home of headphone DIY). If you want to know what's going on with this and want to help steer it, please join that thread.

Thanks.
 
Jul 19, 2002 at 5:47 AM Post #3 of 18
Enough to last 5 weeks, evidently.
 
Jul 19, 2002 at 6:26 AM Post #4 of 18
tangent,

would you consider adding the Alps Blue to your stock? You could buy these for probably less than $10 from THL Audio and sell them for $15. Just a suggestion.

The Alps Blue seem to be pretty hard to get cheap. I'm "in the process" of ordering from THL, but it is taking some time.
redface.gif
 
Jul 19, 2002 at 6:48 AM Post #5 of 18
Jupiter,

To properly buffer people from the delays of getting ALPS Blue pots, I would have to order dozens of the things -- that's bloody expensive, ya know? Also, an order that big would certainly get hit with import duties. So, $15 probably isn't within reach anyway.

Still, call it a "maybe".
 
Jul 19, 2002 at 8:15 AM Post #6 of 18
I'm not sure if it would be worth it for Tangent to get Alps Blue pots. Maybe he'd sell the Alps blue with 1 in 10 boards? Probably not enough to be worth it.

Besides, Tangent has tried hard to keep the board small specifically to fit in the small cases -- in which the Alps blue will not fitting...so a little contradictory to carry them.

Also I think most ppl who want to use the Alps blue will probably be ordering from parts from other places that stock the pot anyway.

Maybe he could buy a bunch of those fake stepped pots? Those are much cheaper than a Alps blue and a lot of ppl might like to try one
 
Jul 19, 2002 at 8:40 AM Post #7 of 18
Quote:

Tangent has tried hard to keep the board small specifically to fit in the small cases -- in which the Alps blue will not fitting...so a little contradictory to carry them.


Ummmm, are you aware that the board has a place to put this part? Yes, it's a little contradictory to use this part on such a small board, but at the moment it's the only readily-available well-known high-quality audiophile-approved board-mount part. (Well, there goes my hyphen quota for the day....)

With v2, we may well be getting rid of the ALPS Blue part, if the Bourns pot Morsel is working on making available is sufficiently good. But I won't be carrying that part -- it would snipe at Michael Percy's business, which I don't want to do since he's taking a risk at making these available.

Quote:

Maybe he could buy a bunch of those fake stepped pots?


Bleh, ptui! I offer these parts to people who ask about them, but I'm not thrilled with them myself. I wouldn't want to offer them explicitly.
 
Jul 19, 2002 at 12:07 PM Post #8 of 18
..though I don't use it.
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Enough people seem to want it and it would truly distinguish v1 from v2.

I'd ditch the big pot outline and those corner cutouts to gain some board real estate.

ok,
erix
 
Jul 19, 2002 at 1:58 PM Post #9 of 18
Thanks Tangent and others for all the work. My 2 cents worth is keep the production quantity small. Since you’re already thinking about Ver. 2 those of us that hesitated aren’t completely out of luck. A limited quantity will help the earlier versions hold value.

I’d like to see crossfeed in the new version.
 
Jul 19, 2002 at 5:53 PM Post #11 of 18
An idea: if you need space for crossfeed, you might consider having that section done in SMD. I'm not sure about the values of capacitors so I don't know how feasible it is but there are some supposedly pretty good PPS film high grade capacitors available, and of course you can get Holcos in SMD as well. It can still be bypassed easily and if someone really wants crossfeed, they will solder SMD. If you use 1206 or 1210 size soldering should not be an issue at all, and then you can also utilize the bottom of the board. I have parts mounted on both sides in my PDAC since the space requirements are quite stringent (77 x 74mm).
 
Jul 19, 2002 at 5:58 PM Post #12 of 18
How about mounting the crossfeed on a small daughter board? With some planning the form of the daughter board could be used for other applications or signal conditioning.

With the META42 the individual parts (resistors, caps etc) can be matched for closer tolerances. Is there anyway to individually tune the circuit sections to optimize the signal? Matching parts and tuning individual amp sections is something that would be prohibitively expensive for a production unit but would fit right along with DIY?
 
Jul 19, 2002 at 6:33 PM Post #14 of 18
Quote:

A limited quantity will help the earlier versions hold value.


Heh. I'm glad you're seeing the up side of this situation, but I'm not trying to artificially inflate the value of existing META42 amps.
smily_headphones1.gif


Quote:

I’d like to see crossfeed in the new version.


I'm considering doing this, but it will mean exchanging the combination ALPS Blue/Panasonic EVJ pot for the Bourns 51 part Morsel is working on making available. I could instead do just the EVJ -- from this feature standpoint alone, it actually makes more sense, but the broader picture demands that the Bourns at least be present. Since space precludes allowing both pot types if crossfeed is also on the board, the Panasonic would have to go.

Is this a problem for anyone?

Yes, aos, going surface mount would avoid this problem altogether, but it just doesn't appeal. I'm not saying "absolutely not", but I will go to a lot of trouble to avoid surface mount, personally. When it's forced on me I grin and bear it, but only then.

Quote:

How about mounting the crossfeed on a small daughter board?


I have a small crossfeed board already, and it's a bear to wire the thing. I suppose I could rig a new version of that board up that will plug into the META42 board with header pins, but the best solution of all would be to put it down on the board if I can. I'll be posting details about this on Headwize when/if I decide it can be done. Please do "vote" on the pot issue, though, as it will figure into whether I attempt this or not.

Thanks for the comments so far, y'all.
 
Jul 19, 2002 at 7:06 PM Post #15 of 18
How about making a set of surface mount pads inside the DIP 8 pads for the main opamp. That would allow people to use the AD8620 or other surface mount opamps without an adaptor
 

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