[Punslayer]

I've been meaning to post pics of the stuff I've been working on for a while, but laziness always gets the better of me. I'll do this chronologically starting with me Meta42, which I recently re-cased and added a battery-pack.

Then the Mini^3 I built recently.

and finally the JaM Box. I didn't actually build any of the parts for this one, just gave them new homes.

From the bottom, this is the Ack! dAck!

And this is a Graham Slee Solo in the middle.

The top is an old Discman, along with an M-Audio Co3 to convert the optical output to coaxial for the dAck! to digest.

It's kind of a mishmash, but I think it's pretty cool and it sounds really nice with the PFR-V1.

 

[Sherwood]

Punslayer, your DIY projects are beautiful, unique and charming.

I am especially impressed with the JaM box, even if you didn't actually construct any of the innards. Many DIYers here are stymied by case work, but clearly you have risen above that.

I see a lot of you in your projects. Great work.

 

[Punslayer]

Sherwood,

thank you very much! My goal in DIY is not just to get good sound, but good sound that reflects my character so your words mean a lot to me. I'm quite an amateur at all this and I can understand why people are daunted by casework (I really need to get some proper tools) but I think that the reward is well worth the effort.

 

[dBs]

Id be worried about those plastic cases having or forming static charges in them =X

 

[Sherwood]

Quote:

Originally Posted by dBs /img/forum/go_quote.gif Id be worried about those plastic cases having or forming static charges in them =X

I wouldn't imagine it would be a problem, so long as the equipment is grounded properly, which it appears to be. Am I wrong here?

 

[Punslayer]

I haven't had any trouble with static electricity with any of these amps, but it's something I'll keep an eye out for.

But I tell you, the JaM Box sounds way better all put together than my system every did as separate pieces

I think maybe it's the new cables

 

[amb]

Quote:

Originally Posted by nsx_23 /img/forum/go_quote.gif Reading through headwize, it seems most people are frying the AD op-amps. Why?

To say that "most" people are frying opamps is a huge overstatement. Most people are successful at first try. You read about the problems because that's why they post there.

There are a couple of reasons why blown opamps happen in the Mini³. First, there is an onboard battery and reservoir caps that store charge. Some newbies don't treat this as a "live circuit" and give it due respect. When making measurements or otherwise mucking with the board, a wayward meter probe or other object could make undesirable short circuits. The second reason is that AD8397 has no internal output current limiting protection, so it's easily blown by a short circuit to certain pins. There are Warnings and Notices in the "initial setup" section of the Mini³ website to remove battery and discharge caps, but they sometimes go unheeded. Third, the simplicity and low cost of the Mini³ attract many first-time or newbie builders, which compounds the situation.

Follow all instructions on the website, build/test it with care, and there is no reason why it shouldn't work at first try.

 

[dBs]

Might be ok with any possible static build up in the cases. I thought about it a bit more after making the post and the only time static charge is a problem is when it contacts a lower potential difference or a ground. In the case of the mini^3 case the entire case has the same potential and if the ground plane on the board is tied to that case it has the same potential. Thus the battery is supplying the potential+battery voltage at all times. In effect its still acting as a ground.

Now I dont have enough real world engineering experience to know if this situation could cause problems in other situations, like if the case were to discharge suddenly (or not suddenly enough), or something else.

Either way, if its been working for you so far, Im sure youll be fine =D

 

[adamus]

not strictly a headphone amp.

Its a 12 wpc el84 pp amp with ecc803s drivers.

Each tube has its own cathode css, el 84's are at 34ma 340v B+, ecc803s has 1ma at 163 on the anodes.

sound? new toy effect hasnt worn off yet but its very promising!

 

[nsx_23]

That is incredible.

 

[linuxworks]

I wanted to add an alignment/test point post to the e12 that I recently built.
I had to hack things a bit but I think I did achieve my goal.

the board after I unsoldered the 2 caps that 'had to be moved', along with the new test post I'll use:

this is with transistors 'moved' a bit to make room, and the test post surface-s
oldered to the board:

and the final shot, showing the tantalum (orange) now put back and bent over slightly; along with the bypass blue (small) cap hiding behind the test post and the trimmer pot

the point of this was to expose the calibration points so that I can *safely* an
d easily align this thing for a nice zero-point ground reference and not have to
worry about probes slipping. even though you only align things once, its nice
to have proper support for it, so to speak

 

[linuxworks]

here's a bass boost mod to a pimeta. a daughterboard sits on top with a relay and an R/C combo. the relay either shorts out the R/C or lets it be in-circuit; when its in-circuit you get extra bass.

the 2 blue 'vertical' resistors are the normal gain controlling R's used in the pimeta. if the bass boost circuit was not being used, those R's would be in the 2 machine pins on the main pc board, below; but since the bass-boost is a series circuit, I got double duty from those R's as physical supports and also keeping the feedback-control loop physically/electrically short.

 

[Forte]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif not strictly a headphone amp.

That looks stunning... Any shots of the internals?

 

[MrSlim]

sorry, duplicate post.

 

[adamus]

heres one channel

The red caps are obbligato's, with an red shrink wrap to insulate (vibration) as they are pressed firmly against the case. Resistors are kiwame or trueohm. lytics are blackgates.