heady

Bram, the virtual ground is wrong. It is not connected to the BUF, only the Signal Ground is connected after the 2134 to the BUF634. Is this in Visio? I have just installed Visio Pro but it doesn't have this type of template. Thanks,

Thanks Bram, before this I tried to do what you did with your Black Amp, ie soldering wires to back of perf board to simulate the strips. It was a mess, so I went back to this type of perf board. Must learn from you.

Wow! I am go for one OPA627 and two OPA637. Plus one OPA2228. Can't wait to find out price of the AD chips. Hey, we DIYers, need all the savings we can get. Thanks Bram.

Re-drawn the layout schematic so is clearer but still a little too crowded. If you are thinking of using this layout, please pm me for the original pic, this is too low res. Until I can get help from bpribadi to provide a Visio version (thanks) , this is the best I can do.

Let me start by sharing these links about soldering techniques: http://www.vishay.com/company/brands/measu...09/609index.htm http://www.circuittechctr.com/guides/7-0.shtml http://www.elexp.com/t_solder.htm

Bram, I am re-drawing the layout on paper, bigger so clearer. I like the idea of TLE instead of using the resistors after I saw the voltage imbalance when using battery. TLE allow battery to drain more before getting distortion. Cost about $4.50 each but the drive to Tuas to collect was insane, so I bought 10 pcs. Now left 5pcs. Burnt one when I connected the power in reverse. Let's have lunch and go to Koba next week. PM me your preferred day (except Fri and weekends). I pick you up.

Bram, I can send you a photo of the layout but it need some explanation. I also found a mistake as I was building it. I did not bias it to Class A, no room. The transistor you saw is the TLE. I am keeping the JFETs for my desktop amp. I got the Nichicon FineGold from Koba, I think it is $2 each. I am trying to fit this into a gold coloured Hudson tin I don't think I want to spend too much on a Hammond. I did buy some enclosures from Koba but will keep them for the full size Pimeta or PPA clone. They also look so nerdy.

domi33, I used the pimeta schematic from Tangent but adapted it to my own layout. I don't know any easy way to draw the layout except by using Visio and I don't have that at the moment. I am now thinking whether to keep the Nichicon FineGold cap or substitute it with a smaller Elna cap of same uF. Problem is the FineGold is just a lttle too fat but it sounds fabulous and the Elna is smaller but I wonder if the sound will change. Decisions, decisions.

Bram, we compare to learn from one another. Otherwise each will be in our own little island. Having said that, I must say that your handicraft is superb and truly a blessing for the eyes. I don't think I can ever approach it but I will do what I can for the fun of it. Besides the music is so enjoyable thru our little creations. I used one side of the dual OPA 2134 as buffer for a TLE rail splitter, for the virtual ground. Strictly speaking, it is probably overkill. The other side of the OPA is used for the signal ground, as per the PPA/Pimeta schematic. I just changed computer and have no Visio to draw the circuit I used but I can take a digital pic of my drawing to share with you what I did. Hope to see you.

Bram, you continue to amaze me with your skills. Good shot and hand-held? Knock me down!

Thanks digi01.

********************************************************************* UPDATE - I dropped idea of fitting this into a Hudson tin. See post dated 7 Oct 2004. ********************************************************************* Hi all, My humble project cannot compare to bpribadi's work. Here is my board of a pimeta clone, without the extras, only one 1000uF electrolytic cap and one 1.5uF film cap for the power rails only. I am now listening to it with a AD8620 for left and right channels while the other OPA2134 is for the virtual ground and the signal ground. 3 BUF634s for L/R/G. Surprising it sounds quite good. I am scratching my head at moment trying to figure a way to fit the cap into the tin. Somehow, my measurement is always slightly out, I am no engineer. Sigh! The boards are meant to fold one on top of the other and so use the base of the tin as heat sink for the buffers. Of course I need to insert insulator sheet inbetween the folded boards. I am trying to see if this is a significant improvement over my 3-channel CMOY. And my initial finding is, yes the sound is better. I can hear the sound is much cleaner. with better separation and sense of the "air" around the voices and instruments. The bass is punchy, dynamic and deep which is surprising as there is only one cap for the whole board. Maybe I just have very imaginative ears.

Thanks Dreamie

Dreamie, will the same layout work with MC cartridge? Thanks.

dreamie, are you using moving coil or magnet pickup? Thanks.

Bram, I was hunting for a nice casing for my second pimeta (ambitious ah, not finish first one which I am trying to fit into sweet tin) in SLT but found only low quality and frankly ugly ones only. Wow the cost of the Hammond is "ouch"!! Our hobby is expensive.

Bram, AWESOME. I have been working on a pimeta, at first I tried to do what you did but it was hard to get the wire to stay flat when soldering it and I gave up and use another type of perf board. You clamped the wire down while soldering? I really like the case, where did you get it? Wow, hope I have a chance to audition it before you sent it to your brother. Man, you are good.

The dentist ate the mints!!

Sorry about the pics but just want to encourage others. This is the internal view. BTW - I use a hole puncher this time instead of a drill and it was so EASY. Hole puncher is $1.35 from Popular bookshop. Get the one with 6mm hole.

Just finished and delivered this cmoy in an Altoid tin to a friend.

Finally cased my 3 channel cmoy. This is the "naked" view. Still missing the LED as I haven't decide what type to use.

kornilius - after folding it, it is a little too wide to fit into the box but with a little push to bend the curved part more, it goes in. Small matter, I just want to give you the complete picture, I am happy with it. bpribadi - the sound is acceptable to Senns people but this phone needs to warm up. Straight out of the box each time, it sounds terrible especially when new. Even when broken in, if not used for more than a day, it needs maybe 10-20 mins to sound better again. I am not advocating the PX200 but it is an acceptable trade-off, the sound versus the portability, to me. I find the in-ear design better in sound but not usability. Each time someone speaks to me, I need to pull out and then place back with the wait for the foam to expand and fit. I guess it's all a matter of taste. Just my opinion.

Well, I'm not sure if my head's big or not but certainly looks big in the mirror. I have the PX200 and it feels ok as the metal headband thingy is not so stiff and do bend. After using it, I have to bend it back a little to fit into the box. But it looks pretty solid so I am not worried about it. I have the DT880 which I prefer but the PX200 is ok, just a little less details but it's almost a third of the price of the DT880. HTH.

I bought them already mounted on the browndog adaptor, from Tangent, paid S$65 for two plus shipping. Ouch!!!!

Hi Bram, am listening to AD8620 on my CMOY. Wow, beats the OPA2228 in separation. The musical instruments are nicely placed in a distinct sound stage and not bright thru my DT880. But the 2228 is good value for money since the AD8620 cost approx S$30 each. Unless you get it free that is.