heady 0 Report post Posted May 13, 2005 (edited) Just want to show my new Pimeta. Got tired of my clone in a lousy looking box so when I decided to buy some pots from Tangent, I also bought his Pimeta board. I decided to use 470uF each for the rails to VG, plus 2 x 1000uF for the rail to rail power caps. Sounds a lot better than my clone, especially since it is biased to Class A. The casing is a Vero enclosure from Koba which I bought on a whim and was waiting for something to fill it. I am at the moment trying out an AD8620 plus an AD843 for the VG. I find the sound just right for my Senns 450 but a little too bright for the DT880. My Grado SR60 doesn't like this opamp, bright but less bass. The OPA2134 sounded good on the Grado. Now for the PPA! I will have to call it quits after that, this is taking me away from the music. Edited May 13, 2005 by heady Share this post Link to post Share on other sites
skyskraper 0 Report post Posted May 13, 2005 woah that enclosure is huge nice work tho Share this post Link to post Share on other sites
heady 0 Report post Posted May 14, 2005 (edited) woah that enclosure is huge nice work tho Thanks skyskraper, after adding the Bulgin battery compartment, there isn't really much space left. Also the front panel space is too limited for me to use RCA sockets for the input. So it isn't that huge after all. I did not intend this amp to be portable so it is ok. My self-made Pimeta clone I will later revise to fit into a smaller portable casing. Edited May 14, 2005 by heady Share this post Link to post Share on other sites
skyskraper 0 Report post Posted May 14, 2005 yeah i figured that it would be living in one place. ive used a similar style enclosure before only smaller and i found it to be quite inconvenient due to the lack of real space considering the bulk whats the next project for u? Share this post Link to post Share on other sites
heady 0 Report post Posted May 14, 2005 whats the next project for u? Populate the PPA clone board I bought from one of our forum members. Still trying to figure out how to get the jfets as cheap as possible. Farnell has them but from different manufacturers, I don't know if that is a problem and the cost is about S$0.90 each when there are S$0.30 equivalents but they are out of stock. Share this post Link to post Share on other sites
Firefox 0 Report post Posted May 15, 2005 Get them off Tangent then.. They're pretty cheap there, I've got a set of 4 pieces of 2N5484's for US$1 from his online shop before. Share this post Link to post Share on other sites
heady 0 Report post Posted May 15, 2005 Get them off Tangent then.. They're pretty cheap there, I've got a set of 4 pieces of 2N5484's for US$1 from his online shop before. I bought a set for the Pimeta but he did mention on his site that these are not suitable for the PPA. Share this post Link to post Share on other sites
Firefox 0 Report post Posted May 15, 2005 I bought a set for the Pimeta but he did mention on his site that these are not suitable for the PPA. If you're looking for the isolation rail JFET's, then they're not suitable. If you're looking for Class A biasing JFET's, they're usable in the PPA board. Farnell is out of 2N5486's?? /me looks at his Farnell bag with 25 pieces of 2N5486's.. Share this post Link to post Share on other sites
heady 0 Report post Posted May 15, 2005 (edited) If you're looking for the isolation rail JFET's, then they're not suitable. If you're looking for Class A biasing JFET's, they're usable in the PPA board. Farnell is out of 2N5486's?? /me looks at his Farnell bag with 25 pieces of 2N5486's.. Thanks Firefox. I mean that Farnell is out of stock of the cheaper 2N5486s and 2N5484s (2N5484 - Farnell 4545849, $0.31 & 2N5486 - Farnell 4503405, $0.31). They have only those that cost nearly a dollar each but each type made by different manufacturers. So I am not sure whether will they work and am not willing to pop nearly $18 until I am sure. Are there any other sources of these in SG? I know RS also have the same type as Farnell in stock. Edited May 15, 2005 by heady Share this post Link to post Share on other sites
Firefox 0 Report post Posted May 16, 2005 Then pay for the $1 Jfets.. It's only $0.69 more and it's not like you need 100 pieces.. Share this post Link to post Share on other sites
heady 0 Report post Posted May 16, 2005 Then pay for the $1 Jfets.. It's only $0.69 more and it's not like you need 100 pieces.. Yes I agree paying $1 per jfet is no major pain but my question was that the two types of jfets come from different manufacturers and so does it make a difference? I have no EE knowledge at all, just buidling the amps by cookbook style, ie follow recipe. Read the data spec also see stars. I am just concern that if I pay $18 for the jfets and then cannot use, wasted right? Thanks Share this post Link to post Share on other sites
Firefox 0 Report post Posted May 16, 2005 Get the BF245C. It will provide sufficient current even if you're using the AD843 opamp. Share this post Link to post Share on other sites
