Looking at my blog statistics I noticed some visits on my now old and very dead Cmoy project. Out of respect for the people who are visiting I wanna give an update on my electronics projects. Since I built that Cmoy headphone amplifier and crossfeed my life changed quite a bit, I don't have the … Continue reading Cmoy headphone amp update.
It came to my attention that Pow Chu Moy the man behind Head-Wize and the Cmoy headphone amplifier passed away in Reno Nevada (US) on February 12, 2016. Kevin Gilmore was the bearer of the sad news in the headphone community Head-Fi. I never had the pleasure of talking with Chu Moy, mostly because his … Continue reading The hero of DIY audio, Pow Chu Moy.
Sometimes I really hate living in Portugal, If I want to buy some JRC4556 for my low impedance headphone amp I must pay 18€ of shipment doesn’t matter if it’s 1 or 30 op-amps, if the purchase doesn’t go above 65€ the shipment must be paid. I get people must get paid to make my shipment but 18€ … Continue reading JRC4556, shipment prices and other rants.
Some audiophile remove dc filtering caps from their source devices saying that they degrade the sound of their setups, usually I read stuff like electrolytic caps suck, bass gets cut off, my (insert device name here) does not have any dc problems, my preamp already has filtering and the list goes on. My questions to … Continue reading Some thoughts about AC coupling.
Solve for -3 db Frequency Solve for Capacitor Value Load Input Impedance (Ohms): 32 Capacitor Value (µF): 680 -3db Frequency (Hz):7.31 Optimal low frequency response (Hz):73.14 After some “study” I went for the 680uf caps. 32 Ohms are the base impedance of my grados. People say electrolytics color the sound, I must be deaf because I … Continue reading My DC coupling caps.
My 9V dual rail cmoy with the Jan Meier Crossfeed (2 positions & bypass). The plastic box is lined with aluminium tape and the perfboards rest on pcb cooper boards, it’s a fully modular project. Opamp made by Burr-Brown (2132PA), I’m using the original ones still made by Burr-Brown if that stuff actually matters to … Continue reading 9V dual rail cmoy.
My Cmoy looks like this right now. The Sigma25s will be in the cmoy box because I don’t want noise to get in the regulated 9V cables and the AC-DC primary will be on a separated box that is shielded inside. The front of the cmoy will also have that wood imitation look, in my … Continue reading Cmoy update.
I’ll drop the virtual ground and go for a true dual rail PSU design.The V ground will be used to test amp boards.Note on dual TLE2426, it’s a bad idea to use 2 voltage references because they will “fight” for the voltage center, so I dropped one of the TLEs.
I need to get them outside my country and they get expensive, I do have 5 little ones for portable use but at 20€ for case you get why I didn’t buy a big one. I could actually shield all the case with that aluminium tape but I’ll just shield the amplifier board & crossfeed … Continue reading Hey! I like your opamp pictures, really great :). Why didn’t you buy a steel or aluminium case for shielding?
Cmoy board using a darn Burr-Brown 2132PA. The JRC’s that I got need at least 9V in each rail to work fine…darn. Next crossfeed section from Jan Meier. I really need to shield these boards.
The DC regulator and rail splitter boards in the headphone amp enclosure. 12VDC to a 9V 7809 regulator to a dual TLE2426 rail splitter that outputs 4.2V to the V+ & V- rails. I flipped the RCA and power back panel after taking this photo, now the PWR jack is closer to the PWR switch. … Continue reading Headphone amp update.
Still need to make the led holes.
I’ll make a dual in the future using the sigma25 dual design, two 9V batteries can be dangerous to headphones if I forget the amp running and that happens a lot.The dual TLE2426 virtual ground I want to make doesn’t worry me much specially when used with the JRCs.Anyway I already have a headphone amp … Continue reading Why not a dual power supply? Or just two nine volt batteries rather than a potentially noisy and high impedance virtual ground?
Headphone amplifier in the works. Not sure if I’ll use 9V batteries or a regulated source, maybe both. Believe or not that’s a lot of money on a table.