kevin gilmore Posted April 3 Author Report Share Posted April 3 opa551 is a cheaper opamp that is good to 60 volts opa445 is good to 90v. at least that is what the pricing used to be 1 Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 3 Report Share Posted April 3 (edited) So, I am good with my four OPA445. Thanks, Kevin for confirming. Edited April 3 by audiostar 4 Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 3 Report Share Posted April 3 On 11/1/2017 at 2:38 AM, mwl168 said: On a side not here, cooling effect is bigger if sands are put on the lower end of the sink. As heat travels up, sink real estate gets used more effectively. Quote Link to comment Share on other sites More sharing options...
JoaMat Posted April 4 Report Share Posted April 4 On the split CFP3 power board it seems to be some pads between the 82R resistors on the bottom layer. What might the purpose of them be? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 4 Author Report Share Posted April 4 surface mount version of the 47uf cap 1 Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 10 Report Share Posted April 10 (edited) On 3/29/2022 at 8:17 PM, audiostar said: Thanks, Pars! Which pins are you using on the lower side, that go into the 14-pin socket, do you have the p/n handy? Thx After ordering something from eBay, I just found the following perfect part that is available from Mouser as well. It is 7pin, round, gold flash, Preci-dip p/n 350-10-107-00-001101. Edited April 10 by audiostar Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 19 Report Share Posted April 19 Meanwhile in the making... 3 Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 19 Report Share Posted April 19 (edited) Hey Kevin, what happens with the amp if someone decide to toggle the ZF/SS switch while the amp is powered on? Just thinking loud that exposing such a switch is actually pretty dangerous, no? @kevin gilmore Edited April 19 by audiostar Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 19 Author Report Share Posted April 19 you get a dc glitch in the output. not enough to cause damage to the headphones. 1 Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 19 Report Share Posted April 19 (edited) Would the Headphone Protector trigger? Thanks again, appreciated! Edited April 19 by audiostar Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 19 Author Report Share Posted April 19 probably not. glich is too fast. try it and let us know. 1 Quote Link to comment Share on other sites More sharing options...
audiostar Posted April 19 Report Share Posted April 19 Will do, thanks for heads up Quote Link to comment Share on other sites More sharing options...
Pars Posted April 19 Report Share Posted April 19 When I was repairing Todd's CFA3, I think I did this, and no, the protector didn't trigger. Also I don't recall much noise in the phones from it either. Probably not the best thing to do, and it has been a while since I worked on this. 1 Quote Link to comment Share on other sites More sharing options...
spector12 Posted June 19 Report Share Posted June 19 Hello I'm on the way to CFA3 mountain, and it's my first time to build DIY amp. Thanks to you guys, I could order PCBs, and buy most parts I need. What I still don't know is how to build my own enclosure(chassis). Is there any reference document or universal(?) enclosure I can use? (I could'n t find it) I always appreciate all you guys and information you shared. Thank you! Quote Link to comment Share on other sites More sharing options...
johnwmclean Posted June 19 Report Share Posted June 19 There is no generic or universal enclosure as such. I recommend having a look at modushop, the pesante dissipante range could be the ticket. But you’ll need to tap heatsinks and drill holes for the panels. Modushop customise as well, so you could have everything done there from your drawings. eBay is another good source for enclosures. Front Panel Express is a great company for getting drilling of your panels done, you need to work with their proprietary software which is downloadable and fairly easy to use. Unfortunately none of this is cheap... 1 Quote Link to comment Share on other sites More sharing options...
johnwmclean Posted July 6 Report Share Posted July 6 https://goldensound.audio/2022/07/04/kevin-gilmore-cfa3-headphone-amp-measurements/ 5 Quote Link to comment Share on other sites More sharing options...
mrjayviper Posted July 12 Report Share Posted July 12 On 3/14/2022 at 12:29 AM, audiostar said: Prior I start desoldering any components from my other boards, I thought I'll ask if anyone might need two fully populated (except Opamps and JFETs) wider boards. Not trying to make any profit, will sell at BOM cost, DM me if interested. what's the width of the PCB including the L-bracket? thanks! Quote Link to comment Share on other sites More sharing options...
mrjayviper Posted July 12 Report Share Posted July 12 (This is the gerber file I'm looking at => cfp3smt2splitamp - CADCAM.zip dated 2022-Feb-07 in the shared Drive folder) - what's the minimum voltage I can use with the amp? - I've been back-reading and I've read mentions of an opamp but I cannot find it in the PCB. - average power consumption? (or shouldn't even think about it considering it requires massive heatsink? 😁) Thank you. EDIT1: The file I mentioned above does NOT have the transistor portion like what I've seen in other DIY pics. What Gerber file should I be using? EDIT2: What's the difference between cfa3production.pdf vs cfa3productionss.pdf Quote Link to comment Share on other sites More sharing options...
mrjayviper Posted July 13 Report Share Posted July 13 if going for the split board, what's the input section? I am looking at the shared folder but it's not so obvious which one to get. Thanks Quote Link to comment Share on other sites More sharing options...
mrjayviper Posted July 15 Report Share Posted July 15 On the left side of cfa3productionss.pdf, there's a schematic on the top right with a 2n4391. But I cannot find it in the cfp3rssfixedss and cfp3rssfixedsssw. Any ideas? Thanks Quote Link to comment Share on other sites More sharing options...
migo Posted July 25 Report Share Posted July 25 Another newborn CFA3 dual mono setup here. Thank you Mr. Gilmore and Audiostar and Mirko! 6 Quote Link to comment Share on other sites More sharing options...
audiostar Posted Friday at 09:43 PM Report Share Posted Friday at 09:43 PM On 3/13/2022 at 1:42 PM, audiostar said: Look what the cat just dragged in 🙂 I have some split boards available, anyone in need for them 😀 just let me know. 1 Quote Link to comment Share on other sites More sharing options...
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