livewire Posted December 25, 2010 Report Share Posted December 25, 2010 Thanks, I thought it might have been already mentioned in some form. I didnt think about it until I saw the word "vendetta". Quote Link to comment Share on other sites More sharing options...
deepak Posted December 25, 2010 Report Share Posted December 25, 2010 Thanks, I thought it might have been already mentioned in some form. I didnt think about it until I saw the word "vendetta". Oops my mistake, thought you meant the two huge Blowtorch threads. Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted December 25, 2010 Report Share Posted December 25, 2010 Only way to get the noise down is with discrete parts. I agree if were talking about the MC input stage.. But I'm not convinced the Klyne is 100% discrete and would love to get a closer look at one. Looks like the same gain modules are used in the line pre section. I'm not sure I'd bother with the Vendetta. It has to be hand-built unit by unit and to do this you really need some decent test equipment. I tried to breadboard one and it was very unstable and drifted all over the place. I'm almost positive the glued devices are violet grade. I can give you some part numbers for very nice SOT JFETs that have lower noise than any of the Toshiba parts, but you probably aleady are looking at those. Quote Link to comment Share on other sites More sharing options...
deepak Posted December 25, 2010 Report Share Posted December 25, 2010 Kevin what is your experience matching the 2SC3421 or 2SA1358? Just curious to get a rough idea how many to order of these to get suitable values... Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted December 25, 2010 Report Share Posted December 25, 2010 Check out the old Dynahi threads on HF where people posted a long list of hfe values to get an idea... Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 25, 2010 Author Report Share Posted December 25, 2010 I have slightly different values for things like R30-31 (100K) but that doesn't matter. Brown Black Black Yellow Brown Red ==== 1 Meg 1% 50ppm ?? Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted December 25, 2010 Report Share Posted December 25, 2010 I believe that's 100K 1% 50 ppm. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 25, 2010 Author Report Share Posted December 25, 2010 try again 6 Band Resistor Color Codes or 5 Band Resistor Color Code Calculator Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted December 25, 2010 Report Share Posted December 25, 2010 You might consider putting a resistor in parallel with C3 in case someone wants to run it with a MM input. Also, a trimmer on the input is lame. Switched resistors (and capacitors) is better. Is Q16 flipped (drain and source flipped that is)? Same with Q14? Is C11 hooked up right? D1, D2 are 15V. Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted December 25, 2010 Report Share Posted December 25, 2010 try again 6 Band Resistor Color Codes or 5 Band Resistor Color Code Calculator I was thinking it was 10.0 x 10^4 Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 25, 2010 Author Report Share Posted December 25, 2010 (edited) i'm sure c11 and c14 are correct. Q16 and Q14 may be in backwards, will look at that soon. D3 and D4 are 1n4746 which are 18v zeners D1 and D2 are 1n4737 which are 7.5v zeners This version has to run as a moving coil unit. Reason, the .1uf 1% cap and 750 ohm resistor at the output of the first part are one of the 3 riaa filters. Another version has the input resistor and pot replaced with a 47k resistor, and then the gain of the input stage reduced by 20db or so by changing around a bunch of resistors. a couple of other things fixed too. Edited December 25, 2010 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 26, 2010 Author Report Share Posted December 26, 2010 So here is a little historical fun. Back in 1975 and 1976 while in college i was building and selling world class phono sections and preamps. (sound familiar...) Virtually all of which are still in use today. So while some things like good circuit design seem to be timeless, other things like double sided circuit boards with heavy ground coverage are new. These days i would add a servo to the thing to make sure there was no DC on the output, something that really did not matter back then, as there were no fully DC coupled power amplifiers. I don't actually remember which of the riaa sections i ended up with, there were at least 3, so i showed the one from Robert Linsey Hood The original fets were ct134, which i replaced with 2sk170 in this schematic. http://gilmore.chem.northwestern.edu/kgphono.pdf this was one of the first boards without a solder mask. http://gilmore.chem.northwestern.edu/opampfront.jpg http://gilmore.chem.northwestern.edu/opampback.jpg Quote Link to comment Share on other sites More sharing options...
livewire Posted December 26, 2010 Report Share Posted December 26, 2010 Primitive elegance... Some things never change (like the dual FET front end). Love the KG logo too! Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 29, 2010 Author Report Share Posted December 29, 2010 there seems to be a growing interest in the phono section... http://gilmore.chem.northwestern.edu/kgphonoservo.pdf not counting the power supply, this is no more than $50 in parts if you use the lsk389, a lot less if you use 2sk170's... With the servo, matching is virtually unnecessary. I'm trying to find the moving coil schematic i did way back when... Quote Link to comment Share on other sites More sharing options...
MASantos Posted December 29, 2010 Report Share Posted December 29, 2010 This phono section would be quite interesting, there are very few discrete diy options out there. Maybe we should start a new thread about it? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 1, 2011 Author Report Share Posted April 1, 2011 (edited) Its time to get back to work on this, now that the other 2 major projects are completed. I've been told to stay away from OLED's because power supply failures can cause burned up lines. So unless someone has a better idea, i'm going to go with this one. http://www.4dsystems.com.au/prod.php?id=114 I want a touch screen, and i want the embedded proc to be able to do i2s to drive the switching etc. Edit: screw it, i ordered both the oled and lcd versions. Also ordered enough stuff to make the thing programmable from wifi. You could do a version with no touchpanel or knobs at all. Edited April 2, 2011 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
deepak Posted April 2, 2011 Report Share Posted April 2, 2011 You could do a version with no touchpanel or knobs at all. Would this be using the linuxworks/AMB attenuator and an infrared sensor? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 2, 2011 Author Report Share Posted April 2, 2011 (edited) The digital attenuator part is similar to, but drives different from AMB's thing. Its still an 8 bit relay thing, with latching relays. I used AMB's calculator for the resistor values. My version drives twice as fast as linuxworks thing. I originally was going to use AMB/Linuxworks thing as is, and give credit but linuxworks turned into such a jerk... And they still have not actually released the thing. Mine may be out before theirs The version with no front panel, i was thinking an ipad app. wifi... infrared? that is SO last century... Edited April 2, 2011 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
spritzer Posted April 2, 2011 Report Share Posted April 2, 2011 RF then...?? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 2, 2011 Author Report Share Posted April 2, 2011 (edited) Well you clearly know there's an app for that So i've been working on stuffing the house with lutron RA2. And there is in fact an ipad app for it. But its too combersome. So i wrote my own. Runs native on a HP slate 500, or any windows box. And even on an ipad inside firefox with my local web server box with ASP. http://gilmore.chem.northwestern.edu/lutronapp.jpg Next week i'm going to automate the 3 bathrooms Full up macro capabilities... Then integrate in the TV's, dvd players, music server... This could go on forever. The preamp app will be just as easy. Source code for this thing (all of my new things) will be available, and for the usual and customary price. Edited April 2, 2011 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
deepak Posted April 2, 2011 Report Share Posted April 2, 2011 The digital attenuator part is similar to, but drives different from AMB's thing. Its still an 8 bit relay thing, with latching relays. I used AMB's calculator for the resistor values. My version drives twice as fast as linuxworks thing. I originally was going to use AMB/Linuxworks thing as is, and give credit but linuxworks turned into such a jerk... And they still have not actually released the thing. Mine may be out before theirs The version with no front panel, i was thinking an ipad app. wifi... infrared? that is SO last century... yes a bit embarrased by the IR remark. ipad functionality with no screen/knobs seems cool to me. I'm in for whatever volume control you feel is the most transparent. I intend to use this preamp in a high end speaker setup. Quote Link to comment Share on other sites More sharing options...
Lil Knight Posted April 3, 2011 Report Share Posted April 3, 2011 Would the digital attenuator be a separate module (which means I can use it with other builds) or 'fixed' into the KGITSOJC? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 3, 2011 Author Report Share Posted April 3, 2011 I suppose i could yank that part out and do it as a seperate board. Quote Link to comment Share on other sites More sharing options...
Kerry Posted April 4, 2011 Report Share Posted April 4, 2011 It would be nice to have a board that would would fit into the standard balanced POTs used for the T2, etc using some sort of pins and would mount above the amp board. A simple plug in. The board would also have a ribbon cable for the I2C control stuff. Not sure if the size would workout, but it would be nice. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted April 4, 2011 Author Report Share Posted April 4, 2011 This is possible, but need to find the absolutely smallest latching DPDT relay that run on 5 or 12 volts. With the current relays, the board would be 7.4 x 2.6 inches and you would need 2 of them. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.