I did notice that, and was wondering how you had preserved some of the grain after using the filler, nicely done
Or at the image site use their menu or right click on an image and select 'copy image link', then in this window (the post creation window) there is an icon for 'image' above -paste the image link into that and it will appear in your post. This is for you @edd2b
Sure, there are many ways to add images to your post, and they all do basically the same thing, just whatever method people are most comfortable with. If posting my own images, I use imgur, I have an account so can just click the BBCode button as shown below and then paste the link here, it adds the img tags for this XenForo website software... BTW, that image is from the Listening to On Vinyl thread over in the long and winding threads forum, one of my occasional forays over there. Just got this new Nova Cardinale record from Superpoze (Gabriel Legeleux), this is my favorite release of the year and it's really fun to have it now on two superbly pressed 180g 45 RPM LPs. The lacquer was cut by Marie Pieprzownik at Translab in Paris, and I think it was pressed at MPO, though no symbol on the records. Beautiful package, wish it was a gatefold, but for around $26 I can't complain, very high quality music and sound, highly recommended album regardless of the format (the digital download is 24-bit, 88.2k, and sounds really nice too).
Been working on some mods of a Realistic 42-2109, basically switching to an external 24vdc linear regulated wall wart. Pulled everything in the power section of the board except for the final capacitor. BTW, this is only a 47uf cap, but there is plenty of room for something larger, so I'll listen to it this way for a while and then maybe try a 1000uf. There are now some unused pads/traces that I could also use to experiment with some additional filtering if desired. My 24vdc linear regulated wall wart has a 5.5x2.1mm DC plug on it, so I found A DC jack on Amazon and made a bushing on the CNC router for it.
Thanks ubiknic. One problem I have is the old borrowed iPad I am using. With no mouse it is difficult to navigate these functions. The ‘copy image link’ isn’t listing and am struggling to insert the Img tags without corrupting the link. I’ll keep trying until it works!
Getting the transformer out of the box does most the work. A lone transistor doesn't reject common-mode voltages though. An RC filter actually requires a series input resistance before cap load also, otherwise you are just using the capacitor's ability to charge and discharge from the ripple and the hope that the current from of interference is limited. Already had another window open. An input filter for four op-amps at ~10mA draw. The voltage drop across the resistor under operation is 0.5V. Diodes with a 0.7V drop allow maximum inrush to charge the capacitors and prevent unbalanced startup; don't use diodes if you don't have a power supply with higher capacitance that can momentarily deliver five amps to a 0.1 ohm short. Low-pass cutoff frequency? 0.0014Hz
New Stereo Rack by Virgil Seaman, on Flickr This is a 3-shelf stereo rack that I have been working on with my friend and neighbor down the street. He has a well-equipped shop in his garage. The shelves are birch butcher block countertops cut to size. The four legs are made of African mahogany. I still have some sanding to do before applying a finish. This rack will replace my older traditional enclosed stereo cabinet. I have a lot of component gear (mainly vintage Luxman with rosewood cases) that I would like to display
Success! Nice job, looks kinda like the Timbernation racks, though with the butcher block instead of the full length planks he uses.
Thanks Davey. Yes, it resembles some of the Timbernation racks in design. The fastening is different and the shelves are not as thick. I enjoyed watching the videos of the owner of Timbernation. In my previous life before retirement I was an Industrial Arts teacher, mostly woodworking.
Here are a few more pictures. Locating the holes for the inserts was a little bit of a pain. But the nice thing is we can move the legs around to any position and fasten them nicely due to the accuracy. IMG_7012 by Virgil Seaman, on Flickr IMG_6965 by Virgil Seaman, on Flickr IMG_7009 by Virgil Seaman, on Flickr
Nicely designed with the insert. Most would have chosen a course threaded fastener directly into wood, would would have eventually failed. The threaded insert is definitely superior. If you ever want to get super tweaky it would be interesting to try brass inserts there as they are less resistant than steel, but that’s probably a difficult tweak to hear an audible improvement from.
The little $38 phono preamp I've been trying seems to have too much loading resistance. I'm not sure how much it has, actually, the board is difficult to follow and measurements/comparisons to other makes/models were not fruitful. Anyways, I always wanted a phono stage with easily changed loading resistance, something where I didn't have to muck with RCA plugs and y-cables/splitters, etc. So I made a bushing that goes behind the faceplate and holds a 5-pin Berg strip connector that was stripped out of an old computer. The other end was wired to the phono preamp board where 100pf loading caps once sat. So now I have a lot of flexibility when it comes to loading, and I don't have to muck with pulling the preamp out and changing RCA plugs, etc., just mute the preamp, swap the resistors, back in action. Could do loading caps instead or in addition to resistors, I suppose. Want to know how it works? Me too, it is 1:30am here and I've been working on several projects tonight and finished late, so I can't try it until morning. I figure worst-case scenario, I made it worse and wasted $38 and some time, about the same as going to a movie these days. And I can always re-use the enclosure to make something else. It does power-up, and I cleaned the stylus so I know it is working, the Q is whether the loading resistors will reduce the HF peaking. Hopefully I learn something.
Update to project above: Unfotunately, this Box01 has what seems to be a very inaccurate RIAA curve. I had thought it was a matter of loading but experimenting with different loading values this morning I see that is not the case. A bit of a shame as the mod on the enclosure to make loading changes easy came out very nicely.
NJM2068MD Hrm, wonder what they are doing with four op-amps per channel in that little box...copying someone else's design probably. My Denon receiver's phono sounds just fine with just one chip. Here's the bandpass I can dial in with three op amps...green with cartridge And TI finally got back in my 2nd choice opamp if ordered direct from them, after ridiculous chip shortage (some on Mouser say "expected 06/2023" or such). $9 each instead of $0.50 for a NJM2068MD though. And 3mm square. BTW, Here's low volume single-stage RIAA THD+N with a cartridge load, NJM2068 shown in green below, vs OPAXXXX: following the noise line up to 3kHz you can see why, although it is good for phono, Japan Radio only gives you non-standard a-weighted specs in their datasheet:
Wow. Of course you're right vinyl being the medium it doesn't matter much but that is an impressive difference! Oh well, I will re-use the enclosure for another project. Maybe I'll make my DIY Muffsy board to fit this box. In the meantime I'm actually very happy w/ the TC-750 you guys told me how to fix the noise issues on ("Phil, put those parts back in"), my response curve is very flat and comparisons between digital and vinyl versions are extremely close.
After months of research and circuit breadboarding I finally have a tentative release candidate (to borrow software development parlance) schematic and PCB design for a Constant Current Draw (pre)Amplifier. I've nicknamed it The Mary Shelley, being a conglomeration of stolen circuits, stitched together, and crudely brought to life. If it's of interest, here are links to the schematic and PCB trace routing. They are very large images so won't paste them here directly. https://imgur.com/4r1hYLd.png (Schematic) https://imgur.com/8BBwvSc.png (Top & bottom trace layout) https://imgur.com/FdEg7gy.png (Bottom trace layout only) I'd be happy for any assessment anyone has. I am still wavering on whether to jump in and actually try building it.
What gauge of silver are you using? Does its 6% improvement in conductivity beat 12 ga copper? You like the lower skin-effect depth of silver, the insulating tarnish, the thermocouple junction of dissimilar metals? Power cables have insulation. If you want a low dielectric, simply for its lower inducement of currents on the ground conductor for safety reasons, UL-rated for healthcare isolated systems XHHW-2: cross-linked polyethylene at 2.2 vs 2.0 vs PTFE. For portable cord, go extreme, Halo-Flex 1000V XHHW-2, for uses in wet, Class I, II, and III, Division 1 and 2 hazardous location. Continuous 90C rated. Up to 7 conductor 10AWG, 9/10ths of an inch thick. Then your problem is the NEMA plugs and lack of shielding. Put a junction box on the back of your amp and hardwire it with an armored flex cable with multiple grounding conductor carrier wires. Are you not an extreme audiophile? Either might save you a few dollars per inch.
Or I could just continue to have fun experimenting and learning. Isn’t that what a hobby should be all about? Is your assumption that I spent an absurd amount of money on silver cable, or that there can be no audible effect. Either way you seem to imply that I may be foolish and you know a better way involving less expensive materials, but I simply aim to share what I made with others here that may appreciate it. Your passive aggressive and demeaning tone is not needed and 100 percent uncalled for.
Just a little weekend project. I noticed on a recent pink noise recording with my AT-OC9/III and Conrad-Johnson EF-1 phono preamp and Lundahl SUT that there was a slight channel imbalance, almost 1dB, fairly consistent across the frequency range. Could be the cartridge, so repeated with a Musical Surroundings Phonomena II+ and it was closer, less than 0.5dB. The Phonomena is a negative feedback design, so you would expect near perfect channel matching in the preamp, whereas the CJ is a no feedback design, so channel matching is somewhat dependent on the matching of the gain device characteristics, in this case JFETs. I verified the Lundahl SUT transformers were well matched when I assembled and tested the unit, so didn't suspect that. So I pulled the CJ preamp from the rack and tested with a 1kHz signal applied to both channels, and there was a little difference, which traced down as expected to the input circuit, which is a differential amplifier using two 2SK117 JFETs, one side to the input and the other to signal ground. I'm sure they were well matched when the unit was new, but that was 1996, and many, many albums in the past. My tube phono preamp is similarly a no feedback design, so also depends on the tube characteristics, and whenever I play around with the tubes, I have to select them using a DMM and signal source to get the channels well matched. Usually doesn't require much messing around, but is an extra step not required in preamps that use negative feedback to set the gain. So I figured I could do the same in the CJ EF-1 by installing pins for the input transistors, then I could hopefully swap them around for a better match, and if needed, get some extras that could be used. The trouble these days is finding authentic Toshiba JFETs, the market is flooded with Chinese counterfeit parts so you have to very carefully compare the molding flash on the plastic case, and the lettering font, etc., to find the real ones. Anyway, I didn't have any 3-pin transistor sockets on hand, but did have some pins scrounged from IC sockets, so just used those pins. I removed the transistors and cleaned and straightened the legs, tack-soldered the pins and adjusted to get them straight, then used some epoxy on top of the board to hold them securely in place, as shown below. After it setup overnight, then I went back and fully soldered the pins and installed the transistors. Hooked up the meter and signal source, and then swapped around transistors and got the channels very close. So buttoned up and back in place yesterday, and playing beautifully... with well matched channels BTW, the second picture also shows the polystyrene capacitors I swapped out previously to lower the input capacitance, stock is 270pF, and the replacements are 47pF. The input circuit isn't cascoded to lower the Miller effect capacitance, and there isn't any loop feedback to keep it low, so it still has around 200pF input capacitance, but I primarily use it with a SUT for LOMC carts, so not much of a concern for me. Love the sound of this preamp, all quality film capacitors, no electrolytics in the chassis, Vishay resistors, no feedback, but it is a full size unit and only does 40-52dB gain, and in stock form has pretty high input capacitance.