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Showing content with the highest reputation on 10/09/2022 in all areas
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T2 psu back panel, design and cut. I wanted to have the pin outs of the sockets for the umbilical chords from the psu to amp to be on the psu back for future reference.. I decided to go for 10degree 0.1mm tip engraving bit for the lettering, 0.025mm depth of cut rather than laser. Screw holes done with 3.175 end mill and main cut outs 6mm end mill. Now I have a good collection of quality bits and little experience now. CNC machining is starting to become FUN 🙂. Its so much nicer and more satisfying watching a CNC cut than using a hand drill and Dremel... Tool changing is a bit of a hassle and then I have to use a Z block and Z probe command get the new Z height reference for the tool sickout. So I try to minimise the number of different tools used. Tape hold-down and CA glue works perfectly. I'm very happy with the surface finish, perhaps the text for the pinouts and lines could be a little narrower, but its certainly not a disaster. Cut still currently in progress: The nice thing about symmetrical panels is that you can always adjust your settings and have another go with the other side... I decided to decrease the line width by half, nock 20% off the size of the socket decals, decrease the socket decal font size, change the style of the lines and reduce the engraving depth from 0.025 to 0.02mm... I think the new version should look a little less blocky and a bit more refined... The 0.02mm engraving depth is slightly too little, other than that I think its an improvement.4 points
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No Sun Nite Jewel 2021 https://album.link/i/1560738062 (link tree needs to be updated) Example: Hard to categorize - the opening track sound like the beginning to a musical. The album is eclectic, pretty, surprising, and probably deeper than appears at first listen. Reminds me of the first time I heard Goldfrapp.1 point
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That wonky scone does not look like it was made by the Scone Mason, but I whole heartedly approve of the table beneath it.1 point
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I was just saying that I didn't know if sapele had those qualities, rather than suggesting it did. The garage door and the front door in SF are mahogany, and the Tonkinois is doing remarkably well in the damp sea air and fog. That looks great Jeff, and the two woods go together beautifully.1 point
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Chopin: Piano Concerto No. 2; Scherzi Seong-Jin ChoLondon Symphony OrchestraGianandrea Noseda 2021 https://album.link/i/1571456295 Example: I have not heard someone attack Chopin like this in a long time. Impressive and very listenable.1 point
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During the last weeks I’ve built a few versions of the headphone protector. One small problem is voltage regulators, 7812 and 7912. Output voltages might differ more than 100mV from “specified “. 7812 at +12.1V and 7912 at -11,9V will move intended references 100mV. To tackle the problem, I made this resistor string. With above resistor string I can handle any deviations of the voltage regulators up to 200mV. If you want something else than +/-60mV trigger points, change the 1K resistor. 2K instead of 1K gives you +/-120mV. I’ve enjoyed working with this protector project a lot. Thanks for designing this Headphone Protector, Kevin.1 point
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I just post it in other thread but I think that it´s a very cool. Many hours for make this thing,,,1 point
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Progy prog day The Human Equation Ayreon 2004 https://album.link/i/1600474851 Example: This really is the album that got me into modern prog - that being beyond the Yes, Genesis, Floyd, ELP, Crimson, etc... that I was listening to. It showed me a modern concept album (this about a person in a coma from a car crash), with a fusion of modern styles and classic elements. Thank you Arjen Anthony Lucassen and all your projects.1 point
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In general, we prefer to avoid spoon feeding newer members and encourage them to do their own research. At some point, Kevin added a 3rd bridge and the capability to use a single bridge with a CT transformer (like amb's sigma22). Obviously you don't use all 3 bridges at once. If you look at the popular post feature on the right side, above, you'll see some of the key posts in this thread. I'm not sure, but jamesmking may have done a version history of the GRLV at some point. I know he did for the GRHV. His July 27, 2021 post shown in the Popular Posts might be a good one to look at. Using the search bar and searching "largecap" will find some info, including a recommendation for what board version to use...1 point
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Here is my CFA2 built on dip 16 sockets as 2 balanced dual mono amps with 2 GRLV power supplies (also built on dip 16 sockets). Balanced input is from a Benchmark DAC and balanced output is to Grado PS500e with Mogami quad 2534 cable (each amp cabled to each ear). There are eight sockets with 125 pins used (3 pins are not used on the opamp) and 40 wires. Six wires go the the heatsink components. First channel is running 150 mA bias and DC offset was 30 mV without the opamp, 0.2 mV with it. Still have to build the other three channels.1 point
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Here is a rebuild Dynahi, now a CFA3 something. CFA3smd engraved on back side of the Dynahi front panel. A green LED in the small S. Diagram of bias (in mA for the first 40 minutes from power on) for servo respective no servo. I think that with the servo it’s possible to build this with just 4 transistors instead of 14 (per channel) on heat sink – time will tell.1 point
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Built a Megatron. Seems to be the perfect amp to build during the seemingly unending shortage of 10m90s. I used up my final few pieces of 10m90s and C2M1000170D for this simple build, and it gave me some mild anxiety and regret for not hoarding up those sands. However, the build experience and result are worth it. Build process and after thoughts I started off with a pair of generic chassis from Taobao. 32cm wide, 8cm tall, 35cm deep. Silver and black anodised aluminium. They weren't available in other finishes but this looks clean enough to me. They do have some minor scratches and dents if you look hard enough though. The casework was done by a laser etching service provider I found on Taobao. The end result was a clean and modern appearance. Inside the PSU are a pair of +/-450V GRHV, +/- 15V GRLV, delay board and a 270VA toroidal transformer. The idea was to create a PSU that can be used by both the Megatron and the Grounded Grid amp units. These components fit the chassis nicely with little room for a third GRHV board for the 300v rail for Megatron. Outputs are split into AC and DC outputs. Transformer specs: The heatsinks for the amp unit were probably redundant since most of the heat comes off from the top. The amp board could probably fit into a smaller and lighter chassis, but I chose the same chassis as the PSU just so that they can stack. The amp build was straight forward and relatively easy compared to a Carbon build or any of the KG dynamic amp builds, due to the low component count. I did not use any boutique components in this build. The coupling caps are Wima, and the voltage rail decoupling caps are Siemens. Volume pot is an EIZZ-style stepped attenuator, internal signal wirings are pure copper. Special care was taken when routing the heater filament wires to avoid hum. Amp testing and adjustment was simple. Just ensure the all the rails are as spec'ed and that's about it. The voltage offset settles automatically after power on. No need to fiddle with any potentiometer when the amp is powered on, so it is much safer to test than the Carbon or the T2 family. Sound I used the Megatron with ES-1A, and here is my impression of the Megatron after comparing it with GG (on the same PSU), Carbon (450V GRHV 15V GRLV) and Mini T2 (triple GRHV). Currently I am using the Megatron with a quad of Mullard XF2 and PSVane EL34PH. The front end tubes are all Valvos. The sound of the Megatron is warm, slightly thick in the mids, and non fatiguing and airy in the treble. It sounds very natural and the imaging is holographic with good recordings. While it is very detailed, it does not ruin joy if the recordings are of poorer quality. Older or poorly mixed recordings have a smooth timbre and organic vibe when heard from the Megatron. While the Megatron's treble is not as extended as the Carbon's, it complements the overall signature to create a very complete soundstage and convincing sense of separation and space. What makes the Megatron standout from crowd lies in its low end - it is an amp for bassheads. It has by far the most THICC bass compared to my other amps, even more than the Carbon. The bass extends as deep as the Carbon, but the Megatron has a nice lift in the mid bass that makes my ES 1a slam extra hard. Listening to EDMs and fast pop tracks on E-Stats is finally satisfying, and I can finally stash away my planars. Carbon is like an antithesis to the Megatron. Carbon is like a clean cutting razor with little tolerance for inaccuracies where as Megatron adds a lot of joy and flavour into the listening experience. Carbon also sounds a little linear. Although the stage is wide, it is not as deep as the Megatron's. GG sounds more organic than Carbon in general. The GG's signature is quite dependent on the tubes. With the XF2s, GG is warm and clean, but doesn't deviate far from the Carbon sound. The bass isn't as tight and fast, and treble could sound stiff and slightly shrill with the wrong tubes - such as the re-issue Mullard EL34. Mini T2 sounds slightly leaner and cleaner than the Megatron, and has a much smaller bass. It is as enjoyable a listening experience for me, but the Mini T2 was much harder to build - by sheer component count. Tube placement and choices Placing the EL34s in this manner shown below allows one to use two matched quads of EL34 if matched octets are unavailable. Initially I used cheap Linlai tubes for the front end and had issues with sound imbalance and hum - turned out that the tubes were the culprits. Switched to some cheap NOS and the issues were gone. So my advice would be to use well built tubes from reputable makers. The 12AU7s affect the sound significantly. The option to roll tubes makes Megatron extra fun to use. More photos of the internals and the back of the amp coming up soon, when I am more free. I would say that the Megatron is my favourite amp - until I build the T2.1 point