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Showing content with the highest reputation on 11/05/2020 in Posts

  1. Mazzy Star live on Late Night with Conan O'Brien 23 August 1994: The highlight of this video is 6'4 Conan offering a handshake to 5 foot nothing Hope Sandoval at the end. She is infamously shy and reserved and it shows in her reaction. Also RIP David Roback. Remember when him dying was the worst thing that happened this year?
    2 points
  2. It represents One Whole Freedom.
    2 points
  3. Fair warning: This is going be an absolutely (film) nerdy post and probably of zero interest to anyone but myself. With that said... For years my friend Brent (listeners of my radio show will know him as bludvesel) has given me shit about the incredibly boring names I use for my computers: 2012MacMini, 2011MacBook, 2015MacBookPro etc. I do this so I always know what I'm looking at on my network. My Wintendo has the imaginative name "Monolith" because it has a huge black case by Fractal Design. Now I have two Macs of the same model and year. With that in mind, I spent several hours renaming all of my Macs. Brent uses musicians that he likes for his machine names. For me that'd be an impossible task, picking which ones. Instead I went with film directors 2012 Mac Mini Quad Core i7: Kubrick, named after Stanley obviously. 2012 Mac Mini Dual Core i7: Fellini, named after Frederico. I considered Antonioni, but I found it too hard to spell. 2010 Mac Mini Core 2 Duo: Ulmer, named after the cult director. Fitting as he was a full generation older. My ailing 2015 Macintop isn't current renamed because it will mess up some dependencies in Traktor (or more to the point, data Traktor uses.) Eventually it will become Bergman.
    2 points
  4. Pineapple Thief, Porcupine Tree... they were good discoveries.
    1 point
  5. I desoldered and tested my 2SK170s and they seem to be fine. In the meantime I figured out the problem with the PSU. One of the voltage limiting zeners was broken and B- was no longer limited to -400V and went to about -450V, but probably not stable? Tomorrow I'll get some replacement parts and that will hopefully fix the PSU and give me options to replace things on the left channel. If B- goes wild, what is the most likely part to break? Nothing looks slightly burned besides maybe one of the PZTA42, but that may be flux from the build. Maybe it'll start working again once the B- is correct again. That would also explain why I get sound during turning on/off as during that time the voltage drops. On the other hand, the right channel didn't break so something has got to be off on the left.
    1 point
  6. I would still like to listen to the bob carver amps..
    1 point
  7. Voted. Just once, despite presidential advice to the contrary.
    1 point
  8. I finished my first SRX+ build yesterday. It is overall quite satisfying. It doesn't have the breathtaking bass or unforgiving resolution of KGSSHV Carbon, but is rather non-fatiguing for long-term listening. I took the SRX+ Gerber file Kevin created (Thanks, Kevin!), added larger footprints in order to use the cheaper tube sockets, TO-92 footprints for the DN2540s and moved the heater-lift resistor dividers to the amp board so the wiring between this and the PSU board can be more streamlined. I also changed the small tubes to use 6.3V heater in order to match the surplus power transformer. The PSU board from Kevin follows JimL's original shunt PSU schematic. I added a normal bias tap in the zener diode string with a copied low pass filter, different lead spacing support on the output film caps in case a certain part number is out of stock. It is also cut short 1/2" from the original. Got too aggressive in fitting these boards into the small chassis. The internal space is barely large enough for the two boards to lay side-by-side. Had to mill off internal supports here and there, and ended up not having enough space for a real volume pot (the place holder is a rotary encoder waiting for a future attenuator board. The build started with a faint hum. Swapping tubes can reduce it to a certain level. Then I found a 55mVp-p saw-tooth ripple on the power, which is not supposed to be there (the shunt PSU has >120dB ripple rejection at power line frequency according to simulation). It turns out, the bias circuit voltage doubler drops its leg on the virtual ground and injects >1mA of ripple current, because the bias has to be ground-referenced. The virtual ground is not really a low-impedance node (about 60 ohm @ 60Hz with two 22uF caps). Any noise on the virtual ground is considered common mode to the shunt regulator, and is pretty much out of the control loop. Besides, with transformer HV voltage suitable for this design (I used 600V center-tapped), the voltage doubler doesn't have enough juice such that the 10M90 bottoms out at the low voltage points. So I modified the bias circuit to have its return tied to the output B+ and let the shunt regulator deal with the ripple current. Pro-bias is still easy to obtain, but the normal bias would have to come from dividing the B+ like in the original SRX circuit. The final assembly has 2.5mV hum in one channel and 5mV in the other. I don't think I can reduce them significantly beyond that without using DC heater and take care of the common mode noise from the header windings, perhaps also need to shield the small tubes. There is always some coupling from the heater to the cathode and it varies from tube to tube. With multiple tubes sharing the same AC heater I don't think you can balance it out completely using a pot, either. This simple amp performs well, THD+N is as low as 0.01% between 35dBV and 45dBV (40dBV being the rated operating voltage for the SR Lambda Pros to output 100dBSPL, which is pretty loud). One thing I'm not too happy about is the -2dB drop @ 20kHz when loaded with the AP (200k ohm + 66pf including cables). So I played a little with the open-loop performance. The driver stage has only -1.4dB drop @ 20kHz when disconnected from the final tubes, but the Miller cap of the 6SN7 is killing the high output impedance common-grid driver stage, dropping it to -9.5dB @ 20kHz. Negative feedback helped but didn't bring it back to ruler flat. It might help with a cathode follower stage before the 6SN7 but then there goes the simplicity. A rolled-off top end could explain the more forgiving sound, though. Thanks again to Kevin and Jim to make this such a fun project. If you are going to build it, I'd suggest using Jim's Revised shunt power supply for SRX Plus or any other dual voltage regulators. And don't use a chassis too small!
    1 point
  9. Does this belong to a Head-Caser?
    1 point
  10. Since I started trying different tubes on my SRX Plus I've noticed that, while the amp is dead quiet with some tubes, some tubes will result in audible hum with no input signal present. After some reading and experiment I decided the hum is most likely caused by leakage current between the heater and cathode of the input tubes. I decided to elevate the input tube AC filament supply. The photo below shows the filament elevation circuit I added this morning. The 12.6vac filament is elevated to about + 56VDC reference to ground. The amp with the same set of tubes went from a bothersome hum to dead silent (knock on woods)!
    1 point
  11. I've mentioned on my show a great many times that it's unwise to get into a bidding war with ambient collectors. Demographically, they are the oldest, most well heeled, and the ones most interested in owning original physical media. Today's example. Mama mia.
    0 points
  12. Luis Troyano, ‘Great British Bake Off’ Star, Dies at 48
    0 points
  13. I had a very scary halloween last night ...and not in a good way. Background: I am mostly blind in one eye. I see very little out of my left one. I was born this way. Had the doctors caught it in time, they could have corrected it. I'd have had to wear an eye patch for several years (arr!) but I'd have gained sight in my bad eye. None of that happened. Last night I lit a candle I got a while ago. It's got 3 wicks and sits in a (rather flimsy) glass jar. The three wicks are a PITA, necessitating turning the candle to get them all lit. I was working on the third when one of the wicks shot off a bit of ash or hot wax and hit me in the face ...right below my good eye. I said "oh shit!" and put down the candle. After insuring I was alright. I looked at the candle. I didn't get hit by wax or ash. The jar shattered and I got hit in the face with a glass shard, a few mm below my one good eye. Ulp.
    0 points
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