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Showing content with the highest reputation on 04/29/2016 in all areas

  1. A great evening of fencing. Lance fenced the former Russian Federation womens foil team member, World Champion and European Champion...he did not win.
    5 points
  2. Probably a South African, we have three distinct usages. "I'll do it now." -- I'm totally not going to do it. "I'll do it just now." -- I might do it later, if I feel like it. "I'll do it now now." -- OK, it's actually on my priority list.
    4 points
  3. Before the rebuild I was running twin turbos that made real power, but with challenges. I use twin Precision 6766 turbos with the dual ceramic ball bearing rotating system. I had to use smaller housings than ideal for fitment as they sit under the car (didn't have the heart to gut all the creature comforts like AC, power steering, ABS braking, etc... to place them in the engine compartment). Believe it or not my car is still very streetable thanks to the boost controller. Additionally, I needed 3" piping to make them work well. 3" piping running under the car and to the air to air heat exchanger is something to see...big as hell and made for fitment issues as well and bending things here and compromising things there. I had some fluid leaks as a result (e.g. pressure side of power steering hoses "massaged"). This also resulted in somewhat "leaky" turbo system due to some bending of the cold side plumbing (think pipes headed to the heat exchanger after the turbos have converted the exhaust to the pressurized air). On top of that there is the oiling system for the turbos. Changing engine oil was a serious PITA due to all the plumbing...2-3 hour ordeal. This will give some context of how much plumbing....before they were powdercoated black Anyhoo, these are the snails which I still run in the new setup... They make stupid power and the power delivery can be very deceptive, unlike my prior positive displacement supercharger which was like a light switch...on or off. No middle. 46mm wastegates [ and 50mm TiAL blowoff valves Air to air heat exchanger The new turbo system is a major leap forward for me. Same elements as above, but much of the plumbing is now integrated into my K-frame, including the oiling. HS
    3 points
  4. The next day has the Atlanta Record Show at the same hotel, same room! Find out more about CanLanta at CanLanta 2016 Website We are now up to 15 Industry Exhibitors! jhm3
    3 points
  5. You're a funny guy, Brent. I like you. That's why I'm going to kill you last.
    3 points
  6. I have received requests to share my adjustment procedures so I thought I would post it here in case others are interested. These steps are based on combination of compiling the excellent information JimL has posted and my own experience. All the trim pots except the 5K ones are for adjusting current setting of the current sources and sinks. And since they all use DN2540 which has quite a variance among samples, these setting will vary but the pre-set values in step 1 should provide a good starting point. You'll then need to fine-tune them a bit. Here are the adjustment/fine-tuning steps of the SRX Plus in sequential order: 1. Initial setup before first power on: (assuming 7mA of output current per triode of the 6SN7GTA/B) Output current source (the 4 100 ohm trim pots close to the large heatsinks): adjust the trim pots to 55 ohm if you are using 180 ohm in-series fixed resistor (250 ohm on silkscreen). These trim pots set the output current of the 6SN7GTA/B Output current sink (the 2 20 ohm trim pots between the upper 12AT7 tubes): adjust the trim pots to 12.5 ohm if you are using 75 ohm in-series fixed resistor (102 ohm on silkscreen). These trim pots set the current sink of the 6SN7GTA/B. Input current sink (the 2 500 ohm trim pots): adjust the trim pots to 410 ohm if you are using 1.2K ohm in-series fixed resistor (1.4K ohm on silkscreen) . These trim pots set the plate voltage of the upper 12AT7 (the ones closer to the 6SN7GTA/B). Adjust the 2 5K trim pots to be in the mid-point. These trim pots are used to balance the voltage of the plates of each of the two triodes of the upper 12AT7 so they are equal. The 5K pot and the 500 ohm pot will interact with each other a bit. 2. Insert all the tubes and power up the amp. If you have a variac, I recommend that you use the variac to gradually bring up the voltage for the first time especially if you are using NOS tubes that have not been powered on for a long time. 3. Check to see if all voltage (filament supplies, B+/B-, and the -20VDC) are all as expected and all the tubes lit up as expected. If everything appears normal, let the amp warm up for about 10 minutes before carry on to next steps. 4. The goal of this step is to set the output current of the 6SN7GTA/B to the desired value (7mA). Measure the voltage drop of the 100 ohm resistors of the output CCS (the 4 resistors between the large heatsinks and the .1uf/400V caps by the edge of the PCB). They should measure about 0.7VDC (0.7VDC/100R = 7mA). Adjust the 100 ohm trim pots to get the 0.7VDC voltage drop on these 100 ohm resistors. 5. The goal of this step is to set the output current sink to 17mA, 3mA higher than the output current. Measure the voltage drop of the 100 ohm resistors of the current sink (the 2 resistors between the 20 ohm trim pots and the single .1uf/400V cap between the two lower 12AT7 tubes). They should measure about 1.7VDC (1.7VDC/100R = 17mA). Adjust the 20 ohm trim pots to get the 1.7VDC voltage drop on the 100 ohm resistors. 6. The goal of this step is to set the two plates of each of the upper 12AT7 to be equal and about mid-way between B+ and ground. So if you are using B+ of 360VDC, the mid way is 180VDC. First attach the DMM probes to each of the two .22uf/1000V coupling caps where they are connected to the plates of the upper 12AT7 and measure the DC voltage between them. (in my case. I purposely left the leads of the coupling caps sticking out a bit so I can clip the DMM probes on them. With the 5K trim pot set at its mid-point, the measured DC voltage between the two plates tells you how well matched are the two triodes of the 12AT7 tubes used. If they are well matched it should be within 5 VDC or so. If it's more than 20VDC you may have problem**.) Adjust the 5K trim pot so the measured voltage is close to 0VDC. Next, move one of the DMM probes and clip it to the power ground (leave one probe still connected to one of the coupling caps) and adjust the 500 ohm trim pot so the measure voltage is about 180VDC (half of the B+). The adjustment of the 500 ohm and the 5K trim pots will interact with each other so you'll need to go back and forth a bit. 7. Let the amp warm up for another 15 - 20 minutes for the tubes to reach their stable operating state then repeat the adjustments again. Measure the balance via the headphone jack like you do with other Stax amps. If the two triodes in each of the 6SN7GTA/B are well matched you should see around 1 or 2 VDC or so. And this is perfectly fine. 8. Measure the offset via the headphone jack like you do with other Stax amps. Adjust the 20 ohm trim pot (output current sink) to bring the offset as close to 0 VDC as possible. 9. Assuming all adjustments are carried out without problem, you are done and ready to listen to music now ? This is an all tube amp without servo so the offset and balance etc. will never be spot on and will vary and drift a bit every time you power on the amp. That’s to be expected. 10. There is an optional step which I have not done myself - you can adjust the 2 100 ohm output CCS trim pots to bring the balance of each channel to 0 VDC. I have not felt the need to do it (maybe I got lucky with the tubes I have). If you choose to do so, try to adjust both trim pots in a converging fashion instead of adjusting only one of the two pots. You'll also need to "coordinate" this with adjusting the 20 ohm pot in step 8. Hope this helps. JimL and others please chime in and correct me. ** In my experience, with the 5K trim pot centered, if the voltage difference between the two plates of the 12AT7 is greater than 15VDC or so, you should still be able to adjust it to 0 VDC but you may encounter problem with buzzing noise. You can move the 12AT7 tubes around to minimize this voltage difference. In my experience, it's more important to have the lower 12AT7 (the one closer to the 5K trim pot) well matched to bring this voltage difference down.
    2 points
  7. Picked up a new Omega X-33 Solar Impulse Limited Edition #129/1924 and will give the other X-33 that I've been hiding to my son for high school graduation, saving the Ti Seiko Astron for his birthday or myself. I have a Titanium bracelet on order to go with it.
    2 points
  8. Once you go connectors, you don't go back
    1 point
  9. Arnaud, I just used 1/4 watt RN60 resistors like Birgir had originally shared. I don't recall if he states it in this way anywhere else but the stock resistors are glued onto the PCB and the leads are tightly spaced, I think I ended up desoldering the original resistors with a pump or braid and then snipped the resistors off the board with a flush cutter. After that is a piece of cake.
    1 point
  10. This Is The End: Venezuela Runs Out Of Money To Print New Money http://www.zerohedge.com/news/2016-04-27/end-venezuela-runs-out-money-print-new-money What did the socialists use before candles? Electricity.
    1 point
  11. Hotel and flights booked, getting in Friday at around 8 PM and flying out Sunday at noon.
    1 point
  12. Pizzicato Five – Happy End of the World
    1 point
  13. 1 point
  14. Was looking forward to black pudding with a poached egg on top, with bacon, post run. But there was (boo hoo) no bacon. So I had to make do with black pudding with poached egg - which was still awesome.
    1 point
  15. "I'm sick of these motherfucking snakes up my motherfucking nose!"
    1 point
  16. Wow, lot's of great food on this page! That round of rib looks fantastic! One of the dishes I had on Monday evening had absinthe in the sauce, I think it was the Piranha dish and it was an amazing blend of flavors. Agree, $80 of electricity from just two sessions with the meat boiler seems a bit much. Are you starting to leave your headphone amp on 24/7?
    1 point
  17. A birth-year starter says more about you than a watch ever can
    1 point
  18. It is super annoying having to authentic authenticator apps then having to set them back up because there is no other way to do so then being at a desktop browser. After which you can finally login to something like LastPass so you can finally sign-in to some stupid two-factor app.
    1 point
  19. Speaking of Chronos - the new additions...
    1 point
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