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Post by chris45set on Jan 24, 2007 18:56:00 GMT
headwize.com/faqs.htm#ampYou may need to scroll down slightly to see the bit about using a power amplifier. Can this work safely with a 45 based SET power amp (made by J. Korneff)? I do not want to damage anything. Tried it without the 100R resistor in series on the + signal lead, used only the 10R paralleled across + and -. Sounded quite good, but any more volume than just a tick up from dead silent was waaaaay more than I want to subject my ears to. I asked the mfgr Mr K and he was less than enthusiastic about running cans from his amp. I just want to be certain I won't blow anything up by using this configuration. Also, will the 100R resistors help bring the volume down to manageable levels? I can always try different values for the 100R if necessary. Finally, are 2 watt resistors of adequate power rating for this application, or should I look for 5 watt or above? Thanks to all for your advice. Chris When I was a child, I caught a fleeting glimpse.
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jan 24, 2007 20:11:24 GMT
for low power amps (1-4 watt range,45 SET is 1W) you won't need to add any resistor at all because the impedance of the headphones will self attenuate the signal.what you WILL need though is some means of switching between speakers/headphones with an external speaker switching box suitable in this case
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Post by chris45set on Jan 24, 2007 21:03:12 GMT
I had my speakers completely disconnected when I tried this earlier, volume was still way too hot. I also use the second set of outputs on the pre-amp for feeding my USB audio ADC for recording vinyl, and can use the volume control on the pre to feed the appropriate level signal to the USB device (very handy). At the level needed to feed the DAC properly, I think I'd end up deaf in short order. The 45 amps are running on their 16 ohm xfmr taps as my speakers are true 16 ohm loads. I just do not want to fry my 45 set by using headphones (HD-650, by the way).
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jan 24, 2007 21:57:37 GMT
Surprising.I use Grados (extremely efficient) on the 8 ohm tap of a single ended 6V6 which is about the same wattage level as a SET 45 and use my system console to set the volume levels.No resistors anywhere. I also have an ASL UHC Signature that i did a review for here years back ; www.head-fi.com/reviews/asl_uhc_rickcr42.htmlI still have and use it though I did have to lose the crap spring clip speaker connectors in favor of barrier strips and I screwed a wood base on then added some non-slip rubb feet so the weight of speaker cables didn't have it walking off the back of the rack or moving with headphones on pull it off the rack from the front If you are handy with a soldering iron and a drill there is a perfect for your situation project here www.avahifi.com/root/audio_basics/index.htmi would point to the exact magazine date but my Adobe Acrobat plu-in just went nuts up for some reason if you find you need more attenuation than the above you could always use a pair of 2 Watt potentiometers wired as rheostats for a variable headphone pad.I would keep the standard series resistor and just add the pad after so the "zero padding" position still leaves the 120 ohm resistor in series
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Post by PinkFloyd on Jan 24, 2007 23:43:03 GMT
www.head-fi.com/reviews/asl_uhc_rickcr42.htmlSuperb review Rick and not "one" spelling mistake I sometimes look back at some of my attempts at reviewing and can't believe I actually wrote the bloody thing! Things are different these days I think we should definitely both go back to our roots and write up one seriously, well composed, good article on something new......... Goldring DR-150 may get my creative juices flowing again..... what about you? I really miss your Uber down to earth comprehensive write ups man. Pinkie.
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rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
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Post by rickcr42 on Jan 25, 2007 0:34:45 GMT
the file I was looking for earlier.seems the resistors are 1K not 120 ohms ;D www.avahifi.com/root/audio_basics/ab_pdf/ab1993-07.pdfwrote it up in MS Word then hit "spell check" before sending it out for public consumption. I read that review and remember how modest my system was at the time though musical in the extreme in a small room with the PP EL84 Scott integrated driving my Optimus PRO LX-4 speakers.The four inch kevlar mid-woofer and a monopole Linaeum tweeter made for a nice transition unlike many cone woofer/planar tweeter combinations and why matching a subwoofer to Quads is such a pain. problem is there is nothing truly "new" just variations on the same theme so in the end just how much can you actually SAY without going to a ramble.Reviews need to have a certain word count to be effective but if the subject is just another amp that pretty much sounds like every other amp or an update of old headphones not a whole lot to get excited about. BTW-I actually did another review on the X-Dreams wireless headphones that use the same technology as is used in the very expensive Grado wireless headphone but sadly went up in smoke along with my computer of the time.One day i may try and recover the hard drive data and post my thoughts it being a WAY better review than the UPC one that was my first ever attempt at being serious not that I pulled it off that would be cool mike the headphones not only being pretty much a total blank but cans that have so far avoided being a flavor of the month,a thing that to be honest disgusts me when everyone climbs on board just because everyone else is then piss and moan when things don't turn out to be exactly what they expected as if "fanboys" with a new toy can EVER give a truly subjective view ;D Nothing really gets my interest any more Mike though i can't say why that is.Might have something to do with once the horse is down and you kick it more kicking is not gonna make it get up so why bother ? I need to be engaged,to have enough interest to give a shit or I don't bother and lately I am not giving a shit much
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