Man of few words....
Gotta love Nelson Pass
SA/4e is nice!!!!
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His 1977 A20 driving Quad ESL57's made me a believer, so much so, I morphed that amp into a massive 2 man lift pure 150w Class-A, that was water cooled, own pump, radiator, and cooling fan. http://www.firstwatt.com/pdf/art_classa_20.pdf Cheers George |
I have only owned the Pass XA30.8 and XP10 so my experience with all of the products are limited, but after spending quite a bit of his time discussing my desires/concerns with him, i recognized that he is not only a brilliant technical wizard, but he truly has a passion for the people listening to the music. A rare combination in a person. |
He is an impressive guy. I love the fact that he routinely shows up at forums and discusses projects and donates designs to DIY'ers. I am always amused at the wanna be engineers that try to redesign his products with after market products like PC, fuses, and other nonsense. If Pass Labs thought that these “mods” improved the sound of their audio they could incorporate them at a fraction of the “retail” price. But they don’t. I suppose he has to leave something to the bottom feeders. |
I’m new to Nelson Pass stuff, being a tube guy i decided to try something different for my Zu Audio Druid speakers. I bought First Watt F2J current source power amp this month (only 100 made), then i quickly ordered the original First Watt B1 buffer preamp by Nelson’s advice. Pass Labs Aleph L and Aleph P were competitive, but for a much higher price, so i’m happy i ended up with First Watt B1. I bought everything used, but Nelson Pass was very helpful by email. So i joined the "club", hello |
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Right, current source amps vs. volage source amps is a big difference. Active gain preamps vs. passive preamps with no gain at all is a big difference too. He has passive preamps which became active after the volume turned up to 9 o'clock (the aleph L series). But if you know what you need for your particular speakers then it's a benefit. For example i don't need much power for my full range crossover-less speakers with 101db sensitivity. Nelson said he use Zu Audio speakers himself (among others). So for my need current source F2J power amp of 5w per channel is enough. And absolutely neutral First Watt B1 buffer preamp (pretty small box) is good match for F2J power amp. Everyone should learn more about FW or Pass Labs products, but Nelson can help with a great support for his products. |
I used a B1 and a First Watt F3 amp for a while with my Superflys. I called the B1 the Transparency Machine. It works great but it's neutral and revealing as all get out, as if you are plugging your source straight into your amp. So much so that a CD player I thought was reference level turned out to be much less so, LOL. |
Whole Lotta Love/ Led Zep You need cooling Baby I'm not fooling I'm gonna send ya Back to schooling A-way down inside A-honey you need it I'm gonna give you my love I'm gonna give you my love Want to whole lotta love Want to whole lotta love Want to whole lotta love Want to whole lotta love You've been learning Um baby I been learning All them good times baby, baby I've been year-yearning A-way, way down inside A-honey you need-ah I'm gonna give you my love, ah I'm gonna give you my love, ah oh Whole lotta love Want to whole lotta love Want to whole lotta love Want to whole lotta love You've been cooling And baby I've been drooling All the good times, baby I've been misusing A-way, way down inside I'm gonna give ya my love I'm gonna give ya every inch of my love I'm gonna give ya my love Hey! Alright! Let's go! Whole lotta love Want to whole lotta love Want to whole lotta love Want to whole lotta love Way down inside Woman, you need, yeah Love My, my, my, my My, my, my, my Lord Shake for me girl I wanna be your backdoor man Hey, oh, hey, oh Hey, oh, hey, oh Ooh Oh, oh, oh, oh Cool, my, my baby A-keep it cooling baby A-keep it cooling baby Ah-keep it cooling baby Ah-keep it cooling baby Ah-keep it cooling baby Loved my old Alph 6. Have a new j7 and a couple of used First Watt amps. NP... Truly my audio hero! |
mikexxyz This needs to be posted up at the voodoo or shillers fuse forum https://forum.audiogon.com/discussions/the-new-synergistic-research-blue-fuses Cheers George |
I've owned Adcom and Forte amps that at least were related to Pass, and have always been impressed by his style and the sharing info thing…cool…I've also noticed few (or any? Paul McGowan maybe, although I'm not sure he puts them in anything) serious amp designers endorsing "magic fuse voodoo," and there's a funny moment in a Youtube interview with Dennis Had (I have one of his Firebottle HO amps) where he laughs off the fuse thing…that interview directly preceded my Had amp purchase. If get tired of my tube "problem" (!) a Pass SA-25 in on my short list. |
BIG fan of Nelson here, starting with DIY B1 buffer, as great as people have written about above. Had F4, aleph 30 and now F7, best of the bunch for me so far (xa25 is on my wish list for the future). Had many other amps too but his class A designs combine all the best qualities for an incredibly satisfying listening experience. He is so generous with his time and advice, answering emails and writing on forums, great sense of humor in his writing too (wish I understood it all!) and that never ending curiosity driving him to the next innovation - wonder what the sit-3 will be like. |
Here ya go George: https://www.youtube.com/watch?v=xLQsEeBKg1E |
One of Nelson's favourites it seems that he thinks highly of, was the Aleph L preamps, really different because it takes the best of both worlds and joins them together. It's a quality passive pre, but as the volume goes higher once it gets to 3 o'clock or higher it slowly turns into active pre for more gain if you need it for low gain poweramps or inefficient speakers. I've had searches out for a used one, but none of the owner ever sell them. Nelson Pass " I don't know why this invention didn't bring me fame and fortune, but who can explain it..... At the 3 o’clock volume control position, the Aleph L offers a direct path from input to output. The only component in the signal path is wire and switch contacts. At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders. Above 3 o’clock, active gain is added to the output signal in 2 decibel increments, for amaximum of 10 dB. As a result, you suffer the effects of active circuitry only when additional gain is necessary." Cheers George |
Yeah the MkI was straight passive all the way, the MkII was passive all the way till 3 o’clock, after which it slowly became active. Nelson introduced this MkII for very low gain amps like some of his, and very inefficient speakers <84db, that need more gain from the preamp. But as he said you paid the penalty if used passed 3 o’clock because it’s now becomes an active preamp with added distortions/colouration’s. Cheers George |
I ended up with original First Watt B1 buffer preamp No problem the B1 buffer is unity gain, which Nelson 1st designed to be a (no name), buffer for my passive "Lightspeed Attenuator" preamp so it could drive one or two very low input impedance amps of his which some of my Lightspeed owners had, this worked a treat for them. Latter Nelson released it and called it the "B1 Buffer", and designed a diy around it on DiyAudio forums, and also I think a ready made retail unit First Watt B1 preamp. Still to me if all is good between passive pre and the amp, no buffer is the best buffer whether it’s got gain or not. And that’s why Nelson says "you suffer the effects of active circuitry only when additional gain is necessary" on the Aleph L, meaning passive sounds better on it up to 3 o’clock on the volume control after which the active buffer with gain comes in, then it’s not quite as good. Cheers George |
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Seems like it become addictive when someone buying First Watt stuff. I decided to buy another preamp for my FW F2J power amp. Soon i will be able to compare my FW B1 Buffer Preamp and Pass Aleph L. After 7 month of using my B1 i realized that i need at least 4 inputs to switch between different phono stages. The B1 has only two inputs, the Aleph L has 4 inputs. Another reason to buy Aleph L was the second output which can be used for an active SUB if i will buy Zu Undertone sub for my Druid speakers. It was not easy to find the latest version of Aleph L which is passive if the volume control knob position is not higher than 3 o'clock. I'm sure that i don't need an active gain in my system, because even with B1 buffer preamp i only use 10-20% of the volume control. It was hard to imagine that less than 5 watt Power Amp (F2J) is more than enough for 101db speakers in my big room. if someone compared the same preamps (First Watt B1 and Pass Labs Aleph L mkII) please share your experience. thanks |
chakster I’m sure that i don’t need an active gain in my system, because even with B1 buffer preamp i only use 10-20% of the volume control.If that’s right B1 has no gain, you don’t need any gain, BUT! your FW F2J is only 2kohm input impedance this doesn’t bode well for any passive or tube preamps, even your B1 has 1kohm output impedance, which is not a good look either into the 2kohm of the F2. You really need a low gain preamp with an output impedance that’s below say 250ohm output impedance for this amp. You could look at the Schiit Ferya low gain with solid state output is 75ohm and the tube output is 210ohm, forget the passive output. Remote, excellent volume pot, cheap! and you can return it. http://www.schiit.com/products/freya Cheers George |
Hi George Actually i have F2 upgraded to F2J by Nelson Pass for previous owner. MOSFETs replaced with JFETs Input impedance is 50k Ohms which is stated in the original manual that i have on hands. But this is F2 manual, not F2J. I realized that F2J input impedance is lower ( approximately 25 Kohm ) "So the F2J is recommended for use with preamps with ordinary to low output resistance – tube preamps without cathode followers will work but will not reap as much benefit at high frequencies. " As Nelson said the F2J has a bit lower input impedance than most are used to, so having a preamp that can provide more current is a good idea. But there is no current production in my B1. He said the Aleph L in my system would be fine! P.S. What i don’t want is a tube preamp, i sold all my tube gear before i bought First Watt. Still have nice mega rare vintage tubes, but i want to sell them too. No more tubes at least in the near future. |