For anyone who might be interested: Nelson Pass-designed ACA amplifier kit "back in stock" :)

mhardy6647mhardy6647 Posts: 17,969
Some of you ("us") have an interest in low power, high performance amplification. Designer-guru extraordinaire Nelson Pass has been an enabler for those willing to turn to the soiled solid state in pursuit of fleapower Nirvana.

Some years back, Pass helped design and develop a simple Class A stereo solid state amplifier on a PC board. The design was turned into a kit designed to teach folks to build and appreciate such an amplifier at "Amp camps" -- thus, the Amp Camp Amplifier (ACA) came to be!

The ACA kit is commercially available but has been out of stock for a while. Overnight I received an e-mail announcing that an updated version of the kit was now back in stock!

https://diyaudiostore.com/products/amp-camp-amp-kit?utm_source=ACA+Back+in+Stock+Notification+List&utm_campaign=0411d3ac9e-EMAIL_CAMPAIGN_2018_03_26&utm_medium=email&utm_term=0_72286d7b2a-0411d3ac9e-261238033&mc_cid=0411d3ac9e&mc_eid=93022bf314

569sjl9zt7l7.png

Just thought it worthy of mention.

Rock on with your respective bad things :)

________________
* Disclosure: thanks to the mad skilz of this forum's ALL212 and the generous beneficence of another Forum member (who will remain anonymous unless he cares to reveal himself), a fancier morph of the original incarnation of this amp is 'in residence' at the Hardy household in the wilds of northern NH. This is a very cool little amplifier for those who can work with ca. 5 watts per channel.
"It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

"Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

"Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
«134

Comments

  • vcwatkinsvcwatkins Posts: 1,647
    Thanks @mhardy6647! Placed an order.
    Den: Rega RP6 (mods) * AT33PTGII * Parks Budgie SUT * Jolida jd9 (mods) * Roon (Sonic Transporter) * Sonore UltraRendu (LPS-1) * Wireworld Plat7 * isoRegen (LPS-1) * Lush usb * PS Audio DirectStream Jr. * Joule-Electra LA-100 iii * Sunfire Sig II * PSAudio p3 * MIT S3 * Polk SRS 1.2 (mods)
    Office Rip: Music Hall MMF5.1se * Speed Box II * DL103r * Lounge Copla SUT * PS Audio NPC * Roon * Bryston bdp-1, Bryston bda-1 * Rogue Cronus Magnum ii * PSA Dectet * MIT s3 * LSA-1 Statement
    Beach: MH mmf2.1 * Denon dl-110 * Belles Phono 20a * Sonos * Chord QuteEX (Pardo PS) * Belles 20a * Pass Aleph 30 * PSAudio Dectet * MIT s3 * Polk SRS 2.3tl (mods) - Revel M22
  • maxwardmaxward Posts: 106
    Thanks! Ever since I retired I’ve been itching to build or modify something. I have some Dynaco kits under my belt, but that was a very long time ago. Nelson Pass spoke to an audio club I belonged to in Portland and I always wanted one of his designs.
    Thorens TD-160C; Sumiko Talisman S; Jolida JD9; Marantz CD-53; Micromega Mydac
    Joule-Electra LA-100; Balanced Power Technology AC conditioner;
    Odyssey Khartago monos (with most factory upgrades); Magnepan MG 3.6R
  • mhardy6647mhardy6647 Posts: 17,969
    Nelson is a clever fellow who knows good sound and is skillful enough to get to it. Best of all, he shares his talent, skill and enthusiasm with the DIY community -- and doesn't look down his nose at those who cannot afford the top-dollar hardware.

    Can't say enough good things about the guy based on what I know of him.

    I mean, anyone responsible for the El Pipe-O subwoofers is my kinda guy.

    qq5zlc8y1ud6.png

    http://www.firstwatt.com/pdf/art_elpipeo.pdf
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • ClipdatClipdat Posts: 3,809
    Interesting:

    "Power per channel 5 Watts per channel (That's 92 decibels coming out of your speakers, assuming you're listening from 10 feet away with 91db efficiency speakers. More than 2 hours at this volume level exceeds occupational safety limits, is more than adequate to annoy your neighbors, and certainly enough to enjoy your music at normal listening levels)"
    Got Dayens?
  • mhardy6647mhardy6647 Posts: 17,969
    edited March 26
    The daily driver at my house is 3.5 wpc, you know?
    The loudspeakers are on the order of 102 dB SPL sensitivity at 1 meter for 1 watt input power.

    There are different pathways to Nirvana.

    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • Viking64Viking64 Posts: 2,676
    mhardy6647 wrote: »
    There are different pathways to Nirvana.
    You should have ended this comment with: "Boot to the head." :p
  • maxwardmaxward Posts: 106
    Currently sold out! Snooze you lose.
    Thorens TD-160C; Sumiko Talisman S; Jolida JD9; Marantz CD-53; Micromega Mydac
    Joule-Electra LA-100; Balanced Power Technology AC conditioner;
    Odyssey Khartago monos (with most factory upgrades); Magnepan MG 3.6R
  • Tony MTony M Posts: 5,452
    And I was going to order one too. :#
    Most people just listen to music and watch movies. I EXPERIENCE them.
  • mhardy6647mhardy6647 Posts: 17,969
    edited March 26
    already?!

    maybe the website itself hasn't been updated(?!?)

    maybe...
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • ClipdatClipdat Posts: 3,809
    Earlier it was accepting orders, now it's listed as sold out.
    mhardy6647 wrote: »
    already?!

    maybe the website itself hasn't been updated(?!?)

    maybe...

    Got Dayens?
  • heiney9heiney9 Posts: 23,728
    All sold out again!

    Dammit, I wanted to build this.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

    Pass Aleph 30 | EE Avant Pre | EE Mini Max Plus DAC | MIT Shotgun S3 | MIT Z P/C's | updated SDA 1C| SQ Box Touch/Welbourne Labs P/S- Tubes add soul!
  • mhardy6647mhardy6647 Posts: 17,969
    dang! sorry, folks :(
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • heiney9heiney9 Posts: 23,728
    Not your fault.....they sold out fast! I put my email out there for the next batch. Very cool kit and chassis.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

    Pass Aleph 30 | EE Avant Pre | EE Mini Max Plus DAC | MIT Shotgun S3 | MIT Z P/C's | updated SDA 1C| SQ Box Touch/Welbourne Labs P/S- Tubes add soul!
  • kharp1kharp1 Posts: 2,383
    Clipdat wrote: »
    Interesting:

    "Power per channel 5 Watts per channel (That's 92 decibels coming out of your speakers, assuming you're listening from 10 feet away with 91db efficiency speakers. More than 2 hours at this volume level exceeds occupational safety limits, is more than adequate to annoy your neighbors, and certainly enough to enjoy your music at normal listening levels)"

    Screw 'em, they shouldn't have moved in next to me! :)
    Main System:
    Joule-Electra LA 100 MKIII
    Pass Labs Aleph 30, McCormack DNA-125, Parasound A21
    Marantz SA-14S1
    Usher CP-6311/Tyler Acoustics Taylo Reference Monitor, LSA-1
    Dual SVS SB2000
    Wireworld Equinox 7 bi-wire, Wireworld Silver Eclipse 7 IC

    Secondary Rig:
    Parasound P5, Audio Electronics by Cary Constellation
    Marsh a200s, Audio Elecrtonics by Cary Hercules
    Pioneer Elite DV-45a, Denon DVD-2910
    Klipsch Epic CF-1, Vandersteen 3CE sig
    Analysus Plus Oval

  • voltzvoltz Posts: 4,945
    These would have been great with my Full range Speakers that are 94 dbl.

    My Omega Super 7 Monitor MK2's
    2 ch- Polk CRS+ * Vincent SA-31MK Preamp * Vincent Sp-331 Amp * Marantz SA8005 SACD * Project Xperience Classic TT * Sumiko Blue Point #2 MC cartridge

    HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
  • mrbironmrbiron Posts: 4,754
    Scat....I would have ordered immediately because I can't find time to drive North... :|
    Zu Audio Omen MK-1B's, Peachtree Decco65, Bryston BDA-2, Cheap TT, PS Audio UPC200, PS Audio AC3's, Zu Mission SC's, HTPC, One, Bottlehead Reduction & Crack w/Speedball
  • mhardy6647mhardy6647 Posts: 17,969
    mrbiron wrote: »
    Scat....I would have ordered immediately because I can't find time to drive North... :|

    I've noticed that -- I may have to avail myself of the United States Postal Service. I gots mad packing skilz...
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • mrbironmrbiron Posts: 4,754
    I know I know...
    I'm a tease with the likes of "yeah, let's set something up for this fall" or "put a date on a calendar and I'll make it work"...

    Is retirement at 33 an option?
    Zu Audio Omen MK-1B's, Peachtree Decco65, Bryston BDA-2, Cheap TT, PS Audio UPC200, PS Audio AC3's, Zu Mission SC's, HTPC, One, Bottlehead Reduction & Crack w/Speedball
  • mhardy6647mhardy6647 Posts: 17,969
    edited March 26
    Depends on whether spending one's golden years livin' in a cardboard box under the freeway is an appealing lifestyle choice. I'm speculating here. I mean, I reckon it's a realistic choice for, say, that Zuckerberg guy. In fact, perhaps he's considering retirement these days...

    pw2pf93a90bg.png

    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • mrbironmrbiron Posts: 4,754
    Sounds fun. Now I just have to find a bridge worth dwelling under.
    Zu Audio Omen MK-1B's, Peachtree Decco65, Bryston BDA-2, Cheap TT, PS Audio UPC200, PS Audio AC3's, Zu Mission SC's, HTPC, One, Bottlehead Reduction & Crack w/Speedball
  • verbverb Posts: 2,689
    @mhardy6647 are these a SE design?
    Basement: Polk SDA 1C's, Micro Seiki MB14 TT, Rotel 1580 Pre, Marantz CD6006 CDP, Carver TX8 Tuner, Conrad Johnson MF2300A Amp, Furman 15PFi Power Conditioner, AQ Diamondback (version 1) RCA IC's, MIT Terminator2 Cables
    Office: PC, Marantz AMP-1, Acoustic Technologies Classic Speakers, Polk PSWi225 wireless sub, MIT AVt2 cables, IFI Purifier2, AQ Cinnamon USB cable
    Spare Room: Dayens Ampino Integrated, Auris BluMe, Polk TSi200's
    Living Room: Pioneer SX-N30 Network Receiver, Pioneer PD10AE CD Player, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi Subwoofer
  • mhardy6647mhardy6647 Posts: 17,969
    edited March 26
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • verbverb Posts: 2,689
    Aw man! I snoozed and I loozed! :smiley: gonna get on the notification list now!
    Basement: Polk SDA 1C's, Micro Seiki MB14 TT, Rotel 1580 Pre, Marantz CD6006 CDP, Carver TX8 Tuner, Conrad Johnson MF2300A Amp, Furman 15PFi Power Conditioner, AQ Diamondback (version 1) RCA IC's, MIT Terminator2 Cables
    Office: PC, Marantz AMP-1, Acoustic Technologies Classic Speakers, Polk PSWi225 wireless sub, MIT AVt2 cables, IFI Purifier2, AQ Cinnamon USB cable
    Spare Room: Dayens Ampino Integrated, Auris BluMe, Polk TSi200's
    Living Room: Pioneer SX-N30 Network Receiver, Pioneer PD10AE CD Player, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi Subwoofer
  • ClipdatClipdat Posts: 3,809
    Sorry bro, I would've ordered one for you had I known you wanted one. I was going to order one but I don't own a soldering iron, and also my testicular fortitude is low.

    I didn't have the balls to attempt it. :(
    verb wrote: »
    Aw man! I snoozed and I loozed! :smiley: gonna get on the notification list now!

    Got Dayens?
  • verbverb Posts: 2,689
    Thanks man. I hear ya. :smile: I’m intrigued by the SE or SET amp discussion. Nice way to dip the toes in. Soldering is not that bad BTW. Pretty easy in fact once you get some practice.
    Basement: Polk SDA 1C's, Micro Seiki MB14 TT, Rotel 1580 Pre, Marantz CD6006 CDP, Carver TX8 Tuner, Conrad Johnson MF2300A Amp, Furman 15PFi Power Conditioner, AQ Diamondback (version 1) RCA IC's, MIT Terminator2 Cables
    Office: PC, Marantz AMP-1, Acoustic Technologies Classic Speakers, Polk PSWi225 wireless sub, MIT AVt2 cables, IFI Purifier2, AQ Cinnamon USB cable
    Spare Room: Dayens Ampino Integrated, Auris BluMe, Polk TSi200's
    Living Room: Pioneer SX-N30 Network Receiver, Pioneer PD10AE CD Player, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi Subwoofer
  • mhardy6647mhardy6647 Posts: 17,969
    no triodes in an Amp Camp Amp :)
    Three "elements" in a transistor, but it just ain't quite the same thing ;)

    If you want to dip your metaphorical toes into the SET water, here're a couple of nice options. L'il pricier, though.

    https://bottlehead.com/product/single-ended-experimenters-kit-3-for-headphones-sensitive-speakers/

    wawdp4tllo2k.png
    (Compactrons, baby!)

    https://bottlehead.com/product/stereomour-ii-stereo-single-ended-integrated-2a3-amp/

    1elbqyyufvl9.png
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • mhardy6647mhardy6647 Posts: 17,969
    edited March 27
    PS Yeah, soldering is not difficult at all. Just wear pants when you're soldering -- that stuff gets hot. ;)

    A PC board based kit like the ACA is particularly easy; point to point requires a little more manual and mechanical dexterity. :#

    There are some PC board based SET amp kits, but they're more like semi-kits* (i.e., not all components supplied), so they require a little bit more of the buyer/builder.

    Here's an example, FWIW (and since we're -- sort of -- on this subject!).

    http://store.triodestore.com/diytubegetsetgo.html
    http://www.diyaudioblog.com/2012/03/diytube-getsetgo-single-ended-amplifier.html

    This is sort of a hybrid between PC board and point to point construction. The 6B4 output tubes used by this amp are a "modern" variant of the classic, venerable 2A3 direct heated triode. The 6B4 differes from the 2A3 "only" in its base configuration (octal vs. 4 pin) and requiring a "modern" 6.3 volt filament voltage (vs. the 2.5 volt filament of the 2A3). It's still a gen-u-ine direct-heated filament triode, though.

    :)

    Current (or at least recent) production Russian 6B4s are still available, too -- though not necessarily very inexpensive. https://www.tubesandmore.com/products/6b4g-sovtek

    _____________________
    * EDIT There might be full kit SET amps available with all of the guts on a PC board... but offhand I cannot think of any.

    7n1u9ek4s0db.png
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • FestYboyFestYboy Posts: 2,448
    Wish I had the editing software to make an instructional video for the forum. The key is tinning the pieces to be soldered and heat control, especially when working with PCBs.
  • mhardy6647mhardy6647 Posts: 17,969
    edited March 27
    FestYboy wrote: »
    Wish I had the editing software to make an instructional video for the forum. The key is tinning the pieces to be soldered and heat control, especially when working with PCBs.
    I wish you did too :)

    ... and to use very good quality solder and a good soldering iron.

    The soldering instructions that will be found in the instruction manuals for old Heathkit or EICO kits are good. Yeah, a video would be better, but they are good.

    The trick, I'd opine, is to work (fairly) hot and fast (as fast as possible, that is) for best results, and to hold the joint nice and steady when/while the solder cools. OK I guess that's two tricks. One of the pitfalls IME is to accidentally jiggle the joint when it's still hot; this causes nasty 'cold solder' crystals (or whatever) to form.

    I do agree that temp controlled is the way to go for any serious work.

    Some components (particularly transistors, diodes and ICs) will benefit from heat sinking while soldering, too.

    10037867374_7b31b94e7f_o.jpgheathkit howtosolder by Mark Hardy, on Flickr10037867354_b039a5e6dc_z.jpgeico solder joints by Mark Hardy, on Flickr

    Like anything else, the best way to learn to do it is to find a mentor and learn at his or her feet (so to speak). Failing that, trial and error (sometimes referred to as trial and success) is also a valid approach. Remember, anything that does not kill one makes one stronger. :)

    EDIT:
    PS Soldering irons aren't the best for certain applications (e.g., soldering down multisection "can" caps, soldering ground busses, and - to some extent - for cable construction, too). At times like that, it is still (IMO) hard to beat the good old time soldering gun.



    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • verbverb Posts: 2,689
    mhardy6647 wrote: »
    no triodes in an Amp Camp Amp :)
    Three "elements" in a transistor, but it just ain't quite the same thing ;)

    If you want to dip your metaphorical toes into the SET water, here're a couple of nice options. L'il pricier, though.

    https://bottlehead.com/product/single-ended-experimenters-kit-3-for-headphones-sensitive-speakers/

    wawdp4tllo2k.png
    (Compactrons, baby!)

    https://bottlehead.com/product/stereomour-ii-stereo-single-ended-integrated-2a3-amp/

    1elbqyyufvl9.png

    Yep. I was intrigued by that amp mentioned by you on another thread. And equally touched by your story as to how the kids put it together. Good memories! I'm sure every time you play it you reminisce. Very heartwarming! :smile:
    Basement: Polk SDA 1C's, Micro Seiki MB14 TT, Rotel 1580 Pre, Marantz CD6006 CDP, Carver TX8 Tuner, Conrad Johnson MF2300A Amp, Furman 15PFi Power Conditioner, AQ Diamondback (version 1) RCA IC's, MIT Terminator2 Cables
    Office: PC, Marantz AMP-1, Acoustic Technologies Classic Speakers, Polk PSWi225 wireless sub, MIT AVt2 cables, IFI Purifier2, AQ Cinnamon USB cable
    Spare Room: Dayens Ampino Integrated, Auris BluMe, Polk TSi200's
    Living Room: Pioneer SX-N30 Network Receiver, Pioneer PD10AE CD Player, Polk RT265 In Wall Speakers, Polk DSW Pro 660wi Subwoofer
«134
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