justinsweber
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Posts posted by justinsweber
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I will not be using a voltage dividing network on this next amp. I wanted as simple a solution as possible… It might not work… but I’m hopeful it will. I didn’t want to take an output tap intended for a speaker and drive it down to be used for phones. The SE-84 takes that approach… I was tying a diffident method. I’ve seen this approach used… as I’m not a phones user I did not evaluate, but when this project is done and scoped… I’ll buy some to listen. The Darling circuit with 8ohm tap outputs ~.750mv… I will see when the transforms get here and are build what it will output given the new output impedances… the napkin math looks very promising but bench testing will tell. The hope is DHT, no feedback and no resistive network… strap the phones to the ¼” socket and call it good.
I based my impedances on looking what several headphone manufactures spec for driving sig vs the phone freq response. Who knows… cant what makes it fun.
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Ive ordered iron for my 1st dedicated unit with impedances for 32 ohm for grados and alike and 600ohm for the wild stuff... I think 300 ohm was used previously with older designs.
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I have my output iron on order for the 1626 SE with 32ohm and 600ohm taps... bing on the phones :-)
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It’s a work in progress bringing the 1626 to phones... I’ve ordered transformers with 32ohm and 600ohm tapp, should cover almost all needs.
If my calc is correct... 750mv SE no feedback... should be worth a listen. As soon as I get it up in prototype... I’ll ask for an audition.
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Apple TV does optical out. I think Joe's DAC will handle. Used Gen 1 Apple TVs have HD and allow for great upgrades. More space plus use if external HD. A used Mac mini would be a fantastic option. I ran one from 3 years ago and upgraded to my current. Went SSD internally and external raid. Mac mini had optimal and USB out.
Another option would be to go SSD on your existing laptop and mirror it. Then no reloading. And the. Go external.
I've looked into Carbonite for backup. Scary idea backing up 1.5tb of media. But should be done.
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Older computer will work great. Load a simple red hat Linux for OS and it can use the USB on your DAC. There is a lot if support for this type solution too. If going with full computer route get as much ram as possible.
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Joe
You don't need a ton of processing power. I think the best budget solution. Is a used orig Apple TV.
Swap out the internal drive for a 1TB and call it good. It will give you optical out. The use a an iPhone, monitor or tv. Best of all. You'll have a good front end and can use a remote.
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These are what Id consider gievn the price point... can go in a tiny cab.
Dayton Audio RS100-8 4" Reference Full-Range Driver $29 each
Dayton Audio DS115-8 4" Designer Series Woofer Speaker $20each -
Too big for my taste... I don't think you'll find true response curves.. but maybe Im wrong.
Look at this bad boy... its what was specs... sounds great... better than the dayton 6.5"
Fostex FE168EZ 6.5" Full Range Sigma Series -
The new Emotiva is a great spinner. I had the model before a regret selling.
$500 new with 5year warranty.
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wow thats a pretty table!
I have a classic 1 but really wanted the VTA.
Congrats!
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Faital HF200 with fastlane audio epitrac 400.
Selenuim D220ti with fastlane audio epitrac HF.
and because Im crazy, http://www.parts-express.com/dayton-audio-dc380-8-15-classic-woofer--295-325.
Im pairing with a ALK Cornscalawal. As its 1st order, I should be able to compensate for the 8ohm.
Im hoping to prove Dave's calc that they should drop in.
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Dayton Audio TW-0.25BK 0.25 cu. ft. 2-Way Speaker Cabinet Pair Gloss Black
paired with
pair (2pcs) HiEND 4inch full range fullrange speaker defy lowther & fostex
Drill a 1" hole in the front for a port and wim bam boom ! The TL version is smaller... but the same great sound!
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Yup... ease enough to do. I might consider. The Kenzie/Darling is a real gem.
I strongly believe that I should also be able to get the same high quality iron with outputs which will be designed/optimized for phones.
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The backloaded cabs were a design from Woden Design http://www.wodendesign.com/fostex.html. The customer brought me the design. When we cut the Baltic for his, we ripped a pair for ourselves. Ive tried with drivers from Fostex... sp ed. 6", AN and the parts express 6.5" point source. I liked the fostex basic.
Re: stiff and sore... WOW! I hurt now.
I was itching to complete the Coxials so they were built before dinner. The cornscalas got started around 11pm for an hour and then I started redoing my 2nd rack... My old stand by amp vs my new personal build plus room for my budget dac and enough room for any of pre amps I have. . (I bought new all thread from ACE for my Salamander rack and cut them down to make as small as possible. Nothing like awake till 4 plugging away on projects.
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Re sales type stuff, happy to answer offline...I don't want to run my welcome out :-).
Give me a call and lets talk.
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As a brief aside... The forums are responsible for almost all I know about audio. The Klipsch forum was where I cam to appreciate, love, list and finally own some heritage products. Dave, Dean, ALK are just some who have helped along the way. Ive learned to cut some wood, understand specs and even voice a speaker its due to their help.
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Thanks guys... really kind. The Coaxial speaker came from a project Dave started and decided the CX12 was the right choice for... I had done some reading about eminence trying to get these speakers into home theaters... I can see why... super imaging. I was poo pooling Dave for adding a Lpad... and was going to orig use a D220... my god that would have been a bad idea. Even with eminence ASD1001she sound hot... The Lpad brings the sound back to where I like it... Dave will tell you I like my tweeter well padded.
I plan to keep the coaxials. but the cornscalas and the full range cabs will be built and placed in cold storage... sometimes the fait of things.
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The coaxial cab and design was all Dave... I just helped her get on her dancing shoes.
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I love transformer coupled outputs for headphones... Im told they behave well to difficult impedance issues.
I offered before... if you'd like to give the Kenzie a listen for 2 weeks Ill send your way.
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I love building stuff... Engines... reloading my computer, amps, etc. I love speakers... I own 4 pair personally, but man build those SOB kills the knees and back. Ive spent the better part of the day coming back from the finisher to get 3 pair of speakers... and completed 1 pair of my own.
The three pair which came home are:
1 a rehash of my very 1st cornscala. I cut the moterboard 5 years ago and held onto it. Combine a Cornwalls detentions, HF200 and the new eliptrac tweeter :-)... good stuff brewing.
2 my personal pair of 42" backloaded cabs for fostex or any 6" full range... WE built the 1st pair for a customer... but cut the wood for a pair for ourselves... no ideas what to do with it... but now its super pretty... 1st time Ive had a full range go deep and sound authentic.
3 Dave's design study/ collaboration on the Eminence 12CX... WOW is that a speaker and half... so smooth and just sound right. When Dave brought it over, it was raw MDF... I didn't even bother listening to it... I tore it down, primered and sent off to the finisher... Now she is back and she can really shake them down. Black lacquer with Sateen finish.
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Thats too funny. The speaker Joe has was a design study... his shipping box even was labeled, simple 4" speaker. I went with a TL for my final version... got the size down in half and able to still have same bass ext.
The simple 4" is a wonderful speaker... Happy to share for anyone wanting to build a bad as speaker. If someone starts a new thread, Ill include cab speaks and link to the driver.
Cabs are .25cu ft with .5" long port, 1" wide. The driver is now AN but is obviously made by same factory. The surround is rubber instead of pleating... Stiff suspension, cast frame, massive magnet for its size. Ive always believed that AN full ranges sound so good because they goosed the voice coil... making them much hotter than they should be... such that in a cab they play right and have amazing HF extension. This 4" has the same properties.
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Kenzie was the brain child of Tom McNally... I think it goes back even further... Known wildly as the darling circuit. Tubes are 12SL7, 1626... "The US Government VT-137 is the commercial 1626. It was designed as an RF power oscillator for conditions where good frequency stability is important. The operating condition was class C and that explains the high negative grid bias. The valve was only designed to provide short pulses of power in the anode tuned circuit. The circuit itself would then ring and generate sine wave outputs." It was described to me as the baby 300b... I think its a much warmer sound... very akin to 6v6 warmth. As usual I want crazy with the power supply. I used to build this amp with Edcor XSE iron... Seemed nothing was lost... a true feat given the specs of the XSE iron. At this point, the Kenzie is a nice implementation of the Darling circuit with a lot of attention paid to the ground scheme and increased, increased filtering and good transformers. For the full range or Heritage crowd its where a lot of searching could end. My business partner didn't believe me or think it was worth building. We had completed his set of split cornscalas and I brought a DAC with vol control over and a kenzie I built for demoing. In his garage the sound was jaw dropping... and the although only 3/4watt it was loud enough to bring a neighbor and the discontent of his wife.
Its not always how many watts, but the quality of the 1st watt. The Kenzie is paired with Iron I think not pretty enough for show up top... but provides the same performance and fidelity that any of my amps do... If it can't to 20-20K... don't use, build or sell it.
I am is the process of building a SE Kenzie... Larger crazier power supply, 10H choke, and iron that is insane to use for such little output... The idea being, why not have log-rhythmic over kill.
Amp Design ?, (especially SE-84 that Justin Builds)
in 2-Channel Home Audio
Posted
Kit... depends on how you consider it... I do buy my PCBs from shannon... I we also have alot of discussion with Shannon, my tech and myself re: changes to the circuit and different parts used.
DIYtube makes amazing PCBS which hare well thought-out.
That said, building them and getting the performance desired has taken many revisions.
The SE-84 is based on Shannon's top-plat and PCB. Specific changes include cathode biasing, feedback value changes and output transformers with different specs... though sources from edcor on this model.
Re: mental enclosure inside the wood... I originally was picking up noise. and so tried this simple suggestion and its worked... Ive now moved onto spraying the inside of the wood plinths with RF shielding which has accomplished the same goals.
KITS or not... an amp should measure well and try to employ the best build practices… I am not Shindo or Audionote… god I wish I were… I don’t make my own caps or wind my own iron… don’t forage my own chassis.
We do buy our own wood, mill it down; finish it to mate to its top-plate. Though I own some of my PCB gerbers outright… I don’t own them all and source from OE supplies who want my business and want to see their ideas get executed well. I ask for the design expertise to aid in building something which is different/improved from their original concept and pay for the advise.
I’ve said repeatedly… if anyone wants advise or would like more intimate details of what I use/ how I do it… call me. I have only received 3 such calls which covered cornscala configurations, sourcing for good iron and how to get a similar wood plinth. I don’t think its fair to ask me to place schematics, build of materials and grounding schemes for public consumption… Happy to share to an individual who wants to build for themselves and takes it upon themselves to ask.
With each of the amps I sell… they start with someone else’s good idea and good implementation of that idea… I try to then put my spin on it… not just solder it together but chose parts and values which make sense for me, and very often are not what are spec’d. In the end, each amp is bench tested, burned in for a several hours and then listened to. I’m not the most handy with a scope… My tech is… but my Cornscala’s sure as shit are revealing of problems… generally I fight noise floor battles… I want vanishingly low noise, good bass extension, neutral presentation and mid HF that floats… If I can hear it then there is a problem.
Re: the orig post… My exp has been circuit, output iron, passive components and grounding to make the largest share of differences on performance. Crapy circuits are real performance killers, but generally will exceed the ability of the iron. Passive components and their inability to remain stable over time or provide reliable/repeatable values has been a historic problem which has gotten considerably better over time. I think there was another post re: building practices… there is own books on this… building practices matter because the physics are non-negotiable and should be respected.
Lastly... if asked... I think Petter Millet and Shannon sparks create truely amazing designs worth exploring and builing.