tpg Posted October 20, 2004 Share Posted October 20, 2004 Hi all- I've had a sudden reappreciation for listening in 2-channel direct mode on my Onkyo receiver. Well... it leaves some to be desired. Bass response is what gets me, mostly. It's response is weak... not very full sounding. I demo'ed a tube amp (push-pull 6L6) for a while that produced amazing bass out of my old KG-2.5's. With the Onkyo, the 2.5's were very weak. Now I am RF-3's, which do better with the Onkyo, but are still kind of dry overall. I am kind of wanting a kit type thing... I am getting bored and want something to do. I figured building an amp kit would get me by, but there are a real shortage of cheap amp kits. I'd like to do tube, but that's be quite expensive. The cheapest is the S-5 kit, but that probably wouldn't be the way to go... I also ruled out Class-A solid state becuase of the higher cost of transformers for it (and difficulty in locating large enough trannies)... plus putting in 200W to get 10W is a little too wasteful. Which leaves me at digital amps... I've been looking into them a little and there really isn't a ton of info. Also not many manufacturers into digital, and even fewer that will sell to normal people who aren't part of larger comanies. Tripaths look to be about the best for the money, though there are some others that caught my eye- mainly the UcD available from Adire. I read the topics in the archives about Tripath amps... and was hoping someone could point out some details about them. I did a test today and found that I am using under 1W to my mains when I am listening "normally", so power is not as big an issue as I had thought. Is there anything specific I should be looking for when selecting digital amps? Leok- do you still build/modify these amps? How much does a completed amp usually cost? Are the things I hear about these amps true- that they share many sound characteristics with tube amps? Thanks all Quote Link to comment Share on other sites More sharing options...
leok Posted October 20, 2004 Share Posted October 20, 2004 Tripath is an easy choice for experimentation because they offer not only a variety of circuit options (single chip, smt, th, multi-chip, etc), but also demo boards with working amps. The demo boards can be upgraded and modified. One has to be somewhat familiar with switching power supply topology to build one of these things from scratch, because the high frequencies and current spikes can make layout very sensitive. I think the reason they are sometimes considered "tube-like" is their lack of the usual ss low power crossover distortion, non-linearity, and noise. (ss amps that take care of those issues are probably also called "tube-like). I find the Tripath amps to be mostly transparent sounding. There is almost no sonic signature at all. They do have a noise floor so I wouldn't build one any more powerful than I plan on really using. There is also a little of what sounds like feedback noise (the front end is an op-amp), so the lower the overall power, the less that will be an issue. Obviously most people don't hear it at all, but is is one advantage the no-feedback tube designs have. My amp is pretty much right off the data sheet for the smallest stand-alone smt package. I do use high quality components, which does matter. I also have big rf beads on all power and i/o to keep radio stations out. Let me know if you have any more questions. I'll try to help. Leo Quote Link to comment Share on other sites More sharing options...
coda Posted October 20, 2004 Share Posted October 20, 2004 Still hoping to coax Leo to perhaps crank out a few units again sooner or later, he's got a fan base in the meantime. I've listened to the prototype at Kelly's on numerous occasions and like what I hear, smooth and open with a nice balance of detail. Surprises me everytime I first walk in with the music on thinking those nice sounds are coming from the Moondogs. Quote Link to comment Share on other sites More sharing options...
tpg Posted October 20, 2004 Author Share Posted October 20, 2004 I have read a lot of good things about the P6D... Tripath's site no longer lists the chip used in the P6D. I am guessing the new one is the TA2020. It looks to be pretty good... Do the evaluation boards come pre-assembled? Or is everything done by whoever orders them? What parts do come with the boards? About how much does one cost to outfit with pretty decent quality parts? Sorry for the tons of questions in a row... I've been looking around a little. The UcD's are nice, but I don't need that much power- it'd be a waste. ST also sells a couple of Class-D chips that might be ok... but I am trying to look into them a tad more. This is my first venture into the digital amp realm, really, but I've been building analog for a couple years now. The ST chips don't seem to be as high quality as the Tripath, and you have to make your own layout, circuit, and everything... ST isn't helping much. Zetex has a Class-D controller chip that they have Eval boards for (for approved customers) that seem to be pretty good as well. I've always kinda liked Zetex MOSFETs. Hmm... so much stuff, so little time. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 20, 2004 Share Posted October 20, 2004 "I'd like to do tube, but that's quite expensive." Not necessarily...... Quote Link to comment Share on other sites More sharing options...
tpg Posted October 20, 2004 Author Share Posted October 20, 2004 Well, I suppose you have a point... it isn't necessarily expensive. The output irons are what kill me. Other parts are cheap... very cheap. But you get into output trannies and a power tranny and you are talking $100+ for decent stuff right there. I am one who doesn't like to tie up huge amounts of money into things I am building from scratch... and I was kind of wanting a project to build on a PCB (I am lazy... I've been doing my own layouts for two years or more and cannot take it anymore). I am not aware of many tube amps with PCB's (other than the S-5). Also, I am intrigued by the Class-D/T ideas... if nothing else, I probably will build up a 1000W Tripath amp to power my sub. My PA amp draws a LOT of current, causing my lights to dim with low-bass effects in movies. The thing has two 20A fuses, if that is any note to how much it can draw... So, a more efficient amp there will definitely be added in the future. I am bored again, mostly... and need something new and exciting to play with. heh Quote Link to comment Share on other sites More sharing options...
3dzapper Posted October 20, 2004 Share Posted October 20, 2004 tpg, Here is a nice EL-84 DIY amp you can build on a circuit board. I'd post pic's of mine but the attach file thimg is still messed up. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=39783&item=5726368474&rd=1&ssPageName=WDVW Shannon has a forum at: http://diytube.com/phpBB2/index.php Rick Rick Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 21, 2004 Share Posted October 21, 2004 You would still have to scrounge up some output transformers. With some time, patience and homework a guy could find some nice OPT's on ebay at a decent price. Lotsa weird auctions regarding audio related transformers nowdays, Caveat Emptor! Some of that old cheap-assed console tube amp iron ain't bad for homebrew projects, if you are going on the cheap. Yard and Estate sales are the way to get cheap tube junk for DIY, IMO. One of my favorite amps is from a 3 dollar thrift store console. Quote Link to comment Share on other sites More sharing options...
djk Posted October 21, 2004 Share Posted October 21, 2004 If you want to mess with the Tripath stuff the $30 Sonic Impact is 10W X 2 and the $100 Teac A700 is 30W X 3 http://www.tommytube.com/Teac-tripath/a_tour_inside_the_teac_a.htm Quote Link to comment Share on other sites More sharing options...
speed3 Posted October 21, 2004 Share Posted October 21, 2004 Bottlehead is currently re-introducing their Single End Experimenter's amp kit for $350 plus shipping. Not bad for a stereo SET amp. Too bad it's only 2 watts per channel. Quote Link to comment Share on other sites More sharing options...
tpg Posted October 21, 2004 Author Share Posted October 21, 2004 speed3- I saw that last night. I actually like the idea... I could use it for a headphone amplifier and for a speaker amp (I don't even ever hit one watt of output when playing Van Halen LOUD...). That'd really probably do best, but, $350 is kind of a lot to throw into a kit. I am still looking at the options... Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted October 21, 2004 Share Posted October 21, 2004 The $30 Sonic Impact looks very quiet up to 5W of output. If you had an ability to run it off of AC instead of batteries (don't know if it comes with this option), you'd have a nice little amp to run with the more efficient Klipsch speakers! Quote Link to comment Share on other sites More sharing options...
tpg Posted October 21, 2004 Author Share Posted October 21, 2004 Yes... it does look pretty good, expecially for the price. You get everything all in one package for $60 less than just the eval boards from Tripath. The option is available to run that amp off of a 12V wall wart, but that's never good enough. heh I could throw together a nice regulated supply with some spare parts... Though batteries do lend less hum and noise, probably. Another manufacturer has caught my eye as well, though their eval boards are more expensive. Maybe I should pick up the little class T amp to mess around with for the time being... hmm decisions, decisions. Quote Link to comment Share on other sites More sharing options...
whell Posted October 21, 2004 Share Posted October 21, 2004 Scroll down the page here in the 2 channel forum and you'll see my feedback about my "test drive" of the Carver Pro ZR 1600 digital amp. They are using the TriPath chipset. Specifically about the bass: this is one of the more fascinating experiences during my test drive. I guess I'm used to "boomier" bass. The Carver seems incapable of boomy bass. It is quite capable of producing bass with weight and detail that I've simply never heard before, and enjoy immensely. Quote Link to comment Share on other sites More sharing options...
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