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wdecho

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About wdecho

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  1. With our speakers any quality amplifier will work. Quality over quality means much more. I have seen 6 watt SET's that sound much stronger than some retail 60 watt SS amplifiers. Advice from an old audiophile who collects amplifiers, do not fall for the numbers game that advertisers try to sell. I was also a number chaser in my youth. Even 96db efficient speakers are extremely efficient for such a small speaker. I would not hesitate to drive them with my SET 2 watt 45 tube amplifier with speakers that are 96db efficient.
  2. Class D

    I honestly have not spent that much time with the 7498 board. The sound from memory is very good much as the 3116 or 3118 with more power. The differences between the better cheap D boards from China are subtle at best. They sound great for what they cost. I would prefer one of them over many retail $400 A/B amps. This is with our speakers that do not require a lot of power to wake up.
  3. Class D

    There is a deal right now where you can purchase the board for $75 and yes it is American made, or I would assume so being it is a evaluation board from Texas Instruments. There is a Meanwell PS at Parts Express that would work fine with this board for $125. Board $75 plus switcher $125 total $200 vs $1500 for the Hypex. If money is no problem I agree go straight for the best known D board right now, the Hypex ncore. http://www.diyaudio.com/forums/class-d/309454-ti-class-evm-board-50-promotion.html
  4. Class D

    The transformer is one I have had awhile and I think it is one I purchased at Parts Express years ago. Maybe 160VA 25V with a bridge rectifier and 30,000uf of capacitance. Probably overkill on the capacitance, 15,000uf would be plenty enough but I purchased a number of them in a deal. The power supply is called a linear one vs a switching power supply commonly used with the cheap Chinese boards. Meanwell makes good reasonably priced switching PS. The DC going to the board is slightly more than the max of the 7498 board but since I already had everything I took the chance the board would not self destruct. It appears to work fine on the board. Inside a case I would go with a 22V to 24V transformer for sure.
  5. Class D

    Here is another decent cheap Chinese board one can purchase on Ebay called TDA7498. All the D boards can be used with a quality switching transformer and perform decently using such. Any handyman around the house can put together a D board amplifier using a switcher very easily and have a decent sounding amplifier for not a lot of money. The 7498 has more power than either the 3116 or 3118.
  6. Class D

    Here is a picture of my purely test build of some Chinese TPA3118 boards I assembled with a 200VA 15V toroid and 30,000uf or capacitance built on a cake pan. Not a build I usually show off but for those looking to just play it is a very easy cheap way to do it. As far as sound these boards are the best sounding for me of all the TPA3116, TPA3118 Chinese boards you can buy them on Ebay for $5 apiece. As far as sound, very respectable, nothing to really fault. There is better out there though but of course for more money. Many run them with laptop chargers and I have done so in the past. Still respectable sounding but I prefer a linear supply to bring out the best of any board. And for critics I know there is a short problem issue with the wires going through just holes but it is going to stay at my house and not going to be moved around. If a short were to occur it should blow the fuse and the build is properly grounded as well. I am not concerned in the least but I admit it is not the proper way to build and should not be done but I am a fearless amplifier builder when it is just for myself. I guess this is a spot for a politically correct disclaimer. Some time in the near future I will tear this build down for another project using the transformer and PS for other boards on another baking pan. If I like the sound enough I give boards a proper case and build. Nothing to fault with these boards, I just have better.
  7. Class D

    I was curious about the power vs distortion of the TPA3255EVM board at 8 ohms. With some googling I came up with .003% THD at around 100 watts into 8 ohms. It appears to be about 125 watts into 8 ohms with .1% THD at around 130 watts into 8 ohms. I like the .2 watt figure of .01% THD and .005% at 1 watt where most of my listening is done at. Impressive numbers for those that like to chase those kind of things. My test is I can listen for hours with this board and still want to play one more CD before cutting it off. Extremely clean and clear with exceptional bass. Very neutral sounding without any coloration. I believe right now today that this is my favorite D board amplifier and I have quite a few of them. http://www.360customs.de/en/2016/09/tpa3251-vs-tpa3255-thd-nach-datenblatt/
  8. Class D

    I finished building a home for my new TPA3255EVM board. I used a 400VA Antek transformer with 30,000uf of capacitance in this build. This amplifier is for those that think they need lot's of power. It will provide a clean 200 watts into 4 ohms and is rated for 315 watts into 4 ohms. I have not done an serious comparisons of this amplifier vs my others. Clean uncolored sound one can listen to for hours without wanting to turn it off. I like it.
  9. Class D

    I have had an interest in the Texas Instruments TPA3255EVM board since it was first introduced. It has been touted by some as being a competitor to the Hypex ncore line. The price for this board is $257 at Mouser but Texas Instruments has lowered the price to $150 on their website. Recently they are offering a 50% discount so for $75 I decided to purchase one. I had been waiting for the Chinese to make a board using the TPA3255 of which they now have. There are two different boards now being offered on Ebay at the present time. The board has outstanding numbers with over 300 watts of power into 4 ohms. I am much impressed with the quality of the board. Much different from all the D boards I have purchased from China. The sound is very quick and dynamic with outstanding bass with my LaScala's. I hardly need to turn on my sub with this board. Perhaps when some complain about the LaScala bass they are just using the wrong amplifier. But granted my LaScala's are not stock and I have improved the bass by using my own Xover. I did do some one song comparisons of this board against my new Hifimediy T4 board and at first I was under the impression the T4 did sound slightly better but I would now say it is just more of a colored sound with vocals. Many might prefer a more colored sound much as the difference in changing tubes in a tube amp. I think I could manipulate the TPA3255 to sound more colored by using a tube buffer, tube pre or possible by using just a film cap but I question why. Clean, quick, dynamic sounding as is. Non fatiguing after hours of listening yesterday. I will post pictures when I finish putting this board in a case. Right now it is hooked up to my test chassis using a 400VA toroid with around 48V's loaded at the board and 45,000 uf of filtering. I know this is not a diy forum but there are members that like to build. This board could be used with just a Meanwell switcher and be an easy first project for someone. PM me if anyone is interested in getting the coupon to get the 50% discount. William
  10. Capacitor question

    Makes sense.
  11. Capacitor question

    Electrolytic caps are marked for polarity by a stripe down one side which is negative. There is such a thing as a non-polarized electrolytic cap as well but you see them mainly in preamps. The 1uf is not there for increase of uf's but improvement of the electrolytic caps. A schematic of Xover network would be nice to see for more explanation. The 100uf caps should be marked on the schematic as what kind they are. OK, I found the schematic by google. The curved plate on the cap symbol means the negative and it shows all caps as electrolytic. If you have pictures of the caps post them for better clarification. I still believe the 1uf is a film. It is as you say that most caps are rated for 10% so adding just 1uf to 200uf would make little sense but it may be the case. I find lots of things that make little sense to me on Klipsch Xovers. A 1uf film cap is not expensive and is a better cap than an electrolytic. It is rare to see electrolytic caps in any Xover actually but when one needs a large value cap there are little choices other than electrolytics.
  12. Capacitor question

    Sure. The 1uf cap is probably a film cap added to 2 100uf electrolytic caps is my guess. If the 100uf caps have polarity marked on them I am correct. A 100uf film cap would be huge and expensive. Also I will guess they are used on the woofer in a 2nd or 3rd order filter and not directly in the audio path. Many think adding a film cap with an electrolytic helps. I add one sometimes myself in power supply cap circuits.
  13. Should I get Tubes or SS?

    Anyone can do some research and find this statement to be true. All other forms of amplification compares their amplifier to class A. The pitch in ads has always been, "This amplifier sounds as good as class A." I have found that a properly designed class A SS amplifier will sound close enough to the sound of a properly designed tube SET. All single ended triodes are class A.
  14. Class D

    I look forward to hearing the comparison to the Hypex mono's. I was interested in the Wiener build on diyaudio but did not pull the trigger and get on the group buy. My Australian friend who put me on the Hifimediy T4 board claims the T3 mono boards are some of the best sounding amplifiers with a linear supply as he has heard and he belongs to an audiophile club in his City and also works part time in a high end Hifi store. I first heard of using the TPA3116 with batteries many years ago as being best. I really cannot fault the TPA3118 boards with my linear PS. It is just that the B&O and T4 has a little more of the indescribable for me to put into words, sound. A class A amplifier even raises the bar slightly higher with my speakers in my room with my hearing. I could live with the little TPA3118 and be satisfied with the good clean sound and strong bass without feeling I was really missing anything if I did not have other amplifiers to compare it to. My SET 300B raises the bar higher over a class A amplifier IMHO with certain music. Hard rockers or modern music lovers would favor one of the class D amplifiers.
  15. Class D

    I have some of the cheap Ebay D boards laying around I have purchased on Ebay during the years. I used a switching PS to try them with at the time I bought them. I decided last week to build a linear supply for the one I considered best with my speakers some TPA3118 mono boards that one can buy a pair of for around $10 on Ebay. I prefer the sound of these boards over the TPA3116 boards I have tried. Supposedly same chip but heat transfer different. As most know there is more to a board than just the chip used. I had a 200VA 15V Antek transformer from another project along with bridge rectifiers and a couple of 15K uf caps in stock as well so it did not cost me anything to build. Amazing the sound one can get for such little money using our speakers. I really cannot fault what I was hearing. I compared it to my B&O Icepower 50asx2 board and I like the B&O better for it's more smooth sounding vocals. But neither sounds as good as the Hifimediy T4 board. All three of these amplifiers sound better than another build I finished this month. It was based around some LJM L12 boards which is a powerful 125 watt class A/B board. Big 400VA toroid along with 90K uf power supply was used to test these boards. At first I liked the sound, nothing really to fault. Somewhat different sounding vocals I thought smooth at first. But after an hour of listening fatigue set in. I tried using it many times after with the same result, listener fatigue. I contribute it to IM distortion at less than a watt being more pronounced. I have found this to be the case of many, not all, class A/B amplifiers I have tried using our efficient speakers. I think the L12 build would be fine with conventional speakers that require around 5 watts to wake up. The boards are reviewed by many users as good but not by me with my speakers. I prefer any of the 3 D boards over the A/B board I just tried. Clear, clean sound is what I hear with the D boards with no fatigue. Right now I really am enjoying the Hifimediy T4 build. I will not go as far to say better than some of my Class A amplifiers but different sounding enough to be enjoyable. Others really really should try this board. Simple enough for any handyman around the house to construct with a switching PS but better yet with a linear supply for those that are willing to try. There are ready built PS boards available on Ebay one could use to build a linear supply with without building one from scratch. Not much involved in building then. Just hook everything together and put it in some kind of case. Cost will be around $250 more or less depending on case choice and one will have an amp that will compare with much more expensive retail ones with superior sound than them.
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