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wdecho

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  1. A DIY Single Ended Class A Kit

    I am glad you finally got to listen with them Carl. Enjoy.
  2. A DIY Single Ended Class A Kit

    I agree. To get the best out of a class A amplifier you need a good linear supply. There was a new Burning Amp Festival Sunday and Nelson Pass presented a new designed ACA kit to be offered at the diyaudio store. I have since tore down my build of this amp not because it did not sound good with a linear supply but I have a BA-1 that is very similar in design with more mosfets in parallel that sounds slightly better. What the appeal is of this simply design is you are listening to one transistor. The other transistor in the circuit is just a cascode with little effect on the sound.
  3. Capacitance Filter Question

    Primary side of transformer, red to red, black to black. On the secondary side blue to blue, green to green. You have two transformers in the donut and in effect you are combining them for more amperage, power. You will then have around 48 volts on one side and ground on the other from the bridge rectifier filter cap PS. I believe what you are trying to describe is what the Sure board is, but then I have not looked at the Sure board. Where the DC output is +, 0, - and that is not what you want with this amplifier. That kind of power supply has 2 banks of capacitor and the secondaries of the toroid are wired in series. Do not do that with this build. The 2 capacitors I used are wired in parallel to increase the capacitance. Positive to positive, negative to negative. To have +48V and a -48V you would have to create a ground. To have a negative -48V it would have to referenced to a ground. All that is needed for this board is a positive voltage and ground. I hope this makes since.
  4. Capacitance Filter Question

    A lot of your questions can be answered by reading this thread starting at September 17th. https://community.klipsch.com/index.php?/topic/172028-class-d/&page=2 1. Some say you can but 30K uf is plenty enough and even 15K uf is probably plenty. 2. I used AN4434 with my build, 400VA 34V. Be careful not to exceed the 53V rating of the board because many D boards will shut down with too much voltage. Using that toroid I think I remember having around 51V with my wall AC. With our speakers 400VA is plenty enough. Those toroids get big and heavy with more VA. Cantilope on our forum is driving 3 of the TI boards with a 800VA. 3. See 2. Very easy to hook up capacitors using a bridge rectifier using better caps and rectifier without paying for Sure board. I believe you said you can solder. Caps hook up positive to positive, negative to negative.
  5. DIY Tube Amplifier Kit 6P3P + 6N8P

    With help on the diyaudio.com forum I solved the problem of oscillation when built as designed. There are blue and red wires on the primary side of the output transformers and the red wire has always been + and the blue wire goes to plate on all the OPT's I have used before. On the pair with the kit the wiring color is reversed. I swapped the primary wires, installed both feedback networks with proper resistance and it now works as intended by the designer.
  6. https://www.parts-express.com/stahl-tools-stssvt-variable-temperature-soldering-iron-station--374-100 Love mine. When dealing with live amp, one hand in pocket rule and you should be fine. Congratulations.
  7. DIY Tube Amplifier Kit 6P3P + 6N8P

    From some research on the web I did find one review where the reviewer claims to have completed the build as is. My oscillation problem was probably caused by wiring too close to heater wires or something. Most pentode designs I have seen do not use two feedback loops though. I do like how the driver section uses a cascode design for enough gain using the 6H8C sent to me or the more common 6SN7 of which they could be replaced with. The design also uses a 5hy choke in the power supply which is a plus. I did replace a few of the parts I had in stock after using the parts sent at first. Mostly just some resistors and a few nichicon caps. Also I changed out the volume pot because the one supplied is a circuit board one that was somewhat scratchy sounding. Nothing one could not live with but I had a decent dual pot in stock so why not. This is a all in one kit that Mike has pointed out was not available a few years back. At least no where near the price point this one sells for. I have since ordered another of the Chinese kits, a FU50 tube build for $222. It is something to occupy my retirement time later this month. I can only wish to complete a build as neat and clean as what Mike Stehr or Maynard does but with some cleaning up of some wires I decided to post a picture of the underside of this build. Probably the cleanest looking of all my tube builds. I may change the coupling caps for some poly ones when I make another Mouser or Parts Express order but the polyester one sent in the kit appears to sound really nice. My cap of choice for coupling has been orange drops for the last few years. Hard to beat for the price at Tubedepot.
  8. DIY Tube Amplifier Kit 6P3P + 6N8P

    I slight amount of ringing. Maynard has offered a solution for eliminating the ringing which I may try at a later date. Not a big deal audible. The square wave is at 1K ohms. The square waves deteriorate above 10K which is expected with the OPT's used. All sine waves from 20hz to 20Khz look fine. The amplifier sounds really good to my old ears.
  9. It has been awhile since I had built a tube amplifier having strayed to building SS amplifiers. A knowledgeable member of this forum who specializes in tube amp repair recently worked on the of the Chinese amplifiers and commented on the decent quality of the iron which is usually the biggest expense of building a tube amplifier. So I started doing some shopping on Ebay and found this kit for such a cheap price. The 6P3P tube is a Chinese 6L6 replacement and the 6N8P is a Chinese replacement for the 6SN7. Here is a link to the kit on Ebay. https://www.ebay.com/itm/DIY-Tube-Amplifier-Kit-6P3P-6N8P-Single-Ended-Tube-Power-Amplifier-Kit/142379525464?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 Iron, tubes, stainless steel drilled chassis and all the parts and components for a complete build for a diy'er or diy'er wannabe. Upon receiving the kit I was pleasantly surprised to find a NOS Russian 5U4C as a rectifier tube and a pair of NOS Russian 6H8C's for the driver tubes. The output tubes were the Chinese 6P3P tubes of which I have replaced with NOS Russian 6P3S ones. I found the Chinese 6P3P's to be decent sounding but the Russian 6P3S's as better. They can be found on Ebay for $20 shipped. One has to build this kit from a schematic but SE tube builds are about as simple as one can get for a point to point build. Solder all the components to the tube sockets using the schematic and then one can hook the components together. I use a highlighter to mark each step of the build for both channels where I know what has been done. The kit went together rather easily in short time but I ran into some problems. I had no music and oscillation on both channels so I had to turn to our tube guru Maynard for advice and assistance. He quickly pointed out that the design had two feedback circuits and from experience with pentode circuits he assured me the oscillation was caused by the circuit from the output to speaker terminal via the 2K ohm resistor to the input of the driver tube. I eliminated this circuit. For proper feedback necessary for pentode circuits I lowered the value of the resistor in the other feedback network to 470K ohm from the 1.5M ohm going from the plate of the 6P3P tube to the number 2 pin of the driver tube. Viola, it then played with no oscillation but with excessive hum. Maynard then pointed out to me that the 3.15V -0- 315V heater 0 wire should be grounded which is used for the driver tube. Upon Maynard's instruction I grounded it to the cathode of one of the output tubes and it is now as quiet as my other tube amplifiers. I now have an excellent sounding pentode tube amplifier with all the tube magic using our speakers. I measured the power and came up with 4.5 watts at clipping which is plenty enough for most using Klipsch speakers. In fact when using my 85db test speakers it drove them with authority. For $192 the deal cannot be beat. For a little more there are finished tube amplifiers from this seller for those that are not diy'ers. Among diy'ers this seller has a reputable reputation. A cheap way for one to experience the tube magic. Much thanks to Maynard for his assistance in helping me finish this build of mine.
  10. JBL 590 vs Klipsch?

    JBL is a respected company that has always been a competitor to Klipsch. The one thing that stands out to me is the sensitivity rating of 92db. Much lower than Klipsch speakers. Should not matter that much with today's electronics though. Good price at $900. a pair.
  11. Class D

    Excellent review. The SIT-11 is to supposedly mimic the sound of a SE triode so it is not unexpected the "tone" it can produce.
  12. The "Little Bruiser" mono flea-power SEPs

    I see it now, hiding from my old eyes.
  13. Got a Fisher 500C for my Cornwall II's

    Brings back memories when stereo ruled. Lovely looking of which you should be proud.
  14. The "Little Bruiser" mono flea-power SEPs

    Where is the schematic for members Maynard? Another nice professional looking build. I can only wish my builds were so neat and orderly.
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