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vixr  HeadWize Fanatic Joined: Sep. 17, 2005 |  Message [#220] posted on: 11-23-2006 08:03 PM CST (US).   |  |  Please ask questions... Its helps to alert others to the issues. I for one have trouble understanding the techspeak of datasheets and schematics... Simple questions and plain answers are best. |
Ferrari HeadWizer Joined: Apr. 29, 2006 | Message [#221] posted on: 11-25-2006 04:59 AM CST (US). | |
I got my buffer board yesterday, really nice tiny board |
. Your explanations coming with the board are very clear. Thanks Greg! The size of the board is no problem for me since I'm using HiFi-2000 GX283 enclosure. Hopefully I have the time to try it out this weekend, otherwise next weekend.gewa HeadWizer Joined: Sep. 22, 2006 | Message [#222] posted on: 11-26-2006 08:28 AM CST (US). | | GregVDS For your Epsilon board, is there a substitute for the MPSA14 because RS doesn't stock this one. EDIT: Never mind the above question I found the answer on AMB's website. Dam'n, this brings us back to the problem discussed a few posts back Regards [Edited by gewa on 11-26-2006 at 08:57 AM.] |
GregVDS HeadWizer Joined: Oct. 25, 2005 | Message [#223] posted on: 11-26-2006 09:48 AM CST (US). | | Ok, Ferrari, you got it, Now the States should see things arrive in the coming week or the next one, Damn I'm stressed by those shippings. Gewa, Hope to hear from you all comments on buffer boards! All the best, GregVDS |
| gewa HeadWizer Joined: Sep. 22, 2006 | Message [#224] posted on: 11-26-2006 10:54 AM CST (US). | | Just for general intrest: I also want to try the new LM4562 from National, just because they where so kind to send me some samples. They came in the SOIC package so I will need one of those Brown-Dog adapters. GregVDS Regards |
| GregVDS HeadWizer Joined: Oct. 25, 2005 | Message [#225] posted on: 11-27-2006 01:31 PM CST (US). | | Hello GEWA, I used 33.4ohms resistors for limiting resistors. This is suitable only for stacked buffer, and gives max allowed current around 360mA. Now for unstacked intersil, you should twice this value, allowing then 180mA. I didn't want to go further (the hard limit by intersil is 200mA). I simply used the formula given in the specs of intersil. How is goind the soldering of the board? All the best, |
| gewa HeadWizer Joined: Sep. 22, 2006 | Message [#226] posted on: 11-27-2006 01:52 PM CST (US). | | I have 62 Ohm resistors which gives me ±193mA and I also have 75 Ohm laying around which will give me ±160mA
Euuhhh,.....haven't started yet Regards |
| xelion Member Joined: Sep. 27, 2006 | Message [#227] posted on: 11-27-2006 06:57 PM CST (US). | | Okay, well I got my boards from Digi the other day and started right off. Now I'm pretty new to all of these things, all I've built are a couple cmoy's, so all these bridge rectifiers and blah just confuse me. I used one of the BOM's on Digi's site, and apparently I got a few of the wrong parts. First. the Bridge rectifies, I got part number 821-DB102G from Mouser Electronics, I've seen a few pictures of the ones on here and they are round and fit perfectly in the board, well mine don't. They are square and the symbols go in the order Obviously they don't fit on the board, so how do I fit them on, am I going to have to get new ones, or can these be used and just run wires from the legs of the chip to the holes. And if I can just run the wires, do the order of the ~ and ~ matter? Second problem. The voltage regulators. How do I fit them on the board? what order do the legs go in, and how do I figure out how I orient them on the board. I got part 512- LM78L12ACZ for VR1 and part 512- MC79L12ACP for VR2. Third: The small variable resistor. They have 3 legs, how do I orient them on the board, similar to the above problem. I noticed on the board that there is a small symbol in one corner, does that mean something? Also the legs on my trimmers are offset, they aren't in a straight line, will I have to run wire in a different order than the legs? They are part 652- 3306K - 1- 202. Again from Mouser. Fourth problem: LND150. I gather that there are several ways to do this part of the project, I want to go with the straight forward way, the LND150, so how do I do that? Where do I put this chip? Is it in one of the Q# spots? I know there is a picture on the main site showing how it all goes, I'm just not sure if that is what I'm supposed to do. And if it is, do I use 2 for this part of the project? I thought only one was needed(although I got 2 anyways) but which way do I orient them again? Fifth problem: Where do I hook in the fuse at? Do I hook it up on the holes marked + and - right underneith the tube socket? There is a metal thing on the center of my tube socket, and a hole just under it. Do I attach anything there? Or is it just there to orient it or something? Sixth problem: The potentiometer. I didn't want to spend 16 bucks on the Alps 97 I think it was, so I got a part number 313- 1240- 100K from Mouser. The description is Audio D-Shaft 100k. Has 6 things at the bottem, can I simply sit it on the board in the holes and solder it up? Or again will I have to run wires accordingly? Seventh problem: Power Supply. I got the TE70053-ND transformer from Digi-Key. It has 8 things on the bottem, where do those hook up? Which one do I wire up to the wall socket and which ones go to the board? Also I notice several places to put power in the board, for 60v, 40v, and 12.6v. I assume the transformer doesn't put out all three of these... so how does that happen? Eighth problem(final one for now Sorry for all the questions, just need some answers. Thanks for bearing with me, edit: Another thing, what is AC1 and AC2? xelion. http://s75.phot...=100_0257-1.jpg is a picture of board so far with most of the parts in question(forgot about the pot) [Edited by xelion on 11-27-2006 at 07:00 PM.] |
tomb Headphone Council Joined: Mar. 1, 2006 | Message [#228] posted on: 11-28-2006 07:14 AM CST (US). | | Hoo-boy - lots of critical questions ... I'll take a crack at it, but let me please emphasize that you should read all of the SOHA Thread 1 and SOHA Thread 2 when you get a chance. The latter part of Thread 1 and much of Thread 2 contains a lot of info on Digi's board.
You need what's known as a WOG-case or WOM-case Bridge Rectifier. The WOM is a round case like a thick button, the WOG is round with a slice taken off the side. I think what you have is not going to work very well, and wiring four separate leads is more trouble than it's worth. If you don't want to re-order from Mouser, Radio Shack has one that will work well: 276-1152 It's much more expensive than it should be at $1.49, but still cheaper than soldering four wires to the one you have. The "~" "~" are the leads that go to the AC - the wires from the transformer. The "+" and "-" are the DC leads. The "+" goes in the square pad on Digi's board - with every part that has polarity, as a matter of fact.
Those look like the TO-92 versions. I would re-order for TO-220 type. They will support more power if you use OPA551's or add the BUF634 to your output. The TO-220's are obivous - the metal tab goes where the horizontal line is drawn across the silkscreen image on the board. Digi did provide a photo on his walkthrough for the TO-92 orientation: taihu.bjtzh.gov.cn/~digi01/pic/VR1.GIF Potentiometer
You should've ordered the Bourns-style 3299W style - they have inline pins. However, the ones you have shouldn't be too tough to bend into place. They might still sit a little bit above the board, but if you're careful in the future when adjusting them, they may do OK. The trimmer screw goes on the end where the circle is drawn inside the rectangle on the board.
This has been documented many, many times. Look at the threads mentioned above, and refer to Digi's walkthrough: taihu.bjtzh.gov.cn/~digi01/soha-v3.0.htm The details are there.
You're mixed up here. The fuse has nothing whatsoever to do with the tube socket. The hole at the tube socket is for an LED - a tube light. Vacuum tubes rarely put out as much light as Hollywood shows in the Mad Scientist laboratory. Common practice is to put a super-powerful LED under the socket. The hole in the socket lets the light shine through into the tube. Better yet, many people will shove the LED into the socket hole. Sometimes you have to drill these holes out, sometimes not. The T-1 or 3mm LED works for inside the socket or on Digi's board. Some other tube amps - like the Millett - use T-1/34 or 5mm LED's. The fuse has to do with your transformer. Please, please, please make sure you have studied hard before you mess with that - or find someone else to do it. If you screw up the power transformer you could get hurt. Asking this type of question does not indicate you are properly prepared to do this, no offense!
I bought the little Alpha pot, too. At one point, Digi had a photo with a similar pot on his board. I hate to tell you - this one ain't it. You will have to panel mount it and solder the leads. Again, purchase the Alps from Amb or Tangent, or you can go to Radio Shack again: 100K Dual-Ganged Stereo Volume Control This one is pretty good, although a bit large - it depends on what kind of case you're using. At least it has lugs that make it easier to solder. The Amb or Tangent version is easiest, but it will set you back $16 plus shipping.
Again, study the data sheet for the Amveco - it's right there on the web page when you select this part number on DigiKey. Or, you can go directly to the Amveco web site and check for that part number's catalog data. DO NOT do this until you have a better understanding than you do right now. IT CAN KILL YOU if you mess it up the wrong way.
Radio Shack has Xicon's in that size at 35V. The higher voltage rating will have no effect except in size - make sure it will fit on the board. Most likely it won't be a problem.
*Sigh* Those are your power inputs from the transformer - two 15VAC plus two center tap grounds. DON'T DO THIS UNTIL YOU KNOW MORE.
Come back after you've studied. Good luck! |
| GregVDS HeadWizer Joined: Oct. 25, 2005 | Message [#229] posted on: 11-28-2006 07:30 AM CST (US). | | tomb, you're fast, and quite hard with Xelion, but I agree, some questions point at some lack of understanding, but we were all somewhere there when we began. Xelion, tomb answered all your points quicker than I could, so I will not do it twice. but regarding your AMVECO, I'm pretty sure everything is printed on the top of the blue plastic encasing. I think the better way to go is to reorder parts from Mouser. I attach here my modified BOM, where I found practically everything. A lot of components are there two or three times. Take your times, follow the links from the BOM, read the datasheets, check size and layout of components legs before ordering, sometimes ordering two candidates is better than reordering, you never know, and the worst is soldering too quickly and powering too quickly, sometimes rendering all your efforts and investment to nil. When it comes to amp building, soldering and testing, I become quite paranoid and stressed (I always plug first the amp, then the mains into a longer cable, then the cable to the wallplug, protecting my face. It can seem silly but an exploding cap is something!). All the best, and follow tomb's advice, read a maximum the thread (they can be saved in an simpler html format, look at the small printer button on top of thread) GregVDS [Edited by GregVDS on 11-28-2006 at 07:33 AM.] Attachment: C2338.xls |
| vixr HeadWize Fanatic Joined: Sep. 17, 2005 | Message [#230] posted on: 11-28-2006 07:56 AM CST (US). | | Wow, tomb is amazing... Boiling down the SOHA build in a single post...it seems to me attempting this build with less than a basic understanding of electronics is very foolish and right on the edge of some tragic misadventure... |
| dBel84 HeadWize Fanatic Joined: May 5, 2006 | Message [#231] posted on: 11-28-2006 09:31 AM CST (US). | | Ok enough of the Xelion bashing, GregVds - got it right , we have all been there and I for one am still on the learning curve. Xelion, a few of the parts you have won't fit exactly into the board and you have 2 options. 1. order the ones that will fit , 2. make the ones you have work. The second option takes an understanding of what you are doing and you need to make sure that you read up where necessary before you try anything adventurous. The transformer you have is the correct one. You need to configure it to run 115VAC - 30VAC as follows: The fuse has been dealt with but it needs to go in line ( series ) with the AC source to the transformer- the hot leg from the house 115VAC. ASK many times if you are unsure, or leave it out. The bridge rectifiers that you have are not aligned correctly and I am recommending that you don't attempt to air wire this based on your limited experience with AC power. If RS has replacements @$1.50 , get them instead. You mention the 60V, 40V, 12.6V, +12/-12V points on the board = these are test points and should reflect the measured voltages after you have correctly installed everything, remember that the volume pot and opamp have to be in place before you measure as there have been some interesting readings without them. You will need a multimeter and understand how to use one to finish this project. To understand how the volatges are achieved, read the explanation in the SOHA article http://headwize....avalli2_prj.php The 12V voltage regulators you have will work perfectly for the standard build which appears to be what you are attempting, the silk screen on the board is wrong and they need to be flipped by 180 degrees. The LND150 CCS is simple and rather than describe in detail how to connect it all up - mb3k has done a great job detailing the process with images http://www.mb3k.com/soha.html Your variable resistor problem is due to the fact that the layout was changed at some stage and that trimpot layout was not used in the end. If you are careful, you can bend the legs into a straight line and it will work fine - this is exactly what I had to do as I created a BOM early in the game and overlooked this detail before placing my order. I am not sure what your audio D shaft volume pot looks like , but they are mostly standard. If you hold it with the legs pointing up in the air and the shaft facing you; the left 2 are in ( L + R ) the middle 2 are out (L + R ) and the right 2 are ground. If the spacing of your pot matches the board, it can be soldered directly to the board - you will need to make sure that it aligns correctly with the traces as the board can accommodate 2 sizes of potentiometer. Good luck and ask before you guess..dB |
| tomb Headphone Council Joined: Mar. 1, 2006 | Message [#232] posted on: 11-28-2006 10:30 AM CST (US). | | Xelion bashing? These kind of questions/mistakes/issues are OK with almost any SS amp and a walwart. They're a little different in dealing with this. Also, it's frustrating because if you guys realize it, we're the ones left holding the bag over the Digi-Runeight squabble. So, if it sounded harsh, my frustration was showing and I apologize. [Edited by tomb on 11-28-2006 at 11:07 AM.] |
| gewa HeadWizer Joined: Sep. 22, 2006 | Message [#233] posted on: 11-28-2006 01:24 PM CST (US). | | My buffer board  Still need to put on the resistors but I'm a bit in doubt whether I go for the 62Ohm or 75Ohm.Regards Attachment: C2339.jpg |
| xelion Member Joined: Sep. 27, 2006 | Message [#234] posted on: 11-28-2006 03:36 PM CST (US). | | Thank you all for the fast replies, I will look more into these problems when I get home (have to leave for work in like 5 minutes.) I realize how dangerous these things are, and I do plan on reading more, especially about the transformer, but I just needed some help finding information, considering I haven't seen any very beginner friendly walkthroughs. Again thanks for the help, and yes I do know it is dangerous, thanks for the concern. Also dBel84, could you explain how to wire the transformer again? Primaries, pin numbers. I guess a look at the data sheet would probably solve my woes. |
| gewa HeadWizer Joined: Sep. 22, 2006 | Message [#235] posted on: 11-28-2006 03:58 PM CST (US). | | xelion,have a look at the attached image. Regards Attachment: C2340.jpg |
| tomb Headphone Council Joined: Mar. 1, 2006 | Message [#236] posted on: 11-28-2006 06:14 PM CST (US). | | Ogre-Tom says thanks to Gewa.  |
| xelion Member Joined: Sep. 27, 2006 | Message [#237] posted on: 11-28-2006 10:37 PM CST (US). | | Ahh, mb3k's tutorial is exactly what I needed. Answered several of my questions. and gewa, is that a picture of my transformer? It doesn't look the same...(sorry if that is a stupid question)edit: yeah so I looked at it some more and it made sense. Just one question, what is L and N? Okay, only questions now: The small pot, yeah, still not sure which direction to orient it. Tomb said that the side with the screw goes towards the diagram on the silk screen, but the screw is on the side, it doesn't face that direction. So yeah. And the transformer fuse stuff. I'm going to look for the data sheet, but then I'm just a little confused on how exactly to wire it. Hopefully I'll figure it out when I read the data sheet. [Edited by xelion on 11-29-2006 at 12:06 AM.] |
| gewa HeadWizer Joined: Sep. 22, 2006 | Message [#238] posted on: 11-29-2006 03:05 AM CST (US). | |
Now you really starting to scare me!
You put the fuse in series with the Life wire of the primary section of the transformer. I strongly suggest that you get yourself acquainted with the basics of electrics before you start wiring up al this stuff. Regards |
| GregVDS HeadWizer Joined: Oct. 25, 2005 | Message [#239] posted on: 11-29-2006 06:00 AM CST (US). | | Nicely done, your buffer board Gewa! 193mA seems very close to the limits of the Intersil (200mA). I would go a little bit lower to stay on the safe side. I hope you guys in the States will begin to receive the boards soon. And very nice pics for the AMVECO wiring! dBel84, I had no bashing intention at all! All, I plan to replace all my Neutrik Locking jack output by Neutrik female XLR, and use the adaptator Neutrik provides, and let it atached to the headphones all the time. This should clear the shorting problem of the output jack. Just an idea. All the best, [Edited by GregVDS on 11-29-2006 at 06:02 AM.] |
| rreynol Member Joined: Oct. 13, 2005 | Message [#240] posted on: 11-29-2006 06:20 AM CST (US). | | USPS was nice enough to leave me a notice yesterday about the package Greg sent. I think I'll have time today to stop by the post office and pick it up. |
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