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Post by Deleted on Jan 16, 2011 12:40:23 GMT
There is another, less exacting, method. Use overlapped tape joins, on the overlap you then use a pointed implement, fine punch etc., to firmly stipple down the joins, golf ball style. Needs to be hard enough to break through the adhevise layer of the top sheet in the join. This is common practice for circuit based window alarm sensors and repairs of same. I've also seen it done to repair large earth planes on broken circuit boards. I'm sure someone will shout BODGE! but it works  |
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Post by Deleted on Jan 16, 2011 14:44:42 GMT
This is the only TRUE way to keep common mode and other HF garbage from entering your amps housing.  Even I do not do this for my own gear but has to be done with the professional equipment I design. Otherwise it simply doesn't pass EMC testing.  With plastic inlets and a filter placed inside the box with wiring between it just simply isn't as good but already good enough for most cases. Mounting a filter with short wires helps of course but this is THE best way of mains entry. |
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Post by gumleguf on Jan 16, 2011 22:38:50 GMT
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Post by clausdk on Jan 16, 2011 22:47:13 GMT
Actually ClausDK made me aware that the Schurther was on sale (80% off!) in a Danish web-shop so I owe that one to him.  Glad you approve and I'll do my best to make sure that the metallic mounting surface connects all around to the copper tape surrounding it. I even got two for myself  I am fiddeling around with some metallic cage also, but more a cage than "just" foil, it will be a proper faradaycage when and if I ever will finish it  As far as I know a Faradaycage is allowed to be made up from a mesh structure and therefore I think it should be possible to get the wires inside without breaking the cage .. Frans ?? A bit like this just covered in wood  Why wood ?? Look at it, it is much more beautifull than all does boring and ugly aluminium enclosures, the metal enclosures has no soul.. It is all a matter of taste I know that, but that is why I use wood, it would be cheaper and much easier just buying an enclosure, but to me most of the bought boxes looks cheap and uninspiring. |
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Post by PinkFloyd on Jan 16, 2011 22:53:01 GMT
There is another, less exacting, method. Use overlapped tape joins, on the overlap you then use a pointed implement, fine punch etc., to firmly stipple down the joins, golf ball style. Needs to be hard enough to break through the adhevise layer of the top sheet in the join. This is common practice for circuit based window alarm sensors and repairs of same. I've also seen it done to repair large earth planes on broken circuit boards. I'm sure someone will shout BODGE! but it works Easiest way is to evostik some baco foil onto the wood panels (before cutting them).... you then have baco foiled panels, glue them together and supplement the joins with some punched (adhesive) copper tape.... a long way round for a shortcut though, at the end of the day (unless you REALLY prefer the 70's look of a DIY wooden enclosure) you're best to go with an all metal housing.... I LOVE real wood speakers but wooden amps (for some reason) remind me of the early 1970's.... "Teak" was all the rage back then.... Unless done VERY well wooden amps (IMO) look like eyesores... this is a "professional" product and, to my eyes, looks like something out of a 1970's, smoked filled, house...  Slightly nicer but that "wood" is still making me think "70's"  Just plain ugly  I quite like this one....  Excuse me while I go and mop the carpet protector   Gotta be the ugliest lump of "wood" on planet earth?  I like Claus's woodwork but think the box is WAY too big  I just can't see why anybody would choose "wood"? If it looked good then YES!.... if it shielded the circuit then YES!... wood really has to be "worked" by a craftsman to look good (not many of them left)..... I'm not being picky but, really.... when it comes to "wood", unless you are a master craftsman, best to leave well alone if "looking good" is the look you are trying to achieve. |
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Post by clausdk on Jan 16, 2011 23:04:54 GMT
Well being a child of the 70s I have a soft spot for teak, but I get your point And that "chest" one is very very ugly.. It is, to me at least, also a matter of DIY, just buying a kit with enclosure is like building it in Lego.. And being a Noob in electronics forces me to be creative elsewhere than in the electronics department |
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Post by PinkFloyd on Jan 16, 2011 23:24:59 GMT
It is not that big  this is one I am working on at the moment, needs a prettier jacksocket and another knob. It is 22*27*7 cm that is not big..and would only hold a small sized Panda.. BTW did you know that pandababies are the same size of a mouse ? Looking good  I had to force it out of you but, yeh..... looking good man |
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leo
Been here a while! 
Team wtf is it?
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Post by leo on Jan 16, 2011 23:53:12 GMT
Wood does look nice but I wouldn't fit any classA amp in it tbh
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XTRProf
Fully Modded
Pssst ! Got any spare capacitors ?
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Post by XTRProf on Jan 17, 2011 2:41:40 GMT
Why wood? (just thought I'd ask ) Why not wood or plastic? It does give no eddy current flow that can affect sound in the first place. Secondly, wood does give any Hifi a Japanese highend Zen look when done properly. As Zen is partly me, I will also give it a go after proper screening. Thanks for reminding me to try it. Thirdly, it's good for variety sake. Just imagine, every amp look the same from the same cabinet. Wouldn't that be boring? We need something like what Chris had done to have a range of design looks. Yeah, I will also include a retro look in one of my HP amp. Arrrgh, Rockgrotto, what has you done to me? I'm fully only speaker system hifi until now ...........  Claus, care to give a tutorial on good wooden cabinet making for wooden cabinet noob like me? We need to have some kind of dovetails to put the thing securely togather, right? |
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Post by clausdk on Jan 17, 2011 9:17:15 GMT
� It is more timeconsuming than difficult to build the cabinets, I will start a new one up in a couple of weeks and will take a lot of pictures of how I do it, but it is really simple just glue sticks toogether and you will end up with a box hopefully |
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Post by gumleguf on Jan 21, 2011 10:06:01 GMT
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Post by victoriaguy on Jan 21, 2011 19:08:10 GMT
What do you folks use to try to ID the small zeners in the kit??
It was touch-and-go for me even with magnifier - I finally picked out 3V9 on one of them...
While on that topic (failing eyesight) - is it something in my settings or the 'board settings' that makes all the quotes appear in microscopic font?
John
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Post by PinkFloyd on Jan 21, 2011 21:14:31 GMT
Don't worry, This is not "censorship" it's simply an attempt to condense this "build" thread into actual "useful" information for any would be builder. The thread is entitled "PANDA KIT BUILD THREAD" and not "what did you have for your dinner today?"..... we can discuss anything else (electric V petrol lawnmower / boxers V briefs / the male "P" spot, fact or fiction?") elsewhere.... This is one of these rare occasions where ONLY salient information pertaining to the construction of the amp should be allowed.... for example, you buy a new TV, the last thing you want to read about is fence preservation, mortgages, the fuel efficiency of a Nissan Micra etc. etc. etc........ you want to know how to tune the damned thing in and operate it! This is the Panda Kit "build" thread and I agree that all "off topic" ramblings should be removed. Mike. |
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Post by Deleted on Jan 22, 2011 16:25:41 GMT
Did some cleaning ...
Went from 12 pages to 5 (didn't do page 5 just yet.
> What do you folks use to try to ID the small zeners in the kit?? <
I use an old salvaged slide projector lens as a magnifying glass for this.
When I was youg I could red it by holding it close to my eyeball... ahhh days gone by.
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joethearachnid
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Old head on young shoulders.
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Post by joethearachnid on Jan 22, 2011 21:57:15 GMT
I use an old salvaged slide projector lens as a magnifying glass for this. When I was youg I could red it by holding it close to my eyeball... ahhh days gone by. I'd like to point out that I'm young and have excellent vision and I STILL had trouble picking out the text on those diodes. In the end I worked it out by looking at pictures of other people's builds and seeing where the slightly bigger ones went. -JoetheArachnid |
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Post by PinkFloyd on Jan 22, 2011 22:16:21 GMT
I use an old salvaged slide projector lens as a magnifying glass for this. When I was youg I could red it by holding it close to my eyeball... ahhh days gone by. I'd like to point out that I'm young and have excellent vision and I STILL had trouble picking out the text on those diodes. In the end I worked it out by looking at pictures of other people's builds and seeing where the slightly bigger ones went. -JoetheArachnid You need the fckin' Hubble telescope to make out those markings.... either that or you have to morph into an ant sized creature and then the text will appear as VERY large..... Unfortunately I don't have the software to turn myself into an ant and have to rely on my eyes / glasses and a magnifying glass (or two) for the moment..... I will upgrade to ANT Vision V2 as soon as funds permit |
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Post by victoriaguy on Jan 23, 2011 4:01:34 GMT
Suppose I had a friend who blew up one of the gold 220uF caps (C14 or C24 between heatsinks and large caps) by foolishly getting the polarity wrong.......
What would be the audio effect of putting a slightly mismatched (Nichigon 220uF, 50v but taller with brown case) in to replace the blown cap. Any predictions?
Would it be better to replace all 4 with the (lower quality??) style matching caps?
Or just forgeddaboutit?
I talked to "my friend" and he says that the amp seems to be working OK......
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Post by Deleted on Jan 23, 2011 11:07:34 GMT
It depends on your audioreligion.
Funnliy enough if my friend did such a thing I would replace them all with the same type.
Probably something that 'hung' from my audioreligious period.
They are in parallel with the big ones and 100nF decoupling so you can even leave them out or replace them with anything between 10uF and 470 uF as long as the value's correspond.
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Post by PinkFloyd on Jan 23, 2011 11:55:39 GMT
Suppose I had a friend who blew up one of the gold 220uF caps (C14 or C24 between heatsinks and large caps) by foolishly getting the polarity wrong....... What would be the audio effect of putting a slightly mismatched (Nichigon 220uF, 50v but taller with brown case) in to replace the blown cap. Any predictions? Would it be better to replace all 4 with the (lower quality??) style matching caps? Or just forgeddaboutit? I talked to "my friend" and he says that the amp seems to be working OK...... Perfectly good to use a different "brand" of 220uF... 220uF is "220uF", much the same way as a potato is a potato. |
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Post by gommer on Jan 23, 2011 15:04:42 GMT
I know this has been answered already, but I might add that I use a small 8x magnifyingglass. With this, it's actually comfortable reading.
I think everyone into DIY should have at least a 6x magnifying glass, a small one (2,5cm/1" dia) is more than enough.
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Post by victoriaguy on Jan 23, 2011 17:35:07 GMT
Re: Nichicon caps I was putting together a component order (for Mouser) and was checking on replacements for the 220uF Nichicon 'gold' caps that came in my kit. I've never paid much attention to electrolytic cap lines or brands -as long as they are fresh they seem to do the job in most of my projects. FYI- the 'gold' caps that came in my hifidiy kit were 'FW' Nichicons @ $0.40 ea. Nichicon makes two 'Audio Grade' caps in this type/size: 'KW' @ $0.50 ea and KZ ('Muse') @ $0.80 ea. The 'Muse' caps are black wrapper with gold stripe. Data sheets: products.nichicon.co.jp/en/pdf/XJA043/e-fw.pdfproducts.nichicon.co.jp/en/pdf/XJA043/e-kw.pdfproducts.nichicon.co.jp/en/pdf/XJA043/e-kz.pdfI ordered the 'KW' caps.. Mouser P/N is 647-UKW1H221MPD John |
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Post by dicky on Jan 28, 2011 18:35:31 GMT
Hi Folks, could someone tell me what value the small yellow capacitors are in the Panda kit? They have 22P written on them - so I assume that is 22pF? Thanks. |
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Post by Deleted on Jan 28, 2011 19:01:27 GMT
Hi Folks, could someone tell me what value the small yellow capacitors are in the Panda kit? They have 22P written on them - so I assume that is 22pF? Thanks. YUP ! |
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Post by dicky on Jan 28, 2011 19:37:46 GMT
Thanks. |
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Post by Deleted on Feb 3, 2011 13:22:46 GMT
This should probably be in the build thread: Here is another tip: I believe it was Leo that correctly mentioned the resistors in the 18V supply circuit that can be exchanged for CCS. That would be my other choice of tinkering with it. IF you have installed 0.4 to 0.5W 18V zeners the optimal current for the CCS will be between 5 and 7mA If the original 1.3W is installed 10-15mA will be about optimum. Installing a CCS will give lower 100Hz hum on the output and make it more stable. CCS can be made in various ways. IF you want to keep using resistors instead of modifying the circuit to CCS, you can calculate the optimal/proper value of the resistors and optimise the zener circuit this way. This is what you need to do: Measure the voltage over R7 (a 1.5k resistor) and R18 (they should be about the same voltage) If you have a 0.4W to 0.5W zener installed calculate R7/R18/R35/R51 as follows: 150 Ohm per Volt so if there is 8V over it.. 8*150 Ohm = 1200 Ohm (-> 1k2) IF you have the original 1.3W zener installed: 82 Ohm per Volt so if there is 8V over it.. 8*82 Ohm = 656 Ohm (-> 680 Ohm) Take any 'known' value nearest the calculated value, doesn't need to be exact. If your calculated value (which depends on the actual output voltage of the transformer) is very close to the original 1k5 leave it in. IF you calculated lower values you can either calculate a value that you can mount in parallel under the board or replace the 1k5 resistor, which is harder to do without damaging the solderpads. Here is how to calculate a parallel resistor value in case the calculated value is LOWER then the already placed 1500 Ohm resistor: 1/optimised calculated value (Ohms) - 1/1500 = 1/parallel resistor. use minimal 0.5W rated resistors. This is easy to do and lowers the remaining hum in the regulator circuit, stability and internal powersupplies's internal resistance. What the 'sonical' advantages are/will/appear to be is for you to decide technically they can/should be substantial enough to become audible. another thing to tinker with is resistors R6/R17/R34R50 which can be deleted (shorted NOT removed) or made considerably smaller. Now they are 1k but can be anything between 0 Ohm and 100 Ohm for instance. NOTE: You should only mod this mod/experiment when you have properly adjusted the zener's bias current as explained above. |
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I had to force it out of you but, yeh..... looking good man 
