pagan
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Post by pagan on Jan 28, 2008 2:22:13 GMT
Jon and Leo If the output trannies are getting very hot, it might be oscilating. The standard BD139/140's were used with the Heatsink i linked to. with standard settings(or a bit above), no heat problem. heat problem if the outputs start oscilating. With the CK2 in standard psu form, problably the normal incorrect/bad component value or earth. see this thread headwize.com/ubb/showpage.php?fnum=3&tid=6605A lot a things already found. For CK2 and External psu and JLH. As i mentioned earlier I don't have a camera to post a pic but I'll see if i can arrange something. For CK2 and onboard psu and JLH? Didn't try it, I prefer LM317/337's over 78/79's Should work though, just watch out for ground loops It should be psu>>>78/79's>>>JLH>>>amp Watch out for running the JLH's earth in parralel with the pcb's.
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leo
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Post by leo on Jan 28, 2008 3:30:26 GMT
Hi Allan, Theres no problems at all here now mate, the amp is dead quiet, I don't even have heatsinks on the JLH BD139/40's and they are only slightly warm. I'm honestly gobsmacked at the difference here The external regulated supply LM317/337 devices are now only warm too. My thought was the recommended BOM 220uf low ESR caps on the standard fixed regs output I'm wondering if there was some stability problems, those caps also had 2.2uf film caps as bypasses
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pagan
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Post by pagan on Jan 28, 2008 9:16:17 GMT
Leo I thought the BOM stated FC's. FM's are lower ESR again and depends what type 2.2uF caps are used. Polyvester or Polyprop... maybe lower still. Or hits the magic ESR spec for the reg to be unstable.
FC's!! there's a lot of builders using FM's on their thread.
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leo
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Post by leo on Jan 28, 2008 9:53:38 GMT
FC is still low esr and also 220R is considered too high to be on the output of a reg
The BOM states below
C37, C38: aluminum electrolytic capacitor 50V low-ESR high-reliability 220µF Lead spacing: 0.200", diameter: 10mm
* Nichicon HE (Mouser 647-UHE1H221MPD) * Nichicon PW (Mouser 647-UPW1H221MPD) * Panasonic FC (Digi-Key P10325-ND) * Panasonic FM (Digi-Key P12397-ND)
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pagan
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Post by pagan on Jan 28, 2008 12:05:07 GMT
FC is still low esr and also 220R is considered too high to be on the output of a reg The BOM states below C37, C38: aluminum electrolytic capacitor 50V low-ESR high-reliability 220µF Lead spacing: 0.200", diameter: 10mm * Nichicon HE (Mouser 647-UHE1H221MPD) * Nichicon PW (Mouser 647-UPW1H221MPD) * Panasonic FC (Digi-Key P10325-ND) * Panasonic FM (Digi-Key P12397-ND) Leo I would have gone for a CRC >> reg >> 100uF >>100nF. But thats me Bypass for low impedance cap? hmmm why not ultra low ESR cap. Then there the area that some regs don't like low ESR caps on the output. ps the FM is lower ESR than the FC
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leo
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Post by leo on Jan 28, 2008 12:16:33 GMT
Well thought I'd build it as standard first, normally if using regulators I don't go higher than 47uf but on the Kumisa pcb theres not much else for decoupling the supplys after the regs
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pagan
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Post by pagan on Jan 28, 2008 12:43:51 GMT
Well thought I'd build it as standard first, normally if using regulators I don't go higher than 47uf but on the Kumisa pcb theres not much else for decoupling the supplys after the regs Leo Now there is !!! Mine was standard once too. FC's and all Well not quite, still havn't tried the 2sk170/2sj74's
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leo
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Post by leo on Jan 28, 2008 12:52:41 GMT
I agree with you and Alex, people need to try these regs, it seems the JLH's are classed as old so are overlooked which seems a big shame. I think we should do a layout for a more compact version If you can find the matched j-fets for a decent price give them a try, I think they sound quite good tbh especially since fitting the JLH's, I'll try some matched transistors and let you know how I think they compare. Which input transistors are you using btw, BC550/560C ?
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pagan
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Post by pagan on Jan 28, 2008 20:40:28 GMT
Leo
Yes BC550C/560C as inputs
"I agree with you and Alex, people need to try these regs, it seems the JLH's are classed as old so are overlooked which seems a big shame.
I think we should do a layout for a more compact version"
Now there's an idea.. It being debugged this week
Ask Sandyk for the layout, i have to go to work now. and give us dome feedback.
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jonclancy
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Post by jonclancy on Jan 28, 2008 20:44:33 GMT
BTW I don't have any hiss now!!! Nice one, mate!
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FritzS
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Post by FritzS on Feb 1, 2008 11:14:46 GMT
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Post by sometrolls2 on Feb 7, 2008 14:16:26 GMT
I have the board, vol pot and jfets on order and now need to get the rest minus case, diodes and phono sockets, is there a single UK supplier that does the recommended parts in terms of the right model cap, resistor etc?
I found some caps that should have been okay in the XCans really nasty so would like the right bits to start with.
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leo
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Post by leo on Feb 8, 2008 2:41:32 GMT
Farnell will stock most of the parts, I'd also recommend fitting the alternative servo rather than the one with 10uf NP caps.
I got the resistors from Maplins to save having to buy packs of 50 for each value, after trying those Dale RN65 resistors before in other projects my IMO is its not worth going to the trouble of importing them, standard metal films are fine
I'd also highly recommend the JLH regulation, it means having to etch extra boards but the performance boost is worth it. I also use an alternative ouput transistors, never been a fan of the BD139/140's
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pagan
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Post by pagan on Feb 8, 2008 11:25:47 GMT
Excuse the wiring as it was quickly lashed up, the JLH ground is connected to the amps star ground Leo And where is the amps star ground connected too?
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leo
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Post by leo on Feb 8, 2008 12:07:42 GMT
Its still going to the JLH ground, the yellow ground wire is soldered to the bottom of the Kumisa pcb. I may try running both the JLH ground and main regs ground to the Kumisa's star ground separate, the way in the pic was just a quick lash up
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pagan
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Post by pagan on Feb 8, 2008 12:56:51 GMT
Its still going to the JLH ground, the yellow ground wire is soldered to the bottom of the Kumisa pcb. I may try running both the JLH ground and main regs ground to the Kumisa's star ground separate, the way in the pic was just a quick lash up Use a 3 pin power cord Active, neutral, and earth that earth is used for star earth. I just use an old offcut of a pcb. the earth from the 3 pin plug to it, then thats my star earth point. chassis earth, JLH, kumisa pcb earth, all go to the star earth
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leo
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Post by leo on Feb 8, 2008 14:29:02 GMT
Thanks Allan, I'll do that soon as I get a case, its still sat exposed IMHO this isn't a bad headphone amp at all, it sounds quite nice with the AT A900 cans but not quite enough drive for the AKG K701's. The psu mods are certainly worth while doing, I'm listening to it now with the PCM1794 dac
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pagan
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Post by pagan on Feb 8, 2008 23:16:52 GMT
Thanks Allan, I'll do that soon as I get a case, its still sat exposed IMHO this isn't a bad headphone amp at all, it sounds quite nice with the AT A900 cans but not quite enough drive for the AKG K701's. The psu mods are certainly worth while doing, I'm listening to it now with the PCM1794 dac Leo With the standard psu components still in circuit, wouldn't they still have some effect?
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leo
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Post by leo on Feb 9, 2008 0:36:57 GMT
Not with the regs removed and the pcb track cuts no
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FritzS
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Post by FritzS on Feb 9, 2008 7:12:07 GMT
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pagan
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Post by pagan on Feb 9, 2008 9:41:42 GMT
Sorry Fritz should have replied. The Jung, ALW and other are very good regs. All the JLH does is "filter" the already reg'd psu. Idea to be used after a LM317/337 to clean up the noise on the voltage line, also provides a very low output impedance, higher current and voltage capabilities, with commonly available components. For a dac etc, I still use a superreg. anything over 50 to 100ma I use the JLH. For a preamp etc, or the front end of an amp, it works very well. only drops <0.3v and side benefit is slow turn on. From what I was told, the japanese liked them too. (with a different psu)
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Post by Deleted on Feb 9, 2008 10:12:47 GMT
Allan How is mini JLH coming along ? Alex
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pagan
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Post by pagan on Feb 9, 2008 10:53:45 GMT
Allan How is mini JLH coming along ? Alex I havn't played much with it, been sidetracked..... I did get(today) some BC327/337's to replace the BC639/640's. Why? ? I used pinouts for the 327/337's and the other pinouts are different. still useable but different, p****d me off. Sill not much difference between the trannies. 80v to 50v 1amp to 800ma. hmmm if they blow they are cheap,,,,,, hehe
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Post by sometrolls2 on Feb 23, 2008 1:58:21 GMT
Can anyone supply the last 4 bits I need: Q13, Q26: NPN medium power transistor TO225 100v 4A Q12, Q25: PNP medium power transistor
I can't find the anywhere doing the NPN and PNP of the same range, and even if I did wouldn't want to pay delivery for 4 transistors.
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pagan
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Post by pagan on Feb 23, 2008 3:14:52 GMT
Can anyone supply the last 4 bits I need: Q13, Q26: NPN medium power transistor TO225 100v 4A Q12, Q25: PNP medium power transistor I can't find the anywhere doing the NPN and PNP of the same range, and even if I did wouldn't want to pay delivery for 4 transistors. Depends on where you are.. Are you looking for the BD139/140's or the 2sa1930/2sc5171 varients? What same/similar package transistors do you have laying around?
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