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Post by kittenyberk on Apr 23, 2008 22:42:14 GMT
Yup, I've ordered a kit, as has a mate. Also, probably worth mentioning (incase anyone doesn't know) national semiconductor will give you a sample of 3 LM4562s for the cost of postage (about a fiver) which makes this amp even better value  |
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Post by Deleted on Apr 24, 2008 0:27:07 GMT
kittenyberk
Cheapskate ! ;D
I understand that not everybody is so lucky with the freebies. Now that chip is well established, it may no longer be available
in this manner ?
BTW, I mentioned that I intended making a 50K 23 position attenuator for the HA. Ordered it yesterday afternoon, on my doorstep before 10am this morning !
Alex
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leo
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Post by leo on Apr 24, 2008 0:50:35 GMT
Thats proof its a good amp if you feel it deserves an attenuator. Expecting this to go onto an ongoing interesting thread  |
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Post by Deleted on Apr 24, 2008 1:09:31 GMT
Leo
I hope it isn't just the Sony headphones that it is able to transform !
Still, if too bright, there is always the option of fitting a smaller value capacitor than the original specified, where I left it out. There is also the option of increasing the value of the output resistor for those headphones that work best (?) with 120 ohms. As well, the original article also describes how to increase the gain if required. I would suggest not using any higher gain than needed , so as to keep distortion low. (Allan , Leo, or myself can assist there if required.)
Alex
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leo
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Post by leo on Apr 24, 2008 1:53:41 GMT
Well normally lower gain , higher bandwidth
What Sony's are they? impedance? is the cable capacitance low
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leo
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Post by leo on Apr 24, 2008 1:55:06 GMT
Sony
MDR- CD780
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Post by kittenyberk on Apr 24, 2008 2:00:28 GMT
Cheapskate ! ;D I understand that not everybody is so lucky with the freebies. Now that chip is well established, it may no longer be available in this manner ? I got 3 of them last week, so I doubt much has changed since then. |
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Post by Deleted on Apr 24, 2008 2:09:37 GMT
Kittenyberk
I have seen reports in DiyAudio of people missing out. perhaps this is because they got too greedy, and ordered too many different I.C.s over a period of time?
SandyK
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leo
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Post by leo on Apr 24, 2008 2:15:52 GMT
Not much info on the datasheet for the LM4562, not even an internal diagram.
Slewrate is quite low at ±20V/μs
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Post by kittenyberk on Apr 24, 2008 3:03:53 GMT
Kittenyberk I have seen reports in DiyAudio of people missing out. perhaps this is because they got too greedy, and ordered too many different I.C.s over a period of time? SandyK I suspect it comes down to luck and timing, only way to find out is by trying. If it came up on a very busy forum, and loads of people ordered them, I'd expect people to miss out, but I doubt that it's too common |
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Post by canjunkie on Apr 24, 2008 6:56:23 GMT
Looks like this thread could go on for a bit. I received the PSU kit yesterday and emailed Jaycar to find out when the headphone kit would be arriving. I got this... I hope they're being conservative with their delivery to warehouse estimate  |
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Post by Deleted on Apr 24, 2008 7:18:35 GMT
canjunkie
Sorry to hear that. Perhaps publication in the U.K. magazine Everyday Practical Electronics in
March 2008 may have have caused a spike in demand ? It was first published in Silicon Chip magazine (Aust. ) in November 2005.
Alex
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Post by dc on Apr 24, 2008 9:19:11 GMT
I got some LME49710NA opamps for the cost of shipping as well.
I believe they're the single version of the LME49720NA which is the updated version of the LM4652NA. I think.
For some reason when I ordered LM4652NA samples a while ago I didn't even have to pay for shipping, go figure!
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Post by canjunkie on Apr 24, 2008 9:33:27 GMT
Thanks Alex, But they do say patience is a virtue and summer is a quieter time for me so the silver lining to the cloud is I'll have more time to tinker about with the thing. And I won't be trying to build it at silly o'clock in the morning. Meanwhile if you've got any further info and even a file for UV etching the PCB for the JLH I'd be grateful if you could email it to me. A decent 12-15V PSU would be useful for a couple of other projects so I could get that built.  |
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Post by Deleted on Apr 24, 2008 9:50:07 GMT
canjunkie
The mini JLH PCB from Allan had a minor design problem. I am waiting for Allan to finalise that correction, but he is away working down Southern NSW for a little longer. I have workable artwork for the JLH shown in the original photo, but it won't fit in a readily available case with all the other stuff, like the case I suggested a couple of posts ago. Why don't you get the case and mount the PSU components in the meantime. BTW, the 1.5uF 63V capacitors in the JLH have 5mm lead spacing, and may not be readily available. You may have to search for some that size. I think Farnell may also stock something suitable, but they are around AU$4 each, whereas the ones from Dick Smith are AU$2 each. Unfortunately, DSE is getting out of components. I will send you a copy of Allan's provisional artwork.
Alex
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Post by canjunkie on Apr 24, 2008 12:04:45 GMT
Email received, Thanks Alex - that should keep me out of mischief for a little while. |
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Post by PinkFloyd on Apr 24, 2008 19:55:30 GMT
I always found those filtered IEC sockets make the sound worse tbh Couldn't agree more Leo! Bloomin' horrid things that suck the soul out of the sonics.... much better strapping a good old class X2 cap across the IEC L/N tags. You don't happen to have any LM4562 kicking about do you Leo? I went hunting for mine today and couldn't locate them for the life of me  I'll be happy to do a swap with you if you do have any at Leo HQ. |
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Post by PinkFloyd on Apr 24, 2008 20:05:12 GMT
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Post by PinkFloyd on Apr 24, 2008 21:12:18 GMT
Looks like this thread could go on for a bit. It should pick up pace once people start realising JUST what an absolute bargain this amp is.... it's not an £8.95 mickey mouse Maplins Vellerman novelty toy... this is a REAL man's headphone amp with bags of tweakability...... £8.95?? yes..... that's all it costs. No wonder Jaycar are quoting "summer" lead times Alex.... the word's got out.... this joint may be small but it still has a heavy punch, I just hope they keep the price of the kit where it is at the moment and don't hike it up.... it's, undoubtebly, the audio bargain of the century to us in the know but exposure always equates to a price hike in my experience.... hopefully Jaycar are not aware of this thread (yeh, RIGHT!!) |
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Post by Deleted on Apr 24, 2008 21:17:53 GMT
Mike
Don't expect wonders just from plugging in an LM4562. It really is the special low impedance PSU that makes it really shine. The bypassing of the fuses helps in that regard too.Making the O/P emitter resistors 0.5W will help protect the fairly robust O/P devices.
Perhaps Canjunkie may be able to make an extra mini JLH PCB ?
Alex
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Post by canjunkie on Apr 24, 2008 23:26:10 GMT
Who me? ;D Looks like I'll have a bit of time before the rest of the kit turns up so I might as well. |
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Post by canjunkie on Apr 24, 2008 23:30:28 GMT
One nice touch in the small print is that even if they do lift the price, I'm guaranteed my back order at the old price - don't see many UK firms doing that.
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Post by Deleted on Apr 24, 2008 23:36:40 GMT
canjunkie
Yes, they are aware of this thread. I let it slip when Mike had a few initial problems with delay. Jaycar normally doesn't lift prices during the life of the catalogue, unless they have large increases in costs. Besides , the Aussie dollar is almost US 95 cents at the moment, and also this kit is 3 years old.
Alex
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leo
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Post by leo on Apr 25, 2008 13:48:44 GMT
I always found those filtered IEC sockets make the sound worse tbh Couldn't agree more Leo! Bloomin' horrid things that suck the soul out of the sonics.... much better strapping a good old class X2 cap across the IEC L/N tags. You don't happen to have any LM4562 kicking about do you Leo? I went hunting for mine today and couldn't locate them for the life of me I'll be happy to do a swap with you if you do have any at Leo HQ. Sorry I'm late getting back mate, been busy, not had time to fart  I only had one of the LM4562 DILs BUT I do have one SMD LM4562 in my stash, would that be ok for you? it obviously needs to be mounted on a browndog if you have one |
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leo
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Post by leo on Apr 25, 2008 14:00:35 GMT
BTW guys the circuit for this amp looks SOOOO similar to a commercial unit out there which is FAR from cheap ;D
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I'll be happy to do a swap with you if you do have any at Leo HQ. 