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Post by PinkFloyd on Nov 10, 2006 21:02:47 GMT
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rickcr42
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Post by rickcr42 on Nov 11, 2006 0:29:50 GMT
Specs out really nice for audio use but if it sounds anything like the last generation of National Semi "audio grade" Op-Amp,the LM877 (I think that is the number anyway) I would take a pass.Always a tough call trying to choose on specs alone and so I too would be interested in the SQ experiences
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Post by PinkFloyd on Nov 11, 2006 12:54:18 GMT
Specs out really nice for audio use but if it sounds anything like the last generation of National Semi "audio grade" Op-Amp,the LM877 (I think that is the number anyway) I would take a pass.Always a tough call trying to choose on specs alone and so I too would be interested in the SQ experiences Can you get samples from National Rick? For some reason they don't want to send to Europe (even if you offer to PAY them) one of the weirdest sampling programmes I have encountered, I registered with them a few years ago and have requested samples on many occasions only to get an e-mail saying I don't qualify as I'm in the UK.... if you could get hold of one, appreciated. Fellow member Nigel alerted me to this chip and he's drooling over the prospect of trying it out in his Chiarra. I am particularly interested to find out what "type" of chip it is (ie: FET? bipolar?) doesn't appear to say in the specs.... +/- 0.1mV offset is very handy indeed I'm looking for dip8 and will evaluate the chip in one of my amps that use a dual dip8 chip. Mike.
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Nigel
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Post by Nigel on Nov 11, 2006 21:11:44 GMT
Hi Mike,
Yeah, I'd love to try this one. I wonder if it's more musical than the OPA 627's?
Cheers,
Nigel
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rickcr42
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Post by rickcr42 on Nov 11, 2006 21:46:24 GMT
Probably.I'll check into it.There was a time I did then I started to get "no to that email address" type messages that to be honest is a bit baffling (maybe they want a corporate email address ? Possibly) since I deal regularly with TI,BB,ADI,Maxxim,Cirrus Logic,etc.,without a glitch. In fact 50% or better of my daily emails are from those characters offering to send me more stuff whether I need it or not National seems to be the hardest of the bunch to get samples from though it was not always that way.I have a suspician it is all the "Gain clone" builders looking to make amps for free that put a twist in the National Semi undies you need to pay closer attention to your own forums dude ;D rockgrotto.proboards39.com/index.cgi?board=m&action=display&thread=1157981100Yup.September 11 I also noticed they are very tight lipped about topology.I am sure some-damn-where there is more info but where ? Sherlock Rick is ON the case-stay tuned for ther skinny that says they have an actual market in mind-the audiophile/audio designer/DIY OpAmp roller-for the product and why it is touted as "audio" grade.I wish others would follow suit because I for one find the new microscopic sized opamps a serious pain in the ass and one that has totally turned me away from the devices as a class of parts.I have BOXES of chips meant for evals that I have zero desire to test at this point knowing A-will mean more "universal opamp eval board" work B-adapters to use them in more civilised products C-for my own designs would have to forego my own in house pc boards and go to a pc board house that i find to be way over priced for small runs D-Even if it IS in DIP form and I find I like it will soon become "obsolete" making all the above work a total fkn waste of my life not a whole lot of choices out there unless you want to go the BB OPAXXX route (boring ) that it seeems will always be with us and maybe a couple of DIP ADI offerings so I personally have lost even what little interest I ever had. BTW-a lot of the "marginal for audio" bipolar input chips can be made better by using your own jfet front end (as it was done before there ever was a jfet opamp ) combined with a REAL output stage run in class-a open loop as the interfece to the outside world. Have two days in a row off for the first time in months so between football/hockey/Nascar/dancing naked around the house with air guitars blazing will see what i can dig up on this chip rickeraptor
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rickcr42
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Post by rickcr42 on Nov 12, 2006 0:21:32 GMT
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rickcr42
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Post by rickcr42 on Nov 12, 2006 3:12:40 GMT
BZZZZZZZZZT !
WRONG ANSWER Buckwheat !!!!!
is rather the LM833 ;D
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Nigel
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Post by Nigel on Dec 8, 2006 13:27:10 GMT
Hi,
I've been using this chip for a few days now. Initial results in the Chiarra seem very promising. I'll post more thoughts after the honeymoon.
Cheers,
Nigel
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rickcr42
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Post by rickcr42 on Dec 8, 2006 14:36:34 GMT
been slacking on this one so this was a good reminder to put in an order (about ten minutes ago )
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Post by PinkFloyd on Dec 8, 2006 23:26:31 GMT
Hi, I've been using this chip for a few days now. Initial results in the Chiarra seem very promising. I'll post more thoughts after the honeymoon. Cheers, Nigel I want it back by the way I need it by the end of the week................ only kidding Expecting a few paragraphs from you on this one Nigel... I trust your ears 99.9% Mike.
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rickcr42
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Post by rickcr42 on Dec 8, 2006 23:39:35 GMT
Check this one Mikester-"free sample" for the bargain rate of ONLY $9.95 in shipping Un-fkn-beleivable ! Be better off buying a whole damn reel of the little pricks if I had an actual use for them
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Post by PinkFloyd on Dec 9, 2006 1:25:41 GMT
Check this one Mikester-"free sample" for the bargain rate of ONLY $9.95 in shipping Un-fkn-beleivable ! Be better off buying a whole damn reel of the little pricks if I had an actual use for them Yup. The hard to source / pricey to ship / much sought after chip is in the hands of my man in the pool Nigel...... Over to you mate.................
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rickcr42
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Post by rickcr42 on Dec 9, 2006 15:00:24 GMT
yup.Otherwise would just as soon pay retail for a couple along with all the associated parts then have the entire deal shipped to me for like $6
connecticut by way of Istanbul ? 20lbs of packing material ?
I can't remember a single order of electronic parts (including a recent order that had vacuum tubes,heavy film & foil caps and JJ dual section electrolytics,also heavy) in the last few years that came in over $8 total shipping price so to ME way overpriced for a coule of skimpy opamps in a teeny tiny plastic package.
should not matter when it is from the original source "instead of secondary "audiophile boutique part high markup/rip-off dealer" sourcing.Hopefully at the minimum the chip is usable somewhere or I will feel like an idiot for paying more for shipping than the "free" part costs at retail. ;D
**
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Post by PinkFloyd on Dec 9, 2006 17:07:30 GMT
Nigel's chip actually came packed in a 30 square foot crate and the postman had to fork lift it into the garden. Special delivery like this costs money Rick
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rickcr42
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Post by rickcr42 on Dec 9, 2006 18:55:45 GMT
well mine better be delivered by a drop dead beautiful 22 year old naked "hottie" and they can keep the freakin' crate (unless she pops out of it of course )
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Nigel
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Post by Nigel on Dec 16, 2006 21:51:36 GMT
Hi,
IMHO in my modest set-up (Chiarra/HD650's fed by Rega Jupiter or Linn LP12) the LM4562 outperforms the OPA 627's. It's a special chip that seems to act as a more open window allowing greater insight into the music. The differences are subtle but nevertheless can be heard & easily appreciated.
Cheers,
Nigel
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Post by PinkFloyd on Dec 16, 2006 22:37:53 GMT
Hi, IMHO in my modest set-up (Chiarra/HD650's fed by Rega Jupiter or Linn LP12) the LM4562 outperforms the OPA 627's. It's a special chip that seems to act as a more open window allowing greater insight into the music. The differences are subtle but nevertheless can be heard & easily appreciated. Cheers, Nigel Short but sweet report Nigel but one which I agree with. In the Graham Slee Solo the LM4562 continues to please my ears and I use the Solo as a tool when I really want to hear everything that's on the recording. "an open window allowing greater insight into the music" is a great way of describing it. Those two OPA627s in your Chiarra are BP versions, by the way, the most expensive version you can get (RS were selling them for around £40 "each" back in the day) so don't bin them Nigel! If you're not going to use them then send them back to me
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rickcr42
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Post by rickcr42 on Dec 17, 2006 1:03:53 GMT
still waiting for the hottie with the special delivery package to arrive then the fun part of figuring out where to stick it (and no comments from you wise guys on where I can stick it either ! ) since i am very op amp audio deprived
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leo
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Post by leo on Dec 20, 2006 1:33:07 GMT
Just came across this site when searching around about the LM4562. I already fitted the smd ones in my Hypex UCD amps which replaced the AD8620's, to my ears the LM's are much better, DC offset on my amps out is even lower than it was with the AD8620's fitted.
I also have a Chiarra headphone amp I've not used for a while so will stick one in that tomorrow, the only thing that concerned me was the decoupling (or lack of it close to the op-amp) I presume these op-amps are behaving in the Chiarra?
Cheers, Leo
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Post by PinkFloyd on Dec 20, 2006 12:27:26 GMT
Just came across this site when searching around about the LM4562. I already fitted the smd ones in my Hypex UCD amps which replaced the AD8620's, to my ears the LM's are much better, DC offset on my amps out is even lower than it was with the AD8620's fitted. I also have a Chiarra headphone amp I've not used for a while so will stick one in that tomorrow, the only thing that concerned me was the decoupling (or lack of it close to the op-amp) I presume these op-amps are behaving in the Chiarra? Cheers, Leo Hi Leo, Have a read a few posts up ^ Nigel has got an LM4562 running in his Chiarra and he prefers it to OPA627 on browndog. Mike.
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leo
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Post by leo on Dec 20, 2006 13:15:05 GMT
Just came across this site when searching around about the LM4562. I already fitted the smd ones in my Hypex UCD amps which replaced the AD8620's, to my ears the LM's are much better, DC offset on my amps out is even lower than it was with the AD8620's fitted. I also have a Chiarra headphone amp I've not used for a while so will stick one in that tomorrow, the only thing that concerned me was the decoupling (or lack of it close to the op-amp) I presume these op-amps are behaving in the Chiarra? Cheers, Leo Hi Leo, Have a read a few posts up ^ Nigel has got an LM4562 running in his Chiarra and he prefers it to OPA627 on browndog. Mike. Hi Mike, I'm just about to fit it in mine;) the only thing that concerned me was stability because the lack of local decoupling but if Nigels is still ok then it should be fine. I'll probably check it on the scope to just to be sure. Just looking around at other diy headphone amps to try out, may give the SDS labs a go next Leo
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rickcr42
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Post by rickcr42 on Dec 20, 2006 14:52:27 GMT
always a good idea to decouple ALL possible inputs to a high gain device but in this case you have a chip that goes directly against the race to ultra high speed and extreme high bandidth making the part a lot more well behaved than most op amps used for audio even though better suited to RF frequency operation.
Look at the usual suspects labeled "audio op amp" from BB,look at the more well behaved chips used for audio duty from ADI (AD825 a good example chip) then check the specs of the above and you will see a common theme mostly and that is SLOW combined with good performance in the AUDIO band.That National has decided to make an audio specific desgn with actual damn through the hole pins is a good sign and one I hope catches on in this age of cell phone chips being forced to audio duty
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leo
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Post by leo on Dec 20, 2006 16:12:53 GMT
always a good idea to decouple ALL possible inputs to a high gain device but in this case you have a chip that goes directly against the race to ultra high speed and extreme high bandidth making the part a lot more well behaved than most op amps used for audio even though better suited to RF frequency operation. Look at the usual suspects labeled "audio op amp" from BB,look at the more well behaved chips used for audio duty from ADI (AD825 a good example chip) then check the specs of the above and you will see a common theme mostly and that is SLOW combined with good performance in the AUDIO band.That National has decided to make an audio specific desgn with actual damn through the hole pins is a good sign and one I hope catches on in this age of cell phone chips being forced to audio duty Hi Rick, Theres no grounds near so rather than have long ground leads from extra decoupling I fitted a stacked film cap across the +/- leg of the op-amp. It looks ok and sounds good They work really well in the UCD amp, theres a CRD on the output going to the positive supply which is its worse PSRR, that made a small but noticeable improvement.
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rickcr42
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Post by rickcr42 on Dec 20, 2006 17:10:40 GMT
for some reason that I seem to have missed the explaining of or if it was have forgotten some opamps like to be bypassed that way,some just at the power inlet pins and some a combination of the above and I wish someone could tell me WHY considering many times the data sheet specs are damn near identical.
I know there is a reason I just can't figure out what the hell it is which would allow getting it right right out of the gate instead of the of the "try it then measure the damn thing" process of elimination....
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leo
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Post by leo on Dec 20, 2006 18:13:08 GMT
It seems fitting a cap across the +/- supply pin improves PSR and distortion performance. It also helps if your stuggling with room to do the normal type decoupling. Only thing is you get double the voltage through the cap but seeing as though its a 63v stacked film thats more than enough
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