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Post by freddypipsqueek on Mar 25, 2010 9:19:51 GMT
After much time and effort I now have a working WNA Mk III with Cascode PSU. Whilst it sounds good (and I will leave on for a week whilst i'm away etc on the basis that it will get better) I'm not sure about the AN843JN Op Amps. Has anybody got any recommendations. I like a quite forward bright sound which I will listen to through K701's and HD590's.
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Post by PinkFloyd on Mar 25, 2010 10:49:24 GMT
After much time and effort I now have a working WNA Mk III with Cascode PSU. Whilst it sounds good (and I will leave on for a week whilst i'm away etc on the basis that it will get better) I'm not sure about the AN843JN Op Amps. Has anybody got any recommendations. I like a quite forward bright sound which I will listen to through K701's and HD590's. LM6171
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Post by freddypipsqueek on Mar 25, 2010 13:12:25 GMT
Thanks Mike
Same as with the Chiarra ?. Is it simply a plug and play change ?
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Post by freddypipsqueek on Mar 25, 2010 23:40:39 GMT
Sorry to trouble you Mike.
In the WNA there are 2 sets of Op Amps. Looking from the back the first in mine are OPA134PA's. the second set are AN843JN. Do I need to replace both sets with the LM6171's - thus 4 in total. I'm looking at the photos you posted late last year which seem to show LM6171's in all the sockets.
Thanks for your time - Or anybody else if they wish to comment !!.
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Post by PinkFloyd on Mar 25, 2010 23:58:06 GMT
Sorry to trouble you Mike. In the WNA there are 2 sets of Op Amps. Looking from the back the first in mine are OPA134PA's. the second set are AN843JN. Do I need to replace both sets with the LM6171's - thus 4 in total. I'm looking at the photos you posted late last year which seem to show LM6171's in all the sockets. Thanks for your time - Or anybody else if they wish to comment !!. The MKlll was optimised around the LM6171..... it is designed to work with the LM6171...... LM6171 in both amp channels BUT only one in the rail splitter..... ie: don't populate BOTH rail splitters.... the other splitter acts as a capacitance multiplier..... Didn't you get a manual with it? I'll be happy to send you my manual, it explains ALL of this in DEPTH..... I can also supply the LM6171 (£5 each)........ Anyways..... don't populate BOTH rail splitters with LM6171 (just one) and fit LM6171 into both slots on the amp board..... It's been a while since I listened to my MKlll, I'll crack the hood one of these days and have a good look..... If you'd like to send yours up to me I'll be happy to fit it out for you free of charge (you pay postage)..... just to keep my hand in Mike.
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Post by freddypipsqueek on Mar 26, 2010 18:33:14 GMT
Mike.
Thanks.
I have 2 op amps in the railspliters (one in each channel) as I'm using a cascode PSU - i.e. 2 channels of the cascode with each feeding one channel of the amplifier. The system is dual mono - psu & all. I Think. When I setup the cascode I had to fit the extra op amp (an extra OPA134PA). I assume therefore that I need 4 ?. If you agree I will paypal £20 to you for 4 LM6171 - I still have you address from "The Little" you kindly sold me - which is now used in the study.
I did get a manual which I read and re-read when workng on the cascode. It only now you have reminded me of the basics that I can see the reference to the design being based around the LM6171 !! - including it's fitting in the rail splitter.
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Post by freddypipsqueek on Apr 12, 2010 19:29:07 GMT
For those who are interested.
I've ended up keeping the AN843JN Op Amps in my WNA.
Three reasons.
1. I've run them for the past 30 hours and they were getting better - I would say faster and more precise - faster is probably the word. How long to Op Amps take to run in ?
2. I have put a TDA1541 S2 chip in my BB2 - replacing the original TDA1541. This seems to of been the DAC equivalent of an Expresso. The start and stop is quite unnerving.
3. I have rewired the line out of the WNA with silver wire. I think this was responsble for the sugar in the Expresso. I've heard that if you use silver cables you need to maintain silver on a length. i.e. the copper wire in the WNA may well have clouded the silver interconnects.
Any comments on 3 very welcome.
The WNA is now singing.
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