FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jun 25, 2007 10:40:55 GMT
Hi,, now I run two AD847 in my modified WNA MKII (with AKG K701 and Marantz SA 7001 KI) My first experience: More punch More "metal" than "soft" in "brass" Music come to the fore Not for quiet sound level - here is the AD843 "king" My opinion - this statements are subjektiv - objective are only ABX tests with two similar amps but different OPA's and a ABX switcher. But this statement is be true for the most of the DIY test's ..... or? Has anyone test the AD847 (singel) or AD827 (dual) too?
|
|
leo
Been here a while!
Team wtf is it?
Posts: 3,638
|
Post by leo on Jun 25, 2007 14:10:27 GMT
I don't have a WNA amp but I have tried the AD827 in various other kit, its a nice op-amp but care MUST be taken when using it, the implementation needs to suit it and also remember its a fast type, if the circuit isn't suited theres the risk of instabillity.
Anyway if the circuit is suitable these are good op-amps
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jun 25, 2007 14:34:52 GMT
|
|
leo
Been here a while!
Team wtf is it?
Posts: 3,638
|
Post by leo on Jun 25, 2007 15:18:21 GMT
It should be fine then, the only reason I mentioned it is because I've known people try the AD827 in other units and noticed the amp gave out varying DC offets and the op-amp overheated which indicates instabillity:)
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jun 25, 2007 17:57:02 GMT
I had the case open and the OPA runs only warm .....
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jun 26, 2007 15:02:55 GMT
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jun 27, 2007 8:49:18 GMT
yesterday I heared "Symphony No. 5 by Gustav Mahler, Georg Solti, and Chicago Symphony Orchestra (Audio CD - 1991)" it was short of perfection
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 13, 2007 9:43:49 GMT
..... addendum ..... We ignore Linear Technology www.linear.com/Now I use two LT1056 in place of the both AD847 There are very little differences .... First test - from the first tick I hear - I am snoopy why after a burning in time Treble (cymbals) are a little bit softer, silkier, darker, more natural Micro Dynamics - more than AD847 - more in background too. 2nd & 3rd test - as far as I can see the LT1056 is a "big player" like AD843 too Natural, detailed sound with good micro dynamics, open wide and deep stage. I think one must be changed: The WNA design use a ferrite bead between the output of the OPA and the powerstage. This is not calculated for other OPA's. The datasheet suggestions of LT1056 use a little cap 10 ... 33 pF in NFB: "When the feedback around the op amp is resistive (RF), a pole will be created with RF, the source resistance and capacitance (RS, CS), and the amplifier input capacitance (CIN ≈ 4pF). In low closed-loop gain configurations and with RS and RF in the kilohm range, this pole can create excess phase shift and even oscillation. A small capacitor (CF) in parallel with RF eliminates this problem. With RS (CS + CIN) = RFCF, the effect of the feedback pole is completely removed." But I don't hear oscillation in audible range or distortion. Only very good sound And all this with an "old design" 5.5 MHz, 14V/us OP - silmilar to the OPA602 Next I will test LT1022 if I get my ordered samples We see .... speed are not essential Gain Bandwidth / Slew Rate LT1056 5.5MHz 14V/us LT1022 8.5MHz 23V/us OPA602 6.5MHz 35V/us OPA604 20MHz 25V/uS AD847 50 MHz 300V/us AD845 16 MHz 100V/us AD843 34 MHz 250V/us LM6171 100MHz 3600V/us
|
|
|
Post by PinkFloyd on Jul 13, 2007 13:51:18 GMT
Have you tried opa602 Fritz? I've just fired my MKlll up today and thought "hello Harry, this sounds good" so I popped the hood and discovered OPA602 on board.... it's been a while since I listened and can't remember fitting the OPA602..... will let her warm up a bit and see how they sound later on. I've got some 847 man, will give them a whirl too
|
|
leo
Been here a while!
Team wtf is it?
Posts: 3,638
|
Post by leo on Jul 13, 2007 19:28:19 GMT
Out of interest has anybody compared the opa602 against the opa604?
|
|
|
Post by PinkFloyd on Jul 14, 2007 11:38:01 GMT
Out of interest has anybody compared the opa602 against the opa604? No But I have compared 602 against 627 and let me tell you it's a very close run thing and you'd have a real tough time telling which was which if you were tied onto a chair and blindfolded.
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 14, 2007 12:40:28 GMT
I dont have a OPA602 but some OPA604 - but if I remember right some DIY dont very happy with the OPA604 in WNA MKIII Next time I will test the LT1022 and the OPA604 too I call David for MKII MKIII PCBs again - no answer till today. Has David another new e-mailaddress?
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 14, 2007 15:34:43 GMT
|
|
|
Post by PinkFloyd on Jul 14, 2007 17:24:12 GMT
I dont have a OPA602 but some OPA604 - but if I remember right some DIY dont very happy with the OPA604 in WNA MKIII Next time I will test the LT1022 and the OPA604 too I call David for MKII MKIII PCBs again - no answer till today. Has David another new e-mailaddress? I will send you a couple of OPA602 Fritz, PM me your details. I have no idea where David is these days, last I heard he was writing a book..... he hasn't spoken to me since I backed out of buying his whole stock of non ROHS parts, not my fault he should have been straight with me and not try to sell me a business that was 100% leaded
|
|
leo
Been here a while!
Team wtf is it?
Posts: 3,638
|
Post by leo on Jul 15, 2007 1:42:21 GMT
Out of interest has anybody compared the opa602 against the opa604? No But I have compared 602 against 627 and let me tell you it's a very close run thing and you'd have a real tough time telling which was which if you were tied onto a chair and blindfolded. Thanks Mike, just wondered as I've never tried the 602's, they look better specced than the 604's. Reason I asked is because one of my hi-fi amps uses a DC servo, the op-amp in that servo effects the sound too, the original op-amp was a OPA604 which I replaced with a 627 (it was the only other fet input op-amp I had handy) Anyway the the 627 sounds much better in the midrange but a little soft in the bass
|
|
|
Post by PinkFloyd on Jul 15, 2007 21:17:13 GMT
Fritz, a couple of OPA602AP on their way to you tomorrow..... got them in a jiffy bag will ship tomorrow. Much the same performance as the OPA602BP but cheaper.... I'm keeping my stash of BP for a rainy day.
Let me know what you think of them in the WNA and please let the amp warm up for 3 days before fully evaluating them.... they get better the longer the amp is powered up.
Mike.
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 16, 2007 8:48:33 GMT
Thanks But - please give the LT1056/LT1022 a chance - free samples for LT1056/LT1022 are open (2 pcs) - last both days I had some sessions .... The LT1056 sounds warm and cold, sharp and soft, analytic and natural - so as the sound-engineer has done his work Highlights Roger Waters, Amused To Death Deeeep natural bass Pink Floyd, Final Cut Good micro dynamics, very subtle in background (slapping shoes, playing children, ..) Today I got my "analog-audio cookbook" from Horowitz/Hill
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 17, 2007 8:44:05 GMT
Pete Townshend "Face the face" (in german we said "fetzt so richtig") deep bass "grummel " and brutal drums Sinéad O'Connor "GOSPEL OAK" had rare heard this so natural and realistic I think this are twice effects - one the LT1056 second - my K701 nearly burned in The K701 is one of the best headphones I ever heared!
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 20, 2007 8:39:42 GMT
Yesterday I got samples of LT1022 My first (subjective) look and feel - the LT1056 sounds better - but I will give the LT1022 a chance to burn in maybe, yesterday I had a bad day to hear?!
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 22, 2007 9:53:13 GMT
additional listenings .... LT1022 sometimes a very little bit muted leadsinger a bit more in background, quieter - but background sound a bit louder clear sound emotionally I missing something but I cannot say what LT1056 sometimes tiny strained in treble at sizzle cymbal, LT1022 does not. This statements are subjektiv and emotional ...... I rate LT1056 emotionall prior to LT1022, but very close ;D I found in my treasure chest some .... OPA 655 focus.ti.com/docs/prod/folders/print/opa655.html400MHz UNITY GAIN BANDWIDTH LOW INPUT BIAS CURRENT: 5pA HIGH INPUT IMPEDANCE: 1012(ohm) || 1.0pf ULTRA-LOW dG/dP: 0.006%/0.009° LOW DISTORTION: 90dB SFDR at 5MHz FAST SETTLING: 17ns (0.01%) HIGH OUTPUT CURRENT: 60mA FAST OVERDRIVE RECOVERY have anyone experince about this? and some too AD845 AD825 (SOIC) OPA627/37 OPA227/28 OPA604 LT1360 LT1363 and ... whats about this?
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 24, 2007 4:16:38 GMT
Thanks - now the OPA602AP is inside ;D
My first short impression without burn in or longer warming up and only one CD "PF FinalCut" ...... nearly perfect - detailled, good micro dynamic .... more later .....
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 29, 2007 11:26:40 GMT
After some sessions I can say (for me) the OPA602AP is one of the distinguished OPA's for the WNA MKII. Very balanced, detaiiled music Better than LT1056 LT1022 AD847 AD843 LM6171 LME49710? I cant say this with guarantee but the OPA602AP is a new star ;D Open to test - but what is your experience about this? AD8065, OPA604, AD845, OPA627, AD825, AD8610, AD9631
|
|
|
Post by PinkFloyd on Jul 29, 2007 11:35:19 GMT
After some sessions I can say (for me) the OPA602AP is one of the distinguished OPA's for the WNA MKII. Very balanced, detaiiled music Better than LT1056 LT1022 AD847 AD843 LM6171 LME49710? I cant say this with guarantee but the OPA602AP is a new star ;D Yes, it's not bad at all is it Fritz? Glad my hearing is still good Oh... plenty or ramblings on most of those chips when used in the MKll AD8065: www.head-fi.org/forums/showpost.php?p=1614982&postcount=598Actually Fritz, I think I covered most of them in this very long thread over at Head-Fi and your good self also appears in the discussion This one..... www.head-fi.org/forums/showthread.php?p=1614982&highlight=ad-8065#post1614982
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 29, 2007 11:59:44 GMT
next time I will heat my iron and solder them into the SOIC adapter. Input caps, lamp, ZOBEL I dont have, only BG 1000 uF output caps (not bypass). But Graham use caps too in Solo!? Belike I get a DC protection from David
|
|
FritzS
Been here a while!
Sound of Blue Danube
Sound of Blue Danube
Posts: 1,364
|
Post by FritzS on Jul 30, 2007 9:10:33 GMT
Yesterday evening I heared Roger Waters "Amused to Death" - this was a extraordinary epiphany ;D I think its near "the end of the flagpole" with my components - another OPA have a rough ride to overcome the OPA602AP in WNA MKII To make a great shift in sound I must change others, ... the CD/SACD player, the headphones, .......
|
|