OPA2134 vs. AD8610

[dorkus]

that's a cool adapter. i think i'll get a bunch.

i'm thinking i'll try the AD825 in the output stage of my MSB Link DAC. the stock chips were motorola, i'm using OP275 now (which i prefer to AD827, which was too bright and "hi-fi"). the MSB uses 2 dual ICs, one for each channel; the 2nd half of each chip is used for DC servo. i'll definitely use the AD825 for output stage but maybe i could play with different opamps for servo? jam has mentioned that the "sound" of a DC servo correlates pretty well with the sound of the opamp employed so maybe i should just match it to the other opamp. i'm assumming pretty much any opamp i use will have adequate DC performance right?

 

[PhopsonNY]

Similar question..?

I have a similar question in this regard.

My big question is this...

The basic description of the Sony's audio circuit as it now stands is;

AD825s as i/v >> opa 2132 as mix (balanced to single ended) >>
ad712 as buffer/servo.

Research suggests that the ad712s might be a weak link and I suspect a significant factor in the sonic signature of the unit.

One half fo the ics act as the output buffer and final gain stage and the other half of each chip acts as the dc servo.

The chips are implemented as so8s so I am limited to a dual so8 as a replacement.

The two choices I have limited the replacements to are
the opa2604...reportedly very musical and
the ad8512...new kid on the block...better electronic specs if ad8610 is anything to go by, then very good sounding.

Please suggest the best one to try.
Any suggestions would be appreciated.

 

[bmwrob]

Re: single so8 to dual dip opamp adapter available from BrownDog

The AD8620 is still vaporware, don't hold your breath on it appearing anytime soon.

Too bad about the 8620. It would have been a nice solution. I'm a little bit concerned about the extra heat the Browndog will generate. There is also the space issue. I might have to move the Takamisawa relay (change?) next to the 2134 to the right on this picture.

 

[morsel]

You won't have to move the relay, the adapter is about the same size as standard dip sockets. If the fit is too snug, place some fine sandpaper on a table and rub the sides of the adapter on it to take down the rough edges. Then it will fit perfectly. Just be sure you don't take away too much on the side that has the trace that runs close to the edge. You can see it if you "candle" the adapter by holding it up to a light and looking through it.

 

[bmwrob]

Well I have ordered the adapters now. Still I haven't been able to locate a place where I can order the amps. I have contacted AD directly and hope they can give me an answer.

Thanks for all the suggestions so far.

 

[morsel]

AD sells direct online. You can pay by credit card.

 

[bmwrob]

AD sells direct online. You can pay by credit card.

Is it that easy! Well morsel, you were faster then AD's customer services. I guess they will come back with the same answer soon.

Anyway thanks for all the help. I will let you guys know my impression of them as soon as it's up and running.

 

[PhopsonNY]

dual ad8620 now available

For all that are interested and can use it,

the ad8620 (dual version of ad8610 is now available)

Hope this helps

http://products.analog.com/products/info.asp?product=AD8620

 

[morsel]

Woohoo! Good news indeed.

 

[PhopsonNY]

Reducing ad8620 supply voltage

Ok time for another stupid question...!!!

As formerly stated, I have 16.6v supply rails for all the opamsp in my SCD777es and I would love to use the ad8620s if they are as good as the ad8610s in my buffer/servo stage and maybe my "mix amp" (balanced to unbalanced) stage. Hence voltage must be reduced to 12v if this is to be possible.

I know Sony suggests and LDO for this but building and installing a daughter board and then cutting the existing supply rails is I know beyond my knowledge/skill. Besides I am not sure what effect it will have on other parts of the system.

Strange Idea, but what if I installed a small resistor at the voltage connection pin of the opamps to be used. I know this is physically difficult, but I remember from High school that V=IR.

I am presuming the current is constant here so with measurement an calculation, I could get this v down to 12.

Please comment and I know I am probably over simplifying the situation.

 

[dorkus]

no resistors in power supply line! unless it is followed by a decent amount of storage capacitance, in which case it becomes an RC filter. but a resistor alone will destroy the performance of the device, the supply regulation will suffer terribly. current is NOT constant at all on the rails.

 

[TK Chan]

------------------------------------------------------------------------

Despite the precision title, I don't find the 627 to sound good at all, in many applications. The opamp is very quiet, analytical, but very hifi - sounds like a better version of the 5534. I think this may be due to the high gain of over 100dB or over and not so great settling, especially in the I/V position. Even as filter or buffer, there seems to be an edge or grain at mid/hi. I always end up removing it.

I've replaced original opamp AD2604 in the SCD-777 with the dual AD825 and after over 50 hours of burn-in, I like the sound very much. The AD825 has a much lower noise level. Much of the hentherto hiss sound that was mistaken as tape hiss was gone, rendering the sound with good clarity and revealing in minute details. The best thing I like is the improvement in the depth of the soundstage. On recommendation of my other friend, I switched the AD825 to a dual 627 and was immediately excited by the sweeter high and deeper bass. However, on the days following more critical listening, I put back the AD825 in and write off the 627. The reason being that the 627 simply didn't deliver as much musical realism as the 825. Its sweetness seems to be made up by blurring the minute details. It is pleasing but in my view sounds artificially hifi.

I am much interested in this new AD8610/AD8620 but it seems the limitation of working voltage does not fit to the SCD-777ES. However, I am much interested in Rob's impending modification to the AX10 which I also have one.

 

[fmak]

I've replaced original opamp AD2604 in the SCD-777 with the dual AD825 and after over 50 hours of burn-in, I like the sound very much. The AD825 has a much lower noise level. Much of the hentherto hiss sound that was mistaken as tape hiss was gone, rendering the sound with good clarity and revealing in minute details. The best thing I like is the improvement in the depth of the soundstage. On recommendation of my other friend, I switched the AD825 to a dual 627 and was immediately excited by the sweeter high and deeper bass. However, on the days following more critical listening, I put back the AD825 in and write off the 627. The reason being that the 627 simply didn't deliver as much musical realism as the 825. Its sweetness seems to be made up by blurring the minute details. It is pleasing but in my view sounds artificially hifi.
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I agree; but you will be better off improving the digital and filter sections, I suspect.

I will get round to this but at present I am trying out different forms of current loading the 825. Sounds much better.

The 8610 is in between the 627 and 825, and needs current loading also.

 

[haldor]

Re: dual ad8620 now available

For all that are interested and can use it,

the ad8620 (dual version of ad8610 is now available)

Hope this helps

http://products.analog.com/products/info.asp?product=AD8620

Did you notice the strange comment in the product announcement?

"The AD8610 swings to within 1.2 V of the supplies even with a 1 k W load, "

What's up with the 1 kW load business? Does this mean something other than the obvious, is this a typo or am I just clueless?

Phil

 

[BrianL]

"W"

It seems that if type fonts get messed up, the Greek Omega
special character gets mapped to "W". Audio Amateur
magazine had their printer reprint a whole issue a
few years ago and mail
it to subscribers due to the same problem.

 

[bmwrob]

Well from planning to implementation it took more then half a year. Two weeks ago I did the first test run with the AD8610 installed. The first test CD was James Taylor’s “Gaia” from the Hourglass album. I must admit I had difficulties to wipe of my big smile from my face. The difference from the old OPA2134 was more then subtle! Right from the start I was hit by a wider, more three dimensional sound stage. The highs were clearer and more detailed. My first impression was that I was missing bass though. This was noticeable when the awesome drums kick in at approx. 3m 50s. Disc after disc, the result was the same. A very impressive treble and a tighter (less pronounced) bass). Now two weeks later I would say that the bass has improved, but are a bit more laidback then when compared with the 2134’s. Which one that sounds best I would say is a matter of taste. As the treble is greatly improved, the overall winner is clearly the AD8610. I would highly recommend anyone to try them out.
AD8610 on Browndog adapters
Prior Installation