SimontY said:
In cd player I've got very good results with ad825-826 in I/V and opa627b in filter/out circuits . I most like this combo.You also can try ad 843 and ad811 in I/V ,but the are high frequency chips and very heavy avoid oscillation plus they very warm and eating around 15ma!
AnthonyAsh said:
😱
The AD811 is a current-feedback op-amp.
This means you can't use it as a drop-in replacement there.
Current-feedback op-amps have recommended resistor values for feedback, and they can't take a cap across the feedback resistor.
So, to summarize, it CAN be made to work as I/V on your player (and a very good one), but you would have to make drastic mods on the I/V and output stage (if more gain is needed).
The AD811 on your player, as you are using it, is oscillating like hell.
AnthonyAsh said:
Cool! I'm very happy with them!
How'd you recommend I bypass them? At the 627s' pins directly?
SimontY said:
Simon, that's a really excellent description of the 627!🙂 BTW I'm really enjoying the OPA637s in combination with AD797s in my phono stage. There seems to be some real magic to the 627s/637s; they provide the fullness and body that is so often eludes op-amp based gear. I look forward to trying them with some proper bypassing.
Edit:
Simon, I would indeed recommend placing the caps right on the pins of each of the individual op-amps. Just my two cents.
SimontY said:
Very simple and works fine:
Low ESR electrolyt cap (Oscon or BG-PK)+polypropylen 0.1uF between + and - .I use BG-PK 10uFx50v+0,1uFx100v BC Components with great result.Just make sure pins will be shorter as possible.
Upupa Epops said:Which solutions and components don't give great results ?
High- ESR electrolitics.Ceramic capacitors.
Upupa Epops said:What is " high value " of ESR ? Which type of ceramic capacitors ?
You want more info than I can give you.TOP SECRET🙂
now, i went ahead and made a fool of myself again, it turns out i ordered opa227, and not the 627 as i was supposed to!
now, i agree that the 134 sounds better than the 604, wich in turn sound a lot better than the 227.
the 637's justy made a load of noise when i tried them.
oh well..
now, i agree that the 134 sounds better than the 604, wich in turn sound a lot better than the 227.
the 637's justy made a load of noise when i tried them.
oh well..
Upupa Epops said:
Yes,it is another reason! Whatever I will write you will tell it is ****.That is the reason.That is way it is top secret🙂
Gaucho said:
Simon, that's a really excellent description of the 627!🙂 BTW I'm really enjoying the OPA637s in combination with AD797s in my phono stage. There seems to be some real magic to the 627s/637s; they provide the fullness and body that is so often eludes op-amp based gear. I look forward to trying them with some proper bypassing.
Edit:
Simon, I would indeed recommend placing the caps right on the pins of each of the individual op-amps. Just my two cents.
😎
Early days yet, but I love these things already! The cost had put me off previously, plus the bother of making boards or sourcing adaptors... Thankfully there are those that can solder well for money and sort it out for you! 😀
AnthonyAsh said:
Thanks. Currently I have 33uF Pany FC under my sockets with ultra short leads, but due to the brown dog things and such, there is still distance.
I will find soldering 3 component leads to each pin too challenging I fear, so I don't think I can follow your advice to the letter. I'll do something tho! 😀
Do these things have a similar character as pre-amp gain stages too? I've just started using a pre-amp very recently, which is a Rod Elliot thing with pcbs. It has OPA2134, which I'll remove and replace with sockets... and do this all again 😀
And as a side-note, I'm hearing amazing new detail in spite of having an additional pre-amp and associated wiring inbetween CDP and power amp! Says a lot about the 627.
Upupa Epops said:
I'm very like your behaviour,whatever discussion takes place,you are in opposition.Very specific way for spending free time?
It is better to use a fast OP like AD825/826 in I/V stage and good /warm sounding OP-s like OPA627 in filter/out stage ?
Or opposite?
Or opposite?
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