[chzplz]

Hi all-

Standard newbie here with standard newbie-type question: I've been reading about all the fun people are having "opamp rolling. What's an opamp? Are they only in SS amps? How does one know if an amp is opamp-rollable? I've got a Little Dot Mk IVSE and a Lisa III - are either opamp rollable? (I just got the Lisa III and am in love, not sure I'd want to mess with it even if I could, but still curious).

More: Assuming I have the option of opamp rolling either of my amps, or if I get one in the future that's opamp rollable, where does one find opamps & what's a typical price range? Are there "vintage" opamps like there are with tubes? And finally, when done right, does opamp rolling produce major "wow" type improvements in SQ, or is it more subtle?

Thanks

Ira

 

[aaron313]

Opamp is short for operational amplifier. There are many types and uses of such a device.

Try wikipedia, and if you have basic math skills you can understand how they work.

 

[chzplz]

Quote:

Originally Posted by aaron313 /img/forum/go_quote.gif Opamp is short for operational amplifier. There are many types and uses of such a device. Try wikipedia, and if you have basic math skills you can understand how they work.

Thanks, I'll look it up, but in the meantime, one more question: why do some say that audio purists look down on opamps (I forget where I read that)?

Ira

 

[richardu]

One has to be careful how one uses op-amps. They are operational amplifiers, not hi-fi audio amplifiers. They can distort the signal in ways which are acoustically bad, but fine in normal op-amp applications. There are some op-amps which are better suited to audio use than others, so the important thing is that a the op-amp has been chosen carefully.

There are op-amps using valves, but these would never be used for audio, as it is easier to design without. Op-amps are used in solid state mainly as they come ready made in ICs and the design is simple.

There are thousands of types available, with prices starting at a few cents each, and going up from there.

 

[eeerie1]

check this out....

 

[aaron313]

^

Heh, I have a printout of that. Actually, it's quite useful. If anyone really wants to learn microelectronics, pick up some used textbooks by Millman. My circuit theory book was crap, so I used the other books. Not an EE, so I didn't give a damn much at the time. Actually, another good reference is by, *gasp,* Bose, of MIT. He used to teach circuit theory, and his course notes are not bad. (But good luck finding them. You could probably buy a copy for $500 or something like that

)

 

[dgbiker1]

The LD MkIV is most definitely not opamp rollable since it's a tube amp. The tubes (which can be tube rolled) are performing the function of the opamp.