[jaredtkatz]

Hi,

I just purchased a pair of Sennheiser HD 25-1 II and I thought they might benefit from an amp, so I got the iBasso D2 Boa. I have ABSOLUTELY NO KNOWLEDGE of portable amps, despite how much research I have conducted. From my understanding, these are portable devices that will enhance the sound from a source (I will be using USB from my laptop or a LOD from my iPhone) and send the signal to the headphones. While I may have exaggerated about my limited knowledge, I still want to understand more about these amps such as the one I just bought, if they can/should be modified, and if the one I chose is suitable for the Senn HD 25-1 II i got.

For example, what the hell is "opamp rolling"? Does this refer to changing the op amps in the portable amp? Is this easy? Can I do it without destroying the amp? Is it worth it?

Is an amp even a worthwhile purchase?

I downloaded all of my favorite albums in lossless formats which sound great, but I want to know if the amp will be worth the 187 I spent on it.

Any knowledge you think I should have on this topic, please fire away.
I want to get the best out of my audio experience.

Thanks in advance

 

[billybob_jcv]

I'm gonna put it right back in your lap - you have the amp and 'phones - how does it sound on your favorite songs with & without the amp? What we think is really irrelevant - tell us what you hear!

 

[jaredtkatz]

touche, but i don't have either yet. I'll have both on tuesday, so i'll share my thoughts then. Until then, please explain any background knowledge on portable amps.

thanks

 

[billybob_jcv]

OK - I'll do my part, here's a bit on "op-amp rolling"...

The heart of most solid state headphone amps is an IC called an operational amplifier (op-amp). It's job is to take an input signal and amplify it into a signal with a higher magnitude (or something like that...). The op-amps used for audio typically each have their own "flavor" or "color" that they impart on the signal - in other words, they may sound a bit different. That, together with the rest of the components and the specific circuit used by the amp, lead to a specific sound signature for the entire amp. Lucky for us, many op-amps are actually pin compatible with each other - and sometimes they can be interchanged within a given circuit. If the amp also has the op-amps in sockets (instead of soldered directly to the board), the op-amps can be swapped to give the amp a slightly different sound. Some amps make note of that specific feature as a selling point for us anal head-fiers. That, in an over-simplistic and I'm sure, completely non-hardcore audio geek nutshell, is op-amp rolling...

 

[Nubster]

So it is the solid state version of tube rolling?

 

[DunninLA]

Noobies should not get too involved into opamp rolling unless you have a lot of spare time to just do it for fun.. the marginal increases in listening satisfaction will come from, in order:

- Heaqdphones sound qaulity match to your ear
- DAP sound quality
- whether you use an amp or not

 

[DunninLA]

Quote:

Originally Posted by Nubster /img/forum/go_quote.gif So it is the solid state version of tube rolling?

Yes, but much less variance one to another than in tubes.

It is equivalent to the SQ differences found between different cables in revealing home systems (silver vs. copper and variations within each style).

 

[billybob_jcv]

IMHO the difference amp model-to-amp model is much greater than the chip-to-chip difference using the same amp, and the difference headphone model-to-headphone model is typically greater than amp-to-amp with the same 'phones.

I also agree that opamp rolling is probably not something a noob should worry about - other than to identify when a head-fier's review is heading down a path he probably shouldn't worry about...