Here are some FAQs that people have been asking me.
Do you do custom work?
Currently I am not accepting new custom build orders (2/22/2009) but I may again in the future on a limited basis. I am attempting to meet need via the pre-build blog. If you have a feature set you’d like to see or a particular amp you’d like to see build then let me know and I’ll log it into a potential builds queue.
Can you finish/fix my DIY amp?
I do not do repair work on any amps other than Rockhopper Audio built amps. I'm sorry.
Can you fix/alter/upgrade an amp from another manufacturer?
I am not currently offering any services for non-Rockhopper Audio amps or components. I'm sorry.
Why haven't you answered my e-mail yet?
A good question and one deserving a good answer. This is a hobby job for me. It is not my main job. I do hold down a regular 8-5 job and I can't always answer e-mails when I'm there. I frequently deal with customer e-mails in the evening. I am committed to answering all e-mail within 48 hours. Please be patient. I promise I will get back to you.
How does amp X compare to amp Y?
I understand that you have questions about how amps stack up next to each other. Unfortunately I do not have a lot of time to answer those kinds of questions. Besides, do you really think I'm an impartial judge? I'm not about to tell you to go buy someone else's amp now am I. There are some great communities of people who love to figh...er, discuss the merits of various different headphone amplifiers. Head-Fi.org has a wealth of information and so does Head-Case.org and Headwize.com. I recommend you search there. Besides there is a very good chance that I have not heard the amp you want me to compare. While I have spent time with many headphone amps, the only ones I've spent significant time with are the ones I've built. I like the amps I build and use them every day, so I'm not just building these to build them; I believe in them as well.
I read that Amp X only costs $X to build and yet you charge $Y? Why should I buy it from you when it can be built for less.
The short answer is because I am building it, testing it and making sure it works properly. I also source all the parts for the build as well. I'm also offering a warranty on it and customer service. All these things cost money. Sure you can build it for less, and if that's your inclination then go for it! It's incredibly rewarding when your first working amp fires up and you get to listen to it. I highly recommend it.
Can I buy a kit or some parts from you?
I'm sorry but I'm not offering kits or parts right now.
What's the difference between the OPA627 and the AD8610/20?
Here is a thumbnail sketch of the what I think are the main differences between the two:
OPA627/637:
The OPA627/637 is a great Op amp with a full soundstage and rich mids and bass. There is a certain detail that is lacking in the AD8610/20 when compared to the OPA627. The OPA637 is a higher bandwidth version of the OPA627 so the 637 has a slightly snappier sound, but still retains that laid-back sound, just not as laid-back. The issue with the OPA637 is that it requires a higher gain (at least 8) where the OPA627 is unity gain stable (1). If you are going to use this amp with high impedance cans (like the Senns) then that won't be a problem, however, a higher gain with low impedance cans means you can't use as much of the volume pot. This is less than ideal since the better tracking on pots generally occurs in the middle of its sweep.
AD8610/20:
The AD8610/20 are also great Op amps. They aren't as smooth as the 627/637 but that's not to say that they are harsh. The bass is tight and fast with detailed mids and highs. Some have said that there is a certain warmth to the mid-range over the OPA627/637. Overall, they aren't as warm and rich as the OPA627/637 IMHO. I would not recommend this with a setup that is already aggressive/detailed... it might be a bit too much. In an overly aggressive system these can come off as a bit harsh. If your setup is more laid-back then these would liven it up a bit.
Can I get a blue/red/green LED on my amp/power supply?
NO! What's wrong with orange? Ok, here it is: My favorite color is orange which is why I like the Rockhopper penguin so much (orange feather on their heads) ergo, that's why I choose orange LEDS for my products. I'm reminded of what the spec sheet for Pete Millett's Wheatfield HA-2 amp said, "This isn't really high-end HI-FI equipment: No Blue LEDS." Besides what other company uses orange LEDS.....huh? what's that? NO ONE!!!!!** That's why I use orange. Some people say that orange LEDs are tacky or ugly....well I feel the same way about blue...so to each their own I guess. No offense of course :)
**OK, Headroom uses them on their Max line of amps, so you'll be in good company with an amp that has an orange LED.