Choosing the correct power amp for my passive monitors, as well as cabling

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Member Since: May 24, 2011

Hello all! :D

I'm new to the forums as well as passive monitors. I have a couple of KRK Rokit R6 passive monitors in my possession and wondered how I know what power amp I should be using.

www.krksys.com/krk-studio-monitor-speakers/r6.html

According to the spec here, 50-150W (8 Ohms) for amplification. Would an Alesis RA-150 be powerful enough?

www.alesis.com/ra150

Or perhaps the 300?

www.alesis.com/ra300

My next question would be, what kind of wiring can I use here? And connections? Is it usually required that I do the wiring myself or can I purchase a polarised wire ready with a banana plug for the monitor end and connections for the amp?

A lot of questions here from a total noob - any help and/or advice would be much appreciated!

Thanks guys

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Administrator
Since: Apr 03, 2002


May 24, 2011 12:47 pm

Welcome to HRC.

I used the smaller Alesis for a long time, it'd do the job more than effectively...

Member
Since: May 24, 2011


May 24, 2011 01:46 pm

Thanks very much :)

Any advice on the best cables to use for that and where to get them online?


Administrator
Since: Apr 03, 2002


May 24, 2011 01:47 pm

if you can use banana plugs do it, and get heavy gauge wire...where to get them, couldn't tell ya, I usually make my own.

Member
Since: May 24, 2011


May 24, 2011 02:01 pm

Cool! Also I noticed that the smaller Alesis has 150W RMS for 8 Ohms bridged - per channel however, for 8 Ohms is only 45W.

The spec for the monitors states that between 50-150W per channel at 8 Ohms is required which would seem to make that amp under powered for these monitors. Sorry to be picky, just wanna make sure I understand :p


Byte-Mixer
Member
Since: Dec 04, 2007


May 24, 2011 02:01 pm

Yeah, rule of thumb is to have more wattage available to the speakers than what the speakers require. I'm running my Reveal 6's (think they're rated 60 or 70W) off my ART SLA-1, which is 100W per channel, and the amp has 2 channels. If the amp supplies less wattage than what the speaker can handle, you could end up driving the amp too hard, and blow either the amp or the speaker.

The R6 appears to handle 100W @ 8ohm, so you'll want an amp that can give at least 100W @ 8 ohm. The 50-150W @ 8 ohm is the recommended amp spec, but I think 50W is too low, so go with something with 100W per channel.

I went through the exact same amp decision process a few years ago when I got everything, and I did a -lot- of reading on the subject. Here, other forums, and just other info in general. Read reviews on different amps and such, and finally settled on my ART.

For some reason I didn't really like the Alesis amps. I didn't think the wattage was enough, etc. So I was looking heavily at the ART SLA-1, and the Samson Servo 300, both which supply enough wattage. But they are a little more expensive than the RA150 at around $270-ish. Course you might find one on the cheap somewhere.

I also always heard good things about QSC and Crown amps, but they were always too rich for my blood, and way overkill for what I needed.

For wiring, I just had a role of speaker cable that I attached banana plus. I think the gauge I got was 14 gauge, but I don't quite remember. 12 gauge might be better. Rob would be the one to answer any questions about wiring stuff up, gauges, wattage, stuff to consider if you end up bridging, etc. I just got that stuff at radio shack.

Actually Rob would also be the one to ask about the amps/speakers specs, wattage vs. resistance, etc. etc. I think I got the gist of it written though.

Member
Since: May 24, 2011


May 24, 2011 02:19 pm

This has been very helpful overall - and I can already tell I'm gonna like these forums. Thanks guys :)

I think the minimum gauge to preserve decent quality is 14 for the wiring yeah

MASSIVE Mastering, LLC
Member
Since: Aug 05, 2008


May 24, 2011 07:48 pm

emotiva.com/upa2.shtm --- Cheap - but freakishly decent stuff.

Member
Since: May 24, 2011


May 25, 2011 06:59 am

That looks really good for the price - however I'm finding it hard to find any testimonials from it being used for anything other than a home hi fi system rack.

Probably not searching hard enough!

MASSIVE Mastering, LLC
Member
Since: Aug 05, 2008


May 25, 2011 09:05 am

It is a hi-fi amp. That's the point.

And (for clarity) I don't mean "hi-fi" like "Best Buy" home theater - I mean actual high-fidelity, class A-A/B, high-current, high draw, ridiculously accurate and fast compared to a typical amplifier.

I'm using the bigger model (XPA2) as a substitute for my Pass Labs X250 while it goes in for service. And I have to say (I almost hate to say**), I can actually work with this thing. And that's saying something.

In any case -- High-fidelity gear ("real" high-fidelity gear) will generally kill just about anything that says "studio" on it as a rule of thumb. And the better studio gear is based on the better high-fidelity designs in the first place.




** When an $800 amp can actually put up a fight against a $6,000 amp without feeling a serious compromise, it must be a helluvan amp for $800...

Member
Since: May 24, 2011


May 26, 2011 01:31 pm

I hear ya - I'm at the very tip of the iceberg with this side of things and have already learned a lot from this forum alone - and thanks for the clarification

Uh, at least one more time . . .
Member
Since: Feb 07, 2007


May 27, 2011 11:35 pm

I'm using Adcom amps I got on E-bay--the GFA 535 amp. I picked it up for about $100.00 (including shipping). I'm using it because I've had another GFA 535 for about 20 years. It's my main "house" amp. I'd always heard (read) good things about Adcom, and I've always liked the sound of their amps and pre-amps. I figured that the Adcom amp and some decent passive speakers might be better than some cheapo active speakers (I mean, how good is the amp inside of a $400.00 set of active monitors? Or realistically, a $200.00 set?) I'm using an AdcomGTP-450 preamp for an interface/router--I'm going to pick up a PreSonus Central Station soon enough (on your advice, MM). Any thoughts on the Adcom stuff? Not to wander off the topic, but what's the breaking point? Where does one start getting the value in active/ passive monitor buys?

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