OT: Please help select studio monitoring amp

Hi people,

transplant from P5 forum here. Even though the topic is not exactly related to Sonar, I feel that there is a lot of knowledge on this forum to answer my questions, so I hope you'll pardon my OT here.

Here is my situation - I had Hafler TA1600 (http://www.hafler.com/techsupport/pdf/TA1100_TA1600_datasheet.pdf) power amp running into KRK ST6 passive monitors for some time now. As of two days the TA1600 decided to to quit on me. I thought I just run to my local GC and pick some similar amp up. Silly me - the world had gone all active and I get those funny looks when I say I need a power amp of 100W per channel. In short I don't see any obvious option right away, but I am not ready to abandon my ST6s yet.

My local GC has Mackie FR800 (http://www.mackie.com/products/frseries/) 205W x 2 @ 8 Ohms. I found few interesting ones online - Samson Servo 300 (http://www.samsontech.com/products/productpage.cfm?prodID=1851&brandID=2) 100W x 2 @ 8 Ohms and Alesis RA300 (http://www.alesis.com/ra300#) 90W x 2 @ 8 Ohms.

My TA1600 was 60W x 2 @ 8 Ohms, which was a bit underpowered for ST6, so bottom end was bit weaker. ST6 is 8 Ohms and rated 100W RMS.

With this I have several questions:

1. I am leaning towards Mackie FR800, but I am worried about 205W mismatch to 100W of ST6 - if I run FR800 at volume 5 instead of 10, would there be serious side effects?

2. In general should I try to match the power of a speaker to the rating of an amp exactly? The 'net suggests that there can be some fuzzyness, 10%-20%, perhaps. Is that true?

3. I read that RA300 has some design falws in its power supply and lets some power line transients to propagate all the way to the speaker - does anyone have any more specific information on this?

4. Any opinions about Servo 300?


Thank you in advance.

Thanks Fog. Cool amp - it might a bit underpowered though.

ORIGINAL: rcross


Hi people,

transplant from P5 forum here. Even though the topic is not exactly related to Sonar, I feel that there is a lot of knowledge on this forum to answer my questions, so I hope you'll pardon my OT here.

Here is my situation - I had Hafler TA1600 (http://www.hafler.com/techsupport/pdf/TA1100_TA1600_datasheet.pdf) power amp running into KRK ST6 passive monitors for some time now. As of two days the TA1600 decided to to quit on me. I thought I just run to my local GC and pick some similar amp up. Silly me - the world had gone all active and I get those funny looks when I say I need a power amp of 100W per channel. In short I don't see any obvious option right away, but I am not ready to abandon my ST6s yet.

My local GC has Mackie FR800 (http://www.mackie.com/products/frseries/) 205W x 2 @ 8 Ohms. I found few interesting ones online - Samson Servo 300 (http://www.samsontech.com/products/productpage.cfm?prodID=1851&brandID=2) 100W x 2 @ 8 Ohms and Alesis RA300 (http://www.alesis.com/ra300#) 90W x 2 @ 8 Ohms.

My TA1600 was 60W x 2 @ 8 Ohms, which was a bit underpowered for ST6, so bottom end was bit weaker. ST6 is 8 Ohms and rated 100W RMS.

With this I have several questions:

1. I am leaning towards Mackie FR800, but I am worried about 205W mismatch to 100W of ST6 - if I run FR800 at volume 5 instead of 10, would there be serious side effects?

2. In general should I try to match the power of a speaker to the rating of an amp exactly? The 'net suggests that there can be some fuzzyness, 10%-20%, perhaps. Is that true?

3. I read that RA300 has some design falws in its power supply and lets some power line transients to propagate all the way to the speaker - does anyone have any more specific information on this?

4. Any opinions about Servo 300?


Thank you in advance.

The basic idea with amps is that you don't want to have to turn it up more then 3/4 of the way if you can avoid it. I like to have a amp big enough so I can get the volume I need with half or less of it's power. It has nothing to do with how the speaker or amp is rated in watts, you can't rely on those numbers. A big amp is always good to have even if the speakers could easily be blown by it if you turned it up too loud. The old rule "don't do that" applies here. You can tell when speakers are in trouble you don't need a meter, if you need louder get speakers designed for that volume level.

There are lots of variables here, including what you are listening to... as in how dynamic are the peaks, how much clipping is already in the content (like modern CDs), speaker design, ohm load, etc. You can't just look at some specs and say... "OK, that will be safe no matter what". You can even burn out speakers rated at much higher wattage then the amp if you run the amp wide open and the amp starts clipping. It's up to you to manage that gain stage just like all the other ones in the studio.

For what it's worth I have the Alesis RA500 and I have not had any power related problems even in a 1962 house in a hood with power problems. Sounds good and clean and has no fan making noise of it's own... good studio amp.

What's your price-range?

Haflers are GREAT amps. They appear on ebay rather regularly,, why not get another?. There are a lot of choices in the market but PA grade gear would be a step down

Hmmmm, I'm afraid $300 won't get you much amp, even used. I'll let you know if anything comes to mind.

It'll be tough but not necessarily impossible.

And you are right about "meaning different things to different people". A lot depends on: the size of your room and how much damping, whether you are operating a paying studio, the type of music being done, and the highest sound level (SPL) that you will listen at. If you could evaluate those and let us know, we can likely better help you. Also, what is the Impedence of your KRK's?

ORIGINAL: rcross

ORIGINAL: SteveJL

A lot depends on: the size of your room and how much damping, whether you are operating a paying studio, the type of music being done, and the highest sound level (SPL) that you will listen at. If you could evaluate those and let us know, we can likely better help you. Also, what is the Impedence of your KRK's?

In a word this is for a bedroom studio - the room is almost square 15'x15' (10' ceiling). Music is a mix of electronica and rock. No idea about SPL, but I tend to use rather moderate sound levels, where I can clearly hear and talk to other people in the room wihtout shouting.

KRKs are 8 Ohm.

OK, yeah, I can see where a 60 w/ch amp would suffice.

Samsons are quiet, not a lot of color involved but tend to fail.

I went thru two before abandoning them altogether, that being said I have also fried a mackie or two in my day.

(Heat is a killer and I keep the amps away from the control room, my bad but hey whatever)

Haflers are great amps once you get in the 200 watt range...

And I am still of the mindset that I'd rather keep my analog path within my control, a lot of the powered speakers don't give me the control I want...

I suppose a lot of it depends on HOW you use speakers in a monitoring situation, we use exclusively prototype D/A converters that are outboard and separate, and we do have a set of the HR824's that we use in on of the rooms, I like to keep the analog listening path as a separate element, so we use Wolfson converter chips, a clean amp, and three sets of small monitors (NS10's some Tannoys and Alesis Monitor Ones-the OLD ones) that we switch thru.

The BIGGEST difference by far we have found is the D to A conversion, it makes a huge freaking difference in how your files hit the speakers, after that we found the amp is the next biggest culprit in color, but color isn't always a bad thing, if you know what color your color is.

Our main tracking room uses some KRK powered speakers that for the general use sound ok (we A/B them between the HR 824's and some Yamaha's), with a sub.

Mix down is a different story, its all outboard D to A and carefully tuned/amp speakers.

Most high end mixing/mastering places use high end custom, like Sterling Sound or believe it or not JBL , (with something like Quested Amps...)

First of all thank you for all the replies. I helped me forming a better opinion.

Now for the really interesting part - turns out the amp did not go bad. Some other piece of equipment went bad and started poluting ground circuit, which made the amp go nuts.

It all started a month or so ago, where the amp would make short bursts of crackly/buzzy noise. It wasn't 60Hz hum, probably some harmonic of 60Hz, but there was clear random noise component to it, such that I did not take it for the hum. Then over following weeks the bursts became more frequent, and finally became one continuos stream of buzzing/crackling.

Fast forward to yesterday. Just for kicks I had plugged the amp into different power circuit and no buzzing. Plug back into the original - buzzing comes back. Plug the amp into original circuit with power ground lifted - no buzzing.

Unfortunatelly I did this after disassembling the poor thing like five times and checking various components for failure. Now I only need to find the other faulty piece of equipment.