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aginhouse

Pro's and Cons - Pro Amp for 2 channel?

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Owning 2 Pioneer SC-1222k receivers (98% of the SC-63 but minus the Elite overhead) and I like the sound better than several DACS and pre-amps going into my Crown XTI-1000. The highs in the XTI will be a little harsher but YMMV. Matching to the pre-outs on the SC-63 will be an issue also for almost any pro amp. The SC Series Pioneer are excellent when run in direct mode STEREO, especially bi-amped.

But Hey, have fun. Just don't blow anything up.

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I don't see any pro to a pro amp with two channel, unless it's free. For similar money there are good choices a plenty for decent power. I just sold a very powerful pro amp, it had plenty power but just not the same finesse as even some mediocre SS's amps. It was not top of the line but a very well known brand. Pro gear is best used in that application for my money, but that's just for me. I know others like em' and that's great, always best to audition then decide.

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best to audition then decide.

[Y]From my experience I think you'll be surprised at how good some pro-amps do in a direct comparison. Some....not all.

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Gents,thank you for all the responses. I had to run out of town for the weekend and was pleasantly surprised to see all the responses. I

'll give the old mans DC300A a shot and see if I can hear a discernible difference. If so I will have a whole nother arena to start exploring. I am just not sold yet that the addt'l power will make a marked improvement in such a small room.

I'll report back. Thanks again

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I am running a Klipsch MCM-3 Grand speaker system with Klipsch 684 subs......and so I have HF, MF, LF, and subs. I am using a digital processor that is an active crossover and so I have 4 amps, for the channels mentioned.

I use some old McIntosh home audio MC-250 and MC-2100 rebuilds from the 70s........and brand new purchased QSC PLX2 1104 and 1804 pro amps. I have had this equipment now for quite some time, a few years.

I would agree with some of the posters here that the QSCs sound good, clean, powerful..........but they disappointed me in direct comparisons to the home audio amps as far as micro-detail, and clarity on the high and mid frequency drivers. They are good.........but nowhere near as good as a nice home audio amp, even a 40+ year old rebuild. I relegated them to bass and sub duty where they shine for their clean power.

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Ok Gents, I hooked up the DC300A for a listen. After going back and forth I noticed a couple things

1. first and foremost I lost about 5db off the same song on the same volume setting. This is based of the readings from my SPL. Not sure it means anything in the whole scheme but I thought it interesting because this is exactly opposite of what I had expected.

2. The instruments on a good recording sound more defined and there is greater separation with the Crown in line. Much better low end. Much more feasable to have a good true 2 channel set up minus the subs.

3. I seem to loose a good portion(or all) of the acoustic calibrations for my room. This is bad because the room is very loud. I will eventually install media curtains and more furniture, but currently its just bare walls, speakers and my leather chair.

I welcome your feed back on this. Why would the sound output be lower then without the amp?.....is it due to a low line out level from my receiver? If I went with an amp line something from Emotiva or Outlaw Audio, built form home use, would it have the same result? Would they be more sensitive to the output from my receiver?

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The SC 63 has discrete amps and good room correction. Not to have good room correction is a step in the wrong direction in this day and age. Excessive power is just unused power. I would not get of my SC 35 for a pro amp IMHO. The beauty of this hobby is that there are so many options to fit everone's taste. The RF 7's do not need more than 200 watts. I would think the SC 63 is smilar to the SC 35, 140 watts/ch, that can swing close to 300 watts with a 4 ohm load.

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Your drop in volume with the power amp is due to the weak signal out the Pioneer's pre-outs. I also have a Rotel RB991, which is designed for the home. The signal is weak with that amp as well.

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Your drop in volume with the power amp is due to the weak signal out the Pioneer's pre-outs. I also have a Rotel RB991, which is designed for the home. The signal is weak with that amp as well.

Shiva, I take from your response that the Rotel is running from the Elite's pre out like I was trying? Were the room corrections sustained or do you feel like you lost them?

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Yes, I was running the Rotel off of the Pioneer's Pre-outs and the room correction did not work as it should. With either the Rotel or Crown, when running the Mcacc it would bump up the volume to plus 12 for the mains, which is as high as it would go and it still did not equal the volume of the center channel. If I wanted it to work and I did, I had to do a little research which led me to find out that the pre-out signal on the Pioneer was weak and to an item called the ART cleanbox pro. Once i installed it and set the gain halfway on it and reran Mcacc it set the mains at -4 compared to +12 as before. I have been using it ever since. On another note adding that unit did introduce a ground loop hum, which I had to eliminate as well. That one desire to add a pro amp did branch out into a few extra steps.

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Basically, it sounds like you ran into an incompatibility between home and pro audio components.......which is pretty common. Levels and impedance mismatches. Then, you need to fix it with the cleanbox which just adds more distortion. A bummer all around.

For instance, I could never get my Peach preamp to work properly with any pro amp or processor. Just a characteristic of the design. Mated with almost any home audio amp, it plays perfectly.

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Thats what Im afraid of.....for me, I think I need to make a basic decision going forward. Work with the receiver, which is very ample for the time being. Or, just decide that I am going to have to make a move to a pre amp/amp combo.......

Is anyone aware of any pre amps that offer airplay and MCACC diagnostics?(I much prefer MCACC over Audssey)

While the separate amp did define the speakers better, Im not sure it was worth headache of what i may be running into. That being said, I may have no choice once I run my full 7.2 setup. That will be a lot of strain for the receiver.

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I would not become disheartened. Its just a little bit of problem solving. If you already have a pair of XLR cables all you need to do is try out the Art for instance which can be had for about $60 on Amazon and returned as well if you don't like it. If it works and you notice the improvement, you are good to go and then you have an amp that will never run out of gas. I know that my Epics though efficient can also seem demanding for an amplifier at times. Mainly, just for fun , I now have 500 watts a side at 8ohms going into a my Epics, which can handle 250 wattts continuous with 1000 watt peaks. For me, it was just something fun to do and it required working the problem awhile until solved.

Enjoy.

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That will be a lot of strain for the receiver.

How so? Are you at least confirming voltages with a multimeter?

This is why using a meter to measure voltage is so critical. If MCACC is applying DSP only to its internal amp, then what you "hear" when using the Crown is unprocessed signal....ie. the raw room response.

Without a waterfall plot comparison to tell you what has changed response-wise, the subjective comparison becomes not between amps, but between non-related factors. [N]

If the intent is to run 7.2 correctly, then all the channels get high-passed. When that happens, amplifier requirements drop substantially.

I have my mains high-passed at 100 Hz and they will never see my AVR's full rated output at 24.5 volts. In fact, at wide open throttle (-0 dB REF and 105 dB SPL at the listening position) they only see a single volt or two. You're RF's would see only 3-4 volts max.

That's still peanuts for an AVR...even with all channels driven.

Throw a power amp into the equation, and now you're totally missing out on the best feature of the SC, the D3 signal path.

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That will be a lot of strain for the receiver.

How so? Are you at least confirming voltages with a multimeter?

This is why using a meter to measure voltage is so critical. If MCACC is applying DSP only to its internal amp, then what you "hear" when using the Crown is unprocessed signal....ie. the raw room response.

Without a waterfall plot comparison to tell you what has changed response-wise, the subjective comparison becomes not between amps, but between non-related factors. No

If the intent is to run 7.2 correctly, then all the channels get high-passed. When that happens, amplifier requirements drop substantially.

I have my mains high-passed at 100 Hz and they will never see my AVR's full rated output at 24.5 volts. In fact, at wide open throttle (-0 dB REF and 105 dB SPL at the listening position) they only see a single volt or two. You're RF's would see only 3-4 volts max.

That's still peanuts for an AVR...even with all channels driven.

Throw a power amp into the equation, and now you're totally missing out on the best feature of the SC, the D3 signal path.

You make a great point about something I had not thought of prior. For a theater application I will have all speakers crossed for small and the subs will be doing the heavy lifting.

As long as I have speakers set and crossed for THX then I should be fine........

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I have my mains high-passed at 100 Hz and they will never see my AVR's full rated output at 24.5 volts. In fact, at wide open throttle (-0 dB REF and 105 dB SPL at the listening position) they only see a single volt or two. You're RF's would see only 3-4 volts max.

This is so true! Setting speakers to small or in the case of Pioneer's quasi bass management, even setting some speakers to large with a xo above 60 Hz relieves the avr of a lot of it's power demands.

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Reviving this slightly older thread because I find myself stuck in the middle of two worlds. I'm building these Cornscala DBB's and struggling to find an appropriate consumer integrated amp that will deliver enough power to drive 2x15" woofers @ 3 ohms per channel. Something like the QSC PLX1802 will deliver more than enough power, but then I need to find a suitable pre-amp and deal with any of the potential issues already mentioned early when one tries to use pro gear in a 2-channel home setup. I've asked a few guys here as well as on AK (likely to the point of being annoying) and the suggestions range from low power SET tubes to vintage SS to modern SS with as many people saying it'll be just fine as there are those saying i run the risk of damaging amps and/or speakers.



How does one make an educated choice with so many options and opinions? I don't have the cash to amp-roll, but I can certainly spend a fair amount once ($2k for amp/preamp or integrated)

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What you need isn't wattage, but CURRENT. At 3 ohms, you want an amplifier that will supply sufficient current without overheating AND have a high enough damping factor to control the woofers well.

Everything that follows is my humble opinion:

Get an amplifier capable of a minimum of 200 watts (more is better)

Get an amplifier with LOTS of power supply capacitance (you'll have to check the specs)

Get an amplifier with LOTS of output transistors (more is better)

Any amplifier that meets the above criteria should be already rated for 4-ohm loads.

I like Emotiva amps - they come with a 30-day return option, they meet the above criteria, and I've used them before with low impedance speakers with tough crossover phase angles and the amps not only provided tight bass but also did so while sounding good and running cool.

Happy shopping.

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A Pro amp with speakon's should work. The speakon's are $4.00 and something from Parts Express. Beside fan noise, no real down side in trying them. I recently got a Berhinger and like the light weight compared to a 40-50 lb amp for the same or more power.

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Good info, and it helps me understand a little better what it is that I need to be looking for. I see now why so many electrical engineers flock to either HiFi or HAM (or both) as their hobbies.

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