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Need suggestion on tube amplifier with XLR inputs

I am looking for a two channel tube amplifier (not sure of the wattage I will need as I am not 100% sure how the wattage correlates to transistor wattage so I will need a recommendation on this as well). My current set up is as follows: Emotiva DMC-1 Pre-amp/processor, Behringer cross-over, Emotiva XPA-5 (5 channel amplifier) and a Krell KSA-250 (2 channel amplifier) I have them connected via XLR cables throughout. I use the Krell to power my two JL-Audio 13W7 subs. I use the XPA-5 to run all other speakers at this time. What I would like to do is purchase a 2 channel Tube amplifier to run my center channel speakers as these are responsible for most of the mids/highs and use the 5 channel XPA-5 to run the surround speakers. My thought is that the center is responsible for most of the sound in a 5.2 system anyway so if I were to put my money on adding quality sound this would be the spot to do it. I need a two channel as I would like to run my tweeter on a separate channel then the mids so as to isolate each signal through the cross-over to have more granularities in tuning each of them. My tweeter has a speaker efficiency of 106 db and my mids are 87 db. If I run them through the same channel the tweeter will obviously overwhelm the mids and does as I have tried this already. So my question is, what 2 channel tube amp would you recommend that would drive 3 4” midrange drivers on one channel and then on the other drive 2 tweeters? I think I need something that would equal around 200 transistor type watts per channel as that is what the other surround speakers have running to them. I thank you in advance for any and all advice!

P.S. I would like to keep the cost under $3000 and am perfectly fine with purchasing used equipment. Thanks again!
ectomorph81

Showing 6 responses by atmasphere

atmasphere's avatar
atmasphere
11,575 posts
 
It sounds like you ideally you'd like a pair of amps that have lots of power on one channel, and just a little on the other -so you can run the high power on the mids, and the low power on the tweeter?
atmasphere's avatar
atmasphere
11,575 posts
 
If you have 3 midrange drivers in each channel I would put them in series since you have an electronic crossover- that will make them easier for a tube amp to drive.

However Jim and Spencer are both making good points- getting the system to blend and work together as a unit is likely your biggest challenge.
atmasphere's avatar
atmasphere
11,575 posts
 
What is the cutoff frequency of the sub? That will make a big difference as to how much power the mids will need. Can you rearrange the drivers in that box so that they are in series?
atmasphere's avatar
atmasphere
11,575 posts
 
Mello, there are not a lot of low power balanced amps out there. Our S-30 is likely one of the few, but it is a stereo amplifier, so you would have to accommodate that if that is how you proceeded. It might be easier to get some smaller amp since the tweeter only needs a couple of watts, and run the amp using half of the balanced signal, while loading the other half so that the balanced operation is maintained.

The midrange is going to need more power- 60 watts might actually be enough, depending on the room. As a side note, I would also try operating the tweeter off of the midrange amp, using an attenuator to reduce its level. You may find it sounds better- electronic crossovers often rob the system of detail.
atmasphere's avatar
atmasphere
11,575 posts
 
Attenuator- L-pad, in this case.

Electronic crossovers really work well for getting more sound pressure, but its debatable whether they help sound quality. Some speakers are of such disparate design that sometimes there is no other way.

In this case if you don't use an electronic crossover the amp that you use for the midrange will have to play the bass as well, so that amp will not likely be able to play nearly as loud. Your tweeter is so much more efficient that you can drive it as an afterthought by any amplifier that can drive the mids. Does your crossover have a balanced output for the midrange amplifier? Can it be set up as a two-way?
atmasphere's avatar
atmasphere
11,575 posts
 
I've yet to see any amplifier that is low power on one side and high on the other.

We make a stereo 30/w channel amp called the S-30 and a several monoblocks. If you put the mids all in series our smallest monoblock, the M-60, may well make enough power to do the job- about 80 watts per channel.

Both have true balanced inputs. The S-30 may well be the lowest power tube amp to feature true balanced inputs.
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