Looking for some thoughts on amplifier choice for Ohm Acoustic F-5015 speakers that I will be getting shortly. Would these sound better with a class D amp or a class AB amp?
I have some space restrictions (17 inch deep open wood shelving with a back wall) that are limiting my amp choices absent a furniture change and I don't want to do that unless totally "painted into a corner" John, the owner of Ohm told me that I should have at least 200 watts at 6 ohms to power the F-5015s. The powered subwoofers built into these speakers come with class D IcePower amps with line level inputs, so the amp that I obtain must have two line level subwoofer outputs.
The two units (2 line level subwoofer outputs, 200 watts around 6 ohms, less than 17 inches deep, don't run hot) that have come up in discussion with John and Evan at Ohm are the class D NAD M32 and the class AB Parasound Halo INT6. I have read that the INT6 doesn't run too hot, so it hopefully would be ok in a piece of wood furniture. After my discussion with Ohm, I saw that the class D Peachtree Nova 500 could possibly work based on the specifications, but can't seem to find any reviews on this higher power Peachtree amp. Another wild-card that would be much more expensive and offer higher power output would be the NAD M12/M22 v2 combo. I am aware that you likely get what you pay for and that the NAD systems are higher priced, especially the non-integrated combo.
Would appreciate your thoughts / amplifier guidance and any additional suggestions.
One qualification on my above post needed for teh f5015 case specifically is that I believe the f5015 has no subwoofer crossover controls on board in which case the crossover has to be done upstream somewhere and those particular amps JS recommended appear to in fact have the sub crossover adjustments and dual sub specific outputs (not just any line level) needed.
I heard the f5015s at capital Audiofest last year. John Strohbeen had them running off an Outlaw receiver somehow with some outboard device providing the needed crossover apparently. I would assume that Outlaw receiver had dual line level pre-amp outputs that fed an outboard pro audio type sub crossover unit of some sort....don’t recall the details. JS could probably tell you more if needed.
That type of setup using a separate subwoofer crossover unit with dual rca line level inputs and dual sub rca line level sub outputs would add some complexity but open up more amp possibilities, including pre-amps with a spare rca connector type line level output (the main pre-amp out would go to the power amp). For example the AudioResearch sp16 tube preamp I use has that and I use it to run a sub with a pair of KEf ls50s.
With an outboard crossover, one amp that comes to mind I have heard and really liked is the tube/Class D hybrid Rogue Pharoah. I think that has a "processor" line level output that could feed an external sub crossover.
Again, I would not make any big investment without running it by Ohm first just to make sure things can integrate properly.
Whatever amp you choose, those speakers should be the absolute bomb!
With separates, just keep in mind that every combo of amp and pre-amp will sound different as well. Tube or no tube.
The key attribute normally for the amp with at least any fully passive Ohms for best performance is high current delivery and damping factor. Class D amps or large bulky, heavy Class a or class a/b amps tend to fit that bill. Tube power amps need not apply IMHO unless one wants to relegate much of the bass to a separate subwoofer, which is uniquely inherent though in @michiganbuckeye's case with the F5015 model specifically.
I find tube amps or even SS amps that emulate tube amps with higher output impedance/damping factor are not ideal. The larger the OHM Walsh driver the less ideal in that bass will be fatter and less refined and articulate and that also tends to mask mid-range detail.
That’s not to say some might very much like the resulting sound, even if things are not all as optimized from a technical perspective.
In general, I find the tube pre-amp/Class D amp combo done well can be very cost effective and deliver that articulate bass as well as all the rest and makes for a sound that one can just sit and enjoy for hours on end.
Again, with the f5015, teh built in Class D amps will in fact handle the bass, so you can likely use most any amp SS or tube to good effect as long as the setup provides the dual line level outputs for sub. Having an active crossover on-board the amp to be able to refine the sub crossover characteristics as needed sounds like a huge advantage as well, which I suspect is why JS recommended those particular amps.
@mapman I have often thought that a tube pre-amp with a Class D amp might make a lot of sense. Conceptually it makes a lot of sense to me as opposed to a tube pre-amp with a tube-amp.. that always makes me wonder what flavor are you getting from the tubes? Plus I like bass, but I want it relatively tight.
@michiganbuckeye I would consider the 5000's neutral. Keep in mind the adjustments on the back do make a difference. For instance with my pass labs preamp and amp, I prefer the mids and treble in the (+) position (mid-bass and bass are left neutral). For a while I had a mark levinson integrated amp I was trying. It was clearly a brighter presentation than the Pass, I ended up turning the treble with it to the neutral position.
I also happen to be in Michigan. Drop me a PM if you are interested in a listen.
I have Walsh Super2 100S3 units like mapman. I power mine with ATI 1502 amp which delivers 150wrms into 8 ohms estimated 180 to the 6 ohm speakers. I have previously run them with a Marantz pm8005 about 90 wrms. Both worked fine but I like separates and use an upgraded preamp which is detailed but not harsh. Both are AB amps and sound good. I have run them with tubes too and they sounded good bjt were too hot for my climate. All amps sounded different. I would try to get some trial amps to see what you like. I have heard the Hint and really liked it. I spoke to John at Ohm when I bought my speakers and he recommended a solid state amp with good current. The Hint provides that. I am not a class D guy but have heard good things about Wired For Sound amps. There is a very long thread on Ohm speakers on tnis site. You might scan that and see what amps others are using.
I'd say both of my current Ohm Walsh speaker pairs are neutral sounding.
I have Ohm F5 series 3, which are similar to yours but one generation older model and no built in subs. The 4 3 way level adjustments on each provide a lot of flexibility with tuning the speakers to teh room and personal preference. I run these off Bel Canto ref1000m monoblocks fed by an Audio Research sp16 tube pre-amp which perhaps adds just a touch of tube warmth.
I also have "Super Walsh 2 100 series 3 which are 8" 100 series 3 drivers in refurbed Walsh 2 cabs. I use those with a Bel Canto C5i integrated amp. This is perhaps the smoothest, most neutral, airy and detailed sound overall I have ever had.
Both amps are Class D and I am a big fan of Class D amps with the OHMs for overall value and performance.
Dep14, I am picking the rosewood finish and the version that has the smaller upper grills and the wood veneered middle portion above the large veneered tapered base (not the other available version with large upper grills like on the original Ohm Fs). I am having a pair of Ohm F’s that I inexpensively obtained remade into these by Ohm Acoustics, as the discount for reusing old speakers is significant.
Of the amps that I listed, 2 are class D and 1 is class AB. The amp you use is class AB. I have read that class D amps work best with "warm" sounding speakers and I have seen some Ohm speaker reviews that use the term "warm" in the description and some that do not include this word. How would you or anyone else reading this classify the Ohms that you have?
You may be amazed by this, but this is a totally blind purchase by me, so I don’t have any experience with Ohms other than a few minutes listening in an aisle way in a used audio store to a very old smaller pair with dated drivers. I am going off of online recommendations to my past posted topics, so all of you that have responded in the past collectively have picked these for me. Thus, keeping up with the spirit of this, you all can collectively help with the amp selection, which I may or may not, as stated earlier in this topic string, be able to audition prior to purchase.
While OHM's love power (and I agree) with the 5015's I believe the can's will be cut-off at 80hz and those class D amps will push the subs nicely.
I've been quite surprised how the OHM's really do showcase different amps. I happen to have a Pass Labs 250.8 and it really does work great with the OHM's. I would take advantage of demoing amps to see what you really like.
I've had a few amps in the system and it's amazed me how different each have sounded. Good luck, those speakers you have on the way are beasts! What finish did you go with?
Those two recommemded amps are probably available from reputable online dealers with a good return policy if needed. Checkout Crutchfield, Audio Advisor etc. Maybe others can suggest one.
A bit more information, my budget is somewhere between $3k to $6k. This includes power amp, pre-amp, DAC and cables, thus the appeal of an integrated solution. Could go new, demo or used, but leary of used unless a significant price discount. Trying to figure out the best cost-effective approach. Not finding local dealers that stock all these options so I can "borrow" them to tryout once I get the speakers. Also, if I so happen to go the used equipment route, I probably can’t "borrow" the unit. Thus, I am looking for those with Ohm experience to help with your wisdom.
I am not looking to include a turntable but would like to hook up my OLED TV and use this audio system that I am starting to piece together. Also I have no plans to add any satellite speakers for surround sound.
I’d go with one of the OHM recommended amps to make sure it has what is needed for that particular model. Which is best for you will depend largely on your personal preference ie aesthetics, size, other features, etc.
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