2. amps-preamps
  3. 134836-96791

Looking for amp advice (punk, rock & reggae edition)

My current amp isn’t doing it for me. Marantz pm6005 which is class D @45 wpc. Speakers are Focal Chorus 807V. It’s very detailed but a little clinical, my biggest gripe is a lack of midbass. According to Stereophile the impedance curve dives to 4 ohm between 100 and 200 hz which is where I think I the problem lies. All indications are that more power is needed to corrrct this which seems plausible as the more volume I give it the more it fills in in that range. The problem is that apartment living doesn’t allow 100db listening sessions.

So, I’m looking for an amplifier (separates or integrated) that has the current needed to round out the sound. The speakers are staying for many more years so replacing them isn’t a viable option, plus I love the sound.

Im interested in going tube but I have no experience with tubes. I have so many questions regarding tubes it could probably be it’s own thread but it seems to me that people love these more than SS on the whole. I’m open to any suggestions though.

My budget is $2500 (used ok but prefer new)

I listen to punk, post punk, lots of reggae (specifically dub), some electronic, a little jazz and some jangle pop (think REM).

Im looking for a warm side of neutral sound with good detail that can keep its composure with fast music yet be gentle enough for jazz. I like bass, if there’s an 808 or that dubby bass guitar, I want to hear it. These speakers do a nice job when the signal is right.

My analog front end is a PDC with a 2M Blue through a Lounge LCR MKIII. All interconnects are AQ Evergreen.

Thanks
gochurchgo
gochurchgo OP
923 posts
 
Well, according to this link I need 47 watts
https://geoffthegreygeek.com/calculator-amp-speaker-spl/

According to this one I need 130.4
http://headphoneaddict.com/power-calculator/

According to this one 90-300 watts if I understand correctly
http://rftech.custhelp.com/app/answers/detail/a_id/24/~/determining-power-needed-for-speakers

Focal’s recommended power rating is 25 - 175 wpc.

The second one makes sense both by the way its laid out and that it would put my need in the center of the suggested wattage by the manufacturer. I don't think wattage is the issue though. Wattage is loudness. It gets plenty loud. I think its current as a large section of the impedance curve is closer to 4ohm than 8 ohm. The little power supply here isn't faring well with the impedance curve and the phase angle (-40degrees according to Stereophile).
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gochurchgo OP
923 posts
 
No.... You're not understanding this problem right at all. Stop thinking about this as a wattage problem. Wattage is an abstraction and those calculators you linked to are not at all telling you what you need to know. Focal speakers are designed to be driven by a voltage source. That's how their sensitivity is described. Efficiency per watt is a very useless measure except for very, very benign loads. For the purpose of this discussion ignore watts completely. We're talking voltage source amps for voltage driven speakers so let's talk voltage and sort out the current next. Once you understand your voltage demands based on the speaker's sensitivity, then we can plug in it's impedance and determine the current demand. Only after we know the voltage and current requirements can we calculate the wattage, which may or may not make any difference based on the class and topology of the amp.


OK, I'm with it. So I need to know the amp's voltage delivery and the speaker's voltage requirement right?

Here is something interesting, a spec sheet thats different than the one I got in the box.
https://www.focal.com/sites/www.focal.fr/files/shared/catalog/document/chorus_807v_w-specification_s...
Interestingly it has a RMS wattage rating which mine does not (not to harp on wattage - this is interesting though).
I can't find either of these two metrics for either product. But I did learn the RMS for the speakers is 110 and thats more than 2x what I'm giving it. Also that the lowest impedance point is 4.2 ohms at 118hz (mid bass!).

AM I on the right path? My thought has been all along that its the bottoming out of the impedance at 4.2 in the mid bass spectrum thats to blame for this. And from what I've read (right or not) is that the only way to combat the impedance is to drive through it with more current, not necessarily wattage.
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gochurchgo OP
923 posts
 
It does. Yes.
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