Hi guys
New to all this so hope I'm posting in the right place.
For a pair of Klipsch RP600Ms would one ACA suffice or would I be better
using two as monoblocks?
These speakers are very tolerant at 96db sensitivity so if anyone has run these or similar I'd be grateful of your input.
With freight the price it is I'd rather get two ACA's straight up if thats the best way to go.
Thanks heaps
Cheers Mike
New to all this so hope I'm posting in the right place.
For a pair of Klipsch RP600Ms would one ACA suffice or would I be better
using two as monoblocks?
These speakers are very tolerant at 96db sensitivity so if anyone has run these or similar I'd be grateful of your input.
With freight the price it is I'd rather get two ACA's straight up if thats the best way to go.
Thanks heaps
Cheers Mike
I went straight to 2 mono blocks myself into a pair of 92 dB/W/m 3-way floor standers. Worked fine in a wooden floor living room. Shaking the windows was doable. You should have no problem with speakers as sensitive as yours, even with a single stereo unit.
Swayed to monos because they hook up to a balanced pre-amp.
If budget can sustain, I'd recommend 2 monos.
Swayed to monos because they hook up to a balanced pre-amp.
If budget can sustain, I'd recommend 2 monos.
One ACA has ower output impedance than run balanced as a monoblok.
The extra power is nice but with typical speakers the impedance curves can cause issues.
My big MTM ML-TLs get a bit fat on the bottom with a pair in mono, it is better with just one.
On the other hand the standMount A10p Mar-Kens work well.
What does the impedance of the Klipsch RP600M look like?
dave
Answered my own question:
Ugly
One ACA will be better than 2, with the high sensitvity, 8w should surely be enuff power unless you ar ein a BIG room, and play at ear damaging levels.
dave
Indeed. OP didn't mention balanced inputs. I refer to parallel unbalanced mode per
https://cdn.shopify.com/s/files/1/1006/5046/files/ACA_Monoblock_Operation_RevA.pdf
That is the nominal impedance, which given the measured impedance curve i posted goes from less than 4 Ω to probably over 25Ω.
With a high output impedance amplifier part of that impedance curve is convolved with the FR so with the wild swings you want a low output impedance amp. The rise in impedance on the bottom will end up causing lumpy bass.
Even just one might have issues with it, but the amp is fantastic and a bargain. I wonder if it is becoming Nelson’s best selling amp ever.
dave
With a high output impedance amplifier part of that impedance curve is convolved with the FR so with the wild swings you want a low output impedance amp. The rise in impedance on the bottom will end up causing lumpy bass.
Even just one might have issues with it, but the amp is fantastic and a bargain. I wonder if it is becoming Nelson’s best selling amp ever.
dave
Thanks for the input guys. I should have been more specific with my initial details.
The plan is for a cd transport and server into Denafrips Ares 2 dac which has balanced xlr outputs. I'm not sure about a preamp or whether I need 1 or 2 amps at this stage, but I do like the Klipsch RP600Ms and will be going with them. Add maybe a Rel T5i sub later but will probably use my little Yamaha SW-P130 sub in the meantime.
I thought it would be a good learning curve to build my own amp. I hope I'm right.
The question is will one or two of the ACAs make me smile most in this setup, and do I even need a preamp after the Denafrips dac?? I'm thinking its the only way to get the signal to the sub, if so would passive be best?
So would 2 ACAs be better than 1 in this balanced mono setup?
Will the fat bottom end that planet10 refers to still be an issue?
Lots of noob questions here. Thanks for your patience
The plan is for a cd transport and server into Denafrips Ares 2 dac which has balanced xlr outputs. I'm not sure about a preamp or whether I need 1 or 2 amps at this stage, but I do like the Klipsch RP600Ms and will be going with them. Add maybe a Rel T5i sub later but will probably use my little Yamaha SW-P130 sub in the meantime.
I thought it would be a good learning curve to build my own amp. I hope I'm right.
The question is will one or two of the ACAs make me smile most in this setup, and do I even need a preamp after the Denafrips dac?? I'm thinking its the only way to get the signal to the sub, if so would passive be best?
So would 2 ACAs be better than 1 in this balanced mono setup?
Will the fat bottom end that planet10 refers to still be an issue?
Lots of noob questions here. Thanks for your patience
Answered my own question:
Ugly
You could make a compensation network to make the impedance curve flatter.
I would recommend to start with the sharp peak at 90 Hz.
The peak at 2.5 kHz might be broader (but I am not sure since it's cut off on the diagram), so it would be second priority, but still worth to deal with; or you could just compensate the full rise happening > 400 Hz.
Compensating the peak at 40 Hz would also be nice, but might involve some rather large inductors. A much easier solution might be to limit the audio input to > 40 Hz using a smaller coupling cap at the input of the amp and forget about the 40 Hz peak.
The other stuff is irrelevant. The higher output impedance of the monobloks is, i am goona make an educated guess), be too high to provide adequate electrical damping to have decently controlled bass, because the speaker has little of it. And that big rise statring at the XO is going to be prominent, i think that is the greater problem.
As mr. brenna says, impedance compensation can be built into the XO — a good example is what Rasmussen has done it with the latest (mk 6?) XO in his
. Warnng: long thread.
But doing that for the Klipsch is a major project — XO is usually the hardest part of a speaker to get right, but then it would not be a Klipsch anymore — you might as well start from scratch.
dave
In my 2 ACA monoblocks we put this capacitor into a socket so that we could easily change input caps. I have a set specifically for a 180 Hz 1st order PLLXO.
dave
It's not quite as involved as you seem to think. You don't touch the x-over at all! You "only" put some additional parts in parallel to the speaker terminals (or the amp terminals, it does not matter).
The simplest form of such an impedance compensation would be to connect an 8 Ohm resistor across the terminals. The amp would then never see an impedance higher than 8 Ohms, and the lowest impedance would be about 2.7 Ohm (the speaker alone has a min. impedance of about 4 Ohm, and the 8 Ohm resistor in parallel to this gives 2.7 Ohm).
This 2.7 Ohm minimum is probably too low for the ACA. It is therefore better to limit the effect of the resistor to those frequency ranges where it's really needed, i.e., where the impedance is high. This is done with inductors and capacitors in combination with the resistor.
If someone would digitize the impedance curve (magnitude) into a data file I could design a suitable impedance compensation network.
I suspect that is true. And mono ones would ony be happy with 2 x th emin impedance as a single channel.
dave
OR you could run them in PARALLEL MODE and then they would handle it. Kind of like I suggested before ¯\_(ツ)_/¯
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