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In Reply to: RE: REVIEW: Parasound P5 Preamplifier (SS) posted by hionfi on February 26, 2015 at 05:09:15
I bought into the class D efficiency mostly to minimize idle temps. I leave my equipment on 24/7/365. My A 23 is quite warm at idle, and fairly hot when I ran it on the 3.5r ribbons, which are double sidedI would need a second A23. Maybe someone wants to trade one for my P3
I found a big improvement running fully balanced systems. The music is much more organic, more fuzz on the peach
Eventually i will get the new Oppo 105, which has balanced out circuit
I will be returning a Audio Quest Forrest optical cable I picked up yesterday ($40). It's very rolled off
I will be picking up a WireWorld SuperNova today but it won't go into my system until late this afternoon.
Patrick Cullen has a coax for $60 that I will probably try as well
Edits: 02/27/15Follow Ups:
I BIAMP my MG1.6 panels with a pair of the A23 to good effect.
The intent is to eventually build a passive LL crossover and gain as much as an additional 3db of amp power. Tough to have too much of THAT with panels!
Too much is never enough
Question for pictureguy:
Re: the comment: I BIAMP my MG1.6 panels with a pair of the A23 to good effect.
My understanding is that you can bi-wire the MG1.6.
Assuming that is true.....
Sounds like you are using one amp for left channel, one amp for right channel. ( this would mean running the A23's in monoblock config)
Have you considered one amp for mid/highs on both speakers, and
second amp for lows on both speaker. (this would mean running the A23's in stereo config).
I've heard different POV's on this.
Have you tried? and if so, results?
thx,
Just a quick reply.
I'm off to the Home Despot for a few 'project' items.
First, the A23, like its bigger brother, the A21 is NOT rated for 4 ohm bridged operation. It might do it, but I won't be the one to run that test. Especially at higher levels.
I DO run one amp per speaker. One channel to the bass part of the panel, the OTHER channel to the mid/tweet. Jumpers are GONE but not forgotten.
And since I low-cut the bass part of the panel at about 60hz or so, i save enough amp power to bump the 50:50 power point to about the 600hz crossover of the panel.
I'm NOT about to 'spllit' the amps and run bass thru one amp and the mid/tweet thru the OTHER. I'd need 2 more runs of speaker wire in that case. Maybe replace what I now use with 12ga Belden from BJC? I'd need just OVER a total of 30 FEET. With one amp behind each speaker I make do with 2x4 foot runs at each speaker. And have plenty of lee-way.
The ULTIMATE GOAL is a passive line level crossover between pre and main amp. BOOM! End of any power problems since that configuration would net me as much as 3db and exceed the power of a SINGLE A21.
Too much is never enough
Hey pictureguy: I'm trying to figure this out, so please excuse if this is dumb question:Parasound site say:
Continuous power output:
125 watts RMS x 2, 20 Hz - 20 kHz, 8 Ω, both channels driven
225 watts RMS x 2, 20 Hz - 20 kHz, 4 Ω, both channels driven
400 watts RMS x 1, 20 Hz - 20 kHz, 8 ΩYour comment included this:
A23, like its bigger brother, the A21 is NOT rated for 4 ohm bridged operation
Can you clarify, I'm confused.
What is a "bridged operation" that causes it to not be able to work?
thanks.
( btw - I have the identical equip : a pair of A23's and a P5 - terrific stuff - and am just trying to sort out best config. with speakers that can be bi-wired)
Edits: 03/04/15
Bridged operation makes the amp 'see' 1/2 the impedance of the load. So an 8 ohm speaker would seem to be 4 ohms TO the amp. The 400 watts x1 IS rated into 8 ohms, which if you'll note is just the addition of the 'per channel' rating at 4 ohms.
If the amps were good to 2 ohms, however, on a continuous basis, you MIGHT see a 4ohm bridged rating. I SUSPECT it might work, but certainly not at high levels or with low sensitivity speakers.
It also may get REAL hot!
I'm running ONE amp per speaker. And based on the crossover of 600hz and that I'm cutting some of the lows from the main speakers, I'd say I'm very near the 50:50 power point so that each 1/2 the amp sees about the same strain.
And ONE tip. IF you are using single ended connection from amp to pre, DO NOT use a splitter. You can use the 'loop out' function and run ONE cable to the amp and a short jumper from that channels out, to the OTHER channel in. I have both channels level at max, but have a mod in mind for that, too.
Does that help?
Too much is never enough
well ---- there's a good chance i'm in the too deep end of the pool (lol)
Let me ask this: suppose i was willing to run 4 individual lines from the amps to the speakers. Would that change anything? Or would it change your comment about the splitter? I'm presuming I need a splitter between the P5 and the two amps, and was planning on same, but frankly, you comment gives me great pause. thx,
First, if you biamp you WILL run 2 pair of wires to EACH speakers.
One set for the lows and another for the highs. Crossover will be done by the speaker and SHOULD be considered. If it is too high or too low a frequency, the amp on one side will be called upon for a high percentage of the TOTAL power needed
READ THIS LINKED ARTICLE. It'll explain a lot. And why you MAY eventually want to consider a REAL Line Level crossover to replace the nasty things IN the speakers. That's where I'm at, and considering. This link is to PART I, so track it down and also read part II.
From PRE to MAIN amp? Using the P5 / A23(s) combination you need only a Left OR Right TO the amp behind that speaker. Go to EITHER channels input. From that channels OUTPUT, loop over to the OTHER channels INPUT. LOOK at the back of the A21/23 amps and you'll see a LOOP OUT connector. Just another RCA. Were you to hook up using either a pre with very high or a main amp with very LOW impedance (output and input, respectively) you COULD run into problems with a splitter. The input impedance for 2x33k ohm in PARALLEL would be 16.5k ohm. You COULD run a splitter with that combo, but why bother? Using the loop function really makes things a bunch easier.
Repeat for the OTHER amp behind the other speaker.
But NOT to worry, the P5 has a usefully low output impedance of maybe 100 ohms. this is VERY low and the chance of an interaction with a main amp (a bad one, anyway) is near-zero.
Too much is never enough
after doing some further investigation I'm gonna try a passive horizontal bi-amp set up with my pair of A 23's. If anyone else has done this, would like to hear from them.
Horizontal is amp 1 for the HF and amp 2 for the LF? Any particular reason, than, why not vertical? I think the ability to locate the amp right AT the speaker and the loop in/out on the Parasounds really trumps other setups.
Depending on speaker and most importantly, the crossover, I hope you are putting about equal strain on each amp. I'm told the 50:50 power frequency is about 350hz which, when I low-cut my panels, actually works out fairly well.
Any urge to try a line level crossover?
Too much is never enough
working backwards on your questions:
no to line level; too complicated and definitely above my pay grade
re: "equal strain": how would I tell or figure that out?
re: horizontal - cuz amps are stereo and not mono's so going to try to push both left and right with stereo for highs, and repeat for lows.
wires are 8 feet - doesn't make any difference where the amps are if the wire reaches.
two additional comments: if amps were mono, would do this vertical.
and... if this doesn't work or sound right, can switch to vertical.
but it's going to be a passive approach either way.
Equal strain to ME is defined as both amps being called upon for about the same amount of power. This means that AT THE LIMIT, both wiill 'redline' at about the same time.
Where is this point? For AVERAGE music, (a statistical thing, I suspect) the point is AROUND 350hz.
If the crossover were say, 1000hz, you may need 70% BELOW and 30% ABOVE that crossover.
Now, there's NOTHING wrong with running identical amps for HF and LF. I'm doing JUST that. I have modest listening habits and seldom annoy the neighbors. But with the 1khz crossover running horizontal, one amp will place FAR more strain on its PS than the HF amp. At least with Vertical, in that situation, you equalize such stress and potentially improve headroom.
My speaker leads were also about 8 feet per side. I snipped 'em in HALF and STILL had plenty! Since I WAS 'all banana', I sent off for some spades and spent an hour at my stereo store and borrowed their crimping tool. I brought all my hand tools, and did the job.
Here is a link to an article on Biamping which ALSO has the frequency / power distribution data.
The article is clearly written and sets you up for Part II.
Too much is never enough
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