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OP... What PreAmp are you going to be using in this setup? Does it have X 2 sets of XLR Outputs, each with plenty of voltage so you can feed a proper signal to each of the Amp Inputs?
If you don't have X 2 pairs of XLR Outputs on the Pre I wouldn't attempt this arrangement as the use of splitters are a true hack job IMO.
I ran a similar arrangement in the past with X 4 Monoblcks and a pair of B&W 803 D2's using a Classe CP-800 Pre with good success.
This PreAmp has multiple XLR Outputs and a total of 18v on tap at the Outputs to drive multiple Amps correctly. |
If you're using two amplifier channels per speaker, that's biamplifying, not biwiring. If that's your plan, you should consider using an active crossover. That's the way to get the most out of biamping.
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eniac26-
Thanks for the question. I am using a marrantz 8802a. I assume it has the ability to push enough voltage? |
It is SOOO much better to use a better stereo amp than it is to bi -amp.
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I did some more thinking on this thread. @eniac26 - wow, I have never seen a normal 2-channel preamp that has more than one "active" XLR output. That Classe CP-800 is pretty unique in this sense! @mgould - Looking at your Marantz 8802A, it actually appears that there is a configuration that allows you to use two outputs for a bi-amp situation. If you go to pages 233 and 237 of the 8802A manual, you can see that you can change the Amp Assign Mode to "9.1ch (Bi-Amp)". It will allow to you select one of three different channels to use as the "bi-amp" channel (either "Front Wide", "Height1" or "Surround Back"). http://us.marantz.com/DocumentMaster/US/AV8802AU_ENG_CD-ROM_UG_v01A_New.pdf |
stringreenIt is SOOO much better to use a better stereo amp than it is to bi -amp. That depends on the speakers. And the amplifiers. And of course, some speakers require biamplification; they can't be used with just a single stereo amp. |
auxinputwow, I have never seen a normal 2-channel preamp that has more than one
"active" XLR output. That Classe CP-800 is pretty unique in this
sense!
It's not unique at all, it's very common. For example, just about every ARC preamp offers two XLR outputs. That's really useful for those who use biamplifaction. |
Cleeds, note that he said more than one "active" XLR output. I interpret that to mean he was referring to the two output connectors on each channel each being driven by its own dedicated output stage, which appears to be the case for the Classe CP-800. But based on schematics I’ve seen at arcdb.ws most or all ARC line stages and preamps which provide two XLR outputs drive both of them from the same output stage, and simply jumper the two connectors together internally. I believe that the same holds true for the great majority of preamps and line stages from other manufacturers which provide two pairs of XLR outputs, and for RCA outputs as well.
In those cases the preamp’s output stage will have to drive the input impedances of both of the power amp inputs to which it is connected, just as if a splitter were used.
And the results could actually be worse than using a splitter, because if a short splitter is placed near the two amp inputs the cable capacitance seen by the preamp’s output stage would essentially be just the capacitance of one cable rather than two. The splitter approach being most likely to provide better results if the preamp’s output impedance is high at high frequencies, and if cable length is long (cable capacitance is proportional to length), and if the cables do not have low capacitance per unit length. In that situation some degree of rolloff and/or undesirable phase shifts may occur in the upper treble region if two long cables are used, which could be avoided or minimized if a short splitter is used in combination with a single long cable.
Regards,
-- Al
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I don't know much about tube preamps because most of what I have dealt with are solid-state preamps and processors. I had seen some DACs and preamps that do have separate actual output circuits for XLR and RCA, however, they are all opamp-based and it's really easy and cheap to just plop in another opamp to drive RCA outputs (and just chain them from the same input stage). In the case of discrete circuits or tube preamps, the manufacturer will have to design and allocate space for an entirely separate tube output stage (in the case of discrete, this could mean another 5" x 5" section of the board or more). This is definitely expensive for the manufacturers to support a situation that might happen 5% of the time. Al may be correct in his statement. That being said, you're right in the sense that ARC (and BAT now that I look) do have multiple XLR outputs. |
You are spinning your wheels.... Your amp is not differentially balanced and therefore you will hear no improvement. Balanced connections actually have 2 separate circuits ...one for the plus and one for the minus signal. What you have is XLR connections that are there for bragging rights. ..that's not denigrating your amp...it probably sounds fine. If it were to have true balanced connections, the unit would cost twice as much.
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Your amp is not differentially balanced and therefore you will hear no improvement. Balanced connections actually have 2 separate circuits ...one for the plus and one for the minus signal. What you have is XLR connections that are there for bragging rights. ..that’s not denigrating your amp...it probably sounds fine. If it were to have true balanced connections, the unit would cost twice as much.
Stringreen, I suspect that you meant to refer to the OPs Marantz 8802A, which is a "network audio/video surround processor/pre-amp/tuner," not to the amp. The model of the OP’s Krell amps has not been stated, and some Krell power amps are fully balanced. Also, it can be inferred from the specs of the Marantz 8802A that it does in fact provide true balanced **connections**, since the specs indicate a "rated output" that is twice as great for the XLR outputs as for the RCA outputs. What it presumably does not have is a balanced internal signal path, which IMO has no relevance to the questions that are being discussed. And as we’ve discussed in past threads balanced connections between components having unbalanced internal signal paths (and, again, the Krell amps might very well be fully balanced) IMO may sound either better than, worse than, or similar to unbalanced connections, depending on the specific designs. Regards, -- Al |
When I was researching the 8802a a while back, I could not absolutely determine if the internal circuits were fully "differential balanced". A piece of equipment could have a true balanced output that is not differential - it depends on how the circuit is implemented. That being said, looking at a detailed pic of the 8802A fully discrete HDAM module (below), I could definitely believe that each module has 2 analog circuits (which would make a truly balanced differential circuit). The HDAM module looks to have a 9-pin connector to the main board, so there are enough pins to support 2 circuits. The 8802A has 13 of these modules, so 2 of the XLR outputs are lacking these circuits (maybe the subwoofer output?). Each module has a couple of 220uf caps along with smaller 22uf caps to power the circuit -- Marantz did an excellent job of designing this 8802 and I would think it's an excellent piece (until you start comparing it to stuff like the Krell). http://www.schwartzpr.de/de/newsroom/Marantz/MarantzAV8802HDAMBoards.jpg |
@auxinput
Yes the CP800 is a pretty unique beast and it took me quite a long time to find such a beast that can do what it does. I still use it today strictly as a PreAmp and get no sense of it being a weak point in my system despite it actually being the least expensive component in my whole rig. Heh, my speaker wire has a higher price tag :)
@mgould
Please share the model Krells you are thinking of using in this setup. I'm inclined to think there must be at least two, 2 X channel amps at your disposal of the same exact type and similar age...etc?
The good news is that IME, the B&W D2 and I suspect the D3 have a pretty high power handling capability so that shouldn't be an issue unless you go full crazy mode. I was pushing my "Upper Section" with a Mono amp capable of 575w into 2ohms and the " Lower Section" was pushed with a matching separate amp of the same capability and the speakers never even blinked. My neighbors would have been knocking before the speaker even showed signs of braking a sweat. My balls ran out usually in the 112db range at seated position.
Anyway, based on what I'm hearing regarding the PreAmp at play you may be better served by Bi-Wiring until a more suitable Pre can be obtained. No offense meant by my statement :)
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Sorry guys, I have the Krell Chorus 7200. I was going to use 6 of the channels in a bi-amp format for the front three channels.
I am also going to do atmos and therefor will use the other 7 channel amp for all remaining speakers. I looked at the pages in the manual and was wondering if I will lose two channels by going with what auximput stated in his post. I would rather retain those additional channels for additional speaker. I am thinking that the 802s would like the additional power of the biamping. Thoughts?
Thanks for all of your help guys. |
The Krell and Marantz are not differentially balanced. The balanced connections are for bragging rights.
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From this Krell 7200 datasheet: The signal path is fully complementary and balanced. Independent complementary pre-driver and driver stages for the positive and negative output transistors make the output stages extremely fast and linear. Also, the fact that its balanced input impedance is twice its unbalanced input impedance is very likely indicative of a differentially balanced receiver stage being provided for its XLR inputs. That would be the case even if it did not have a balanced internal signal path. And as I previously indicated, it can be inferred from the specs on the Marantz that its outputs, or at least most of them, are most likely driven from differentially balanced output stages, regardless of whether or not its internal signal path is differentially balanced. Therefore, as I said earlier: ... balanced connections between components having unbalanced internal signal paths (and, again, the Krell amps might very well be fully balanced) IMO may sound either better than, worse than, or similar to unbalanced connections, depending on the specific designs. Regarding: I looked at the pages in the manual and was wondering if I will lose two channels by going with what auximput stated in his post. As I interpret the reference Auxinput provided to page 237 of the manual you would be able to configure the Marantz such that you could use two left + right output pairs (for example, Front and Front Wide) for purposes of biamping two speakers. But that would apparently require you to use a splitter for the center channel, as well as requiring you to utilize two pairs of output channels on the Marantz for one pair of front speakers. So I suspect it would be best to use a splitter on all three of the channels that you want to biamp with the Krell. The very high 200K impedance of the Krell’s balanced inputs should minimize or eliminate any downside of using a short splitter at its inputs, in conjunction with a single XLR cable per channel of whatever length is necessary. I can’t answer the last question, about the likelihood of benefiting from the additional power in this specific case, although I wouldn’t be surprised if it does turn out to provide significant benefit. Good luck. Regards, -- Al |
