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Post by monkumonku on Apr 10, 2023 22:38:50 GMT -5
I have a 5-channel Carver Sunfire amp that has both RCA and XLR inputs.
Question - is it harmful to the amp to have different preamps connected to the RCA and XLR at the same time? Obviously not with both of them on, but having both connected and only one preamp turned on at a time. The amp does not have any switch between XLR and RCA so I am presuming that both inputs are live simultaneously.
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Post by ttocs on Apr 10, 2023 23:29:26 GMT -5
I am absolutely certain of one thing, that folks like vcautokid will know much better than I. But, my first thought is concern about mixing in an additional Ground from the added preamp at the input of the amp, even when one preamp is off. Grounding issues are easy to create. |
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Post by vcautokid on Apr 11, 2023 2:15:35 GMT -5
Typically speaking I would defer to the documentation or technical support if you are not sure. Typically you chose one or the other. Balanced or Single Ended. What is the model Sunfire are we talking about? One of the Cinema hfe_sunfire_cinema_grand_std_sig_series_ii_en.pdf (1.84 MB) Grand models for instance? If the amplifier does not have specifics for isolating balanced and unbalanced unlike some of the Emotiva amplfiers of the past. xpag3_6_rear34-1.webp (45.42 KB) And present, the switch allows selection of Balanced XLR or Single ended unbalanced RCA on the Tiff like connectors here. On the cinema grand instructions start on page 12 and go from there. They are looking like either or, not both from what I can see here in the pdf instructions here. Got from Hifi-engine. www.hifiengine.com/manual_library/sunfire/cinema-grand.shtml |
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Post by mgbpuff on Apr 11, 2023 9:37:22 GMT -5
I would think a safer way to use two preamps into one power amp would be to use the preamps in series with one output (preferable the balanced one) going to the amp. Proper level adjustment may be a little involved when the second preamp is input selected.
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DYohn
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Post by DYohn on Apr 11, 2023 9:57:15 GMT -5
A bigger problem than the amp is what can happen by connecting the two preamp outputs together. With no switch isolating RCA from XLR you will be shorting the two outputs together. Might not be a good idea. You don't want to let the magic smoke out of your preamp...
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Post by 405x5 on Apr 11, 2023 10:02:40 GMT -5
I have a 5-channel Carver Sunfire amp that has both RCA and XLR inputs. Question - is it harmful to the amp to have different preamps connected to the RCA and XLR at the same time? Obviously not with both of them on, but having both connected and only one preamp turned on at a time. The amp does not have any switch between XLR and RCA so I am presuming that both inputs are live simultaneously. I am currently using the signature version of the Sunfire amp. you describe. My advice would be not to even consider such a thing without an AB switch box. |
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Post by monkumonku on Apr 11, 2023 10:09:32 GMT -5
Thanks all, for your replies. Vincent - it is a Carver Grand Signature amp. I have the instruction manual but it doesn't say anything about addressing my question.
I guess to be on the safe side it is better to have either or connected, rather than both. Thanks again!
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KeithL
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Post by KeithL on Apr 12, 2023 15:19:23 GMT -5
Depending on how the amp is wired, it could be bad for either the amp, or the preamps, to have two preamps connected to the XLR and RCA inputs at the same time. Or it could be no problem at all. It depends on how both the amp and the preamps are wired internally. Some amps may simply tie the two inputs together... while some may actively sum them. Likewise, some preamps may not mind having their outputs tied together, but others may become distorted, or actually be damaged, if you do so. (You could also end up with weird situations... like one preamp becoming distorted, or cutting out entirely, if the other one is turned off...) There's no way to know, one way or the other, without having actual schematics, unless the manufacturer says one way or the other. I assume that, by "in series", you mean: - having the outputs of one preamp connected to one of the inputs on the second preamp - then having the output of the second preamp connected to the inputs on the power amp I would tend to agree that would probably be safe... And there are a few very specific circumstances where it might make sense... However, in most cases, it would be a very bad idea in terms of sound quality... (When a signal goes through both it will be subject to the total of the noise and distortion introduced by each - added together.) It would be much better if one preamp or the other has a "home theater bypass" or something like that. The best and safest solution would be one of those little passive "input selector switchboxes"... The ones where you push a button to select the input you want to use... a nice simple cheap one should work fine... (And you will want to switch it while everything is off... before you turn everything on.) I would think a safer way to use two preamps into one power amp would be to use the preamps in series with one output (preferable the balanced one) going to the amp. Proper level adjustment may be a little involved when the second preamp is input selected. |
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Post by mgbpuff on Apr 13, 2023 8:32:22 GMT -5
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KeithL
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Post by KeithL on Apr 13, 2023 9:33:20 GMT -5
I was assuming he would just stick with unbalanced for everything. A "passive" device that converted between balanced and unbalanced would have to use a transformer... which I would NOT recommend. (To be quite blunt, cheap transformers tend to not be very good, even expensive ones aren't great, and they are all fussy about things like source and load impedance.) And, while there are a few little active devices which probably aren't bad, you really don't gain anything by doing it that way rather than just using unbalanced all around. This actually looks like it would do the job just fine... and I've generally heard positive thinks about Douk (Little Bear) gadgets... However I would also note that you have to read the fine print carefully. It looks to me like, in this particular situation, it will do what you want (allow you to switch between two inputs - one balanced and one unbalanced ) - just fine. However it IS only doing "a pseudo-balanced conversion"... When you go from balanced to unbalanced you are simply routing the signal (+) from the balanced source to the RCA output and ignoring the signal (-). (This is exactly the way we do it on our balanced-to-unbalanced adapters and is the proper way to do it if your balanced source has active driven outputs rather than transformer outputs.) But, when you go the other way, from an RCA input to an XLR output, it is NOT giving you a balanced output. (It's routing the signal from the RCA input to the signal (+) on the XLR and simply tying the signal (-) on the XLR to ground.) (There's nothing wrong with doing this... but you are getting "an unbalanced signal on an XLR connector" rather than a true balanced signal.) In short, it does everything you might think it does, EXCEPT convert an unbalanced input to a balanced output. Another way of saying that is that it converts from RCA to XLR but NOT from unbalanced to balanced. (This means that, depending on how the balanced input on whatever you're connecting it to is wired, it may or may not drive it properly.) (But, yes, if you have balanced inputs, they will indeed give you balanced outputs.) |
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Post by 405x5 on Apr 13, 2023 14:35:03 GMT -5
I wouldn’t want to miss an opportunity to point out what a match made in heaven the Sunfire Cinema Grand Signature amplifier is when paired with the Emotiva XMC one as I have been living with that since 2014.  |
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Post by monkumonku on Apr 13, 2023 14:57:37 GMT -5
I wouldn’t want to miss an opportunity to point out what a match made in heaven the Sunfire Cinema Grand Signature amplifier is when paired with the Emotiva XMC one as I have been living with that since 2014. View AttachmentI've got nearly the same thing except an XMC-2 and you are correct - what a nice match! I got the Sunfire from a Lounge member a few years ago and it has worked perfectly. |
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Post by 405x5 on Apr 13, 2023 16:42:26 GMT -5
I wouldn’t want to miss an opportunity to point out what a match made in heaven the Sunfire Cinema Grand Signature amplifier is when paired with the Emotiva XMC one as I have been living with that since 2014. View AttachmentI've got nearly the same thing except an XMC-2 and you are correct - what a nice match! I got the Sunfire from a Lounge member a few years ago and it has worked perfectly. ….Bought this new from a dealership back in 2001 along with its Theater Grand II counterpart processor. No such thing as HDMI yet. The only thing I’ve done is clean the dust off it! |
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Post by leonski on Apr 17, 2023 20:34:35 GMT -5
Thanks all, for your replies. Vincent - it is a Carver Grand Signature amp. I have the instruction manual but it doesn't say anything about addressing my question. I guess to be on the safe side it is better to have either or connected, rather than both. Thanks again! Unless they SAY it's OK, than don't.....good idea. As for that switch box linked? At 70$ each, you'd need 350$ worth for a 5 input system.... For the DIY inclined? This is, after all, only a switching problem. And can easily be figured out for a single channel than 'cloned'. I designed a box for a friend at a church, once. And they built it and it worked FINE..... Rule would be to use BREAK BEFORE MAKE switching. Good luck sourcing these switches OR perhaps old-school RELAYS....which would need some kind of power supply for actuation. |
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