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#1
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I have found a "reverse RIAA" module
I found at http://www.hagtech.com/ a "reverse RIAA" module for
allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. |
#2
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On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote:
I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#3
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yep, seems like a really bad idea to me!
"Stewart Pinkerton" wrote in message ... On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#4
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"Stewart Pinkerton" wrote in message ... On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? He said that he needed another line input and had only the mag phono input left on his device. An inverse RIAA pad/ filter is appropriate if he can't just re-wire his device or use an external switch. Hope he doesn't have particularly high expectations of how it will sound relative to a regular line input. |
#5
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"Bill" wrote in message
I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. Be aware that you have to drive it with a certain source impedance, or its much-vaunted precision goes to #&%% in a handbasket. |
#6
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Bill wrote:
I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. Graham |
#7
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Richard Crowley wrote:
"Stewart Pinkerton" wrote in message ... On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? He said that he needed another line input and had only the mag phono input left on his device. An inverse RIAA pad/ filter is appropriate if he can't just re-wire his device or use an external switch. Hope he doesn't have particularly high expectations of how it will sound relative to a regular line input. Indeed ! It'll be somewhat second rate at best, rather noisy, and the response won't be exactly flat due to component tolerancing affecting the response curves. It's a 'port in a storm' I guess. Graham |
#8
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"Pooh Bear" wrote in message ... Richard Crowley wrote: "Stewart Pinkerton" wrote in message ... On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? He said that he needed another line input and had only the mag phono input left on his device. An inverse RIAA pad/ filter is appropriate if he can't just re-wire his device or use an external switch. Hope he doesn't have particularly high expectations of how it will sound relative to a regular line input. Indeed ! It'll be somewhat second rate at best, rather noisy, and the response won't be exactly flat due to component tolerancing affecting the response curves. And yet, more accurate and quieter than vinyl! |
#9
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Karl Uppiano wrote: "Pooh Bear" wrote in message ... Richard Crowley wrote: "Stewart Pinkerton" wrote in message ... On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? He said that he needed another line input and had only the mag phono input left on his device. An inverse RIAA pad/ filter is appropriate if he can't just re-wire his device or use an external switch. Hope he doesn't have particularly high expectations of how it will sound relative to a regular line input. Indeed ! It'll be somewhat second rate at best, rather noisy, and the response won't be exactly flat due to component tolerancing affecting the response curves. And yet, more accurate and quieter than vinyl! Sssshhh ! You're not supposed to say that ! You might hurt someone's opinions. Graham ;-) |
#10
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"Pooh Bear" wrote in message ... Karl Uppiano wrote: "Pooh Bear" wrote in message ... Richard Crowley wrote: "Stewart Pinkerton" wrote in message ... On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. But did you find a reason why anyone would wish to do this - aside from testing an RIAA preamp? He said that he needed another line input and had only the mag phono input left on his device. An inverse RIAA pad/ filter is appropriate if he can't just re-wire his device or use an external switch. Hope he doesn't have particularly high expectations of how it will sound relative to a regular line input. Indeed ! It'll be somewhat second rate at best, rather noisy, and the response won't be exactly flat due to component tolerancing affecting the response curves. And yet, more accurate and quieter than vinyl! Sssshhh ! You're not supposed to say that ! You might hurt someone's opinions. Graham ;-) I have a reverse RIAA custom built by McIntosh for authorized servicers to repair their stuff in the old days. I think this one dates back to the stereo tube units, judging by the small wirewound resistors with painted color dots for the codes, etc. Interesting. Mark Z. |
#11
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In article ,
Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. Isaac |
#12
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"Isaac Wingfield" wrote in message
In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. I thought we were talking about testing preamps, not cartridges. |
#13
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Isaac Wingfield wrote:
In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. And if you don't know what cartridge the user is going to attach....... ? What then ? Graham |
#14
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"Isaac Wingfield" wrote in message ... In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. Isaac Absolutely wrong. The reverse RIAA was provided to authorized servicers for the purpose of testing and repairing phono preamp sections without having to hook up a turntable, and accounting for the equalization so that EQ problems would also be readily spotted. Even if it were just for testing frequency response, it would still be useful for engineering and production purposes. Another use which was barely mentioned in this thread was the very useful task of hooking another line-level input to a receiver which doesn't have enough of these. Tandberg and some earlier Onkyo models come to mind, since they lacked enough auxiliary inputs. Yes, the addition of a device ahead of the phono input would compromise ultimate fidelity compared to a regular input, but even if this concerns you, a phono input could be used this way for the audio output of a TV, game, or other lesser-quality signal. Mark Z. |
#15
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"Isaac Wingfield" wrote in message ... To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. Not if you are testing the pre-amp! TonyP. |
#16
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In article ,
Pooh Bear wrote: Isaac Wingfield wrote: In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. And if you don't know what cartridge the user is going to attach....... ? What then ? Then you really don't know what the system's performance is going to be. Surely you don't imagine that a "calibrated" RIAA preamp will have the same frequency response *from a record* regardless of which cartridge you attach? It's a very interesting experiment to use an inverse-RIAA network to "calibrate" a preamp, and then hook up the cartridge of your choice and check the response using the test record. Most RIAA preamps are "pretty close" without calibration anyway. The only reason to use the inverse network is to "fine tune" things, and if you ignore the cartridge's effect when you do the tuning, you may wind up further off than when you started. Isaac |
#17
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"Isaac Wingfield" wrote in message ... In article , Pooh Bear wrote: Isaac Wingfield wrote: In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. And if you don't know what cartridge the user is going to attach....... ? What then ? Then you really don't know what the system's performance is going to be. Surely you don't imagine that a "calibrated" RIAA preamp will have the same frequency response *from a record* regardless of which cartridge you attach? It's a very interesting experiment to use an inverse-RIAA network to "calibrate" a preamp, and then hook up the cartridge of your choice and check the response using the test record. Most RIAA preamps are "pretty close" without calibration anyway. The only reason to use the inverse network is to "fine tune" things, and if you ignore the cartridge's effect when you do the tuning, you may wind up further off than when you started. Isaac What about repairing and testing broken phono circuits? Mark Z. |
#18
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"Isaac Wingfield" wrote in message
In article , Pooh Bear wrote: Isaac Wingfield wrote: In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. And if you don't know what cartridge the user is going to attach....... ? What then ? Then you really don't know what the system's performance is going to be. Surely you don't imagine that a "calibrated" RIAA preamp will have the same frequency response *from a record* regardless of which cartridge you attach? Agreed, but that is a different question. It's a very interesting experiment to use an inverse-RIAA network to "calibrate" a preamp, and then hook up the cartridge of your choice and check the response using the test record. Been there, done that. Most RIAA preamps are "pretty close" without calibration anyway. The only reason to use the inverse network is to "fine tune" things, and if you ignore the cartridge's effect when you do the tuning, you may wind up further off than when you started. Agreed. |
#19
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Isaac Wingfield wrote:
In article , Pooh Bear wrote: Isaac Wingfield wrote: In article , Pooh Bear wrote: Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. That's how we test RIAA inputs ! I didn't need some commercial company to tell me how to do it though. To have any hope at all of accuracy. the *only* way to test RIAA inputs is using a proper RIAA test record. If you don't include the cartridge in the test, it's worthless. And if you don't know what cartridge the user is going to attach....... ? What then ? Then you really don't know what the system's performance is going to be. Surely you don't imagine that a "calibrated" RIAA preamp will have the same frequency response *from a record* regardless of which cartridge you attach? It's a very interesting experiment to use an inverse-RIAA network to "calibrate" a preamp, and then hook up the cartridge of your choice and check the response using the test record. Most RIAA preamps are "pretty close" without calibration anyway. The only reason to use the inverse network is to "fine tune" things, and if you ignore the cartridge's effect when you do the tuning, you may wind up further off than when you started. Well..... If you hadn't already noticed from my earlier posts, I've used an inverse RIAA network to define testing of products at the manufacturing stage to verify the correct equalisation. The RIAA curve is well- known. It's a standard. If your cartridge has a lousy response it's *not* a fault of the equipment that complies with the standard. Nuff said. Graham |
#20
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On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote:
I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. Congratulations! Why? |
#21
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"Laurence Payne" wrote in message news On Sun, 28 Nov 2004 09:10:00 -0500, Bill wrote: I found at http://www.hagtech.com/ a "reverse RIAA" module for allowing line sources into phono inputs. It reverses the frequency response curve and pads the level to around minus 50-60. Congratulations! Why? Wants to severely compromise gain staging, overload sensitivity, and freq linearity. geoff |
#22
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"Geoff Wood" wrote in message ... Congratulations! Why? Wants to severely compromise gain staging, overload sensitivity, and freq linearity. Yes, but surely there are cheaper ways to do that :-) TonyP. |
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