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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Adding Pre-Out / Main-in to an integrated amplifier. Second try.
Trying to add a Main-in/Pre-out to a Sony amplifier:
(There were useful replies, in an earlier thread, from K. Robinson, Jerry G. and NSM about this topic) The amplifier model: Sony TA-F590ES, with motorized volume control. The amplifier has an "adaptor loop" with bridged IN & OUT cinch(RCA) connectors before the volume control. The aim is to insert a 2-way active crossover, and resend the high-range output to the Sony. The adaptor loop won't do since it come before the volume control. One point worth mentioning: the "Pre-out" and "Main-in" under discussion need not have "universal" characteristics, since they will *only* be dealing with an active crossover (and perhaps an equalizer.) It has been suggested by NSM: "post a circuit diagram and several of us could tell you where to add them" Here are the block ad circuit diagrams: http://nom.de.plume.free.fr/temp_files/ The diagrams are for the TA-F590ES and a variant, the TA-F690ES. The latter has a Pre-out, but no Main-in. We are discussing here the TA-F590ES (Please consider that the content of the files may be copyrighted.) Thank you, in advance, for your contributions. |
#2
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wrote in message ... Trying to add a Main-in/Pre-out to a Sony amplifier: The amplifier has an "adaptor loop" with bridged IN & OUT cinch(RCA) connectors before the volume control. The aim is to insert a 2-way active crossover, and resend the high-range output to the Sony. The adaptor loop won't do since it come before the volume control. What will you do with the low out? I would do almost anything to use the adaptor loop. N |
#3
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The low-out will go to a powered subwoofer.
(I don't really understand your statement " I would do almost anything..." Just a problem with subtleties of English.) On Sat, 22 Jan 2005 20:59:27 GMT, "NSM" wrote: What will you do with the low out? I would do almost anything to use the adaptor loop. |
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"SansAdresse" wrote in message news The low-out will go to a powered subwoofer. (I don't really understand your statement " I would do almost anything..." Just a problem with subtleties of English.) OK. "I would do almost anything..." == that is so easy and everything else is so hard. I use an unpowered subwoofer. For your case, I would tap the low off from the speaker outputs, combine them and feed that to the powered subwoofer. That way the remote vol control will still work as expected. I'd use two 100 ohm resistors feeding a 10 ohm resistor and connect the powered subwoofer input to the connection point. N |
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The idea is to cleanly separate the frequencies (I am just going by
the textbook!), and to avoid sending to the main speakers the low frequencies which may drive them into distortion. (Bach's organ music is played on the system.) ================================================ On Sat, 22 Jan 2005 23:38:00 GMT, "NSM" wrote: The low-out will go to a powered subwoofer. I use an unpowered subwoofer. For your case, I would tap the low off from the speaker outputs, combine them and feed that to the powered subwoofer. That way the remote vol control will still work as expected. I'd use two 100 ohm resistors feeding a 10 ohm resistor and connect the powered subwoofer input to the connection point. |
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SansAdresse wrote:
The idea is to cleanly separate the frequencies (I am just going by the textbook!), and to avoid sending to the main speakers the low frequencies which may drive them into distortion. (Bach's organ music is played on the system.) You shouldn't have to worry about distortion in a subwoofer, but I admire your fortitude. Yes, you are doing it the 'right' way, but certainly you are doing it the 'hard' way. I'd try NSM's solution first, then if you have objectionable distortion.... jak ================================================ On Sat, 22 Jan 2005 23:38:00 GMT, "NSM" wrote: The low-out will go to a powered subwoofer. I use an unpowered subwoofer. For your case, I would tap the low off from the speaker outputs, combine them and feed that to the powered subwoofer. That way the remote vol control will still work as expected. I'd use two 100 ohm resistors feeding a 10 ohm resistor and connect the powered subwoofer input to the connection point. |
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You shouldn't have to worry about distortion in a subwoofer
The distortion would be in the woofers of the main speakers. Yes, you are doing it the 'right' way, but certainly you are doing it the 'hard' way. I'd try NSM's solution first, then if you have objectionable distortion.... I did buy the powered subwoofer and the crossover (a venerable Nakamichi model), only to discover that the jumpered connectors on the back of the Sony integrated amp are an "accessory loop" (pre-volume control) and not a Pre-out/Main-in pair. I would expect higher quality reproduction if things are done the "right way": not just less distortion, but cleaner sounding music. Are you saying that the difference wouldn't be perceptible? [PS: Changing the amp means getting also a new tuner since the latter get its remote control signals from the amp.] On Tue, 25 Jan 2005 12:14:42 -0600, "jakdedert" wrote: SansAdresse wrote: The idea is to cleanly separate the frequencies (I am just going by the textbook!), and to avoid sending to the main speakers the low frequencies which may drive them into distortion. (Bach's organ music is played on the system.) You shouldn't have to worry about distortion in a subwoofer, but I admire your fortitude. Yes, you are doing it the 'right' way, but certainly you are doing it the 'hard' way. I'd try NSM's solution first, then if you have objectionable distortion.... |
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"SansAdresse" wrote in message ... I did buy the powered subwoofer and the crossover (a venerable Nakamichi model), only to discover that the jumpered connectors on the back of the Sony integrated amp are an "accessory loop" (pre-volume control) and not a Pre-out/Main-in pair. I would expect higher quality reproduction if things are done the "right way": not just less distortion, but cleaner sounding music. Are you saying that the difference wouldn't be perceptible? I did browse through the diagrams you posted. Adding the connections you desire is going to be performed in the 'no fun' zone. Try the easy way for now, and if you are not happy I'll try to give you a more technically correct answer. -- N |
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Note that I don't need a full fledged Pe-in/Man-out pair, which must have "universal" properties (driving a variety of external power amps for instance.) I just just need a "loop" after the volume control where I can hook a high quality active crossover. On Tue, 25 Jan 2005 12:14:42 -0600, "jakdedert" wrote: SansAdresse wrote: The idea is to cleanly separate the frequencies (I am just going by the textbook!), and to avoid sending to the main speakers the low frequencies which may drive them into distortion. (Bach's organ music is played on the system.) You shouldn't have to worry about distortion in a subwoofer, but I admire your fortitude. Yes, you are doing it the 'right' way, but certainly you are doing it the 'hard' way. I'd try NSM's solution first, then if you have objectionable distortion.... |
#10
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SansAdresse wrote:
You shouldn't have to worry about distortion in a subwoofer The distortion would be in the woofers of the main speakers. Yes, you are doing it the 'right' way, but certainly you are doing it the 'hard' way. I'd try NSM's solution first, then if you have objectionable distortion.... I did buy the powered subwoofer and the crossover (a venerable Nakamichi model), only to discover that the jumpered connectors on the back of the Sony integrated amp are an "accessory loop" (pre-volume control) and not a Pre-out/Main-in pair. I would expect higher quality reproduction if things are done the "right way": not just less distortion, but cleaner sounding music. Are you saying that the difference wouldn't be perceptible? Not necessarily. I'm just saying that the results may be perfectly acceptable for the application, by going the route NSM detailed: ie dropping the speaker sig to an appropriate level for the input of the sub with a resistor network. This is considerably less work than adding pre outs to the amplifier and should work quite well. In fact, you could 'kludge up' a network with just the resistors and a pair of RCA cables connected to the 'B' speaker outs in half an hour or so. If you do not like the results--or you have a lot of time on your hands and like to experiment--suss out the preamp wiring in your amp and go it the hard way. If you have limited experience, you may end up destroying your reciever; in which case you can then get one which has a sub output or at least a preamp out. jak |
#11
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On Thu, 27 Jan 2005 10:31:39 -0600, "jakdedert"
wrote: If you do not like the results--or you have a lot of time on your hands and like to experiment--suss out the preamp wiring in your amp and go it the hard way. One part of my question got lost in the discussion: We don't need a full-fledged Pre-out that can drive a power amplifier, with all that goes with that. We only need to *insert* a line level active crossover (a "simple" filter) on the signal path after (right after?) the volume control. Can't that be done on the cheap? Just cut the signnal path and insert two pairs on cinch connectors Out==In. Are you saying that the difference wouldn't be perceptible? Not necessarily. I'm just saying that the results may be perfectly acceptable for the application, by going the route NSM detailed: ie dropping the speaker sig to an appropriate level for the input of the sub with a resistor network. This is considerably less work than adding pre outs to the amplifier and should work quite well. In fact, you could 'kludge up' a network with just the resistors and a pair of RCA cables connected to the 'B' speaker outs in half an hour or so. If you have limited experience, you may end up destroying your reciever; in which case you can then get one which has a sub output or at least a preamp out. |
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On Thu, 27 Jan 2005 19:07:12 +0100, SansAdresse
wrote: One part of my question got lost in the discussion: We don't need a full-fledged Pre-out that can drive a power amplifier, with all that goes with that. We only need to *insert* a line level active crossover (a "simple" filter) on the signal path after (right after?) the volume control. Can't that be done on the cheap? Just cut the signnal path and insert two pairs on cinch connectors Out==In. That's what I would do. |
#13
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SansAdresse wrote:
On Thu, 27 Jan 2005 10:31:39 -0600, "jakdedert" wrote: If you do not like the results--or you have a lot of time on your hands and like to experiment--suss out the preamp wiring in your amp and go it the hard way. One part of my question got lost in the discussion: We don't need a full-fledged Pre-out that can drive a power amplifier, with all that goes with that. We only need to *insert* a line level active crossover (a "simple" filter) on the signal path after (right after?) the volume control. Can't that be done on the cheap? Just cut the signnal path and insert two pairs on cinch connectors Out==In. BTW, nothing should be "cut" in order to simply give you a line level out. That would interupt the signal path...an example of why I think you should try the easy way, first...requires very little technical knowledge and *NO* opening up of the unit...much less any modification. To do it correctly, you find the appropriate point in the signal flow...preferably the input to the power amp drivers. At that point, you can 'try' merely connecting cables to the sub x-over input. My guess is that this will (maybe) affect the overall signal level to the unit's power amps...perhaps do other interesting things as well. If it does, then you'll need to construct a unity-gain isolation stereo amp...and feed the output of that to your x-over. If you want to convert to a full biamped system, using the receivers built in amp for either the highs or lows, then another stereo amp for the other section, that's an altogether different animal than you first presented. jak |
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If you want to convert to a full biamped system, using the receivers built
in amp for either the highs or lows, then another stereo amp for the other section, that's an altogether different animal than you first presented. This what it is about: the subwoofer is powered, it has its own amplifier and line level inputs. I need to insert a crossover, send the low-pass part to the sub, and keep the high-pass part to feed it back to the integrated amp. That's a very classical scheme: INTEGRATED AMP - (Pre-out) --- [...Active crossover...] INTEGRATED AMP - (Main-in) --- [High pass]...[Low pass] --- POWERED SUB Thank you for your time. ================================================== ======== On Thu, 27 Jan 2005 12:53:32 -0600, "jakdedert" wrote: SansAdresse wrote: On Thu, 27 Jan 2005 10:31:39 -0600, "jakdedert" wrote: If you do not like the results--or you have a lot of time on your hands and like to experiment--suss out the preamp wiring in your amp and go it the hard way. One part of my question got lost in the discussion: We don't need a full-fledged Pre-out that can drive a power amplifier, with all that goes with that. We only need to *insert* a line level active crossover (a "simple" filter) on the signal path after (right after?) the volume control. Can't that be done on the cheap? Just cut the signnal path and insert two pairs on cinch connectors Out==In. BTW, nothing should be "cut" in order to simply give you a line level out. That would interupt the signal path...an example of why I think you should try the easy way, first...requires very little technical knowledge and *NO* opening up of the unit...much less any modification. To do it correctly, you find the appropriate point in the signal flow...preferably the input to the power amp drivers. At that point, you can 'try' merely connecting cables to the sub x-over input. My guess is that this will (maybe) affect the overall signal level to the unit's power amps...perhaps do other interesting things as well. If it does, then you'll need to construct a unity-gain isolation stereo amp...and feed the output of that to your x-over. |
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"Gary J. Tait" wrote in message ... On Thu, 27 Jan 2005 19:07:12 +0100, SansAdresse wrote: One part of my question got lost in the discussion: We don't need a full-fledged Pre-out that can drive a power amplifier, with all that goes with that. We only need to *insert* a line level active crossover (a "simple" filter) on the signal path after (right after?) the volume control. Can't that be done on the cheap? Just cut the signnal path and insert two pairs on cinch connectors Out==In. That's what I would do. This is not your old style basic circuit diagram. It looks more like a refugee from the space station. It's doable, but not trivial to add the required outputs. -- N |
#16
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SansAdresse wrote:
If you want to convert to a full biamped system, using the receivers built in amp for either the highs or lows, then another stereo amp for the other section, that's an altogether different animal than you first presented. This what it is about: the subwoofer is powered, it has its own amplifier and line level inputs. I need to insert a crossover, send the low-pass part to the sub, and keep the high-pass part to feed it back to the integrated amp. That's a very classical scheme: INTEGRATED AMP - (Pre-out) --- [...Active crossover...] INTEGRATED AMP - (Main-in) --- [High pass]...[Low pass] --- POWERED SUB Thank you for your time. Do you already have a suitable stereo active x-over? Have you decided what the x-over point should be? The sub amp should have an low-pass filter, so all you really want to do is reduce the amount of low frequency info sent to the main amplifier and speakers, right? In that case--although I would still try the resister network first [KISS theory]--you could try to find a suitable take-off point in the amplifier which comes after the volume control, but *before* the tone controls (if such exists...the tone controls could come before the volume, in which case you're screwed....). That way, you could send unequalized audio to the sub input, and use the amps tone controls to reduce the l-f signal to the main speakers. Sorry, but I still think you're *way* overcomplicating this. Try tapping the speaker output and see how it works. You might like the sound of the main speakers complimenting the output from the sub (be sure to try the phase switch in both positions). You can achieve much the same as the above by simply turning down the bass control on the amplifier and turning up the sub..... jak |
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