DYohn
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Post by DYohn on Mar 13, 2015 19:20:36 GMT -5
I do not understand the modern impetus to eliminate preamps from systems. Did some self-proclaimed audiophoole expert out there on the Interwebz post some blog about how preamps are evil? Just get a preamp and your system will work. Period.
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Post by rcheliguy on Mar 13, 2015 20:21:15 GMT -5
Why is this a good vs. evil issue?
I had a speaker placement issue and now my system sounds great and works great.
Let me quote your signature block, "Inaudible is inaudible and you don't get extra brownie points for making it twice as inaudible as another solution. - Kevin Haskins "
When I had a record player and a tape deck and a CD player and a VCR I needed a preamplifier as a switch box and volume control.
Now I'm ripping hundreds of CD's and from now on I'll just play from playlists of ripped CD's and downloaded HDTracks.
The OPPO 105D is my CD/DVD/BD/SACD/HDCD, USB reader, DAC, headphone amp in addition having a balanced XLR preamplifier output stage.
For that matter it is also an AV receiver of sorts since I have my DVR plugged into it by HDMI and it has native Netflix support which I use.
What we are seeing is a convergence of digital feeds.
I've found nirvana in FooBar2000 as a means of organizing all of my music that doesn't stream over the Internet. It talks by Asynchronous USB to the OPPO 105 and feeds the Sabre 32 DAC dedicated to the stereo channel.
I have THREE total components here if you don't include remote sources for my music which could be my computer in the other room, or Pandora across the Internet.
This is change, but change is good.
Please explain why in the world I want another remote control, more cables and another piece of equipment to become obsolete if I don't need it?
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Post by plm on Mar 14, 2015 3:11:10 GMT -5
The Control Freak is sitting in its box and will probably never be used. I don't want anything in the analog music stream if I can help it. Once again, I'm only talking about when my OPPO is at 1 on a 0-100 scale that I'm using this. First thing in the morning before my wife is up. I guarantee that I'm not hearing any artifacts at these extremely low volumes. The rest of the time the OPPO volume is perfectly fine and I think having that inline would be a deficit. Going back to your "why is this about good versus evil" comment then what makes you think having anything in the analog path will be a negative? It sounds like you don't have your gain staging well matched, which is why you're resorting to high levels of digital attenuation by stacking it. The Control Freak is a potentiometer. It's passive. It doesn't add a sonic signature to the audio, and can actually increase your signal/noise ratio. I find that with the sensitivity of the speakers I use, the XPR-1s are still higher gain than I need with their 29dB of gain, so rather than run my preamp at a low range of volume, I use fixed -10dB attenuators at the input to each amp, essentially reducing each monoblock's gain to 19dB. That lowers any noise that occurs post-volume control on the preamp by 10dB, and therefore serves to increase my S/N ratio in my system, so the effect of adding a passive component is actually positive. The Control Freak is simply a variable version of the same. If you're wanting to eke out the best sound quality from your system and you already have it, then why not simply give it a try?
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Post by rcheliguy on Mar 14, 2015 5:09:06 GMT -5
If you're wanting to eke out the best sound quality from your system and you already have it, then why not simply give it a try? I have a fundamental personal bias towards simplicity and I'm happy with how it works right now. Also it may be passive, but how does putting a higher impedance on the preamplifier cables impact the effective ratio of the OPPO's output impedance to the amplifier's input impedance? BTW I'm actually curious about how that would work. Given that the Control Freak is a 10K ohm variable resistor. What would be the resistance needed for 10dB of attenuation? Since it is reducing the signal, I suspect it effectively adds resistance to the output stage of the OPPO to create the voltage drop seen across the input stage of the amplifier. Your XPR-1's have an odd characteristic. According to the website specs they have a 51K ohm input impedance when balanced, and a 100K ohm impedance unbalanced unless that was a typo. Usually the balanced input has the higher impedance or they are nearly identical. Anyway you have more "margin" to work with on your XPR-1s in terms of the ratio between the input and output impedance go. The whole idea behind most components is that they should disappear and not affect the music signal. What better way to have something disappear than to not have that component in the loop.
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DYohn
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Post by DYohn on Mar 14, 2015 12:02:07 GMT -5
I have a fundamental personal bias towards simplicity There's "simple" and then there's what works. Knock yourself out with whatever you want to do of course, but please stop suffering under the delusion that your way is the "right" way. And if you come onto an audio forum asking for advice please stop arguing with it when you get it. Geezus.
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Post by plm on Mar 14, 2015 13:12:19 GMT -5
Also it may be passive, but how does putting a higher impedance on the preamplifier cables impact the effective ratio of the OPPO's output impedance to the amplifier's input impedance? BTW I'm actually curious about how that would work. Given that the Control Freak is a 10K ohm variable resistor. What would be the resistance needed for 10dB of attenuation? Since it is reducing the signal, I suspect it effectively adds resistance to the output stage of the OPPO to create the voltage drop seen across the input stage of the amplifier. You are actually doing two things. One is you are lowering the input impedance of the amp, as far as the Oppo is concerned, which means the output stage has to be able to drive a lower impedance load without impacting its frequency response. This could be a challenge with the Oppo given its difficulty matching directly with some components, which is why I recommended that you should 'try' this. At the amp end, you're effectively increasing the output impedance of the Oppo, but the amp isn't going to care. The ratio between impedances is only important in terms of the output stage of the prior component being able to properly drive the load presented by the following component without impacting frequency response. Given that the Control Freak is 10K, you have to treat it as 2 resistors in series, with the output taken from the junction of them when you are attenuating. For -10dB the 'top' resistor tied to the signal in would be effectively 6.8K, and the 'bottom' resistor tied to ground would be 3.2K. The bottom resistor also has the load of the amp in parallel, so would be 3.2K || 33K in your case, i.e. 2.9K, so your overall resistance would work out to be 9.7K. This is the load the Oppo would see. The whole idea behind most components is that they should disappear and not affect the music signal. What better way to have something disappear than to not have that component in the loop. This is true, but you do seem to choose to ignore that both digital attenuators in your system are also components in the loop. Just because they are provided in the same box doesn't mean they are not there. If you use them, they are in circuit. It's kind of like defeatable tone controls. In your instance, the Oppo may not like the Control Freak because of the choice of 10K at the pots in it, but it's a zero cost option to try it out. Finally, if you do try it, run the XLRs out from the Control Freak straight into the amp and if you have to use XLR cables then use them between the Oppo and the Control Freak. You don't want a passive preamp to have to drive any longer cables than is absolutely necessary. That's why I build my pads into XLR M/F adapters right at the input to my amps so there is no cable whatsoever after them.
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Post by rcheliguy on Mar 14, 2015 18:00:51 GMT -5
Thank you for all of the your advice.
Sorry if I came off as argumentative.
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Post by TUGA Audiophile on Mar 15, 2015 6:08:51 GMT -5
IN GENERAL: digital volume controls reduce bits to reduce volume. You are almost always better off leaving a digital volume control at 100% and using an actual analog volume control in a preamp to adjust the signal to the amp. Preamps are good things. +1
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Post by Kent on Mar 15, 2015 9:18:07 GMT -5
Honestly if you want the best possible sound use a pre amp. If you grab a XSP-1 Gen 2 (which is a perfect match for your amp) you can try it for yourself and return it within 30 days if you're not happy. It's a win win for you either way. You have fantastic speakers (I've owned various Martin Logans) that bring out every detail and I'm confident you will hear a difference for the better.
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DYohn
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Post by DYohn on Mar 15, 2015 9:57:09 GMT -5
Let me quote your signature block, "Inaudible is inaudible and you don't get extra brownie points for making it twice as inaudible as another solution. - Kevin Haskins " I just noticed that you quoted Kevin, but the context you tried to use this quote in leads me to believe that perhaps you don't understand why his quote is important. What Kevin means is that once a signal is inaudible, it no longer matters. For example if S/N on a piece of gear is -90db it is inaudible, and making it -100 db does not make it better, it's still inaudible. You can't hear it. It doesn't matter. Adding links in an audio chain does nothing except add the control and flexibility of that link. It does not degrade the signal nor add noise nor anything else as long as you choose gear with the proper specs and use interconnects designed for the purpose you need. Your system needs a preamp, or at the very least an analog volume control. Add it. Your issues with reduced digital resolution will disappear.
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Post by brutiarti on Mar 15, 2015 12:45:09 GMT -5
I'm in the same boat as rcheliguy regarding using a digital source as preamp but i don't believe in sound quality degradation for using an analog volume preamp (a good one, of course). I wanna use a NAD M51 as preamp and get rid of my parasound one but only to simplify my setup and save some money. i quote this from Stereophile regarding volume control on the M51 " The M51's volume-control technology is impressive, though. According to NAD, "The extreme headroom afforded by the 35-bit architecture allows for a DSP-based volume control that does not reduce resolution. Even with 24-bit high definition signals, the output can be attenuated by 66dB (very, very quiet) before bit truncation begins." I wonder how that volume control compares to the OPPO one, or if oppo make such claims about their volume control
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Post by Gary Cook on Mar 15, 2015 16:46:53 GMT -5
Your XPR-1's have an odd characteristic. According to the website specs they have a 51K ohm input impedance when balanced, and a 100K ohm impedance unbalanced unless that was a typo. Usually the balanced input has the higher impedance or they are nearly identical. Anyway you have more "margin" to work with on your XPR-1s in terms of the ratio between the input and output impedance go Balanced (XLR) connections are typically quoted as impedance per leg, hence 51K for the + to neutral and 51K for the - to neutral. Hence the amplifier sees 102K. Of course it's not quite that simple due to the differential circuitry involved, but the take away is it's not always possible to directly compare impedance between RCA and XLR connections. As pointed out in an earlier post, using the pre amp built into an Oppo 105 is still using a pre amp, so by not including a designated (separate) pre amp doesn't mean that we are eliminating the requirement for a pre amp. We need something to amplify the signal from the source sufficiently for it to be used by the power amplifier. The real question is is the 105 pre amp better than, say, an XSP-1. I've never compared an XSP-1 with a 105, but I have compared a USP-1 to a 105 and the USP-1 better suited my system and my ears. My guess would be the XSP-1 would be an even better pre amp, hence a no brainer in a back to back with a 105 pre amp. Cheers Gary
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Post by lionear on Mar 15, 2015 19:42:48 GMT -5
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Post by rcheliguy on Mar 19, 2015 16:41:40 GMT -5
That is what I've heard from a number of people who USED to have some pretty expensive separate DAC's and preamplifers and just use an OPPO 105D now to directly drive their amplifiers. The bottom line is that what I have now sounds absolutely fantastic and I'm completely happy with it! So the big question is why would I want to rock the boat if I'm hearing amazing sound with fantastic spacial imaging? I've heard many stereo systems in the high 10's of thousands to 100K+ systems, so it's not like I have no point of reference. As I said before the only real issue I had was speaker placement. That is sorted now. In my eyes this is mission accomplished, great sound has been achieved! I don't believe I would hear any difference at all if I were to switch between any of a number of high end preamplifiers and the output directly coming out of this OPPO.
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Post by lionear on Mar 20, 2015 11:02:54 GMT -5
That is what I've heard from a number of people who USED to have some pretty expensive separate DAC's and preamplifers and just use an OPPO 105D now to directly drive their amplifiers. The bottom line is that what I have now sounds absolutely fantastic and I'm completely happy with it! So the big question is why would I want to rock the boat if I'm hearing amazing sound with fantastic spacial imaging? I've heard many stereo systems in the high 10's of thousands to 100K+ systems, so it's not like I have no point of reference. As I said before the only real issue I had was speaker placement. That is sorted now. In my eyes this is mission accomplished, great sound has been achieved! I don't believe I would hear any difference at all if I were to switch between any of a number of high end preamplifiers and the output directly coming out of this OPPO. I think the point I wanted to make was that the Oppo's built-in output stage might not be the final word. The ModWright mod replaces it with a very high-end output stage - which propels the Oppo up to "among the very best". An alternative to the ModWright mod would be to connect the Oppo to a preamp, and have the preamp's output stage drive the power amp - and you should get some additional features like switching between different inputs, a Balance control, and in some cases, the ability to invert the phase. All those things are absolute requirements for me. But that's just me. Of course, adding a preamp has the potential of affecting the sound negatively so one has to choose carefully. However, there's the potential of getting better sound, too. The ModWright mod, and Arnie's endorsement of it, indicates to me that the Oppo's output stage could be improved on. Please note that I say "could". It's entirely possible that adding a preamp may not be a good thing in your system - it will depend on the preamp and amp. I wouldn't be surprised if Arnie has Genesis 1 (or even better) speakers so the ModWright mod may be a great performer in areas that only a handful of speakers can show. At the end of the day, however, the most important thing is to build your system, according to your priorities, according to your likes and dislikes and according to what you hear and don't hear - to derive enjoyment. There's no right and wrong answer. We're just answering your questions, based on our knowledge and experience.
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Post by rcheliguy on Mar 20, 2015 11:31:48 GMT -5
I appreciate answers to questions.
Also please keep in mind that I'm not claiming my stereo is the "ultimate" system. There are 3 more expensive higher end speakers in the ML lineup above what I own and the same goes for everything else.
I've heard some amazing stereo systems over the years. I think mine sounds very good. Going from very good to "Oh My God That's Amazing!" is very expensive. More importantly I believe I would need a completely different room if I ever wanted to reach that point.
So while I'm quite sure that there are better preamplifiers out there than what is built into my OPPO, the real issue is what I will hear going through an XPA-2 and ML Ethos speakers.
I'm extremely happy with the sound quality I'm getting for the buck I've spent. I have a nice clear sound stage with pinpoint placement of instruments, the frequency response is excellent. I'm tickled with the bass I'm getting. While I know that there are many systems that go lower than my Ethos, I have all the tight kick that I need to be satisfied with my purchase.
I understand the concept of diminishing returns in audio very well, and I think at this point I would be throwing money away to try to improve on the sound I currently have unless I built a dedicated audio room.
Also now that I'm completely satisfied with how things are working I'm not highly motivated to start experimenting. I've watched too many people go down the hole of constantly swapping out components on some religious quest. That's not me.
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Post by rcheliguy on Mar 30, 2015 19:43:37 GMT -5
FYI, just so there is no misinformation about this, the OPPO can invert phase and it does switch between all the inputs I have. DVR by HDMI cable Computer by asynchronous USB USB stick media WiFi streaming by Pandora Wifi native NetFlix support. WiFi use of any media on any networked device CD, SACD, HDCD, DVD, DVD-A, BD That doesn't mean it is all things to all people, but it does have those features already. It does not have balance.
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Post by AudioHTIT on Mar 31, 2015 10:29:53 GMT -5
As pointed out in an earlier post, using the pre amp built into an Oppo 105 is still using a pre amp, so by not including a designated (separate) pre amp doesn't mean that we are eliminating the requirement for a pre amp. We need something to amplify the signal from the source sufficiently for it to be used by the power amplifier. The real question is is the 105 pre amp better than, say, an XSP-1. I've never compared an XSP-1 with a 105, but I have compared a USP-1 to a 105 and the USP-1 better suited my system and my ears. My guess would be the XSP-1 would be an even better pre amp, hence a no brainer in a back to back with a 105 pre amp. Cheers Gary Though how can you actually compare the 105's preamp to the XSP-1 (or any other). If you are using the analog outs from the 105 (likely balanced) you still have the 105s preamp in the path, the best you can do is eliminate any digital attenuation - which I would argue at 32 bits is inaudible. All you can really do is compare a 'raw' 105 preamp to a 105 with an XSP-1 in the path. Yes, you can make a determination which you like better, but you're not really comparing preamps. As someone who prefers the XDA-2 directly to my amps (without the XSP-1), I'm behind the OPs mission for a simple signal path and don't think adding a preamp should be the place to start (as he's discovered). This is what the hobbie is about, coming up with a desired system and seeing if it meets or exceeds your expectations or anything you've previously built. Maybe in the end he will prefer a preamp, but I'm also in the 'less is more' camp and don't see the need to add a preamp (until or unless it can be shown to be necessary).
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Post by Gary Cook on Mar 31, 2015 14:40:07 GMT -5
As pointed out in an earlier post, using the pre amp built into an Oppo 105 is still using a pre amp, so by not including a designated (separate) pre amp doesn't mean that we are eliminating the requirement for a pre amp. We need something to amplify the signal from the source sufficiently for it to be used by the power amplifier. The real question is is the 105 pre amp better than, say, an XSP-1. I've never compared an XSP-1 with a 105, but I have compared a USP-1 to a 105 and the USP-1 better suited my system and my ears. My guess would be the XSP-1 would be an even better pre amp, hence a no brainer in a back to back with a 105 pre amp. Though how can you actually compare the 105's preamp to the XSP-1 (or any other). If you are using the analog outs from the 105 (likely balanced) you still have the 105s preamp in the path, the best you can do is eliminate any digital attenuation - which I would argue at 32 bits is inaudible. All you can really do is compare a 'raw' 105 preamp to a 105 with an XSP-1 in the path. Yes, you can make a determination which you like better, but you're not really comparing preamps. As someone who prefers the XDA-2 directly to my amps (without the XSP-1), I'm behind the OPs mission for a simple signal path and don't think adding a preamp should be the place to start (as he's discovered). This is what the hobbie is about, coming up with a desired system and seeing if it meets or exceeds your expectations or anything you've previously built. Maybe in the end he will prefer a preamp, but I'm also in the 'less is more' camp and don't see the need to add a preamp (until or unless it can be shown to be necessary). Based on my comparison, admittedly my ears, my speakers, in my room, I prefer the sound with the digital volume on the 105 set to zero and the USP-1 doing the pre amplification ie; voltage in is lower than voltage out. I did this back to back several times over a couple of months, with more than my ears doing the listening. I don't know the 105's circuitry design but my assumption would be that with digital volume at zero it's not doing any "pre amplification" as such. At the very least the USP-1 would present a different load to the 105 as it would provide a different source to the power amplifier. Perhaps it was the family friendly matching of the Emotiva USP-1 to the Emotiva XPA-5. Cheers Gary
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Post by rcheliguy on Apr 1, 2015 10:07:20 GMT -5
Based on my comparison, admittedly my ears, my speakers, in my room, I prefer the sound with the digital volume on the 105 set to zero and the USP-1 doing the pre amplification ie; voltage in is lower than voltage out. I did this back to back several times over a couple of months, with more than my ears doing the listening. I don't know the 105's circuitry design but my assumption would be that with digital volume at zero it's not doing any "pre amplification" as such. At the very least the USP-1 would present a different load to the 105 as it would provide a different source to the power amplifier. Perhaps it was the family friendly matching of the Emotiva USP-1 to the Emotiva XPA-5. Cheers Gary The OPPO's DAC's are taking the digital signal and creating an analog ~ 2V signal no matter what you do with it. If you use the balanced outputs you get common mode rejection. If you use the RC jacks you don't so you will lose some of your S/N ratio. I doubt you will notice it, but there is that. Because 32bits is so much wider than any music sources dynamic range, there is no impact on the sound possible with the digital volume. So I believe the only thing left that could possibly impact the sound is impedance matching. OPPO claims that anything between 10kohm and 100kohm will work with 47kohm being ideal. They implied it had more of an impact on how much volume (0-100) you needed to select reach a certain listening volume level than over the sound quality. I won't discount the possibility of a 33kohm vs. a 47ohm impedance having some impact on the sound quality. Any amplifier with a 47 or 50kohm impedance should sound identical to a properly matched preamplifier that had no impact on the sound. That said, if you like the feel of an analog knob, it like any other subjective thing will feed into how you perceive what you are listening to. It is very nebulous, and without someone else touching all the equipment in a blind A/B testing at identical volume levels it would be hard to do an objective comparison. The kicker is that I don't believe I would hear a difference if I hooked up a preamplifier and that alone would impact my perception as well. Psychologically I would be much more likely to not notice a difference even if there were one because it would conflict with my current opinion.
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